1705 best practices of wire harness manufacturing
TRANSCRIPT
Best Practices of Wire Harness Manufacturing
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Agenda
➢Topic: Building wire and cable harnesses
➢ Basic considerations of the best industry practices
➢Discussion on the total cost of ownership of wire harness manufacturing
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“Best Practice”Best Practice – “a procedure that has been shown by research and experience to produce optimal results and that is established or proposed as a standard suitable for widespread adoption ”
• Not a fixed rule
• Not a standard
• Refer to manufacturer’s recommendations
• Refer to standards or procedures required by the organization
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IPC/WHMA-A-620Requirements and Acceptance for Cable and Wire Harness Assemblies
• Developed in cooperation with Wire Harness Manufacturer’s Association® and IPC
• Most recent version: IPC/WHMA-A-620C
• Materials, methods, tests, and acceptability criteria
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Other Standards & Certifications• UL
• Establish traceability
• In accordance with a harness diagram furnished by the end-use manufacturer
• Generally designed for a specific application
• Government
• Private organizations
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PreparationCutting and Stripping
• Automated machines – programable• Wire characteristics• Length• Memory
• Manual• Small lots, prototypes
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PreparationCutting and Stripping• Cut length
• Tolerance• Accuracy• Consistency
• Strip length• Terminal manufacturer
recommendation• Tolerance • Accuracy• Consistency
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PreparationCutting and Stripping
• Proper stripping methods and tools• Eliminate, minimize strand damage
• Some strand damage allowed• TARGET
• Perpendicular to access• All the same length• No damage
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PreparationWire Insulation Damage
• Acceptable• Slight uniform impression from
stripper for gripping• Fraying should be agreed upon
• TARGET• Trimmed neatly• No pinching, pulling, fraying,
discoloration, charring or burning
• Defect• Cuts, breaks, cracks, splits• Reduce insulation thickness• Uneven or ragged pieces of
insulation
Image credit: Carson Dunlop; Zeus Inc.
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Crimp Terminations• Most common method of
harness terminations
• Improper terminations:• Opens
• Shorts
• False Positive
• Equipment failure
• Many options
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Crimp TerminationsCrimp tools
• Manual• Small number of crimps• Simple
• Powered• Lugs• Electric, hydraulic high pressure
• Small production lots
• Larger wire, high pressure
• Terminals• Large production lots
• Highly automated
• Precision, repeatability
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Crimp TerminationsBasic Requirements
• Correct wire
• Correct terminal
• Proper wire preparation
• Correct tooling
• Proper equipment calibration and set up
• Proper training
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Crimp TerminationsPowered Crimp Tools
• Highly automated
• High quality, repeatability
• Adjustable speed
• Terminals on reels
• Easy to use, change-over
• Multiple terminals and variations
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Crimp TerminationsManual Crimp Tools
• Matched tool and die• Proper crimp for chosen
terminal and wire
• Ratcheting feature• Will not release until
proper crimp is executed• Uniform crimp
terminations
• Adjustable and calibrated
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Crimp TerminationsProper Crimping
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Crimp TerminationsProper Crimping
• Conductor crimp• Mechanical compression of the metal terminal around the wire conductor
• Continuous conductive electrical path
• Conductor brush• Wire strands past the conductor crimp
• Ensures mechanical compression over the full length of the crimp (strip length)
• NOT extend into contact area
• Insulation crimp• Strain relief
• Hold insulation as firmly as possible without cutting into conductor strands
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Crimp TerminationsProper Crimping
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Crimp TerminationsCrimp Defects
• Causes• Incorrect tool, set up, or calibration
• Incorrect wire preparation
• Strip length• Too short, not fully inserted – weak mechanical and electrical performance
• Inserted too far – weak mechanical and electrical performance
• Loose wire strands• Reduced electrical performance
• Potential short circuit or arc to other contact
• Reduced mechanical performance
• Crimp height• Too high – Poor compression, voids – weak mechanical and electrical performance
• Too low – Cut, fracture conductor wire – weak mechanical and electrical performance
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Crimp TerminationsCrimp Defects
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Crimp TerminationsProcess Verification
• Pull test• Correct crimp tool for terminal, wire
• Calibration of crimp tool
• Verify crimp – adjust process, tooling
• Preproduction test• Destructive
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Crimp TerminationsProcess Verification
• Crimp height• Correct crimp tool for terminal, wire
• Calibration of crimp tool
• Verify crimp – adjust process, tooling
• Preproduction AND process control• Non-destructive
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Precision cut
Precision strip
Manufacturer’s recommended crimp
Crimp height verification
Continuity-tested, assembled harness
Best PracticesIdeal Process for Consistency
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Other Processes •Twisting of wire
•Soldered terminations
•Ultrasonic welding
•Splices
•Over-molding
•Potting
•Connectorization
•Assembly and wire measurement
•Marking and labeling
•Securing
•Shielding
•Protective coverings
•Testing
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Total Cost of Ownership• How to respond to market demand quickly while enabling
business objectives?
