to 34a-1-1
TRANSCRIPT
TO 34A-1-1TECHNICAL MANUAL
ADDITIVE MANUFACTURINGQUALIFICATION OF
TECHNICIANS, MACHINES ANDFACILITIES
This manual supersedes TO 34A-1-1 dated 15 March 2021.
DISTRIBUTION STATEMENT A - Approved for public release; distribution is unlimited. PA Case Number 20-05426. Other requests for thisdocument shall be referred to 406 SCMS/GUEE, Robins AFB, GA 31098. Questions concerning technical content shall be referred toAFLCMC/EZPT-MTO.
Published Under Authority of the Secretary of the Air Force
23 AUGUST 2021
Dates of issue for original and changed pages are:
Original. . . . . . . .0 . . . . . 23 August 2021
TOTAL NUMBER OF PAGES IN THIS PUBLICATION IS 40, CONSISTING OF THE FOLLOWING:
Page *ChangeNo. No.
Page *ChangeNo. No.
Page *ChangeNo. No.
Title . . . . . . . . . . . . . . . . . . . . . . 0A . . . . . . . . . . . . . . . . . . . . . . . . 0i - vii . . . . . . . . . . . . . . . . . . . . .0viii Blank . . . . . . . . . . . . . . . . . . 0ix . . . . . . . . . . . . . . . . . . . . . . . . 0x Blank . . . . . . . . . . . . . . . . . . . . 01-1 - 1-7. . . . . . . . . . . . . . . . . . .01-8 Blank . . . . . . . . . . . . . . . . . . 02-1 - 2-13. . . . . . . . . . . . . . . . . .02-14 Blank. . . . . . . . . . . . . . . . . .03-1 - 3-4. . . . . . . . . . . . . . . . . . .0Glossary 1 . . . . . . . . . . . . . . . . . . 0Glossary 2 Blank . . . . . . . . . . . . . 0
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LIST OF EFFECTIVE PAGESINSERT LATEST CHANGED PAGES. DESTROY SUPERSEDED PAGES.
NOTE The portion of the text affected by the changes is indicated by a vertical line in the outer margins ofthe page. Changes to illustrations are indicated by shaded or screened areas, or by miniaturepointing hands.
* Zero in this column indicates an original page.
A USAF
TABLE OF CONTENTSChapter Page
LIST OF ILLUSTRATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iv
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v
SAFETY SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix
1 ADDITIVE MANUFACTURING METHODS, GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . 1-1
SECTION I ADDITIVE MANUFACTURING METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.1 ADDITIVE MANUFACTURING METHODS, GENERAL INFORMATION . . . . . . . . . . . . 1-11.1.1 Introduction to Manufacturing Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11.1.1.1 Formative Manufacturing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11.1.1.2 Subtractive Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11.1.1.3 Additive Manufacturing (AM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
SECTION II PERSONNEL TRAINING/QUALIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.2 TRAINING/QUALIFICATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31.2.1 Training Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31.2.2 Training Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31.2.2.1 Formal Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31.2.2.2 On-the Job Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-41.2.3 Qualification Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-41.2.3.1 Personnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-41.2.4 Requirement for Special Task Certification and Recurring Training . . . . . . . . . . . . . . . . . . . 1-41.2.4.1 Air Force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
SECTION III AM EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.3 AM EQUIPMENT OVERVIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51.3.1 Procurement of AM Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51.3.2 Allowance Standard (AS) 783 or Air Logistics Complex (ALC) Specific AS . . . . . . . . . . . . . 1-51.3.3 Purpose of Centrally Procured AM Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51.3.4 Locally Purchased AM Equipment Authorized in AS 783 . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51.3.5 Service Contracts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
SECTION IV PROCESS CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.4 PROCESS CONTROL OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51.4.1 Reason for Controlling the Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-51.4.2 Scope of Process Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-61.4.2.1 Process Control Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-61.4.3 Process Control Documentation Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-61.4.4 Establishing a Documentation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
SECTION V REPORTING NEW OR IMPROVED AM PROCESSES. . . . . . . . . . . . . . . . . . . . . . . . . 1-7
1.5 REPORTING AM PROCESSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-71.5.1 Need for Reporting New and Improved Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
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1.5.2 Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
2 METAL ADDITIVE MANUFACTURING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.1 OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12.1.1 Direct Metal Laser Melting (DMLM) General Information . . . . . . . . . . . . . . . . . . . . . . . . . 2-12.1.2 Annual Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22.1.3 Metal Powder Hazards in the DMLM Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22.1.3.1 Inhalation Hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22.1.3.2 Ingestion Hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22.1.3.3 Skin Hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22.1.3.4 Fire Hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22.1.3.5 Chemical Hazard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-22.1.3.6 Ignition Sources and Mitigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-32.1.3.7 PPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42.1.3.8 Fire Suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42.1.3.9 Notifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-52.1.3.10 Dust Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-52.1.3.11 Materials for Passivation of Condensate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-52.1.4 Powder Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.4.1 Material Specific Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.4.2 Apparel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.4.3 Virgin vs Reuse Powder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.4.4 Reuse Increments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.4.5 Reuse Sieving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.4.6 Reuse Powder Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.5 Equipment List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.6 Facility Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.6.1 Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62.1.6.2 Climate Controlled Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.3 Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.4 Walls and Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.5 Ceilings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.6 Doors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.7 Windows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.8 Floor Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.9 Floor Surface. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.10 Floor Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.11 Temperature and Humidity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.12 Air Exchanges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.13 Oxygen Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72.1.6.14 Size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82.1.6.15 Utilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82.1.6.16 Electrical Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82.1.6.17 Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82.1.6.18 Inert Gases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-92.1.6.19 Other Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-102.1.7 Machine Qualifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112.1.7.1 Approved Printers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112.1.7.2 List of Qualified Machines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112.1.7.3 Qualification Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112.1.7.4 Qualification Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112.1.8 Post-Processing Process Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112.1.8.1 Part Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112.1.8.2 Heat Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
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2.1.8.3 Part Separation and Support Material Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.4 Band Saw . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.5 Wire EDM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.6 Surface Enhancement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.7 Media Blast. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.8 Abrasive Tumbling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.9 Shot Peening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.10 Sanding and Polishing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.11 Finish Machining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.8.12 Geometry Inspection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.9 Quality Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.9.1 Non-Conforming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.9.2 Dimensional . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-122.1.9.3 Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-132.1.9.4 Non-Destructive Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-132.1.9.5 Typical Anomalies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-13
3 POLYMER ADDITIVE MANUFACTURING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
3.1 FUSED DEPOSITION MODELING® (FDM) PRINTERS . . . . . . . . . . . . . . . . . . . . . . . . . 3-13.1.1 FDM® General Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13.1.2 Equipment List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13.1.3 Safety. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13.1.4 Facility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23.1.4.1 Environmental Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23.1.4.2 Electrical Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23.1.4.3 Compressed Air Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33.1.5 Machine Qualification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33.1.5.1 Approved Printers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33.1.5.2 List of Qualified Machines. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33.1.5.3 Machine Qualification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33.1.5.4 Qualification Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-43.1.5.5 Requalification of the HP/AICS Package after Material Change. . . . . . . . . . . . . . . . . . . . . . 3-43.1.6 Model Material Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-43.1.7 Post-Process Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-43.1.8 Quality Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-43.1.8.1 Non-Conforming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-43.1.8.2 Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Glossary 1
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iii
LIST OF ILLUSTRATIONS
Number PageTitle
1-1 Upskin, Downskin, and Core Regions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21-2 Core Exposure Pattern Hatching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-21-3 Geometry Slices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31-4 Single Slice Print Extrusion Path. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-32-1 EOS M 290 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-12-2 DMLM Print Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
LIST OF TABLES
Number PageTitle
1-1 Field Unit AM Training Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-42-1 DMLM Equipment List for Printing Qualified Metal Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-62-2 Typical Temperature and Humidity Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-72-3 Typical Equipment Housed in Climate Controlled Environment . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82-4 Example (EOS M 290) Electrical Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-82-5 Example (EOS M 290) Argon Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-92-6 Example (EOS M 290) Compressed Air Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-102-7 Typical Equipment Housed in Non-Climate Controlled Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-102-8 Reasons to Requalify Metal AM Machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-112-9 Anomalies Inherent to the DMLM Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-133-1 FDM Equipment List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13-2 Potential Safety Hazard Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13-3 Example (Fortus 900mc/F900/450mc) Weight and Space Requirements. . . . . . . . . . . . . . . . . . . . . 3-23-4 Example (Fortus 900mc/F900/450mc) Environmental Requirements . . . . . . . . . . . . . . . . . . . . . . . 3-23-5 Example (Fortus 900mc/F900/450mc) Electrical Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33-6 Example (Fortus 900mc/F900) Compressed Air Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-33-7 Major Sub-system Equipment Affecting Build Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
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INTRODUCTION
1 PURPOSE.
Additive Manufacturing (AM) is the manufacturing process through which three-dimensional objects are created by buildingup layers of material. The two standard classes of AM materials covered in this technical order include:
• Polymers
• Metals
2 SCOPE.
This publication contains the concepts, process controls, and theory of AM methods and shall be used as a guide indevelopment of AM procedures and manuals. AM procedures shall be detailed step-by-step instructions with illustrations soqualified technicians can perform the required process. In addition, this manual provides guidance in safety guidelines. Whenthe guidelines of this manual conflict with details in a depot local process order, or a weapon system specific directive, thedepot local process order or weapon system specific directive shall take precedence. This manual consist of the followingchapters:
Chapter 1 ADDITIVE MANUFACTURING METHODS, GENERAL INFORMATIONChapter 2 METAL ADDITIVE MANUFACTURINGChapter 3 POLYMER ADDITIVE MANUFACTURING
3 ABBREVIATIONS.
All abbreviations used in this manual are shown in the list of abbreviations below. Standard abbreviations are in accordancewith ASME Y14.38, Abbreviations and Acronyms for Use on Drawings and Related Documents.
