Truckin with Aluminum Aluminum Welding from A to Z

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Gwen Potter
6 years ago
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1 Truckin with Aluminum Aluminum Welding from A to Z Chris Anderson Zane Michael

Aluminum Welding vs. Steel Process differences Aluminum Welding Process Features Starting and Stopping Dual Pulse for Cosmetics Wire Feeding: Push or Pull?

2 Aluminum Welding vs. Steel Process differences Aluminum Welding Process Features Starting and Stopping Dual Pulse for Cosmetics Wire Feeding: Push or Pull? Anderson case for push Zane case for pull Aluminum Trailer Production Equipment considerations for larger structures Robot Reach vs. More Robots Wire delivery for mobile robots Sensor selection Outline

3 High Thermal Conductivity Makes it difficult to get puddle to fuse at start(cold lap) Heat travels along joint and preheats weld Weld bead can widen if nothing else is changed Low Melting Point Once mat l is heated it melts quickly AL puddle is very fluid and can run quickly (esp. 4043) Little color change between solid/liquid aluminum Without red to orange color change in steel, it can be difficult to judge how much heat is in AL part. Fast Solidification Rate Can often travel faster than steel Rapid freezing of puddle leaves depression in crater Aluminum vs. Steel - Basics

4 Arc Starting Need to burn in at start Hot Starting Travel short distance with Hot settings Steel uses dwell at start to build puddle, this will promote cold lap with AL Lift Starting retracting wire with pull guns Dual Pulse Alternating Heat Settings at 2-5 Hz Can produce GTAW like cosmetics with GMAW Can balance Heat Input in long welds producing uniform bead width May be power source or robot based; best when it includes a change in wire feed speed to get high/low current settings Arc Ending Need more time to fill puddle Will be at least 1 second and often more for larger welds Two stage crater is advantageous for fill 1 and fill 2 Back stepping crater can help move depression from end of weld Controlled burnback to minimize the ball (key to good start) Travel Angle deg push angle promotes flat bead, reduces smut (steel=5-10 deg) Faster freeze allows faster travel speeds Aluminum Process Considerations

5 High Thermal Conductivity Makes it difficult to get puddle to fuse at start(cold lap) Heat travels to thicker member and causes puddle to favor one side Puddle favors upper leg Arc Starting Lack of fusion at toe of weld

6 Arc Starting Need to burn in at start Hot Starting Travel short distance with Hot settings Steel uses dwell at start to build puddle, this will promote cold lap with AL Slope current can gradually reduce heat (if supported) Current 5-15 mm Arc Starting Motion

7 Parameters can be balanced to minimize size of the start Lift Starting retracting wire with pull guns Used to create more stable arc start Arc Starting

8 Dual Pulse Alternating Heat Settings at 2-5 Hz Can produce GTAW like cosmetics with GMAW Can balance Heat Input in long welds producing uniform bead width Dual Pulse TIG like cosmetics

9 Dual Pulse Video

10 F = OFF F = 5 Hz F = 2 Hz Frequency controls spacing

11 Ref. Power source or Robot based

12 Why did trucking customer reject welds? Sealed welds on tanks

Arc Ending Need more time to fill puddle Will be at least 1 second and often more for larger welds Two stage crater is advantageous for fill 1 and fill

13 Arc Ending Need more time to fill puddle Will be at least 1 second and often more for larger welds Two stage crater is advantageous for fill 1 and fill 2 Back stepping crater can help move depression from end of weld Controlled burnback to minimize the ball (key to good start) Arc Ending Fill the puddle

14 Single Step Crater Fill and slight depression Two Step Crater Fill1 and fill 2 Current Arc End Crater Fill < 100 Amps

Reduces stress riser of crater Current < weld current

15 Arc End Back Step Crater Use heat of weld to fuse end (dwell) Reverse direction a few mm and fill depression Reduces stress riser of crater Current < weld current (Fill 1) < 100 Amps Dwell at End 5-15 mm Arc End Motion

