Precision machining company Tolt Machine Works’ (TMW, Carnation, WA) core capabilities include fitting cumbersome parts into mechanisms with large machining volumes and precisely measuring features over a large measurement volume, but it recently added a new skill to its list of specialties: Vintage machine tool restoration, as evidenced by its recent resurrection of one of the world’s biggest coordinate measurement machines (CMMs).
This machine, originally sold by Italian manufacturer D.E.A. to Boeing in the late 1980s, will be the centerpiece of Tolt’s metrology department. With probes that could travel a span of more than 40 feet along the curved surface of an airplane component and measure that entire surface with an accuracy of a few thousandths of an inch, the CMM’s capabilities were certainly worth restoring. Tom Demogines, project manager of the lengthy task--and president of Quality Measurement Technology, with 30 years experience in the coordinate metrology industry--recently spoke with Quality about the CMM’s evolution.
Tom Demogines: When I was hired in 1986 by DEA (Digital Electronic Automation) to manage CMM sales in the western USA and Mexico, one of my primary responsibilities was to work as account manager with respect to CMM purchases by Boeing Co. My first sale to Boeing was the largest CMM ever to be delivered in North America and installed in 1987. This was a DEA Lambda 5712 with measuring strokes of 500 inches by 160 inches by 100 inches. The CMM was used for large aircraft tooling and reverse engineering. [It] was uniquely designed for Boeing by having a foundation designed and built for assembly of an additional 250 inches, which would have been a total of 750 inches [or] 62.5 feet. As time went on, the extra length was never added, retrofitting with new controls considered, but then the Boeing Tooling Dept was moved from the facility and the CMM was sold for scrap. It was moved in pieces to Eastern Washington and lived in an old potato shed for much of the last 10 years.
Some months ago I was introduced to Jim Kajiya, founder of Tolt Machine Works, who was starting a manufacturing facility that would be capable of large-scale, exotic metals machining. Jim plans to pioneer new manufacturing technologies using older machines with good bones and the large Lamda fits in well as the centerpiece of his manufacturing philosophy, [which is that] we need to be a good machine shop first. Tolt Machine Works plans to implement the philosophy and teachings of W. Edwards Deming.
TD: [After] agreeing to be project manager for getting the Lambda installed and operating, I began to assess the condition of the machine. As I listed items needing attention, I realized everything needed attention. The scales were corroded and rusted, air bearings were scratched and scored, and we had no confidence in the air hoses as they had been sitting in a shed with years of very cold and very hot temperatures. Even the bolts were looking like they wouldn't last much longer. After my third survey of the machine, I came to the conclusion the gear boxes were missing. These were the main drives for the machine and two of them were required to drive the large bridge across the rails. I asked Jim to check with the seller to see if they had been left behind, but Jim assured me that as they were loading the CMM there was a scrap truck picking up the leftovers just before the potato shed collapsed. A few days later I received an email from Jim saying they found the gear boxes in the rubble. This was a huge relief as these gear boxes are no longer manufactured and the only alternative would be to reverse engineer and build them ourselves.
Quality: What challenges did you encounter?
TD: Once we had somewhat of a plan, the work began of degreasing, derusting, scraping, sandblasting and every other imaginable way to get parts cleaned. We had known that major problem areas were the fittings used in the air system and along with the hoses we replaced every fitting encountered. Since the air gap between the bearings and guideways is .0005 inches or less, and water and oil going to the bearing have been a major cause in bearing collapse, we felt replacing the fittings would eliminate one potential issue. It was entirely possible this may have been the reason that maintenance personnel at Boeing replaced the original orifice-type bearings with New Way porous graphite bearings in some areas of the machine.
Quality: What other tasks were involved?
TD: Once the main rails were placed on the columns, we called in a local company to mechanically align those components. Morley Machine Tool Alignment [Milton, WA ] worked with us to level and make the rails parallel and straight. The Z-axis ram was removed, reground and replaced along with re-worked air bearings and the carriage was set in place on the CMM bridge, and then mechanically aligned.
With the addition of new Heidenhain scales, Pantec dual-drive controller, wireless joystick control, and DMIS software, it appears the old CMM ain't what it used to be. Whereas the old operation of the CMM was done at the workstation and driving of the CMM was with the tethered joystick box, we have incorporated a completely wireless control station that can be used anywhere within or near the envelope of the machine.
This project was not exactly like turning lead into gold, but really taking an old, tired and abandoned machine and recycling it back to its original precision and capability. Not to mention it has become one of the highlights of my CMM career.
Editor’s note: The CMM’s restoration should be fully completed by March 2011. Stay tuned for a podcast and video footage of the Lambda’s completion at www.qualitymag.com