°C degrees Celsius°F degrees FahrenheitAF Air ForceAF MTO Air Force Metals Technology OfficeAF RSO Air Force Rapid Sustainment OfficeAFI Air Force InstructionAFMCI Air Force Material Command InstructionAFMAN Air Force ManualAFTO Air Force Technical OrderALC Air Logistics ComplexALT AlternateAM Additive ManufacturingAP Attaching PartsAR As RequiredAS Allowance StandardATTC Advanced Technology and Training CenterAWB Airworthiness BulletinCAD Computer-Aided DesignCAGE Commercial and Government EntityCFE Contractor Furnished EquipmentCNC Computer Numerical ControlDLA Defense Logistics AgencyDMLM Direct Metal Laser Melting
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DoD Department of DefenseEDM Electrical Discharge MachineESD Electrostatic DischargeESDS Electrostatic Discharge SensitiveETIMS Enhanced Technical Information Management SystemFDM Fused Deposition ModelingGFE Government Furnished EquipmentHAZMAT Hazardous MaterialHCI Hardness Critical ItemsHEPA High-Efficiency Particulate AirHVAC Heating Ventilation and Air ConditioningHz HertzI&S Interchangeability and SubstitutionIPB Illustrated Parts BreakdownJQS Job Qualification StandardkW kilowattMAJCOM Major CommandMIS Maintenance Information Systemmm milimeterMPL Maintenance Parts ListNDI Non-Destructive InspectionNFPA National Fire Protection AssociationNHA Next Higher AssemblyNI Numerical IndexOJT On-the Job TrainingOSHA Occupational Safety and Health AdministrationPAPR Powered Air Purifying RespiratorPCAMS Process Control Automated Management SystemPN Part NumberPPE Personal Protective EquipmentPSI Pound-force per Square InchPSIG Pound-force per Square Inch, GaugeRDI Reference Designator IndexREF ReferenceSCMS Supply Chain Management SquadronSD Static DissipativeSDS Safety Data SheetSMR Source, Maintenance, and RecoverabilitySPO System Program OfficeTCTO Time Compliance Technical OrderTO Technical OrderTOMA Technical Order Management AgencyUOC Usable on CodeUPA Units Per AssemblyV Volt
TO 34A-1-1
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4 RELATED PUBLICATIONS.
NOTE
When searching technical order (TO) numbers in the Enhanced Technical Information Management System(ETIMS) catalog, please use the wildcard (*) after typing in the TO number. Many TOs are not available in paperformat, (i.e., digital (WA-1) or Compact Disk (CD-1)). This ensures TOs in all media formats will populate thesearch.
The following publications contain information in support of this technical manual.
List of Related Publications
Number TitleASME Y14.38 Abbreviations and Acronyms for Use on Drawings and Related DocumentsDODI 5330.03_AFI 33-395 Defense Logistics Agency (DLA) Document ServicesTO 00-5-1 AF Technical Order SystemTO 00-20-1 Aerospace Equipment Maintenance Inspection, Documentation, Policies, and Proce-
duresTO 00-25-234 General Shop Practice Requirements for the Repair, Maintenance, and Test of Electri-
cal EquipmentTO 34A-2-1 General Procedures and Process Controls and Metals Additive ManufacturingTO 34A-3-1 General Procedures and Process Controls and Polymers Additive ManufacturingTO 42B5-1-2 Gas Cylinders (Storage Type) Use, Handling, and Maintenance
5 RECORD OF APPLICABLE TIME COMPLIANCE TECHNICAL ORDERS (TCTOS).
List of Time Compliance Technical Orders
TCTONumber
TCTOTitle
TCTODate
None
6 HARDNESS CRITICAL ITEMS (HCI).
The HCI symbol ( ) establishes special requirements limiting changes and substitutions and that the specificparts listed must be used to ensure hardness is not degraded.
If included, items with nuclear survivability requirements are marked with the HCI symbol ( ). All changes to, orproposed substitutions of, HCIs must be approved by the acquiring activity.
7 ELECTROSTATIC DISCHARGE SENSITIVE (ESDS) ITEMS.
All ESDS parts shall be handled in accordance with the ESDS device handling procedures in TO 00-25-234.
If included, items containing ESDS parts are marked with the ESDS symbol ( ).
8 IMPROVEMENT REPORTS.
Recommended changes to this manual shall be submitted in accordance with TO 00-5-1.
TO 34A-1-1
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SAFETY SUMMARY
1 GENERAL SAFETY INSTRUCTIONS.
This manual describes physical and/or chemical processes which may cause injury or death to personnel, or damage toequipment, if not properly followed. This safety summary includes general safety precautions and instructions that must beunderstood and applied during operation and maintenance to ensure personnel safety and protection of equipment. Prior toperforming any specific task, the WARNINGs, CAUTIONs, and NOTEs included in that task shall be reviewed and under-stood.
2 WARNINGS, CAUTIONS, AND NOTES.
WARNINGs and CAUTIONs are used in this manual to highlight operating or maintenance procedures, practices, condi-tions, or statements which are considered essential to protection of personnel (WARNING) or equipment (CAUTION).WARNINGs and CAUTIONs immediately precede the step or procedure to which they apply. WARNINGs and CAUTIONsconsist of four parts: heading (WARNING, CAUTION, or icon), a statement of the hazard, minimum precautions, andpossible results if disregarded. NOTEs are used in this manual to highlight operating or maintenance procedures, practices,conditions, or statements which are not essential to protection of personnel or equipment. NOTEs may precede or follow thestep or procedure, depending upon the information to be highlighted. The headings used and their definitions are as follows:
Highlights an essential operating or maintenance procedure, practice, condition, statement, etc. Failure to complycould result in injury to, or death of, personnel or long term health hazards.
Highlights an essential operating or maintenance procedure, practice, condition, statement, etc. Failure to complycould result in damage to, or destruction of, equipment or loss of mission effectiveness.
NOTE
Highlights an essential operating or maintenance procedure, condition, or statement.
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CHAPTER 1ADDITIVE MANUFACTURING METHODS, GENERAL INFORMATION
SECTION I ADDITIVE MANUFACTURING METHODS
1.1 ADDITIVE MANUFACTURING METHODS, GENERAL INFORMATION.
1.1.1 Introduction to Manufacturing Processes. Manufacturing processes can be divided into one of the three followingcategories: Formative, Subtractive, and Additive.
1.1.1.1 Formative Manufacturing. Processes that shape a raw material (liquid or solid) into a final part through the useof tooling and molds include casting, molding, and forging among others. While the initial investment in dedicated toolingmay be high, these processes are suitable for high volume production because they ultimately may result in low part cost &fast cycle times.
1.1.1.2 Subtractive Manufacturing. Processes that produce a part by removing material from stock. These processesinclude machining, grinding, lathe-turning, and shearing among others. Subtractive manufacturing offers increased designflexibility over formative processes with minimal tooling, but it generally results in increased part costs and manufacturingcycle times.
1.1.1.3 Additive Manufacturing (AM). Processes that generate a part by fusing material together layer-by-layer, directlyfrom 3-dimensional electronic geometry data. While AM unit part cost is often higher, these processes are extremely flexibleand can produce a part with minimal lead time and often zero tooling. While each AM process has its own uniquelimitations, there is no inherent penalty for geometry complexity and with the rapid advances in AM materials and processes,part costs and cycle times continue to improve. Approved methods are discussed below.
1.1.1.3.1 Direct Metal Laser Melting (DMLM) Process Details. DMLM is an additive manufacturing process that useslasers to selectively melt ultra-thin layers of metal powder to build a three-dimensional object. Objects are built from astereolithographic file generated from a Computer-Aided Design (CAD) data.
a. The DMLM process begins with a recoater blade spreading a thin layer of metal powder on the print bed. Next, a laseris used to create the cross-section layer of the object by completely melting powder particles. The print bed is thenlowered by the height of one layer thickness and a recoater arm passes over the build plate applying another thin layerof powder. This process is repeated to create the next object layer. After all layers are printed, the excess, un-meltedpowder is brushed or suctioned away and can be recycled for future builds. During the print process, the build chamberis filled with an inert gas, usually argon, to prevent oxidation.
b. In this process, the print parameters vary for different portions of the part. The print software performs an analysis ofthe part and determines upskin, downskin, core, and contour regions (see Figure 1-1). The exposure pattern for thecore section of the part is in the form of hatchings that are offset by an angle from one layer to another (see Figure1-2). The contour of the part, which forms the outer edge of the part, is usually exposed to lower power to providebetter surface finish. The print parameters for upskin and downskin, which are the upper and lower surfaces respec-tively, could be different from the core region and are determined by the software. The print parameters used for theupskin and downskin regions could affect the surface quality of the printed part. Since the downskin region is notdirectly connected to the build plate or supports, it cannot easily transfer heat away from the part and retains heatduring the print process. As a result, the downskin is usually exposed to lower heat to improve surface quality.
TO 34A-1-1
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c. In most cases, upon completion of the print process and removal from the printer, all metal parts will undergo a stressrelieving heat treatment process prior to removal from the build plate. At this point, parts are removed from the buildplate using a band saw or a wire Electrical Discharge Machine (EDM) and can undergo any machining necessary tocomplete the manufacturing process. A second heat treatment procedure may be required at this point to create desiredmaterial characteristics.
1.1.1.3.2 FDM Process Details. The Fused Deposition Modeling (FDM) build process is an additive manufacturingprocess in which thermoplastic filament is heated to its melting point and extruded through a heated extrusion nozzle toproduce AM parts. This melting of filament requires the use of thermoplastic polymers and does not work with thermosetpolymers. Three dimensional CAD geometry is used to generate a print file by slicing the part into layers as shown in Figure1-3. Unlike DMLM, the FDM process does not create a fully dense part. Instead, the print head first traces the perimeter ofeach print layer with a bead of filament called a “contour” as shown in Figure 1-4. Next, the print head fills the interior ofthe cross section with “rasters.” Rasters vary in angle from one layer to the next for better adhesion and overall part strength.While layers can be printed almost fully dense, there are often air gaps remaining between rasters due to part geometry.Sometimes rasters will purposefully be printed with gaps to reduce the overall part weight and build time when strength isnot a concern. Once a single cross-section layer is complete, the print head moves on to next slice increment layer andcontinues to print until the part has been completed layer by layer.
Figure 1-1. Upskin, Downskin, and Core Regions
Figure 1-2. Core Exposure Pattern Hatching
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SECTION II PERSONNEL TRAINING/QUALIFICATION
1.2 TRAINING/QUALIFICATION.
1.2.1 Training Introduction. All personnel require formal training and/or On-the-Job Training (OJT) prior to operating orperforming maintenance on AM machines.
