GETTING IN GEAR
When a rebuilt CMM from the 1970s that was being used for gear inspection lost its repeatability, specialty transmission manufacturer Cotta Transmission replaced it with a Wenzel bridge-type CMM from Xspect Solutions that was equipped with inspection software and a level of basic gear measuring capability that optimized the inspection process and improved measurement variation by over 200 percent.
Posted: October 6, 2011
“After listening carefully, they were able to develop a program for us that took advantage of a combination of circumstances and ultimately gave us the machine we wanted within our budgeted cost and delivered on time. They actually ended up being ahead of time on an offer that many other CMM manufacturers failed to beat.”
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 spreadsheet.
“Equipment suppliers like us understand that manufacturers are pinching pennies just like everyone else,” smiles Mills. “They are looking for the best quality product at a reasonable cost. However, for Cotta, we were able to put together a proposal that involved a special CMM that we had already loaned to another customer while waiting for a larger Wenzel machine to be built for them. 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,” adds Wells. “We ended up with a new Wenzel structure with new controller, probing, PC and software for a very attractive package price. And we received software that included the gear measuring module that allows us to develop basic gear data right here on our CMM. This 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, Cotta technicians had already successfully created part programs from CAD and inspected a number of part designs. The quality team duplicated the study that had been conducted earlier on the old CMM on their new Wenzel and the results showed a 213 percent improvement in the measurement variation!
The CMM operators liked the ability to preview machine movement with the OpenDMIS software. “We also purchased an offline OpenDMIS software seat that allows us to develop new inspection programs while the machine is being used,” explains Wells. “The decision to purchase this additional seat was the result of some feedback we obtained from another Xspect customer who wished they had an offline software seat. Also, as part of our purchase package, we received four days of training for three of our people.”
The shop did another interesting thing. Because the old CMM was not worth rebuilding again, the team 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,” states Wells. “Xspect offered to take our old Renishaw PH9 probe in trade for the PH10M that was supplied with the CMM, and also gave us a useful styli change rack that mounts directly on the base plate.”
The installation and calibration of the Wenzel CMM was well within the needed time frame, which was notable because the machine was configured when the installation was taking place. “Communication with the administrative and technical personnel of Xspect was seamless, including the coordination of any of the loose ends that normally occur with a project like this,” concludes Wells. “We were even allowed to tour one of their other customers to get familiar with the same CMM prior to the arrival of our machine. This has been a very successful project.”
Cotta Transmission Company, LLC, 1301 Prince Hall Drive, Beloit, WI 53511, 608-368-5600, www.cotta.com.
Xspect Solutions, Inc., 47000 Liberty Drive, Wixom, MI 48393, 248-295-4300, Fax: 248-295-4301, www.xspectsolutions.com.