• What is the best use of your limited resources?
• Wouldn’t you prefer to concentrate on your core business?
• Where else can your reduce or eliminate overhead?
• Is there an opportunity for improvement in your supply chain or production processes?
• How can you manage overall corporate risk?
• How do you remove the bottleneck in your supply chain?
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Total Cost of OwnershipPrimary cost factors
•Materials
•Labor
•Delivery
0%
20%
40%
60%
80%
100%
Facility Overhead
Labor
Material
Other
AX
IS T
ITLE
AXIS TITLE
Automobile Wire Harness Cost Components
Graph credit: Ask, Laseter.
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Total Cost of OwnershipMaterials
• Cost of materials• Best price?• Not only driver
• Inventory• Multiple vs. individual?• Space constraints?• Excessive?• Slow/Non-moving?
• Equipment and tooling• Cost?• Variations?
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Total Cost of OwnershipLabor
• Processing• Consistency?
• Optimal utilization?
• Inventory• Simplify ordering?
• Management?
• Receiving?
• Equipment• Maintenance?
• Calibration?
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Total Cost of OwnershipDelivery
• Quality
• Cost• International?
• Domestic• Low run, prototyping?• Reduced lead time?• Simplify?
• Customized• Kitting?• Fast-track projects?
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Questions?Sunflower Electrical Systems
8302 Hedge Lane Terrace, Suite H, Shawnee, KS 66227
+1-913-894-1442 [email protected]
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Sources• Ask, Julie A. and Laseter, T. (1998, January). Cost Modeling: A Foundation Purchasing Skill.
Strategy + Business. Retrieved from https://www.strategy-business.com/article/9625?gko=ba075.
• best practice. (2017). In Merriam-Webster.com. Retrieved May 16, 2017, from https://www.merriam-webster.com/dictionary/best%20practice.
• General Motors Upfitter Integration. (2017). Electrical Best Practices. Retrieved from https://www.gmupfitter.com/publicat/electrical.pdf.
• IPC. The Seven Sins of Wire Harness Assembly (DVD-60C Script). Retrieved from http://www.ipctraining.org/dvd/60c/script.pdf.
• IPC and Wire Harness Manufacturer’s Association. (2012). Requirements and Acceptance for Cable and Wire Harness Assemblies (IPC/WHMA-A-620B).
• Molex, LLC. (2017). Hand Crimp Tool Specification Sheet, Order No. 63811-6000, Doc. No. ATS-638116000, Revision: E. Retrieved from http://www.molex.com/pdm_docs/ats/ATS-638116000.pdf.
• National Aeronautics and Space Administration. (2017). Crimping, Interconnecting Cables, Harnesses, And Wiring – National Technical Standard. Retrieved from https://prod.nais.nasa.gov/eps/eps_data/145968-OTHER-002-006.pdf.
• Sarkar, S. (2017, May). Successful revolutions need suppliers. ISE Magazine, 34-39.