Cleveland, Ohio – Manufacturers often use 3D measurement data to verify features on complex parts, ensuring that the finished component meets standards to exacting degrees. At American Hydroformers Inc. (AHI) in Fort Wayne, Indiana, engineers did just that, but they got even more value out of the system on the early end of their manufacturing processes, before more precise forming operations took place.
The shop produces safety-critical components for automotive frames and other structural parts. Employees fit bent tubes into complex dies, fill the steel or aluminum tubes with water, and dial up the pressure until the steel conforms to the shape of the die, creating the net-shape part. This tube hydroforming technique, growing in popularity with automakers for decades, handles complex materials and creates lighter, more consistent parts than stamping and welding.
General Manager Mark Blasi says with orders increasing at AHI, the process bottleneck wasn’t coming from the hydroforming process, it was coming from CNC tube bending.
“Tooling wears on those, mandrel walls wear out,” Blasi says. “You have to have the same shape to within a millimeter or so, because if you don’t, the part doesn’t fit the die. You’d have parts that were coming out of the die where you didn’t want, so as the die closes, it would skive the part a little bit. You’d end up with pinches in the die as well as parts that wouldn’t pass final quality control.”
Until about a year ago, AHI employees used mechanical gages to check tube accuracy before placing parts into the hydroforming die. The gages required employees to place bent tubes into a nest, and the part would only fit properly if the tube’s dimensions were in spec. In practice, Blasi says, it was too subjective. Depending on how people put the tubes in the fixtures, one person could get it to pass while another would consider it a failed part.
To solve the in-process part-checking problem and to validate prototypes for other AHI work, Blasi chose to invest in a Faro Edge ScanArm HD, a portable 3D measurement system with attachable laser scanner for both tactile probing and non-contact 3D scanning, that can quickly generate 3D models of bent tubes, allowing engineers to compare those scans to CAD master files to check for deviations.
Repeatable tube processing
“With the mechanical gages, you’d set the part in and you’d have certain clearances in certain areas,” Blasi says. The company needed more consistent results, he adds.
The Faro ScanArm, on the other hand, is fully repeatable. As tooling wears on the pipe bender, deviations in pipe shape show up more quickly, allowing employees to address problems before tubes fail during hydroforming.
“It shows us exactly where we are. One of our engineers is really good at that, and he can solve bent-tube issues in 10 or 15 minutes. That used to take us hours and we were never really sure we’d identified the problems,” Blasi notes.
Read more: Faro laser scanning improves American Hydroformers quality