January 2008 Edition
QUALITY CONTROL
Accuracy With the Right Touch
In order to meet a deadline, a precision machine shop outsourced its inspection process
The part and fixture for a GM part produced by Riverside Machine was too large for the shop's quality assurance equipment, so it turned to GKS Inspection Services for help
Almost every company has a specialty in which it excels. On the other hand, each shop might also have an area where it is less than expert. Knowing the difference can mean a profit or a loss. It takes a smart company to know when to try a process in-house, and when to outsource it to a company specializing in that area. Riverside Machine, Genoa, OH, found that it needed inspection accuracy capabilities it did not have, so it outsourced the work to its benefit.
The precision machine shop, whose business includes design and fabrication of customized industrial and consumer parts, was awarded a fabrication job from GM with a 12-week project timeframe. The completed product, a convertible roof for the Pontiac Solstice, had to arrive at GM's manufacturing plant in Mexico by the end of the 12-week period. A requirement of the job was production part approval prior to the first production shipment of product because it was a new part from a new supplier.
Riverside Machine built the tooling for manufacturing the convertible roof. When it came time to inspect it for accuracy, the error tolerances it needed were tight and its tooling was too large for handling by its usual inspection equipment. Under a deadline, the company decided it had to outsource inspection. It contacted GKS Inspection Services, Plymouth, MI.
The Chosen Inspectors
GKS Inspection Services has been a provider of dimensional inspection, 3D laser scanning, and terrestrial scanning services since 1981. The company has experience with all kinds of inspection projects, using both laser and traditional measuring methods. Because the tooling Riverside Machine needed measured was very large, the GKS metrologist went onsite to Riverside Machine's facility.
Use of a 12' Platinum Faro PCMM arm from GKS Inspection Services let Riverside Machine meet both its accuracy requirements as well as a tight deadline for delivery of parts to General Motors
"Many of our customers prefer on-site inspection of their parts due to their large size or proprietary nature, and we have the capacity to service them quickly," Steve DeRemer, general manager of GKS, said.
As per its standard inspection procedures, Riverside Machine requested contact digitizing with GKS' portable coordinate measuring machine – PCMM – and touch probe, manufactured by Faro Technologies Inc., Lake Mary, FL. GKS was onsite the next day with its touch probe and 12' Platinum Faro PCMM arm. GKS' system configuration includes Faro's CAM2 measurement software and contact probes, along with a Laser Design SLP-330 laser scanner and a high-end laptop PC loaded with Geomagic software. The Platinum Faro Arm's 0.0005" accuracy betters traditional CMMs, hand tools, and other portable CMMs.
The Process
The convertible roof assembly fixture had movable features which needed to be in precise locations. The GKS metrologist inspected 26 critical locations with the PCMM. Riverside Machine had provided GKS with the blueprints for the assembly fixture which showed the location of each detail and the fixture's nominal dimensions. GKS compared the touch probe results to the print nominal values to determine whether all areas of the part were in spec.
With Faro's CAM2 inspection software, an inspection report was quickly generated showing that the majority of the fixture was already within tolerance. It also allowed for real time corrections and re-measurement of the few features that were slightly out. If a detail needed further machining, the location was removed from the fixture and machined; similarly, if the detail needed to be shimmed, the shims were added as the inspection progressed.
"Riverside Machine was able to use the inspection data to quickly determine the locations of the features and assemble the tooling precisely to spec," the GKS metrologist said.
After the initial inspection by GKS, Riverside was able to dial in its fabrication process to the point of not needing GKS to go onsite. Riverside could ship the fixtures directly to GKS Inspection Services for final inspection.
Riverside Machine shipped the GKS-inspected tooling to the OEM's manufacturing plant in Mexico on schedule. The parts were made there and then shipped back to the GM assembly plant in Bloomington, DE.
"GKS' response time was great. We had no down time," Brad Linnebur, sales manager at Riverside Machine said. "We were up and running very rapidly and got the assembly to its destination on time. Everybody was happy." Faro Technologies Inc.
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