Servo-based press transfer system maximizes productivity, flexibility for automotive supplier
Venest Industries, an automotive parts supplier based in St. Catharines, Ontario, Canada, needed an automated transfer system that could be parked away from the machine bed during progressive operations and die changes, so that new dies could be delivered to the press via an overhead crane.
As with profit margins, the margin for error in the metal forming industry is becoming tighter and tighter—choosing the wrong equipment or delaying new technology investments can quickly make a pressroom uncompetitive. And these days, once you get behind, it's almost impossible to catch up.
Venest Industries, an automotive parts supplier based in St. Catharines, Ontario, Canada, viewed its latest technology purchase as an essential business decision. "It's simply a matter of survival," said Shaun Reycraft, program manager at Venest. "We have to scrutinize every operation to see how we can maximize efficiency and stay at the technological forefront. If we don't, we risk losing a substantial amount of profitable business."
When Reycraft and his team researched an automated transfer system for a newly acquired, 800-ton PTC press, they studied the alternatives and received six detailed proposals. "We knew the more we could get out of a transfer system, the more we'd be able to get out of our new press—in terms of productivity and ROI," Reycraft said. "That's why we were determined to find a system that offered the most potential with the fewest compromises."
Meeting the specification for Venest's new press transfer system was not as straightforward as it first appeared. The 4-year-old press was acquired from another subsidiary of Magna International, Venest's parent company, and was intended to replace a 400-ton transfer press equipped with a cam-driven transfer system.
The PTC press, however, was designed for a progressive-die configuration and set up to produce a single part. "It was the exact opposite of what we needed," Reycraft said. "We needed a configuration that could accommodate a broad range of both progressive and transfer jobs."
Required operational flexibility significantly complicated the transfer system. The new transfer system had to be parked away from the machine bed during progressive operations and during die changes, so that new dies could be delivered to the press via an overhead crane. "That was our basic challenge—getting a system that would reach in when it was needed, and get out of the way when it wasn't," Reycraft said.
Space constraints provided other potential headaches. The 800-ton press was installed in an area previously occupied by the 400-ton unit, putting available room for the transfer system at a premium, especially when the transfer units were parked away from the bed during progressive operations or die changes.
Of the half-dozen proposals presented to meet these requirements, the automotive supplier chose an AP&T Speed Transfer CD40 x 4 system for the 800-ton press. "The system is space-efficient and it showed AP&T clearly understood what we needed," Reycraft said.
The modular nature of the system was another feature Reycraft liked. To fit the transfer units in a small space, AP&T engineered a mounting for the system's Y beams to allow unrestricted transfer operations, including the complete retraction of the transfer units during die changes and progressive operations (see Figure 1). Because of limited room, beams were mounted on the press's external frame instead of between its columns. "The AP&T transfer units took up considerably less space than the systems submitted in the other proposals," Reycraft said.
To fit the transfer units in a small space, AP&T engineered a mounting for the system's Y beams to allow unrestricted transfer operations, including the complete retraction of the transfer units during die changes and progressive operations.
Installation was another area where Venest set some high goals. All work, up to system commissioning, had to be accomplished during the plant's two-week shutdown in July 2005. "We gave them a very small window," Reycraft said. "Once the mountings were installed, everything went like clockwork. Some debugging was needed once production started, but everything was up and running on time."
Unlocking Press Potential
Venest's new transfer system has allowed production speeds to increase by nearly 50 percent in some cases, the company said. The supplier's old press maxed out at 15 strokes per minute (SPM). Its new press and transfer system combination often runs at speeds up to 22 SPM, and Reycraft estimated the average productivity for all transfer jobs is about 20 SPM.
"When you're talking about hundreds of thousands of parts per year, a difference like that really adds up," Reycraft said. While all the productivity improvements are not only because of the transfer system, Reycraft said he believes the transfer system is enabling the press to operate at its full potential.
Part of unlocking that potential has to do with maximizing a press's operational flexibility. Venest's transfer system has infinitely variable placement all along the X, Y, and Z axes and a Siemens control system with a user-friendly graphic interface.
"The transfer system can be easily programmed to accommodate virtually any part that can fit in the press," Reycraft said. "Currently the transfer system is handling parts that range in widths from about 4 inches to 4 feet; everything from a bracket that weighs barely a pound to an 18-pound cross-member."
While the old 400-ton press could handle only three jobs, the new 800-ton unit is currently running twice as many different transfer jobs, with more to be added this fall. All this is in addition to the work the press does while in progressive mode (20 percent of the work done on the press). "If you can do every job faster, you can do more jobs on the same machine," Reycraft said.
However, other factors contribute to the new system's enhanced productivity. For example, the transfer system's ability to park away from the press bed permits fast and easy changeovers to different or progressive operations. Also, the transfer system is nearly maintenance-free. The only preventive maintenance requirement is bearing lubrication, Reycraft commented. When the occasional operational glitch has arisen, AP&T engineers in Sweden have been able to troubleshoot the system in Canada via modem.
"With the cutthroat competition out there, you've got to be the first through the door with the best technology," Reycraft said. "Any of the proposed transfer systems would have helped us improve productivity over the previous press. But 'improvements' alone are no longer enough. These days you've got to maximize your productivity and your ROI to stay competitive. And we're confident the transfer system we chose is allowing us to do that."
Venest Industries — Magna International Inc., 2032 First St. Louth, St. Catharines, ON L2R 6P9, 905-641-9110, www.venest.com
AP&T North America Inc., 4817 Persimmon Court, Monroe, NC 28110, 704-292-2900, firstname.lastname@example.org, www.apt.se
STAMPING Journal is the only industrial publication dedicated solely to serving the needs of the metal stamping market. In 1987 the American Metal Stamping Association broadened its horizons and renamed itself and its publication, known then as Metal Stamping.