What is good fit up? And why is it crucial to the success of a welding project?

Dan Allford, President of ARC Specialties and the host of Roboticist Chronicles, meets with Dave Hebble, ARC Specialties’ Technical Services Manager, to expand on the idea of fit up and explain it to the rest of the company. The two have worked together since the late 70s, with Hebble acting as Allford’s mentor ever since.

You can trace a lot of robotic system failures to poorly fitted parts, explain Allford.

“With machining, you impose your will on the part. You take the part and you remove everything you don’t want… In welding, the part imposes its will on you. In other words, the shape of the part we can’t change – we just have to deal with it.”

Hebble also touched on defining the scope and flow of a welding project before getting started on it. “What is good fit up?” he asked. “Good fit up means something different to each person, so before you start, that needs to be defined.”

Allford added that, to him, fit up meant three things: joint accuracy, fixture accuracy and robot accuracy. All of those things could potentially add even more confusion to the process, emphasizing the importance of defining the flow.

“Before you can figure out which problem to fix, you’ve got to figure out which problem you have,” he said.

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