16 Travel Angle deg push angle promotes flat bead, reduces smut (steel=5-10 deg) Faster freeze allows faster travel speeds Water Cooled Torch! Reduces swelling of wire in tip Aluminum is hot spray arc even at low amps Watch Gas Coverage Straight bore nozzle; recessed tip Welding Considerations (1) Fe Al

Clean Material Oil and excessive oxide will result in soot and porosity Clean with Stainless Steel brushes Use SS tooling details with Al, does not melt together U shaped

17 Clean Material Oil and excessive oxide will result in soot and porosity Clean with Stainless Steel brushes Use SS tooling details with Al, does not melt together U shaped drive rolls for Al Teflon or plastic consumables Avoid sharp edges and breaks in feed Brass jump liner at tip helps w/heat Reduce breaks in feed system Welding Considerations (2)

18 Touch Sensing Possible with Aluminum, but softer wire may limit search speeds due to bending Don t use wire brake! Pull gun can keep wire in constant position Through Arc Tracking Not possible with current signal only Some manufacturers working on hybrid signals Laser Sensors Generally, most reliable sensor on Aluminum Need to evaluate surface condition and reflectivity Welding Considerations - Sensors

19 Push with Aluminum Chris Anderson, Excellence in Robotic and Automated Arc Welding Award Winner Pull Gun for Aluminum Zane Michael, Salesman Wire Feeding Push vs. Pull

Largest robotic aluminum welding installation at a single site in North America More than 120 welding robots 35,000 parts/week with 90+ welds/part 3,000,000 arc starts per week with push-only feed

20 Largest robotic aluminum welding installation at a single site in North America More than 120 welding robots 35,000 parts/week with 90+ welds/part 3,000,000 arc starts per week with push-only feed system More than eight years of production Push Only Feed w/wc torch Feeder on upper arm Limit feed distance Motorized bulk dereelers Power Source with positive starting 2,000 arc start test in 1990 s GMT 800 Radiator Support Push Only Experience

21 Introduction of Thru-Arm robots has shortened feed distance and reduced torch cable bends and flexing Push Feeding for aluminum

22 Push Only Video

Push-Pull Feed systems are often promoted by power source manufacturer Wire feed speed synchronized by power source control Improved arc starting (lift start) with wfs control at the

23 Push-Pull Feed systems are often promoted by power source manufacturer Wire feed speed synchronized by power source control Improved arc starting (lift start) with wfs control at the torch Insurance for feeding soft alloys (3/ ) Water-Cooled for Aluminum May be Pull only torch on robot with remote assist feeder Motorized bulk assist feeders Pull Torch for Al Feeding

24 Push Pull Video

25 Push-Pull can provide specialty capability for thin mat l Push-Pull req d for thin mat l

26 Fronius Robacta Lincoln SA Aluminum Best of Both Worlds Push-Pull for Thru-Arm Robots

27 Larger size parts to weld Long reach robots; push pull consideration Multiple Robots; cover longer rail assemblies Robots on tracks; wire drum on carriage Sensors; touch sensing or laser sensors.. NOT through arc Examples of some layouts for Trailer Mfg. Key Factors for Truck Welding

28 Long Reach Robots for Trailers

29 Combine Sub-Ass y, Final Ass y

30 Bulk Trailer System

31 Multiple Robots on Long Ass ys

32 Flat Bed Trailer snip-it

33 Pull Torch for Feed Assist Feeder for Bulk Bulk Wire Feed for Al

34 Trailer System 1 Trailer System 2 Robot on Track = Tow Wire Drum

35 Laser Sensors for Aluminum

36 Tool Boxes Correguted Panels Point Laser Seamfinder Appl

37 Lap Joint on Boxes - OK

38 Al Sheet Panel Too Reflective

Multi-Purpose Mechanized Welding Carriage

WEL-HANDY MULTI Multi-Purpose Mechanized Welding Carriage Feature & Benefits Two Models Available Standard and Programmable Stitch/Tack Multi Weld Process Standard and Programmable Stitch/Tack Multiple