1.2.2 Training Requirements. Training requirements will be conducted using formal training and OJT. Formal training isfurther broken-down to include on-line training and in-residence training. All personnel shall be qualified, in writing anddocumented in accordance with Air Force Instruction (AFI) 36-2760, AFI 36-2650, AFI 21-101, Air Force Material Com-mand Instruction (AFMCI) 21-100 and/or other local directives. Depot facilities may use requirements developed in accor-dance with local procedures, provided they meet the minimum requirements as defined in this general practice. See Table 1-1for Field Unit training requirements.
1.2.2.1 Formal Training. Formal training shall be required for each process and type of equipment utilized in order toproduce airworthy components. The formal training requirement will include an AM on-line operator course and an AMin-residence operator course. Formal training conducted at a location other than Advanced Technology and Training Center(ATTC) shall be approved by the Air Force (AF) Metals Technology Office (AFLCMC/MTO) and reported to the AF RapidSustainment Office, (AFLCMC/RO), prior to being accomplished.
Figure 1-3. Geometry Slices
Figure 1-4. Single Slice Print Extrusion Path
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a. On-line Operator Training: On-line courses are a prerequisite to in-residence training. Training will consist of famil-iarization and overview of AM technologies that have been qualified to produce airworthy components. Operatortraining is a self-paced, module based course. Contact Air Force Rapid Sustainment Office (AF RSO) for on-lineoperator training location.
b. In-Residence Operator Training: Training will be conducted at an AF ATTC, or an AF MTO approved location.Operators will receive machine and/or process specific training, which will qualify the operator to produce airworthycomponents on a qualified machine, utilizing qualified materials. Typical training at an ATTC can last up to ten (10)duty days for metal machine training and five (5) duty days for polymer machine training. Contact the AF RSO foradditional details and coordination of in-residence training.
1.2.2.2 On-the Job Training. Hands-on training for the practical application of the AM equipment and/or process shall beprovided by the work center and shall be provided by personnel who have completed formal training and are qualified asOJT trainers. OJT alone will satisfy the training requirements for operations outside of those needing formal training perTable 1-1. All OJT shall be documented in accordance with AFI 36-2760, AFI 21-101, AFMCI 21-100 and/or other localdirectives. See Paragraph 1.2.3.1 for further guidance.
1.2.3 Qualification Requirements.
1.2.3.1 Personnel. Qualified AM machine operators shall be a Senior Airman (E-4) or higher, minimum 5 Skill level (orCivilian/Contractor equivalent). Document completion of formal training, qualification training and/or OJT on AF Form 797,Job Qualification Standard (JQS) Continuation Sheet (or electronic equivalent), Civilian Training Plan, or approved Main-tenance Information System (MIS).
1.2.4 Requirement for Special Task Certification and Recurring Training.
1.2.4.1 Air Force. The weapon System Program Office (SPO), Major Command (MAJCOM), AF RSO, or FabricationFlight Chief may determine special task certification and/or recurring training requirements for AM tasks. Document specialtask certification in accordance with AFIs 21-101, AFMCI 21-100, 36-2650, and/or local directives.
Table 1-1. Field Unit AM Training Requirements
CategoryTraining Requirement
On-line Training In-Residence Training OJTCat 1: Training Aids,Tooling-Fixtures/Jigs
X
Cat 2: Non-Structural,Non-Critical Vehicle*
X
Cat 3: Structural, Non-Critical Vehicle*
X X X
Cat 4: Critical Vehicle* X X XCat 2A: Non-Structural,Non-Critical Aircraft*
X X X
Cat 3A: Structural, Non-Critical Aircraft*
X X X
Cat 4A: Critical Air-craft*
X X X
* For specific applications that fall within each category, contact the cognizant engineering authority
TO 34A-1-1
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SECTION III AM EQUIPMENT
1.3 AM EQUIPMENT OVERVIEW.
1.3.1 Procurement of AM Equipment. Procurement of AM Equipment. AFLCMC/RO (Rapid Sustainment Office) willcoordinate on the purchase of AM equipment (3D printers) costing more than $50,000 including equipment utilized in theprocess development, printing, and post-processing of AM printed components to ensure they align with larger Air Forcegoals of standardization, interoperability, repeatability, efficiency, networking, and quality control.
1.3.1.1 AFLCMC/RO is the Air Force focal point to coordinate the enterprise AM approach. Air Force organizations maysubmit requests to AFLCMC/RO via Sharepoint at https://org2.eis.af.mil/sites/21761/am/_layouts/15/start.aspx#/ or by emailto [email protected]. Questions may also be directed to AFLCMC/EZPT-MTO (Metals Technology Of-fice) by email to [email protected].
1.3.2 Allowance Standard (AS) 783 or Air Logistics Complex (ALC) Specific AS. This document identifies the typesand quantities of centrally procured, weapon system-specific, and special purpose AM support equipment authorized for bothfield and ALC AM organizations. The 404th Supply Chain Management Squadron (SCMS) manages the AS equipmentaccounts. AM machines and special purpose support equipment are not currently listed in an AS and are locally funded andpurchased.
a. The Air Force Chief of Staff (AF/CC) requires the management of all AM printers regardless of cost, on accountableproperty records. AM/3D Printers with an acquisition cost below $50K will require the unit commander’s writtenapproval to accompany the property record. AM/3D Printers with acquisition cost $50K or greater will require RSOoversight and approval.
b. Account for all AM printers, also known as 3-D printers, in Accountable Property System of Record (APSR) DefenseProperty Accountability System - Property Accountability (DPAS-PA) module in accordance with AFI 23-111, Man-agement of Government Property in Possession of the Air Force and Department of Defense Instruction (DoDI)5000.64, Accountability and Management of Department of Defense (DoD) Equipment and Other Accountable Prop-erty.
1.3.3 Purpose of Centrally Procured AM Equipment. Head Quarters United States Air Force directs the use of stan-dardized AM equipment and processes whenever possible and has assigned authority for this direction to the Air Force RapidSustainment Office (AFLCMC/RO). During the acquisition process, new equipment is both laboratory and field-tested toensure safety, deployability, sensitivity, repeatability, and maintainability. The use of non-standard AM equipment must becoordinated through the cognizant engineering authority, SPO, AS 783 Manager, and/or the AFLCMC/RO.
1.3.4 Locally Purchased AM Equipment Authorized in AS 783. Equipment items for AM processing shall not bepurchased locally without the knowledge and approval of the AFLCMC/RO and MAJCOM Functional Manager. Consum-able support items and replacement parts may be purchased at any time without approval.
1.3.5 Service Contracts. AM equipment is intricate and sophisticated machinery that requires long term service contractsto enable the user to receive maintenance and upkeep that is beyond the organization’s capabilities. Each unit must reviewthe machine manufacturer’s specific service contract requirements to determine the machine-specific requirements in order tomanufacture and/or print qualified parts. Service contract requirements will be coordinated and funded by the owningorganization, with the assistance of and reported to AFLCMC/RO.
SECTION IV PROCESS CONTROL
NOTE
Process control overview is discussed in this manual. Specific process control procedures are located in TechnicalOrder (TO) 34A-2-1 and TO 34A-3-1.
1.4 PROCESS CONTROL OVERVIEW.
1.4.1 Reason for Controlling the Process. Process control is essential to achieving consistent and reliable results fromAM building processes. A well-regimented AM process control program will remove variability and ensure stability in theprinting process. A complete program will facilitate machine to machine conformance to deliver a stable process.
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1.4.2 Scope of Process Control. All areas are interrelated and have to be tuned to each other to achieve quality prints.If any one of these requirements is altered, the final outcome of the process will change, regardless of the operator’sproficiency. All frequency requirements for method-specific process control checks are published in TO 34A-2-1 and TO34A-3-1. Process control is a general term used to encompass the actions and documentation required by establisheddirectives and logic.
1.4.2.1 Process Control Areas. Areas that fall within the scope of process control are as follows:
• Training and the demonstrated practical skills of operators
• Environment
• Material controls
• Equipment controls (e.g., operational and performance capability or Test Measurement Diagnostic Equipment usercalibration)
• Written instructions (i.e. Technical Orders)
• Adherence to written operating instructions (if required)
NOTE
Machine scheduled maintenance will be conducted per the applicable machine-specific owner’s manuals and/ortechnical orders, and documented per TO 34A-3-1 and TO 00-20-1
1.4.3 Process Control Documentation Requirements. Documentation of process controls are completed to verifyconformance to established requirements in the areas described above. These requirements may be documented through theuse of automated products (e.g. Process Control Automated Management System (PCAMS)), and/or use of AFTO Form 244,AFTO Form 95.
a. Separate documentation shall be maintained for each AM method, machine, and material with established processcontrol requirements.
b. Process control requirements shall not be documented on the same form used to record machine maintenance. Docu-mentation of process controls shall be recorded on a separate form, or automated product, yet may be of the same typeand/or series (e.g. PCAMS, AFTO Form 244, AFTO Form 95).
c. As a minimum, this documentation shall reflect each element of process control with respect to required time intervalsbetween checks, date of accomplishment for each check, condition of element checked, corrective action taken (ifrequired), initials of the person performing test, serial number or identification number of the element tested, manu-facturer, lot or number if applicable, and date put into service.
d. Unless otherwise directed, only the most recent required documentation that provides a satisfactory history concerningequipment and materials needs to be maintained.
1.4.4 Establishing a Documentation Method. MAJCOM Functional Managers may determine the specific method theirassigned AM facilities will utilize for documenting process control verification. Methods may include the mandatory use ofautomated products (e.g. PCAMS) and/or AFTO Form 244, AFTO Form 95.
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SECTION V REPORTING NEW OR IMPROVED AM PROCESSES
1.5 REPORTING AM PROCESSES.
1.5.1 Need for Reporting New and Improved Processes. Developing new AM processes is expensive and timeconsuming. Techniques and procedures may be applied to all aircraft where similar problems exist. Interchanging informa-tion on AM processes between operating commands can reduce maintenance costs and enhance safety. Users should contactthe cognizant engineering authority, SPO, MAJCOM Functional, the AFLCMC/RO, or their Supervisor for guidance on newand/or improved processes.
