Engine exhaust tube component maker triples production output-up to 11,000 parts per hour with zero rejects using a combination servo-controlled cold saw cut-to-length and brush deburring system
When Cosmos Manufacturing installed a Rattunde combination servo-controlled cold saw cut-to-length and brush deburring system to produce some of its components for small engine exhaust tubes, last year, it expected to improve productivity. What it didn’t expect was the triple production output that resulted, increasing part production to 11,000 parts per hour with zero rejects.
Rattunde Corp., Grand Rapids, Michigan is the five-year-old subsidiary of Germany’s Rattunde & Co. GmbH, a machine tool builder of tube, pipe and bar processing equipment. The company operates a service centre in Burlington, ON, to service its Canadian customer base.
The Rattunde system, incorporating a servo-controlled cutoff saw and brush deburring mechanism, is consistently producing up to 11,000 parts per hour at Cosmos, according to Mike Jemilo, the end user’s general manager. “This number represents triple the output production for Cosmos. Better still, it’s been in operation more than a year and we have not reported a single reject, with only routine maintenance and zero downtime due to machine problems. This is truly a win-win scenario for the machine tool builder and us alike.”
At the heart of the Rattunde system, according to Richard Stadler, company president, is the computer numerical control (CNC) system—a Siemens Sinumerik 840D CNC, Simatic S7 PLC with various analog and Profibus modules, plus numerous Simotics servomotors, motor protection devices, circuit breakers and other components supplied by Siemens.
At Cosmos, this Rattunde system is used to process mill-length tubes to customer-specified dimensions, using a fully NC-controlled cold saw. Cut-to-length parts are then automatically measured for dimensional accuracy and brush deburred. Because of the overall improvements in automation, speed and parts handling, plus the precision of the Sinumerik CNC system, Cosmos is further experiencing significant reductions in parts handling, secondary operations and final assembly.
The primary products being produced on this equipment at Cosmos include mountings, connectors and sections for muffler tubes in dozens of lengths, typically in 3/8-in., 7/16-in., 12 mm and 1/2-in. sizes. Products are routinely run in mild steel, aluminized steel and stainless steel on the same Rattunde system, with offline pre-programming done by the Cosmos engineering team. The final products are sold by Cosmos to leading manufacturers of chain saws, leaf blowers, lawn mowers and other small engine-powered equipment.
Jemilo says Cosmos was impressed with Rattunde’s service. “From the initial contacts with their application engineering, through the build process, commissioning and on-site training, we’ve been extremely impressed with their work—very professional and responsive. Our previous system had nowhere near the production of the Rattunde solution and we are already working with this supplier on our next system.”
From the machine tool builder’s perspective, the same relationship is echoed about Siemens. Alec Banish, vice president at Rattunde, says “we were asking Siemens to do some fairly complex operations in motion control, including 13 total axes with an articulating gearbox, plus the conveyor and part articulations, spindles and servomotors.” He further noted the scalloped motion of the ID/OD brushing with disc transfers all presented unique motion challenges for the control hardware and software alike. “The Siemens servo technology automated our entire process in a totally controlled, high precision manner, allowing customers such as Cosmos to process a wide variety of materials, dimensions, shapes and lengths with easy-to-manage presets.”
Banish adds that “the Siemens support is greatly enhanced by the remote monitoring capability of the Sinumerik CNC. About 70 percent of our issues are resolved remotely, working between us and Siemens or directly with the customer’s plant personnel.”
Prior to the implementation of the Rattunde system, all the piece part work done at Cosmos required two or three saws, with the attendant fixturing, parts handling, logistics and labor costs. These bottlenecks in production were eliminated by the fully automated and single operation processing of the tubes provided by the Rattunde system. Four tubes are processed per cycle, with servo control of the entire bundle, as it moves through the saw, brush and loading zones on this fully integrated machine line.
From a factory utilization perspective, the prior system at Cosmos ran in three shifts for six days, each week. Today, with the Rattunde system on the floor, occupying a far smaller footprint, one shift per day working just five days produces the same output with far superior quality and virtually no rework, according to company sources.
Rattunde president Richard Stadler is happy with the power of the control products. “We’re using all ten channels and pushing the axis capability to some extreme limits, but have seen absolutely no problems in signal degradation or processing speeds. All the operator needs to do is provide a size range indication onscreen and all the relevant programs appear for easy selection. Repeatability is obviously critical for our customers, who often process dozens of shapes and sizes per shift.”