Welding Process Improvements for Virginia Class Submarines
By Nancy Porter on Thursday, October 20th, 2011
Steve Massey and I are knee deep in a Navy ManTech project for General Dynamics Electric Boat (GDEB). If you want to hear more about this project, I’m presenting project results at AWS FABTECH on November 15th at 9:00 a.m. in the Shipbuilding Session #4. Following is a high level summary of the project.
Continuously reducing manufacturing costs of the Virginia Class Submarine is a high priority for GDEB and the U.S. Navy. The objective of this project is to reduce costs by decreasing welding labor by 20% via improvements in technology, processes, and procedures. Specifically, one semi-automatic gas metal arc welding (GMAW) application and its associated air carbon arc backgouging operation are being replaced with a mechanized welding/backgouging solution. The project team developed a unique approach to selecting a mechanized solution that involved the trades in the decision making process. The resulting solution was embraced by all levels of the organization.
Baseline welding and backgouging processes were documented. Functional requirements for the new welding system were developed. Candidate suppliers of mechanized solutions were identified; the three most promising systems were demonstrated and tested at General Dynamics Electric Boat (GDEB) for 30 days. The preferred system was then selected based on hands on evaluations and acquisition cost analysis. With the preferred system, EWI optimized the welding process to maximize productivity within GDEB’s existing Navy qualified welding procedures. GDEB then conducted shipyard evaluations that resulted in productivity gains that provided data necessary for capital purchase request justification.
The shipyard evaluations were conducted by fabricating the target application with both welding approaches: semi-automatic GMAW (the baseline process) and mechanized GMAW using the preferred solution. Given the size of the target application, the shipyard evaluations were conducted over several months. On average, the welder using the mechanized system was able to complete 4 weld joints and set up a fifth during a nine hour shift. The semi-automatic welder was able to complete less than 1.5 weld joints in a nine hour shift.
In addition to the productivity gains, this project team developed a unique mechanized solution identification methodology that eased the cultural paradigm shift from manual to mechanized welding. Instead of the solution being a top down implementation, the trades evaluated the candidate systems and had a voice in the system selection process. This approach is also applicable to other industries where shifting from semi-automatic welding to mechanized or automated systems is desired.
The equipment identification and selection process was a novel approach that can be used by any industry interested in implementing mechanized welding solutions to increase productivity. Involving the trades in the decision making process was key to identifying a solution embraced by all levels of the organization.
If you’re at AWS FABTECH on November 15th, come to the Shipbuilding Session #4 at 9:00 a.m. and get the juicy details.