1.5.2 Authority. The authority for reporting new or improved AM processes or new applications of AM methods iscontained in DAFGM2020-63-149-01, Department of the Air Force Guidance Memorandum Establishing Use of AdditiveManufacturing (AM).
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CHAPTER 2METAL ADDITIVE MANUFACTURING
2.1 OVERVIEW.
2.1.1 Direct Metal Laser Melting (DMLM) General Information. DMLM is a powder bed based additive manufacturingprocess that can be used to print metal parts with complex geometry. Machines such as the EOS M 290 (see Figure 2-1)incorporate innovative DMLM technologies to produce accurate and functional metal parts. Many metals have been qualifiedfor use with the EOS M 290 including titanium, stainless steel, Inconel, and aluminum. Depending upon the part size andorientation requirements, multiple parts of a common or different design can be built at the same time.
The DMLM process (see Figure 2-2) produces a metal part from three dimensional solid Computer-Aided Design (CAD)geometry. The CAD model is manipulated using specific software to orient and support the part in the machine work en-velope. The model geometry is then sliced into virtual layers to ultimately generate a build file that can be downloaded tothe machine. At the start of the print process, a thin layer of powder is applied to a metal base plate inside the inert atmo-sphere of the build chamber. A laser located above the powder layer selectively melts the powder via an exposure patterndefined by the build file. Upon completion of this layer, the build platform lowers one slice thickness and the recoaterblade spreads a new layer of metal powder. Layer by layer, a 3D part geometry is printed within the build chamber sur-rounded by un-melted powder. Upon completion of the build, the printed part along with the build plate are unpackedfrom the surrounding powder and removed from the machine.
After removing the printed part and the build plate from the machine, the part enters the post-process stage. Post-processsteps are dependent upon the specific part and material requirements. Typically, parts will undergo an initial stress reliefheat treat prior to part separation from the build plate. Additionally, parts may also undergo a property enhancement heat
Figure 2-1. EOS M 290
Figure 2-2. DMLM Print Process
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treatment, support structure removal, post-process machining and finishing operations as well as dimensional and Non-Destructive Inspection (NDI).
NOTE
Consult with your local Bioenvironmental, Safety Office, Fire Department, and powder specific Safety Data Sheet(SDS) prior to storing and handling metal powders.
2.1.2 Annual Training. Annual metal powder safety training shall be provided to Additive Manufacturing (AM) techni-cians and shop personnel who routinely work around the metal AM areas. At a minimum, the training shall include thehazards, safe handling techniques, and necessary actions in case of a fire.
2.1.3 Metal Powder Hazards in the DMLM Process.
Failure to wear gloves, protective clothing, and respirator; or failure to use non-sparking metal tools and naturalbristle brushes can result in inhalation and explosive hazards. Failure to comply with this requirement could resultin injury to personnel and/or extensive damage to the equipment.
The DMLM process uses metal powders that can become airborne dusts. The powders and dusts pose specific hazards thatneed to be understood. The hazards can be broken down into five main areas: inhalation, ingestion, skin sensitivity, fire, andchemical hazards.
2.1.3.1 Inhalation Hazard. Inhalation hazards are present whenever a person is exposed to or working with powders inthe maintenance, upkeep, and use of metal AM machines requiring the use of respiratory protection and Personal ProtectiveEquipment (PPE).
2.1.3.2 Ingestion Hazard. The ingestion hazard of metal powder is similar to other industrial processes. Standard shopprotocols should be followed by prohibiting tobacco products, eating, or drinking in the industrial area and washing handsbefore using tobacco products or eating and drinking.
2.1.3.3 Skin Hazard. A small percentage of the population is allergic to various metals. The most common metal allergiesinclude nickel, cobalt, and/or alloys containing these materials. Developing an allergy may take repeated or prolongedexposure to these metals. Impervious gloves with adequate wrist and/or arm protection should be worn while handlingpowders to reduce the likelihood of allergic reactions.
2.1.3.4 Fire Hazard. Technicians must understand the potential causes of fires and follow procedures to prevent andextinguish fires when they occur. Many substances in powder form may present a fire or explosion hazard when suspendedin the air in sufficient quantity; examples include sawdust, grain, bread flour, powdered sugar, and metal powders. Smallerparticle sizes are generally more combustible.
2.1.3.4.1 Potential Fuel Sources. Aluminum and titanium powders in particular, along with all types of metal conden-sate and all types of metal contaminated filters regardless of metal type, are potential sources for a fire while being handled.
2.1.3.5 Chemical Hazard. The SDS for particular powders in use will provide detailed information. The followinginformation is intended as general in nature.
2.1.3.5.1 Aluminum Powders and Water Reaction. Aluminum reacts with water; this is an exothermic reaction whichreleases hydrogen gas and a large amount of heat. Aluminum powders and contaminated filters must be kept away fromwater and moisture. Wet vacuums used to clean up aluminum and/or alloys containing aluminum (such as Ti-6Al-4V) thatuse water must have an additive to prevent the formation of hydrogen gas.
2.1.3.5.2 Titanium Powders and Nitrogen Reaction. Titanium metal must be printed using argon as the inert gas.Nitrogen must never be used as the inert gas because it will allow titanium to burn during the DMLM process.
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2.1.3.5.3 Acids and Bases. Several of the powders are not compatible with acids, bases, or both. The powders must bestored away from areas with acids and bases. If the facility has Fused Deposition Modeling (FDM) printers with a causticsupport removal tank, metal powders must be kept away from the caustic support removal tanks and rinse areas.
2.1.3.5.4 Condensate and Filters. Filters and metal condensate particles are especially combustible outside of the AMmachine because of the very small particle sizes and exposure to ambient air. Condensate and filters are not considered adanger when in the AM machine in an inert atmosphere.
2.1.3.5.5 Combustible Metal Powders. Metal powders other than aluminum and titanium are not typically a fire hazard;however, very fine particles may still be combustible. Consult the powder specific SDS for further information.
2.1.3.6 Ignition Sources and Mitigation.
2.1.3.6.1 Hot Work. Hot work such as open flames, welding, cutting, grinding, and other spark-producing operations shallnot be performed in the AM room. Signs shall be posted indicating no open flames or ignition sources at each entrance to theAM production area.
2.1.3.6.2 Electrostatic Discharge (ESD) . Static electricity can build up in people or equipment and when dis-charged, causing metal powder or condensate to ignite in certain conditions. The main factor affecting the potential for thistype of fire is the particle size and suspension of the powder in the air (dust cloud). Additional information on can befound in chapter 7 of Technical Order (TO) 00-25-234. The potential for to cause a fire is mitigated by strict adherenceto the following guidelines:
• Bonding and Grounding.Ensure there is proper bonding and grounding of the equipment to each other and to thefacility ground.
• Personnel ESD Requirements. Personnel shall use either Static Dissipative (SD) footwear and mats or Ankle/Wrist grounding straps when operating or performing maintenance on a DMLM machine.
2.1.3.6.3 Static Dissipative Requirements. Static dissipative footwear shall be used in conjunction with static dissipa-tive mats and/or static dissipative floor.
• Compliant Footwear. Compliant footwear is labeled by the manufacturer with “ASTM F2413” and the code “SD”.If compliant footwear is not readily available, a wrist or ankle grounding strap shall be used and electricallybonded to the machine.
• Static Dissipative Mats. Static dissipative mats must be bonded to the machine and visually checked to ensure thebonding wire is serviceable and connected to the machine before each use. If serviceability of the bonding wire isin question, it should be checked for continuity with an ohmmeter. A static dissipative floor may be installed in lieuof using a mat.
• Ankle or Wrist Grounding Straps. These items shall be visually checked for serviceability before each use. If aparticular procedure calls for a wrist or ankle grounding strap, SD shoes and mats shall not be used as a substitute.
• Tools. Only non-sparking, conductive metal tools (e.g. stainless steel and aluminum) shall be used.
• Brushes. Natural bristle brushes shall be used. Synthetic brushes may build up static electricity which coulddischarge and be a source of ignition.
2.1.3.6.4 Fire Risk Reduction Procedures. These procedure must be followed to reduce and/or mitigate the risk of fire.
• Closed Containers for Transportation and Storage. Powders shall be transported and stored in closed containers. Theoriginal containers in which the product was shipped shall be used. See PARA 1.6.4.3.3
• Vacuums. Vacuums rated for combustible metal dusts shall be used. Standard shop vacuums or High-EfficiencyParticulate Air (HEPA) vacuums are not an acceptable substitute, and shall not be used. Vacuums should only beused for collecting residual amounts of powder and dust. Bulk spills shall be cleaned up with non-sparking con-ductive metal scoops and tools before using a vacuum.
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• Powder Removal Before Post-Processing. All powder should be removed from the build plate before postprocess-ing. Powder shall be removed by brushing, vacuuming, and then tilting. Precautions shall be taken to avoid thespread of powder throughout the room. Powder removal should be done inside the build chamber, on a downdrafttable, or inside a specially designed cabinet.
• Post-Processing. When sanding or grinding metal parts, dust generation must be minimized and appropriate vacu-ums and downdraft tables should be used.
• Housekeeping. Metal dusts are combustible and must not be allowed to accumulate beyond 1/32 inches deep. Ageneral rule of thumb is that if the color of the object is obscured, the dust is too thick. Most dust explosions areactually a double explosion; a small initial shock-wave does little damage but knocks other dust loose to fuel amuch larger explosion that causes significant damage.
• Housekeeping Program. Shops shall have a written housekeeping program for their metal AM area. This programwill specify the cleaning frequency and document the cleanings that actually take place per local guidance.
• Powder Storage. Powders shall be stored in closed, sealed containers. Titanium and aluminum powders shall bestored in designated, approved flammable storage cabinets, in accordance with Air Force Manual (AFMAN) 91-203, separate from flammable liquids. Powders should be stored separate from acids and bases unless allowed bythe SDS.
