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Checking and assembly fixtures for stampings and injection-molded parts typically have a wide array of part details, all of which require inspection by CMMs to insure fixture accuracy. Having the ability to write inspection programs fast, and having the confidence in the accuracy of the CMM to provide the highest level of quality, is what is most important to designers and builders of this type of tooling.

Liberty Tool, Inc., a job shop specializing in the design and manufacture of checking, SPC, CMM and attribute fixtures requires CMM measuring capability to insure the high level of precision demanded by their aerospace and automotive customers. Rob Hoy, quality manager for Liberty Tool, says, “Because of the nature of our customer base, and the requirement of ISO 9001:2000 for aerospace and automotive tooling, we’ve always had CMM measuring capability. As a matter of fact, we have used three different CMMs for a number of years. Two of those machines, a horizontal Mora and a horizontal Poli-Globo, are manually operated units, and the third is a gantry-type automatic Numerex.

”Our programming experience was primarily based on Caps & Edges™ software. However, as Liberty’s business has expanded into additional precision machining areas, specifically in the fabrication of complicated aerospace carbon fiber and composite parts and tooling, it became necessary to upgrade our CMM inspection capability to provide faster programming and measuring, and to accommodate larger size parts.”

Hoy explains, “Although my title is quality manager, basically I run the CMM operation. I do all the measuring and write most of the inspection programs myself. When management was convinced that we needed to upgrade our capability, it was my responsibility to make the right capital equipment recommendation. I started perusing the Internet and found Xspect Solutions, Inc. I was impressed with their broad range of machine and software capabilities, and the fact that they rebuilt and remanufactured all types of CMMs, gave me the confidence that they could recommend the best machine and software for our fixture and parts applications, as well as one that was within our budget restrictions. At the time, I was not aware that Xspect Solutions was also the North American representative for Wenzel CMMs . . . machines that I had a lot of respect for because of their robust granite construction and precision measuring reputation. Keith Mills, Xspect Solutions president, personally visited our facility and worked with us to determine the best machine for us.

”We really wanted a new machine, and were thrilled to be able to purchase a Wenzel LH87 bridge-type CMM with a measuring envelope of 800 mm x 700 mm x 1000 mm. The machine was packaged with the industry standard Renishaw TP200 probing system with volumetric accuracy of 2.5 microns and a maximum 3D measuring speed of 700 mm/sec with maximum acceleration of 2,000 mm/sec2. This probe system provides us with additional part digitizing and reverse engineering capabilities. We also have the HT400RC wireless teach pedant – which I really like. It eliminates the tedious keyboard interaction necessary with conventional CMM teach pendants. With just one joystick, it basically has everything I need right in my hand.”