Content area
Full Text
Preventing heat distortion on high-speed welded parts has been an on-going challenge in manufacturing. But, through a joint effort, Lindgren Automation lnc. and Van-Rob Stampings Inc. found that employing a portable CMM can help predict how parts will behave during the welding process.
The evolution of manufacturing of welded steel parts are made just took a leap forward, thanks to experimental work by a welding tool maker and a portable CMM. Lindgren Automation Inc., Concord, ON, develops custom fabrication machines, primarily for automotive customers throughout North America and Europe. One specialty is the design and construction of carrousel/ferns wheel fixtures to hold parts for MiG/laser/spot robot welders to weld into single structural pieces. For instance, they make welding cells that assemble bumpers and front and rear sections for cars and tracks.
The problem with high-speed welding, though, is once parts are heated, they distort around the hot zones. Fixture builders, such as Lindgren, have to build the ability to anticipate distortion into their equipment in such a way that the finished part is produced "on the nominals."
Anticipating Distortion
A contract to build multiple carrousel fixtures for a new truck part propelled Lindgren engineers to rethink their approach to the problem. Tooling development is divided into design and construction, process refinement, and proof testing phases with too much time spent adjusting blocks and pins in the fixture to get the final product within specifications.
In reality, more time is spent tuning the equipment than building it. "Parts in a welding fixture really have three dimensional statescold, as the individual pieces are loaded, hot, as they are welded, and somewhere in between, as they cool down and distort from welding," said Ed Wazny, project manager for Lindgren. "Historically, we would spend a massive amount of time setting the blocks and pins on a fixture just to make small changes in how a piece would be handled."
The new truck project posed a potential nightmare of distortion-caused problems. The part is a "cross-car" (dashboard) beam for the redesigned Ford F-I $0, for what is known in the industry as the P 221 Program. This beam joins the left and right "A" pillars and adds rigidity to the frame, as well as mounting points for dashboard...