2.1.3.7 PPE. PPE includes the use of protective clothing, and equipment as identified below.
• Garments. Flame resistant outer garments (i.e. jackets) shall be worn when handling powders, condensate, andcontaminated filters; this does not apply to items in closed, sealed containers. Outer garments shall be designed toprevent accumulations of combustible metal dust in pockets, cuffs, etc. They should be of a smooth material thatallows dust to be readily vacuumed or brushed off. Garments should meet National Fire Protection Association(NFPA) 2113 or a similar standard and should not be made of a material that generates or stores static electricity.Powders should not be allowed to accumulate on the garments. Garments should be vacuumed and laundered asnecessary according to manufacturer’s instructions and should not be worn outside metal AM production area.
• Respirator. Personnel handling powder shall use a Powered Air Purifying Respirator (PAPR) with a P100 HEPAcartridge or better. This applies to pouring powder, adding and removing powder to machines, sieving powder, andremoving condensate and contaminated filters. The PAPR provides both respiratory and eye protection.
• Gloves. Gloves used in AM processes require strict adherence to safety for proper usage.
• Disposable Nitrile Gloves. Disposable nitrile gloves shall be worn while working in a build chamber or testingpowders. Gloves that provide adequate wrist protection (e.g. 12 inches long or longer) should be used. Powder freegloves should be used. Example products that will meet these requirements include Ansel part numbers 92-605,93-163, and 93-263.
• Flame Resistant Gloves. Flame resistant gloves shall be worn when changing condensate containers and contami-nated filters. The gloves should have a relatively smooth finish and provide adequate wrist protection. Knit glovesare not acceptable. Cowhide welders gloves and firefighter’s gloves are appropriate.
• Footwear.SD, hard-toed footwear per ASTM F2413, should be worn. See Paragraph 2.1.3.6.2, .
2.1.3.8 Fire Suppression.
Water shall not be used on metal fires. Water will fail to extinguish most metal fires and will react violently withaluminum releasing heat and flammable hydrogen gas. Failure to comply with this requirement could result ininjury to personnel and/or extensive damage to the equipment.
Metal fires are extremely dangerous and require unique fire-fighting techniques identified below.
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• Class D Fire Extinguishers. Only class D fire extinguishers shall be used on metal fires and shall be present in theprinting area. The chemicals employed by these extinguishers and their method of application are designed specifi-cally to control powder metal fires. Only trained personnel should operate fire extinguishers.
• Class ABC Fire Extinguishers. Class ABC fire extinguishers should not be in the area unless required for otherprocesses. If ABC fire extinguishers are in the area, they shall be marked in a visible location “Not for use on metalfires”. Only trained personnel should operate fire extinguishers.
• Sand. Dry fine quartz sand (silica sand) of 20 mesh or smaller can also be used to control metal fires. It is typicallyapplied by laying the sand around the perimeter of the fire with a long-handled shovel made of spark-resistantmetal. The amount of sand to use in dependent upon the size of fire.
2.1.3.9 Notifications. Base environmental, safety and fire department must be aware of the presence of combustiblemetals and the types and quantities being stored in the work center/section.
2.1.3.10 Dust Collection. This topic addresses the collection system, requirements, and cleaning required to prevent ahazardous situation.
2.1.3.10.1 Dust Collection System. Dust collection systems should utilize the wet type collection system. Dry typecollection systems and installation must be approved by the base fire marshal. Dry type systems need to be located outsideand have deflagration venting among other requirements. Original Equipment Manufacturer-approved filter media should beused; if alternate filter media must be used, it should not be made from synthetic fabrics that accumulate static electriccharges.
NOTE
The interior of the duct work must be regularly cleaned to prevent deposits from accumulating.
2.1.3.10.2 Requirements. Dust collection shall meet requirements of NFPA484, designed for use with combustible metaldusts.
2.1.3.10.3 Disposal. Metal powder will be treated as hazardous waste unless otherwise directed from the base Bioenvi-ronmental Office. Passivated powder from wet separators must be disposed of in hazardous waste bins. Powder cleaned upmust be passivated and disposed of via hazardous waste containers. Any shop towels, gloves, or other consumables thatcome in contact with metal powder must also be treated as hazardous waste and disposed of in a metal container withself-closing lid.
2.1.3.11 Materials for Passivation of Condensate. Passivation materials authorized for use with the EOS M 290 arecaptured below.
• Dry Quartz Sand. Dry quartz sand size 0.1 milimeter (mm) to 0.8 mm maximum (less than 0.7 mm is preferred).Also known as washed and dried silica sand.
• Quikrete Fine Sand. Quikrete Commercial Grade Fine Sand # 1961 is preferred (Quikrete Medium grade # 1962may be used as a substitute).
• Wedron Silica Sand. Wedron Silica Sand # 480, 460, 430, 420, 410, 530, 520, 510, or 730.
• Silicone Oil. Polydimethylsiloxane viscosity < = 20 centistokes and flash point > = 170°C.
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2.1.4 Powder Handling.
Mishandling of metal powders may create explosive and inhalation hazards. protection and PPE shall be usedwhen pouring or transferring metal powders. Failure to comply with this requirement could result in injury topersonnel and/or extensive damage to the equipment.
2.1.4.1 Material Specific Tools. Tools, sieves, and other equipment that come in contact with metal powder shall bematerial specific to avoid cross-contamination (i.e. tools for aluminum based alloys shall not be used on titanium or cobaltbased powders). Contamination of one type of metal with another could lead to improper printing as well as hidden defects.Tools shall be cleaned before and after use per TO 34A-2-1.
2.1.4.2 Apparel. Apparel, including flame resistant jackets and gloves, should be material specific. If it is not materialspecific, it must be thoroughly vacuumed before use with metal powders. Disposable gloves shall not be reused.
2.1.4.3 Virgin vs Reuse Powder. Fresh powder that has not been used within a DMLM machine is considered virginpowder. Powder that has already been used in the build chamber of the DMLM process is considered reused powder.
2.1.4.4 Reuse Increments. Each print cycle for a powder shall be tracked. The powder should increment such that onecycle through a printer will produce reuse 1 powder and a second cycle will result in a reuse 2 powder. For example, afterreuse 1 powder is used for a build, the next build becomes reuse 2 and so on. If two different reused powders are combined,the mixture becomes the higher reuse number. For example, if you mix reuse 4 with reuse 8, the new mixture is reuse 8.
2.1.4.5 Reuse Sieving. Reused powder shall be sieved prior to removal from the machine. Sieving removes unwantedlarge particles and clumps to help control particle size distributions required for printing with DMLM printers.
2.1.4.6 Reuse Powder Storage. Powder removed from a machine for storage shall be stored either in the originalcontainer, or an identical container that housed the same metal alloy powder (e.g. Aluminum AlSi10Mg is a different alloythan Aluminum Al6061-RAM2 percent and cannot be stored in each other’s containers). Lids shall be closed/sealed. Con-tainers shall be labeled indicating the reuse number as well as the weight. Reuse labels shall be placed on the container, notthe lid. Safety warnings and content information shall not be covered.
2.1.5 Equipment List. Table 2-1 is an example of the equipment that is used to print qualified metal parts with DMLMtechnology. Any deviation from the lists located in TO 34A-2-1, WP 003 00 requires approval by AFLCMC/RO.
Table 2-1. DMLM Equipment List for Printing Qualified Metal Parts
Part (Tool) Number NomenclatureEOS 1225-060221 EOS M 290 DMLS SystemHAAS VF2 or equivalent Vertical Milling CenterPROTROTRAK K3 EMX or equivalent Milling Machine (Manual Mill)IEPCO PM750S or equivalent Media Blast CabinetAirgas Y13-CP820LP or equivalent High Pressure Argon ManifoldAlpha Omega Series 1300 or equivalent Oxygen SensorInert PL-HE-2GB-1250 or equivalent Powder cleanup cabinetRUWAC NA 35 or equivalent Wet Separator
2.1.6 Facility Requirements. Users shall review this section, along with coordinating with the Air Force Rapid Sustain-ment Office (AF RSO) and reviewing the manufacturer’s latest installation guide and JEDMICS drawing, prior to designinga facility or embarking on a facility modification. Consideration should be given for the addition of more AM machines inthe future.
2.1.6.1 Size. Sufficient size of the AM facility should be ensured. Actual dimensions are dependent on specific equipmentchosen and space necessary for specific work tasks such as post-processing. An area of 400 square feet per printer is areasonable initial estimate, but actual size will depend on the specific layout and quantities of equipment.
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2.1.6.2 Climate Controlled Area. Metal AM machines require a climate controlled area to operate properly and deliverconsistent high quality parts. The machines shall not be located near local heating or cooling sources such as a radiator, airconditioner, or direct sunlight (see Paragraph 2.1.6.11). Printers shall be installed in a closed room meeting the requirementsoutlined in the following subsections.
2.1.6.3 Construction. Room construction requires consideration of metal powders by minimizing the areas where dustcan collect. In addition to being electrically conductive, metal powders may pose the risk of a flash fire when combustibledusts are present. It is unlikely that the conditions for a dust fire will be met as long as proper safety precautions arefollowed, such as following proper storage, use, and handling procedures. Safety precautions limit the amount of dust in theair to insufficient concentrations. Further information on the dust hazard analysis can be obtained by contacting AFLCMC/EZP.
2.1.6.4 Walls and Partitions. Walls and partitions shall be of one-hour fire rated construction unless required otherwiseby local building codes. Walls shall be smooth to prevent dust collection and facilitate easy cleaning.
2.1.6.5 Ceilings. Ceilings shall be installed of drywall type, drop-ceiling tiles, or equivalent means. The purpose of theceiling is to prevent any dust accumulation on exposed rafters or joists. Ceilings should be of one-hour fire rated construc-tion unless required otherwise by local building codes.
2.1.6.6 Doors. Doors shall be self-closing and shall be of one-hour fire rated construction unless required otherwise bylocal building codes.
2.1.6.7 Windows. A window or several windows between the climate controlled area and the rest of the shop should beincorporated for improved situational awareness.
2.1.6.8 Floor Requirements. The location must be free from interfering vibration per manufacturer’s specification. Thefloor shall be flat, and level in accordance with manufacture specifications.
2.1.6.9 Floor Surface. The floor surface must be free of gaps so metal powder cannot be trapped, suitable for wetcleaning, and be anti-slip and resistant to solvents.
