microelectronics clean room electrical and computer engineering orbital tube welder by clayton...
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Microelectronics Clean RoomMicroelectronics Clean RoomElectrical and Computer Electrical and Computer EngineeringEngineeringOrbital Tube Welder
by Clayton Gatewood
OverviewOverviewGeneral InformationSafetySet-upTube Preparation: facing,
cleaningOperationWeld SchedulesWeld Evaluation
by Clayton Gatewood
Orbital Tube WeldingOrbital Tube WeldingGas Tungsten Arc
Welding (GTAW) process
Fusion WeldingModel 8 Weld
HeadModel 207A Power
SupplyArgon Gas
CylinderFacing ToolARC Machines, Inc.
by Clayton Gatewood
Gas Tungsten Arc Welding (GTAW) Gas Tungsten Arc Welding (GTAW) ProcessProcess
Used to weld tubing that remains in-place while the tungsten electrode rotates around the target joint.
Material edges are heated by an arc and are fused together without a filler.
by Clayton Gatewood
SafetySafety Electricity Hazard: Shock, RF
Starting, Pacemaker, Electric Storage Devices
Fire Hazard: Clothing, Sealed Containers, Welded Material Hot to Touch
Harmful UV Radiation (eyes and skin)
Toxic Fumes from Welding Stainless Steel, Hexavalent Chromium (lung cancer)
Air Displacement by Argon Gas Factory Training Essential Keep Hands and Fingers Clear Compressed Gas Cylinders Cleaning Chemicals
by Clayton Gatewood
Set-UpSet-UpEnsure Power is
OffConnections:
Weld Head, Argon Gas,main power cord
Apply Argon (¼ turn) @ 20 psi
by Clayton Gatewood
Tube PreparationTube PreparationFacing
by Clayton Gatewood
Welding CleanlinessWelding CleanlinessMaterials to be welded must be
free of grease, oil, rust, dirt, paint and other contaminants.
Dirty materials can result in porosity, discoloration, slag deposits, and generally poor quality welds.
by Clayton Gatewood
OperationOperation Align target joint with
tungsten electrode Connect Argon Purge
Line and set for 5 psi (for ¼” OD tubing)
Select Weld Schedule Ensure Power Supply is
“Ready to Weld” Press “Seq Start” Prepurge, Weld,
Downslope,
Postpurge
by Clayton Gatewood
Weld Schedule Weld Schedule DevelopmentDevelopment
An orbital tube weld may be done in 4 or more levels.
It must include enough time for tie-in before the downslope.
by Clayton Gatewood
Weld SchedulesWeld SchedulesPre / Post Purge
TimeUp / DownslopeRotation DirectionRotation DelayPulse ModeRotation ModeRPM (Rotor Travel
Speed)Level TimesLevel AmpsBackground AmpsPulse Times
by Clayton Gatewood
Power Supply SequencePower Supply Sequence
by Clayton Gatewood
Sample Weld SchedulesSample Weld Schedules
by Clayton Gatewood
Weld EvaluationWeld Evaluation60 to 80% overlap
on outer diameterPoor rotation delayBorescope to
inspect inner diameter
Full penetrationNo cracks,
undercut,crevices, pits, or embedded or protruding material
by Clayton Gatewood
Weld ProfilesWeld Profiles
by Clayton Gatewood
Weld DefectsWeld DefectsWeld Problem Probable cause(s)
Lack ofpenetration to I.D.
1) Insufficient amperage2) Tungsten offset3) Change of heat number4) Sulfur mismatch5) Variable wall thickness
OD Concavity 1) Too much amperage2) Gravity (heavy wall)3) Very low sulfur
ID Concavity 1) Excessive ID purge pressure
Discoloration of ID(oxidation)
1) Excessive oxygen and/or moisture in IDpurge gas2) Moisture and/or oxygen in or on tubing3) Chemical residue from EP4) Leak in purging set up5) Pinched gas hose
Misalignment 1) Dimensional tolerances - out of round2) Wall thickness mismatch3) Worn out TCIs4) Poor workmanship
Porosity 1) Moisture in purge gas2) Moisture or dirt on weld components
Excessive slagging 1) impurities in base material especiallyoxides of aluminum, calcium, silicon
by Clayton Gatewood
Argon Purge and OxygenArgon Purge and Oxygen
Left to Right = effect of increasing levels of oxygen in the argon purge
by Clayton Gatewood
Possibilities …Possibilities …
by Clayton Gatewood
Works CitedWorks Cited"MODEL 207 Operator Training Guidelines."
Arc Machines, Inc.CD-ROM.Pacoima, CA: Arc Machines, Inc., 2007.
Model 207 Microprocessor-Controlled Power Supply.1 Nov. 1996. Arc Machines, Inc.. 16 Oct. 2007.<http://www.arcmachines.com/prodMed/m207ps/m207ps.html>.
by Clayton Gatewood