Automated Weld Facing Tools Modified to Perform Back Gouging

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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
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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
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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

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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)
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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)
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Solution

• Perform assessment at BIW, NGSB-GC and GDEB to
  understand problems
• Develop prototype tool requirements to address
  shipyards 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.

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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
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Solution

• Validate the track weld shaver concept for
  shipyard application

Shaver and track lab test set-up
Lab test results
Weld shaver in production
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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
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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.)
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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
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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)
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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
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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

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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
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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
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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.

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Contact Information
Name Organization Title Phone Email
John Foster BIW DDG1000 Hull Representative 207-442-3464 john.foster_at_biw.com
Steve Davis BIW Lean Process Engineer 207-442-1728 stephen.davis_at_biw.com
Robert Kirkwood NGSB-GC DDG1000 Hull Representative 228-935-1546 robert.kirkwood_at_ngc.com
Kevin Roossinck NGSB-GC Sr. Welding Engineer 228-935-5761 kevin.roossinck_at_ngc.com
Tim Freidhoff NMC/CTC Project Engineer 814-269-2876 freidhof_at_ctc.com
Bruce Horn NMC/CTC Project Manager 814-269-2351 hornb_at_ctc.com
Gene Franke NSWCCD Technical Advisor 301-227-5571 gene.franke_at_navy.mil
Rick Zebrowski PMS 500, Program Office Stakeholder 301-227-4410 richard.zebrowski_at_navy.mil
Edwin Erlbacher PushCorp, Inc. President 972-840-0208 erl_at_pushcorp.com
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Technology Transfer Movie