2.1.6.10 Floor Load. The floor where the machine will be installed must meet the machine-specific manufacturer’sspecifications.
2.1.6.11 Temperature and Humidity. The Heating Ventilation and Air Conditioning (HVAC) system shall be capable ofmaintaining both the temperature and humidity within the machine-specific manufacturer’s specifications. Typical tempera-ture and humidity requirements are shown in Table 2-2. The HVAC system must overcome the waste heat generated by theAM machines, lighting, body heat of personnel working in the area, and any other equipment operating in the room. Forexample, the waste heat generated by the EOS M 290 AM Machine (1.2 kilowatt (kW)) and the coolant system (2.8 kW) 4.0kW. The coolant system may be located in an adjacent room outside of the climate controlled area if necessary. A tempera-ture and humidity gauge should be installed in the room.
Table 2-2. Typical Temperature and Humidity Specifications
Temperature °F Relative Humidity59-68 80 percent maximum, non-condensing69-77 60 percent maximum, non-condensing
2.1.6.12 Air Exchanges. There are no special requirements for air exchanges. Standard practices can be followed as longas the system can maintain temperature and humidity requirements.
2.1.6.13 Oxygen Sensor. Metal AM machines and other support equipment will use inert gas during processing. There-fore, an oxygen sensor such as the Alpha Omega Instruments Series 1300 Oxygen Deficiency Monitor or equivalent, shall beinstalled near the AM metal machines where potential exposure to inert gas could occur. A minimum of two oxygen sensorsshould be installed in the AM metal machine room, per manufacturer’s recommendations. Typically, sensors require a 120Volt (V) outlet and are installed 12-36 inches above floor level for heavier than air applications (argon).
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2.1.6.14 Size. The climate controlled environment must be large enough to accommodate all equipment listed Table 2-3.There must be sufficient clearance between machines, walls, and passageways must be large enough to fully open machinedoors and perform maintenance. Clearances required by AFMAN 91-203 shall be maintained for access to fire extinguishers,circuit breakers, and eye washes. An area of 400 square feet per printer is a reasonable initial estimate, but actual size willdepend on the specific layout and quantities of equipment.
Table 2-3. Typical Equipment Housed in Climate Controlled Environment
Equipment and Accessories for Climate Controlled EnvironmentTransformerMetal AM MachineAir-Water Cooling SystemRecirculating Filter System-Pre-Filter StageRecirculating Filter System-Fine Filter StageWet SeparatorAntistatic MatDedicated toolboxWorkbenchFlammable Storage Cabinet for Metal PowdersStorage for other miscellaneous supplies used in the roomMetal Waste Container with Self-Closing LidClass D Fire Extinguisher, 25 pounds. rating or LargerFire BlanketPPE Storage for PAPRs and Flame Retardant Clothing (may be stored elsewhere, but this is the ideal location)Eye Wash (If required by your local safety office)
2.1.6.15 Utilities. The utilities outlined below will be considered for proper set-up, installation, and use of a metal AMmachine such as the EOS M290.
2.1.6.16 Electrical Classification. The location is not classified as a hazardous location; standard electrical wiring prac-tices are sufficient.
NOTE
Powders are processed in an inert atmosphere, there is minimal handling and exposure of the metal powders to theambient environment, and dust accumulations outside of the machines are almost non-existent; furthermore, thesafety section of this TO requires users to have a housekeeping program to ensure there are no hazardousaccumulations of metal dust outside the machine.
2.1.6.17 Electrical. Installation of sufficient electrical supply, transformer, and power line conditioning must be ensured torun the AM machine and associated equipment. An uninterruptable power supply may also be used to support electricalloads during brownouts and power outages.
2.1.6.17.1 Dedicated Circuit. Metal AM machines must be connected to a dedicated circuit and protected with appropri-ate current protection device(s) (circuit breaker/fuse). There must be no large electric motors connected to the same circuit toavoid interference with the power supply to the lasers. For example, a dedicated 480V, 3-phase, minimum 32 ampere circuitis required for the EOS M 290.
2.1.6.17.2 Transformer. In many cases, a transformer will be provided with the metal AM machine and must be locatedin the same room. For the EOS M 290, the transformer will provide power for the machine which supplies power to thecooling system and the filter systems. Typical electrical requirements are listed in Table 2-4.
Table 2-4. Example (EOS M 290) Electrical Requirements
EOS M 290 Electrical Requirements ValueConnection: Fixed 480V, 3 phase
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Table 2-4. Example (EOS M 290) Electrical Requirements - Continued
EOS M 290 Electrical Requirements ValueVoltage Fluctuations: +6 percent to -10 percentFrequency: 50/60 HzRated Short Circuit Current: 5 kANominal Power: 8.6 kWCurrent Consumption (maximum): 15.5AMain Fuse Protection: 3X32A
2.1.6.17.3 Standard Auxiliary Electrical Outlets. It is recommended to have additional auxiliary outlets available foreach machine for use with miscellaneous equipment. For example, a minimum of (1) standard 120V 20 ampere auxiliaryelectrical outlet and (1) standard 240V, 20 ampere (minimum) outlet should be available per machine.
2.1.6.18 Inert Gases. Typically, argon or nitrogen will be supplied to the metal AM machine for the printing processdefined by the part specific technical data package. See AFMAN 91-203 and TO 42B5-1-2 for use, handling, and mainte-nance of gas cylinders.
2.1.6.18.1 Argon.
Nitrogen is not to be used with titanium based alloy due to risk of fire and explosion. Failure to comply with thisrequirement could result in injury to personnel and/or extensive damage to the equipment.
Argon may be supplied from high pressure cylinders, a cryogenic dewar, or a bulk cryogenic system. The supply system maybe located outside of the climate controlled area, but the gas will need to be piped to the machine. If using high pressurecylinders, it is recommended that a six cylinder high pressure cylinder manifold be utilized. Additionally, two high pressure/high purity argon cylinders must be installed for argon backup on the other side of the changeover regulator.
• Alarm Package and Change-Over Regulator. A continuous supply of argon is required; therefore, an alarm packageand change-over regulator are required. Airgas part number Y78820ALPK or equivalent meets this requirement.
• Argon Requirements. An example of argon requirements (EOS M 290) are listed in Table 2-5.
Table 2-5. Example (EOS M 290) Argon Requirements
EOS M 290 Argon Requirements ValueMaximum Pressure: 79.8 psi (5.5 bar)Minimum Pressure: 72.5 psi (5 bar)Minimum Argon Purity: Argon 4.6 (purity 99.996 percent)Minimum Flow Rate to be provided: 3.6 SCFM (6 m3/hr.)Consumption during building Maximum 1.8 SCFM (3 m3/hr.)Consumption during the building process: Approximate 0.36 SCFM (0.6 m3/hr.)
2.1.6.18.2 Nitrogen Inert Gas. If argon is not utilized, nitrogen may be required for a metal AM build process. In thecase of the EOS M 290, the machine generates nitrogen from an on-board nitrogen generator supplied from shop air.
2.1.6.18.3 Waste Gas Removal. Due to potential exposure of argon and other waste gases, the machine waste gas mustbe vented and removed to the outside atmosphere per the machine manufacturer’s specifications. EOS recommends twodifferent options to remove the waste gas: (1) direct discharge to the outside atmosphere or (2) a connection to an internalwaste air extraction system in the building where the machine is located. EOS specifications for both options follow.Additional option consideration must be according to machine manufacturer’s specifications.
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2.1.6.18.4 Direct Discharge. Direct Discharge must have gas-tight connections and a non-return flap to prevent wastegas from back flowing. The maximum allowed length of the waste gas hose is 32.8 feet.
2.1.6.18.5 Connection to an Internal Waste Air Extraction System. This system must have leak-free connections anda nonreturn flap to prevent waste gas from back flowing. The maximum allowed length of the waste gas hose is 32.8 ft.When the machine is in operation the waste air extraction system must be operational. The waste extraction system flow ratemust be ≤ 10 m3/hr. and have a maximum pressure difference to ambient pressure at the discharge point of ±5 mbar.
2.1.6.18.6 Compressed Air Requirements. Most metal AM machines require a compressed air supply that is cleanerthan normal shop air and meets certain specifications. Considerations must be taken and machine-specific manufacturer’sinformation must be referenced. An example (EOS M290) of compressed air requirements are listed in Table 2-6. Theserequirements can be met with a Pneumatic Plus Modular Air Unit (part number: SAU4030M-N04G-MeP) with particulatefilter, coalescing filter, and air regulator.
Table 2-6. Example (EOS M 290) Compressed Air Requirements
EOS M 290 Compressed Air Requirements ValueMaximum Pressure: 145 psi (10 bar)Minimum Pressure: 87 psi (6 bar)Nominal Pressure: 102 psi (7 bar)Consumption when used to generate: 20 m3/hr. at 102 psiConsumption with external inert gas supply: 1 m3/hr. at 102 psiSolids (ISO 8573): ISO 8573 Class 1 (particle size ≤ 0.1 mm, particle density ≤
0.1 mg/m3)Water Content: ISO 8573 Class 4 (pressure dew point ≤ 3°C and must not
contain any liquid water)Oil Content: ISO 8573 Class 1 (oil concentration ≤ 0.01 mg/m3)
2.1.6.18.7 Non-Climate Controlled Area. This area is used for post-processing and may be part of an existing machineshop. This area will need the standard utilities found in machine shops including electrical service and compressed air. Theequipment listed in Table 2-7 will be located in this area.
Table 2-7. Typical Equipment Housed in Non-Climate Controlled Area
Equipment and Accessories for Non-Climate Controlled AreaMedia Blast Cabinet (Could be multiple types)Horizontal Band SawWire Electrical Discharge Machine (EDM)Heat Treatment FurnaceComputer Numerical Control (CNC) Mill, 4-AxisDowndraft Table with Belt SanderFAROArm EdgeGranite Cart for FAROArm EdgeWork BenchesTool BoxesClass D Fire Extinguisher (25 pounds minimum)Eye Wash
2.1.6.19 Other Considerations. Other consideration include water requirements and computer work station.
2.1.6.19.1 Water Requirement. A local tap water supply and a drain is needed for filling the wet separator vacuumsystem.
2.1.6.19.2 Computer Work Station. One Non-Classified Internet Protocol Router Network computer work station withappropriate software is required for AM machine(s).
