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Automated Weld Facing Tools Modified to Perform Back Gouging. Bruce D. Horn and Timothy G. Freidhoff NMC/ CTC. American Welding Society New Welding Technologies Conference June 15-16 2010, Ft. Lauderdale, FL. Outline. Integrated Project Team Problem and Solution
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Automated Weld Facing Tools Modified to Perform Back Gouging Bruce D. Horn and Timothy G. Freidhoff NMC/CTC American Welding Society New Welding Technologies Conference June 15-16 2010, Ft. Lauderdale, FL
Outline • Integrated Project Team • Problem and Solution • Implementation Results and Benefits • Conclusions and Movie • Questions Project Outcome, Commercially Available Tool by PushCorp, Inc. Manual Hand Grinding (Photo courtesy of NGSB-GC) NMC Weld Shaver Concept
Integrated Project Team • Bath Iron Works (BIW): Technical contributor and end user • General Dynamics Electric Boat (GDEB): Technical contributor • Naval Surface Warfare Center - Carderock Division (NSWCCD): Navy technical advisor • Navy Metalworking Center (NMC): Project management and technical lead • Northrop Grumman Shipbuilding - Gulf Coast (NGSB-GC):Technical contributor and end user • Office of Naval Research (ONR): Project funding and support • PMS 500 DDG 1000 Program Office: Stakeholder • PushCorp, Inc.: Industry partner
Weld Reinforcement Problem • Butt welding of hull and deck panels produces weld protrusion reinforcement that exceeds DDG 1000 fairness limits • Hand grinding is currently the only solution to removing weld • Hand grinding is detrimental to the workforce, resulting in frequent injuries and costly medical expenses Weld reinforcement cross section example (i.e., not DDG 1000) Current weld removal process (Photo courtesy of BIW)
Problem • Hand grinding is slow, further increasing production costs. • There are ≈ 21,000ft of weld reinforcement to remove per hull Flat orientation ≈ 45% Vertical and horizontal orientation ≈ 25% each Overhead orientation ≈ 5% (Photos courtesy of BIW)
Solution • Perform assessment at BIW, NGSB-GC and GDEB to understand problems • Develop prototype tool requirements to address shipyard’s design requirements • Weld width up to 2.25" and height up to 0.3125" • 20 ft/hr weld removal rate versus 3 ft/hr (1" wide weld x 0.3125" high) • Remove 80% of weld height without damaging adjacent panel • Individual component weight approximately 75 lbs or less • Straight and contoured panels (40“ minimum radius, concave and convex) • Flat, vertical, horizontal and overhead orientations • Tool compliance to plate surface for maximum weld removal.
Solution • Develop concept utilizing a commercially available weld shaver Slotting cutter Weld shaver Force control Carriage Safety strap Magnets Track Weld seam Vertical orientation Flat orientation Horizontal orientation
Solution • Validate the track weld shaver concept for shipyard application Shaver and track lab test set-up Lab test results Weld shaver in production
Solution WSF Alpha Prototype Tool Force Control 100 lbs Vertical Axis Slide 2” Shaver 3.7 HP AC Servo Horizontal Slide 2” Rare Earth Magnet 220 lbs 2 Axis Rotation 2 Axis Shaver Rotation Track Quick Connect Cam 7075 Aluminum Flex Track 40” R Min
Solution • Contract PushCorp, Inc. to develop track weld shaver concept and commercialize technology TWS91 commercially available tool from PushCorp, Inc. (Photo courtesy of PushCorp, Inc.)
BIW Implementation Results 60 ft of hull butt weld removed at approximately 60 ft/hr Finished hull weld (No hand grinding of weld required) 3 in. wide x 12 ft long weld (75% labor reduction) Photos courtesy of BIW
BIW Implementation Results 15 ft of hull butt weld removed at approximately 125 ft/hr Overhead orientation Ship lifting lug weld removal (Photos courtesy of BIW)
NGSB-GC Implementation Results Finished hull weld 60 ft of hull weld removed at approximately 240 ft/hr 30 ft of weld removed at approximately 60 ft/hr Photos courtesy NGSB-GC
Track Weld Shaver Benefits • For panel and lifting lug weld removal, the estimated cost reduction for DDG 1000 is $924,000/hull • Safer for the workforce • Removes up to 90% of the weld height at a rate up to 240 ft/hr • Automatic removal of weld between 0.375 and 3 inches wide • Better for the environment • Also being used to remove weld from ship lifting lugs • Applicable for any applications requiring weld removal • The track weld shaver system can be used to perform multiple operations (shaving, back gouging, sanding, welding and burning) • Back gouging and sanding operations identified as additional capabilities and having potential for implementation
Track Weld Shaver Benefits • Track weld shaver technology has potential back gouging use • Back gouging total estimated cost reduction for DDG 1000, LHA-6, LPD-17 and NSC is $2,626,000 (Photos courtesy of NGSB-GC) 55° “V” 84 ft/hr NGSB-GC 12mm “U” 57 ft/hr BIW Manual carbon arc back gouging Mechanical back gouging HSLA-100 with MIL-120S-1 (Sample courtesy of BIW) Mechanical back gouge cross section HSLA-80 plate
Track Weld Shaver Benefits (Photo courtesy of NGSB-GC) (Photos courtesy of BIW) Manual sanding Belt sander added to track weld shaver to blend shaved weld Finished 3 inch wide weld using belt sander
Conclusions • Track weld shaver technology is safer + faster than current hand grinding process, which = cost reduction • Weld shaving estimated cost savings = $2.77M • Back gouging estimated cost savings = $2.63M • Track weld shaver system is currently implemented at the shipyards to remove weld reinforcement • Track weld shaver technology has the potential to be used for back gouging, sanding, welding, and burning • Back gouging needs further refinement and being considered for implementation by shipyards • Track weld shaver system is now commercially available from PushCorp, Inc.
