Automated Tack Welder

Note: Details on this post are generalized to keep repair details confidential. All information published on this page are published methods. Any geometry and images shown are fictitious and only shown to demonstrate the thinking process.

August 2019 – October 2019

Project Scope

Repair

One of the main repair scopes that we do at Pratt & Whitney Dallas Airfoil Repair Operations is to replace burnt sheet metal that controls airflow through turbine vanes.  In order to replace, the old sheet metal is removed through milling and then tack welded on.

Task

Our team had acquired an automated tack welding machine, however, the robotic programming was not fully fleshed out due to the machining vendor’s contract expiring so I stepped in to finish the programming.

Roles and Responsibilities

1. Learn FANUC robot programming through the Teach Pendant.
2. Complete the tack welding sequence for the full replacement of sheet metal and honeycomb.
3. Work with the machining vendors as necessary to troubleshoot issues I ran into.

Challenges

1. Honing weld parameters to get a good tack weld – too much heat  will burn a hole through sheet metal, too little heat and the sheet metal will not adhere.
   
2. Alignment tolerance of sheet metal to part.
   
3. Understanding how the previous operation (milling off the damaged plate) affects tack welding operation, and how the success of the two operations will yield success into the final operation, laser welding.
   
4. Reduce turnaround time per program.

Results

1. Optimized automated tack welding programs for 6 different features across 4 different product lines.
   • Repeatable results
   • Reduced variability
2. Provided feedback for the milling process and improved part surface finish for tack welding preparation.
3. Reduced cycle time by 50%.
4. Trained engineers, technicians, and maintenance staff by providing:
   • Standard Operating Instructions for general use.
   • Detailed Operating Instructions for specific products.
5. Freed operator time reduced ergonomic issues caused by manual tack welding.

Room for Improvement

1. Tools will need to be created in order to assist with holding down plates and prevent shifting during tack welding.
2. Some initial manual welding will be necessary, need to create space for manual work and space for automated work.
3. Obtain RoboGuide software to allow for remote programming rather than manual programming through teach pendant.
4. Process is automated but not smart – a vision system to detect where the plate is and adapting the tack weld sequence would complete the automated repair.

Skills Learned

• FANUC Teach Pendant Programming
• Tools used for milling
• Tack welding
• Experimentation and exploration
• Collaborating with machining vendors and upper management