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2.1.7 Machine Qualifications.
2.1.7.1 Approved Printers. Only printers approved by AFLCMC/RO may be qualified to print airworthy parts andequipment per Airworthiness Bulletin-1015.
2.1.7.2 List of Qualified Machines. A list of qualified machines will be maintained by AFLCMC/RO by location andserial number. AFLCMC/RO will publish the qualified printer list.
2.1.7.3 Qualification Requirements. All metal AM machines will require qualification after installation on-site or underother circumstances where modifications or repairs occur to major sub-system equipment that can significantly change thebuild quality. (See Table 2-8). Qualification frequency and requirements will be found in TO 34A-2-1, WP 002 00.
Table 2-8. Reasons to Requalify Metal AM Machines
Reasons to Requalify Metal AM MachinesAnytime the machine is moved within or between facilitiesWhen there is a change in powder type or manufacturer unless the new powder complies to the same material MILspecification to which the machine was previously qualifiedOther considerations as defined by AFLCMC/RO
2.1.7.4 Qualification Procedures. The qualification processes will be established and will vary by machine manufac-turer. For machine-specific qualification steps and build preparation, see TO 34A-2-1, to include sub-work packages for allmaterials supporting the production of approved aircraft parts. Qualification Build files will be controlled and distributed bythe AF RSO. If qualification specimens cannot be tested in an ASTM certified laboratory locally, contact AF RSO forassistance.
2.1.8 Post-Processing Process Overview. This section provides a general overview of the most common post-process-ing steps required for metal AM parts along with the technologies and techniques currently being used for these operations.Operations include part marking, heat treatment, part separation and support material removal, surface enhancement, finalmachining, and inspection. This list should not be interpreted as a required sequence. The manufacturing operation flow andoperation requirements will be dictated by the engineering drawing requirements, material processing procedure standards,and manufacturing documentation specific to the component being made.
2.1.8.1 Part Marking. Part marking can enhance traceability through the manufacturing process and may provide addi-tional benefit throughout the product’s lifecycle. A common method of tracking parts is to incorporate embossed or debossedpart and serial numbers into the printed geometry of the part.
NOTE
If traceable unique identifiers are not printed directly into the part geometry, components can be marked duringpost-processing with various techniques including: (1) laser etching, (2) engraving with a CNC mill, (3) manuallyinscribing, or (4) dot peening as required per specification or drawing.
2.1.8.2 Heat Treatment. Heat treatments may be performed on AM parts for both stress relief and material propertyenhancement. The heat treatment requirements and capabilities are material dependent. Exact processing requirements arecalled out on the engineering drawing in detail, or by referencing the appropriate heat treatment (material specific) specifi-cation.
a. The stress relief heat treatment is a critical part of the process, and in most cases, must be done prior to separating thecomponent(s) from the build plate. Metal AM introduces significant residual stress into components through the localrapid heating and cooling of material throughout the build process. If part separation is done prior to stress relief,residual stresses will most likely result in warpage of the part and dimensional non-conformances.
b. A second heat treatment procedure may be required to alter the material’s grain structure and deliver more desirablemechanical properties. Exact processing requirements are called out on the engineering drawing in detail, or byreferencing a heat treatment specification. The process point of when this second heat treatment should take place inthe manufacturing sequence may be specified on the engineering drawing. Both Stainless Steel 17-4 PH and Ti-6Al-4Vrequire a vacuum or inert atmosphere heat treatment while Aluminum is heat treated in an air atmosphere.
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2.1.8.3 Part Separation and Support Material Removal. Parts may be separated from the build plate using either aband saw or Wire EDM. The band saw will have higher separation speeds, while the Wire EDM will produce more preciseand accurate cuts.
2.1.8.4 Band Saw. If separation by band saw is the specified method, it is recommended to use a carbide tipped blade.The carbide tipped blade requires less cutting force, is more wear resistant, and offers a higher feed rate than a standard steelblade. A water based flood coolant should be used during band saw separation to reduce the blade temperature and providelubrication at the cutting surface. A band saw should be used when flatness and location of the separation plane is notcritical. Band saw removal is a good option when breakaway supports are used to elevate the part above build plate.Breakaway supports are sacrificial so flatness and location of these features are non-critical.
2.1.8.5 Wire EDM. These machines have the ability to produce precise and accurate cuts when used properly. When partseparation only requires a continuous straight cut parallel to the build plane surface, an operator will only need to tram in thebuild plane to be square to the wire travel plane. Standard wire EDM technical data packages defined wire voltages, currents,and feed rates do not typically accommodate the machining of thick, exotic materials.
2.1.8.6 Surface Enhancement. High surface roughness is characteristic of DMLM printed parts. High surface roughnesscan be problematic when fatigue life and various other design considerations are critical. Excessively rough parts may alsomake datum and dimensioning schemes more difficult to control and interpret. It is often beneficial to utilize surfaceenhancement processes to minimize these issues. While there are many available surface enhancement techniques, eachprocess has varying degrees of effectiveness and limitations. Only perform surface enhancement per specification or draw-ing.
2.1.8.7 Media Blast. This technique bombards the component surface with some type of abrasive media to knock off thepeak material of the roughness profile. Media blast is a very cost effective method to achieve an initial limited reduction insurface roughness. 17-4PH SS is often blasted with steel shot, while Ti-6Al-4V must be blasted with ceramic media.
2.1.8.8 Abrasive Tumbling. This technique vibrates components in a container filled with abrasive media. Media size andoperating cycle time can be adjusted to control the finish.
2.1.8.9 Shot Peening. Shot peen will knock off material peaks similar to the media blast process while simultaneouslyinducing a compressive surface layer which increases fatigue life. One undesirable aspect of implementing a shot peenoperation for high mix, low volume AM components is that each part requires a customized NC program.
2.1.8.10 Sanding and Polishing. These techniques can also offer a significant improvement in surface quality. Manualapplication of these techniques must give consideration to material removal control, labor stress, and operation cycle time;while automated implementation of these techniques may require customized NC programing for each unique AM compo-nent.
2.1.8.11 Finish Machining. Final machining is often required for additive parts when tight tolerances are specified on theengineering drawing. This is especially true when considering hole size, flatness dimensions, and feature relationships thatspan across long distances. Finished machining may also be required when geometry is modified or support material isadded for improved printability. If another surface enhancement process is not feasible or adequate, it can be advantageousto combine media blasting with finish machining to improve the surface finish.
2.1.8.12 Geometry Inspection. Final part geometry will require inspection by means such as gage blocks, gage pins,calipers, micrometers, height stands, surface plates, dial indicators, chamfer plunger gages, and laser scanners or touchprobe, etc. Examples of such measurements include thicknesses, widths, depths, and diameters.
2.1.9 Quality Process. Per TO 34A-2-1 it must be ensured that the DMLM System is adequately controlled to consis-tently produce quality parts.
2.1.9.1 Non-Conforming. All non-conforming conditions shall be rejected. Contact AFLCMC/RO for assistance.
2.1.9.2 Dimensional. Dimensional requirements are specified as part of the Part Specific Drawing Package. Dimensionalcapabilities and part geometry limitations are dependent on the material to be printed.
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2.1.9.3 Visual Inspection. A visual inspection procedure shall be conducted on each part post build completion andcompared to the descriptions of acceptable and unacceptable anomalies outlined in TO 34A-2-1 and on the Part SpecificJEDMICS Drawing Package.
2.1.9.4 Non-Destructive Inspection. NDI requirements will be defined on the Part Specific Drawing Package.
2.1.9.5 Typical Anomalies. The anomalies outlined in Table 2-9, some of which may not be detectable by visual inspec-tion alone, may occur during a DMLM process which may or may not be acceptable as defined by the Part Specific DrawingPackage and the cognizant engineering authority.
Table 2-9. Anomalies Inherent to the DMLM Process
Anomalies DefinitionBroken Support Structure Any portion of the part which has separated from build plate or part uninten-
tionally.Horizontal Seams/Witness Lines Lines perpendicular to the build direction potentially caused by build stop-
pages, inter-pass time changes and part movement during the build process.Build Stoppage Interruptions in the build process caused by machine and process issues (such
as machine failures or re-coater arm jams) or external issues (such as interrup-tion of utilities).
Indication Any linear or non-linear discontinuity that is located in the AM part such as acrack, porosity, foreign inclusion, lack of fusion, etc.
Pinhole Surface porosity.Lack of Fusion Incomplete melting of an area of the additive build where powder was not
fully penetrated/fused to part potentially caused by contamination, laser degra-dation or thicker than expected powder layers.
Inclusion An entrapped foreign substance in the deposited metal.
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CHAPTER 3POLYMER ADDITIVE MANUFACTURING
3.1 FUSED DEPOSITION MODELING® (FDM) PRINTERS.
3.1.1 FDM® General Information. These systems incorporate innovative technologies that produce accurate and func-tional polymer parts. Stratasys’ FDM technology also provides prototype parts, including internal features that can be used tofield-test form, fit, and function.
3.1.2 Equipment List. The equipment listed in Table 3-1 shall be used to print qualified polymer parts with FDMtechnology.
Table 3-1. FDM Equipment List
Equipment DescriptionFortus 900mc with the HP/AICS (Aircraft Interior Certifi-cation Solution) package installed and Stratasys Equiva-lency Kit
3D printer used to print parts/items that require airworthi-ness determination per Airworthiness Bulletin (AWB)-1015.
Fortus 900mc with Ultem 9085 license 3D printer used to print parts/items that do not impact air-worthiness per AWB-1015.
Fortus 450mc with Ultem 9085 license 3D printer used to print parts/items that do not impact air-worthiness per AWB-1015.
Insight™ Software Package This is the software used for slicing the stereolithographyfiles used to print parts. This package also contains ControlCenter, the software used for communicating with the For-tus 900mc.
Generic Non-Classified Internet Protocol Router Networkcomputer workstation
This computer is used to send print jobs to the Fortus900mc, and monitor jobs in the print queue.
Ultem 9085 modeling material This material is manufactured with strict requirements andtraceable back to the manufacture and is produced in bothcertified and production grades.
