“I can’t use a paint robot for my process. I don’t have part models, I don’t have programmers, and no robot can reach all my large parts.”
Robins Air Force Base (RAFB) was looking for a flexible, turnkey robotic system to apply performance coatings to a myriad of parts for several different aircraft platforms.
RAFB was in a situation many aerospace companies and depots find themselves stuck in when it comes to considering robotic automation. They did not have 3D part models for their massive quantity of parts, which means the robotic paint paths have to be hand taught by a skilled robotic path programmer familiar with painting (otherwise known as a unicorn). Having over 100 parts means the programmer would need to be on staff at all times ($$$) and stop processing production parts to program and test spray each new part (days of production loss).
The coating robot had to fit in an existing spray booth and be able to spray multiple parts in the same booth at the same time from programs including the F-15, C-17, C-130, and C-5. The tooling included simple carts that don’t present the parts in the same position or orientation, and there are multiple variations of carts holding the same parts. Additionally, the parts range from massive pieces that fill the 30’ x 50’ booth down to simple table top components. Other challenges included:
- No Models
- No Repeatable Tooling
- No Robotic Programmers
- Over 100 High Variation Parts
- Aerospace Coatings & Performance Requirements
- Existing Spray Booth Restricting Robotic System Design
- Customer Wants to Load Multiple Style Parts in Random Locations
- Hexavalent Chrome Exposure Issues
To reach as much of the booth as possible, Aerobotix used FANUC RoboGuide and SolidWorks to custom design an X, Y Gantry system with an underslung CID1 FANUC P-350 high-precision paint robot. The gantry support columns are out of the way of the part flow and allow the robot to reach the footprint of the booth while in eight axes of coordinated motion.
To facilitate efficient programming of the random parts, ABX segmented the paint booth into four separate quadrants for the medium sized parts and paint tables. A part or table is then positioned within a quadrant to facilitate creating a robot path template. The parts were categorized into five basic shapes which allowed the software to automatically build a robot path based on several key features of the part. To gather these key features, a distance-sensing laser on the end of the robot arm records part positions in 3D space as the operator jogs to the corners of the part. The custom HMI interface and robot logic walks the operator through the path building process through prompts and screen shots. Using these corners of the part, the software uses one of the template paths from the five categories to triangulate the robot path to fit the surface location, part length, and orientation. The unique robot paint path is generated and then stored for future use with information about the part type and position. When this type part is processed a second time, the robot shifts the paint path to the part’s new position. The operator can also load multiples of a part in the booth, touch-off, and spray several at once or even mix parts to fill the booth up.
Being able to deliver a gantry system with a simple, quick method to teach part paths provided many benefits to RAFB. A trained operator or on-site engineer can now teach the bulk of the paint paths automatically and then amend the program for detailed areas. Additionally, the system provides the utility and flexibility to paint a variety of off-aircraft parts from different programs, including the ability to paint multiple parts at the same time.