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LMC Workholding Success Stories
Baldor Electric Turns to Face Drivers and Atling Steady Rests for Machining Motor Shafts
Mechanical face drivers might be the best way to turn parts. They allow turning applications to achieve increased flexibility to lower cycle times, turn both the smallest and largest of parts and even allow interrupted and heavy cuts.
The major benefit of a face driver lies in its ability to allow a part to be turned completely, from one end to the other, in one operation. Some parts that are routinely cut using face drivers include automotive transmission parts, crankshafts, cam shafts, pinion gears, electric motor shafts and axles up to 36-inch diameter.
At one time, heavy cuts were thought to be an issue with face drivers because of part slippage. However, this no longer is true, especially with mechanical face drivers. Interrupted cuts also were thought to be an unacceptable application for face drivers. But today, these types of cuts can be done easily and with fast feeds and deep cuts, providing a boost in productivity.
Meeting motor production challenges of heavier mix of “specials”
Andy Schaffer is a manufacturing engineer tech at Baldor Electric Company, Ozark, AR. His area of responsibility includes the machine shop including every CNC in the plant. In addition to tooling responsibilities, he does some CNC programming and sets up each new machine from scratch. He also is the “go-to” guy when changes in product mix start to bog down production efficiencies.
Baldor Electric Company designs, manufactures and markets electric motors, drives and generators. It has 15 locations in the United States and one location in England. “In this plant,” Shaffer says, “we produce three-phase and single-phase motors ranging from 5 horsepower to 175 horsepower. We shipped our first motor back in 1994. Today, we have between 180 and 185 persons employed at this facility.”
“During the last five years, we’ve seen our production mix flip-flop from about 80-percent standard motors with 20-percent specials, to 20-percent standard motors and 80-percent specials,” Schaffer explains. “This has caused a lot of problems because we now have much shorter production runs. Often an operator will produce just one or two shafts, which leads to frequent changeovers and lost production time.
“We used to change setups just once or twice a day,” Schaffer continues, “now I’ve actually seen instances where an operator has changed from one part setup to another as many as 23 times in one day. In addition to lost production time, we had issues with run out quality (TIR improvements of 20% or more on most parts) and holding other tolerances on our more critical shafts, especially when we were machining harder materials.”
In an effort to solve some of these problems, Schaffer obtained a mechanical face driver from LMC Workholding and began to test it on one of Baldor’s CNC turning centers. Although he had been disappointed with the performance of a hydraulic face driver and a mechanical face driver produced by a competitor in the past, he was pleased with the results he experienced with the unit. “I told the LMC guys to put their money where their mouths were and give us a chance to test it under production conditions…and they did,” added Schaffer. “We ran it hard for a month and it convinced us. Now a days it’s hard to get anybody to give you a chance to try it out for free and feel confident in guaranteeing the results…but they did.”
Impressive cycle time reductions of 30%+ using the Face Driver from LMC Workholding
“We started using the face driver and we had great results,” Schaffer reports. “In addition to better part quality, on some of our shafts we reduced cycle time by 30 percent. Since then, we bought a second one and put in on another machine. Recently we bought another one to put on a new machine. Eventually we plan to have all of our CNC machines equipped with them because it will help our operators to get back up to the production speeds we had when we were running bigger lot sizes.”
“When we first began testing the mechanical face driver, we were looking for something to help get the operators up to real world numbers compared to where we were and where we were headed,” Schaffer explains. “We were looking for a 25- to 30-percent cycle time reduction. When we got everything lined out, we actually got to our 30-percent cycle time reduction on most of our parts.
“On some of the shorter and less complicated parts, there were little or no cycle time savings because they were already so fast,” Shaffer admits. “But for many parts, the first piece probably used to take about 30 minutes to get out. They probably can do it now in roughly 10 to 15 minutes.”
A major improvement on longer shaft turning with the Atling Steady Rest from LMC Workholding
“Where we usually run into issues is with shafts 36 inches and longer,” Schaffer continues. “Sometimes we’ll run into chatter problems, but if this happens, we just use LMC’s Atling Air Steady Rest to stabilize it. For example, on specific shaft ranges in length from 30 to 36 inches, it was taking us some 30 to 45 minutes to machine this part because we were taking such light depths of cut.”
“When we began using the Atling Steady Rest in conjunction with the face driver, we were able to run the part in just nine minutes because we were taking about three times the depth of cut,” Shaffer reports. “We went from a .100-inch to a .370-inch depth of cut with a speed of 1,000 rpm and a feed rate of 20 ipm. I think we had been running around 800 rpm with a feed rate of 10 ipm. We could get more aggressive with it because we were holding it on both ends. Not only did we cut cycle time by more than 67 percent, but TIR also is better.”
One “mistake” that led to impressive results
“One time, we had an operator that was running 2¼-inch bar stock,” Schaffer remembers. “He pulled up a 2¾-inch program and made changes to it to run his next order. But when he got done, he forgot to ‘edit and quit’ it so he put a 2¾-inch bar in the machine and ran a 2¼-inch program. It ran the shaft and did not throw it out. It took off about .900 inches of material and held onto the part. And, that was without the steady rest, just strictly the driver. When I saw that, it really impressed me.”
“Overall,” Schaffer says, “we turn from 2-1/4-inch material, all the way up to 4-inch bar. Lengths vary from 16 inches to 42 or 44 inches. Our heaviest shaft probably weighs around 70 or 75 pounds.”
Tackling the difficult jobs in Ozark, capital investments key
“Baldor has always had a reputation in the marketplace for high quality and we currently run the shortest lead times of anyone in the industry,” observes Ryan Waite, Plant Manager. “One of the things we have pushed in the last 10 years is that most of our competition has gone offshore in pursuit of cheap labor. Baldor has chosen the strategy of investing capital within our existing facilities to increase productivity. Incorporating LMC’s face driver is one aspect in that it reduced cycle times. Business is beginning to swing heavily to the custom side because we do run such short lead times and we do produce such high quality product.”
“Generally we are taking on business that a lot of people would not run--lower volumes and more difficult items to produce,” Waite says. “What we have seen with our shaft production, is much more stringent tolerances and much longer shafts machined out of more exotic materials. Because we have seen an increase in cycle times for these products, it has caused us to look at many other machining alternatives to reduce cycle time and set these products up offline so we can continue the standard production at regular flow rates.”
“Shaft machining has been the biggest change for us in the past year in terms of difficulty in the shafts we are beginning to see,” Waite observes. “This includes the amount of exotic materials, the tighter tolerances and the size of motors we produce because of the size of the rotor we have to put on. We are starting out with 3 inch to 3-3/8 inch bar stock and we are turning it down to a ¾-inch final diameter. This can be much more difficult than it sounds.”
The entire LMC Workholding line includes…
- LMC hydraulic power chucks, cylinders and wheel chucks;
- Atling & Richter Steady Rests;
- Face drivers, as well as live and dead centers.
LMC Workholding
P.O. Box 7006 • 1200 West Linden Avenue
Logansport, IN 46947-7006 USA
Phone: 574-735-0225 • Fax: 574-722-6559
E-Mail: info@LMCworkholding.com