Ultem 9085 support material This is the sacrificial material used to support the modelingmaterial.
Drying oven This oven is used for drying material to less than or equalto a moisture content of 0.01 percent. It is also used forreheating the parts to aid in removing support material af-ter printing.
General hand tools Such tools include, but are not limited to, picks, puttyknifes, and craft knifes. These tools are used for separatingsupport material from the part that was printed.
NOTE
Any deviation from this list requires approval by AFLCMC/RO.
3.1.3 Safety. All servicing shall be performed by qualified personnel. There will be times when areas of the system mustbe accessed where potentially high voltages, hot temperatures, and/or moving mechanical components could cause severeinjury. Table 3-2 lists potential safety hazard areas.
Table 3-2. Potential Safety Hazard Areas
System HazardBuild Chamber When performing operations within the heated build chamber of polymer AM machines and/or
when handling hot parts, thermally insulated gloves and safety glasses shall be worn.
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Table 3-2. Potential Safety Hazard Areas - Continued
System HazardGantry Use extreme caution whenever accessing this area of the system. The servo drive system is ex-
tremely powerful so care must be taken. The XY pinch hazard between the timing belts and pul-leys is minimized by locking the hood and door while building and disabling the motors whenthe top hood or door is open. If adjustment must be made to this component contact the manu-facturer.
Z-Stage The Z-Stage and Z-Stage servo motor can cause severe injury. The Z-Stage crushing hazard isminimized by locking the door during Z-Stage movement and disabling the Z-Motor when thedoor is open. When adjusting the height of the Z-stage using the touchscreen, always wait for amovement to complete before commanding another movement. Repeatedly pressing the move-ment key can result in uncontrolled machine movement and can result in injury or damage tothe equipment. If this situation is encountered, immediately press the red emergency stop button.If adjustment must be made to this component contact the manufacturer.
3.1.4 Facility. Large polymer AM machines such as the Fortus 450mc and 900mc/F900 systems are capable of generatingvibrations dependent on part build geometry and material characteristics. This consideration will need to be taken intoaccount if locating the system near vibration sensitive equipment. Weight and space requirements may vary by make andmodel of machine. For detailed information, refer to your machine-specific manual, and JEDMICS drawings 201991927Stratasys Fortus 450mc Facilities Installation Guide, or 201991926 Stratasys Fortus F900 Facilities Installation Guide. Anexample of weight and space requirements for the Fortus 900mc/F900 and Fortus 450mc are listed in Table 3-3 below.
Table 3-3. Example (Fortus 900mc/F900/450mc) Weight and Space Requirements
Fortus 900mc/F900Weight 6325 pounds Shipping: 7247 poundsWidth 110 inches Operating space: 166Depth 67 inches Operating space: 141Height 80 inches Operating space: 116
Fortus 450mcWeight 1325 pounds Shipping: 1500 poundsWidth 51 inches Operating space 99 inchesDepth 35.5 inches Operating space 84 inchesHeight 78.1 inches Operating space 102 inches
3.1.4.1 Environmental Requirements. Temperature, humidity, and heat output requirements will vary by machine manu-facturer. Always consult your machine-specific manual or site preparation guide for detailed information. An example ofenvironmental requirements for the Fortus 900mc/F900 and Fortus 450mc are listed in Table 3-4 below.
Table 3-4. Example (Fortus 900mc/F900/450mc) Environmental Requirements
Fortus 900mc/F900/450mc Environmental Requirements ValueOperating 60°F to 85°FHumidity 20-80 percentHeat Output Up to 26,000 BTU/hour
NOTE
Polymer AM machines are for indoor use only.
3.1.4.2 Electrical Requirements. The facility power is required to meet power quality and nominal voltage requirements.Operation of the system outside the required range is not recommended due to degradation of the system performance andshortened component life expectancy. An example of electrical requirements for the Fortus 900mc/F900 and Fortus 450mcare listed in Table 3-5 below.
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Table 3-5. Example (Fortus 900mc/F900/450mc) Electrical Requirements
Fortus 900mc/F900Power 13.5 KVAVoltage 230VAC nominal 3-phase service with 5 percentFrequency 50 to 60 HzFull Load Current on All Three Phases 34 AmpsBreaker 40 AmpsMax Inrush 570 Amps for 2msWiring Three wire plus ground
Fortus 450mcVoltage 208VAC nominal 3-phaseFrequency 50 to 60 HzWiring Three wire plus ground
NOTE
230 VAC as measured phase-to-phase at the input connection to the printer. Facilities wiring should be designed tomeet the + or -5 percent voltage tolerance requirement at the printer under all operating currents ranging up to 34Amps.
3.1.4.3 Compressed Air Requirements. Polymer AM machines may/may not require shop air. The Fortus 900mc/F900both have an onboard pressure regulator. The system has onboard particle filtration, water, and oil separation. Input airshould be non-lubricated and non-condensing, (see Table 3-6). The Fortus 450mc has an on-board compressor and does notrequire shop air.
Table 3-6. Example (Fortus 900mc/F900) Compressed Air Requirements
Fortus 900mc/F900/450mc Compressed Air Requirements ValueInput 90-120 psiFlow 14 CFM minimumTemperature 95°F maximum
3.1.5 Machine Qualification.
3.1.5.1 Approved Printers. Only FDM printers approved by AFLCMC/RO may be qualified to print airworthy parts andequipment in accordance with Airworthiness Bulletin (AWB) 1015.
3.1.5.2 List of Qualified Machines. A qualified machine list will be maintained and published by AFLCMC/RO bylocation and serial number.
3.1.5.3 Machine Qualification. All FDM machines will require qualification annually, or following any modifications orrepairs that occur to major subsystem component that can significantly impact build quality. A list of these subsystems is inTable 3-7. See TO 34A-3-1 for qualification procedures.
Table 3-7. Major Sub-system Equipment Affecting Build Quality
Sub-System ComponentsHead-Critical Sub-Components Drive motors, heater blocks, drive wheels, on-board electronics.Platen The platen is the surface on which parts are built. Scratches in the platen can re-
sult in lack of vacuum.X, Y, or Z Motor-Mechanism These drive belt or screw controlling gantry motion or platen location. Observed
faults, shifts, and motion failures will result in replacing these motors and requir-ing requalification.
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Table 3-7. Major Sub-system Equipment Affecting Build Quality - Continued
Sub-System ComponentsGantry Rail-Structures This holds the head, bridge and controls and maintains rigidity during x and y
motions.Master On-Board-Computer This is the machine control system.Universal Power Supply Critical component of the electrical system to regulate incoming power to all elec-
tronics on an FDM System.
3.1.5.4 Qualification Procedures. The qualification processes will be established and will vary by machine manufac-turer. For machine-specific qualification steps and build preparation, see TO 34A-3-1, to include sub-work packages for eachmachine and material license combinations supporting the production of approved aircraft parts. Qualification Build files willbe controlled and distributed by the AF RSO. If qualification specimens cannot be tested in an ASTM certified laboratorylocally, contact AF RSO for assistance.
3.1.5.5 Requalification of the HP/AICS Package after Material Change. To requalify the HP/AICS some processcontrols in TO 34A-3-1 must be completed and documented on the qualification build checklist.
3.1.6 Model Material Control. Model material will be procured in accordance with technical requirements.
3.1.7 Post-Process Overview. Stratasys offers a diverse variety of model materials which are used in conjunction withtwo basic types of FDM support materials. Soluble Release (SR) Support material can be dissolved in a solution ofheated-water and cleaning agent, while Breakaway Support Structures (BASS) must be manually removed. The CertifiedUltem 9085 modeling material uses only BASS support.
3.1.8 Quality Process. Per TO 34A-3-1 it must be ensured that the polymer AM machine is adequately controlled toconsistently produce quality parts.
3.1.8.1 Non-Conforming. All non-conforming conditions shall be rejected. Contact AFLCMC/RO for assistance.
3.1.8.2 Visual Inspection. A visual inspection procedure shall be conducted on each part following build completion andcompared to the descriptions of acceptable and unacceptable anomalies outlined in TO 34A-3-1.
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GLOSSARY
ADDITIVE MANUFACTURING (AM) — The manufacturing process through which three-dimensional objects are cre-ated by building up layers of material.
COMPUTER AIDED DESIGN (CAD) — Use of computer systems to aid in the creation, modification, analysis, oroptimization of a design.
COMPUTER NUMERICAL CONTROL (CNC) — A method for automating control of machine tools through the use ofsoftware embedded in a CNC microcomputer attached to the machine/tool.
CONTOUR — A printed bead of filament which traces the perimeter of each print layer during Fused Disposition Model-ing.
DIRECT METAL LASER MELTING (DMLM) — Process that uses lasers to melt ultra-thin layers of metal powder tobuild a three-dimensional object.
FORMATIVE MANUFACTURING — The manufacturing process that shapes raw material (liquid or solid) into a finalpart through the use of tooling and molds. These processes include casting, molding, and forging among others.
FUSED DISPOSITION MODELING (FDM) — Additive manufacturing process in which thermoplastic filament is heatedto near-melting and extruded through a heated extrusion nozzle to produce AM parts.
SAFETY DATA SHEET (SDS) — Instructions for proper handling, storage, and disposal; and current SDS directives.
PERSONAL PROTECTIVE EQUIPMENT (PPE) — Approved protective clothing/equipment (gloves, apron, eye protec-tion, etc.) for the chemicals, materials, and tools being used.
RASTERS — A printed bead of filament used during FDM which fills the interior of the cross section and can vary in anglefrom one layer to the next for better adhesion and strength.
STANDARD CUBIC FEET PER MINUTE (SCFM) — The gas volume per minute at atmospheric pressure and 75°F.Commonly used when planning facilities gas flow requirements.
SUBTRACTIVE MANUFACTURING — The manufacturing process that produce a part by removing material from stockshapes and sizes. These processes include machining, grinding, lathe-turning, and shearing among others.
NUMERICAL CONTROL (NC) — The automated control of machining tools (drills, boring tools, lathes).
WIRE ELECTRICAL DISCHARGE MACHINE (WIRE EDM) — Device used to precisely and accurately separate AMparts from a build plate in a parts continuous straight cut parallel to the build plane surface.
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