Case Studies: Large Volume is Not a Problem
December 1, 2009
A fast way to verify large production fixtures and parts of construction and agricultural equipment has been discovered by engineers at the South Dakota location of Gehl (West Bend, WI). The portable K-Series optical coordinate measuring machine (CMM) from Metris (Leuven, Belgium) is positioned on the production floor and is used to measure points of choice via the wireless tactile SpaceProbe. This ergonomic metrology system enables Gehl to halve the time spent on the geometric verification of chassis and driver compartment assemblies, while also yielding deeper insight when troubleshooting equipment prototypes.
At the production site in Madison, SD, engineers manufacture skid and track steer loaders and telescopic handlers designed at the company headquarters in Wisconsin. To monitor production quality, Gehl staff conduct geometric measurements right at the production line.
“Quality control involves the inspection of selected geometric features and surface points on steel parts after being stamped, drilled and painted,” says Joseph Palmiotto, quality assurance manager for Gehl in Madison. “We not only monitor finished parts, but also verify mechanical fixtures used for part production and assembly of chassis and driver compartments, for example. To more efficiently execute metrology tasks on components of various sizes, we moved from an articulated measuring arm with a limited reach to a Metris K-Series system that covers a considerably larger measuring volume.”
Zero Setup Time“The K-Series system impacts productivity big time,” says Dale Yeager, Gehl quality technician. “The optical CMM immediately activates a measurement volume that fits an entire loader vehicle, even with its lifter moved in the most upward position. Using the wireless tactile SpaceProbe, we can walk around and measure predefined points sequentially, as visually shown on the PC screen.”
The metrology software that comes with the K-Series system automatically displays where the next measurement point is located. And when touching the point, the software provides instant confirmation regarding measurement validity. Yeager says that quality technicians define inspection procedures by clicking the desired points on the graphic user interface and enter the points in a macro to record the process flow.
Faster Inspection, Instant Feedback“Overall, we realize 50% inspection time gains,” says Yeager, attributing this to K-Series’ zero setup time and optical CMM that covers all inspection points from a single position. “The absence of mechanical constraints creates superior operator comfort, which allows the inspection of hundreds of points in and around a skid steer loader to be performed a lot faster. After taking measurements in one production line, we readily move the system to another line using the cabinet roller and optical CMM trolley. Overall, the system is used five to six hours a day by different operators in our production facility.”
K-Series consistently reaches accuracy level of 1.5/1,000 of an inch, and outputs the data in any graphic or numerical format. Instant data feedback is critical in production, but also beneficial when assessing prototype vehicles of new models. Yeager explains that K-Series is sometimes brought in to quickly trace the root cause of specific assembly issues. “In the case of a load arm bushing problem, Gehl metrology engineers traced the source of the problem with the SpaceProbe without having to disassemble the load arm. As K-Series saves time and supports engineering, our colleagues at Gehl engineering headquarters in Wisconsin now use the same metrology system.”
Integral Part of ManufacturingInspecting telescopic handlers or larger assemblies measuring 10 feet or more seems quite challenging. Joseph Palmiotto says that he is considering the purchase of additional optical CMMs, which would enable him to double or triple the measurement volume. As an alternative, his team uses magnetic reference spheres to leap frog measurements taken from multiple camera standpoints.
Palmiotto is impressed with K-Series because measurement time is cut in half, and production staff is eager to tune the process based on the inspection results. “Where they initially backed down our internal metrology services, they are now begging for it. Portable ergonomic metrology systems such as K-Series increase the acceptance of metrology and make it an integral part of our manufacturing operations.”