When a manufacturer of industrial and specialty transmissions determined that its old CMM was beyond its useful life, Xspect Solutions came up with a unique proposal that combined a new Wenzel bridge-type CMM equipped with OpenDMIS software and a level of basic gear-measuring capability to optimize current needs.
Beloit, WI-based Cotta Transmission Co., LLC recently purchased a new Wenzel LH 12.30.10 CMM (right), equipped with OpenDMIS software with a special gear-checking module.
“When I joined Cotta as the quality manager, the organization was already extremely discontented with their current CMM equipment,” explained Todd Wells, quality manager. “Actually, the CMM operators were using the DCC CMM as a manual machine because of fears it would crash, and they would often reinspect product multiple times because they had little confidence in the results. A team was assembled to rectify the situation.”
The 1970s-era CMM in use had been rebuilt once, and an accuracy study confirmed it was not repeatable. “For example, we performed one study where the same part was inspected several times on a program that was written to run in automatic mode,” said Wells. “The measurement results varied more than 220% from the required design tolerance. With this new knowledge of the CMM’s inability to repeat, the team mandated subcontracted CMM inspection for specific parts with tolerances too critical for the old CMM, and until a new CMM could be purchased.”
Subcontracting vs Purchase
Wells estimated that the work level would require an expenditure of at least $100,000 over the next 12 months to accommodate subcontracting to an outside service. A new CMM was needed to insure the company’s commitment to its customers and continued delivery of a competitively priced quality product on time.
“Our desire was to purchase a new Wenzel CMM, and we liked OpenDMIS software, but we were not confident our budget or timing requirements would permit it,” says Wells. “We contacted Xspect Solutions, Wenzel’s operation here in North America, and discussed our situation with Nick Moceri, Xspect’s regional sales manager and Keith Mills, president there. After listening carefully, Xspect Solutions developed a program for us that took advantage of a combination of circumstances that ultimately gave us the machine we wanted within our budgeted cost, delivered on time. . .which actually ended up being ahead of time and included an offer that many other CMM manufacturers failed to beat.”
“Equipment suppliers like Xspect Solutions understand that manufacturers are pinching pennies just like everyone else,” says Keith Mills. “They’re looking for the best quality product at a reasonable cost. Wenzel CMMs are considered by many to be the best constructed and most mechanically accurate CMMs in the world.”
Precision manufactured impala black granite bases and bridges, intrinsic precision and hemispherical-cylindrical air bearings, and standard Renishaw probing systems offer volumetric accuracy of 2.5 microns. As a result, Wenzel machines are typically not the cheapest CMM on the market.
Innovative Proposal
“However, for Cotta, we were able to put together a proposal that involved a special CMM that we had loaned to another customer while waiting for a larger Wenzel machine to be built for them,” explains Mills. “Because we already had the ‘loaner’ CMM being returned, we were able to make the necessary arrangements to tie in the logistics and machine exchange as well as customize the CMM to meet the Cotta accessories and software needs. The new machine and software would be able to handle the entire range of products Cotta is producing.”
“We had been looking at machines equivalent in size to the Wenzel 12.30.10 that were 1995 vintage. We ended up with a 2008 Wenzel structure with new controller, probing, PC and software for a very attractive package price,” Wells adds. “In addition, we received software that included the gear-measuring module allowing us to develop basic gear data right on our CMM. This also allowed us to move our small gear-measuring machine out of the CMM room and into a location closer to our gear manufacturing department.”
Within a week of installation, company technicians had already successfully created part programs from CAD and inspected a number of part designs. The study previously conducted on the old CMM was duplicated on the new Wenzel; the results showed a 213% improvement in measurement variation. In addition, the CMM operators liked the ability to preview machine movement with the OpenDMIS software. An offline OpenDMIS software seat was also purchased as a result of feedback from another Xspect Solutions customer, allowing Cotta to develop new inspection programs while the machine is being used. And, as part of the purchase package, Cotta received four days of training for three people.
Reusing Parts from Old Machine
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“We did another interesting thing,” Wells says. “Because our old CMM was not worth rebuilding again, we decided to dismantle it and use the granite base and bridge and turn them into inspection surface plates. We had them lapped and calibrated and have them in use again in our shop (right). Xspect Solutions also offered to take our old Renishaw PH9 probe in trade for the new PH10M that was supplied with the CMM, and also gave us a useful styli change rack that mounts directly on the base plate.”
The Wenzel LH 12.30.10 is a bridge-type CMM with a measuring envelope of 1,200 x 3,000 x 1,000 mm which provides adequate table capacity for some of the larger transfer cases that Cotta produces. With this machine design, the Y-axis guideway is machined directly into the granite base plate, providing optimal long-term accuracy and stability. The machine has a maximum 3D measuring speed of 700 mm/sec with maximum acceleration of 2,000 mm/sec2. It is equipped with a Renishaw PH10M probing system and a HT400 teach pendant, which eliminates the tedious keyboard interaction necessary with conventional CMM teach pendants.
“The installation and calibration of the Wenzel CMM was well within our needed time frame, which was notable because the machine was configured when the installation was taking place,” Todd Wells concludes. “Communication with Xspect Solutions’ administrative and technical personnel has been seamless, including the coordination of any of the loose ends that normally occur with a project like this. We were even allowed to tour one of Wenzel’s other customers to get familiar with the same CMM prior to the arrival of our new machine. This has been a very successful supplier/customer project.”