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EMAG has a long history, starting back in 1867 in Bautzen, Germany, as an iron foundry and engineering works. Re-established 60 years ago in Eislingen, Germany, in 1952 to make lathes and special-purpose machines, today it makes manufacturing systems for precision metal components from its headquarters in Salach, Germany. Its machines range from basic round-part vertical turning centers to machining centers with as many as six axes handling large workpieces. They perform turning, milling, grinding, hobbing, drilling and more as singular purpose setup or combination machines.
The tools manufacture primarily automotive, off-highway, agricultural and oil field components. For example, EMAG tools are involved in transmission components for agricultural vehicles, such as gears, ouput shafts and idlers. “If you look at a dozer from the outside, you have a chain,” notes Peter Loetzner, CEO of EMAG’s U.S. subsidiary in Farmington Hills, Mich. “There are two large precision wheels that drive that chain. There are idlers on the bottom. Our machine can make all these round components.”
EMAG’s equipment differs from typical vertical lathe machining centers, whose head stock is mounted, typically horizontally, and a turret turns to do the machining. “Our turret is mounted in a concrete base, so it’s not moving,” Loetzner explains. “We have a head stock that moves outside of that design. That gives us better precision and better tool life.”
The machine builder takes pride in its ability to produce high-precision parts. In one example, Axle Alliance in Redford, Mich., needed to hold to a 25 µm tolerance for 390 mm diameter steel ring gears during hard turning, which is done prior to grinding the gear teeth. EMAG worked with Axle Alliance to develop a probing process that ultimately delivered a variation of less than 15 µm. Axle Alliance now uses six machines built at EMAG’s headquarters in Germany, each dedicated to a part line.
Another example comes from Precima Magnettechnik in Brückeburg, Germany, whose customers expect absolute perfection from, in this case, housings for brakes used mainly for wind turbines. Precima had had issues with machine vibration causing negative effects on tool life and surface finish. However, the rigidity of EMAG’s turning machines and the vibration damping quality of the base allows for the very high feed rates and cutting speeds required in precision hard-machining. Precima now runs four vertical pick-up turning machines from EMAG.
Loetzner gives much of the credit for the machines’ capabilities to long-time partner Siemens. EMAG has standardized on the Siemens Sinumerik 840D CNC platform, specifically the solution line and power line. Loetzner likes, in particular, that the CNC controller is an integral part of the PLC, and they are able to do almost everything through the CNC, including making it look like a PC for the operator. The common look and feel for the operators makes for easier onsite commissioning and cross-training, Loetzner adds.
In one recent case study, EMAG needed to provide grinding, turning and turn-grind machines to a major agricultural equipment builder, and the machine builder relied on the 840D CNC. “We needed to devise a control solution that would satisfy all the needs of the various machines we were supplying to this demanding customer, based on a common platform, to enable easier design, integration, startup, commissioning on-site and training for our customer’s operations and maintenance personnel,” Loetzner said at the time.
Similar control technologies are used on EMAG’s newer-technology machines, including laser welding and electrochemical machining centers. These technologies have little impact on the control or automation schemes, Loetzner notes, because they still are essentially performing the same task, whether in a dry, lubed, gas-cooled or underwater environment. Only the sensors and encoders need to change to accurately feed the relevant data to the control. In fact, the controls are often much simpler because the axes of motion are fewer, though more multi-axis and workpiece manipulating machines are being developed.
The CNC also enables remote monitoring over a wireless network so that process engineers can see what the operator sees on each machine. The agricultural equipment customer mentioned has used the remote monitoring capability on a wide variety of EMAG machines for several years, with all data communicated through a single information network that’s accessible by both EMAG and Siemens. Through this arrangement, they have been able to significantly reduce downtime, service calls and troubleshooting identification time.
More than 75% of the EMAG machines at this customer site are equipped with robotic devices. The lights-out capabilities this provide make remote monitoring that much more important. Remote monitoring can be done directly through the Sinumerik CNC in a one-on-one exchange with the customer, Loetzner notes, or even a three-way exchange involving Siemens as well.
While happy with the precision capabilities, EMAG’s focus on future development is trying to decrease the downtime between producing components. “On the automation and the part handling, the challenge is you want the machine to run and make parts all the time, right? But once a part is done, you have to take it out and put the other in,” Loetzner says. “Those non-productive times are the biggest enemies.”
EMAG reduces those times partly by use of the Japanese chaku chaku principle. Meaning “loading loading,” the idea is to bring various process steps as close together as possible to improve the speed between the processes. EMAG’s vertical machining centers not only fill a much smaller footprint on the plant floor, they also improve chip flow. Also, all of EMAG’s machines are self-loading, with a servo-controlled shuttle traveling through the machine, but not through the work envelope, Loetzner notes.
“While we have shown the industry we can master any part to highest precision, over the last five years we’ve been more and more focused on tightening non-productive time,” Loetzner says. At IMTS in Chicago in September, 2012, EMAG showed a new machine generation that significantly reduces the non-value add times. “Our chip-to-chip time was between 6 and 7 seconds for typical automotive gear,” Loetzner says. “Now it would be a second or less.”
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