Page 24 - MetalForming-Jan-2018-issue

...include power uncoiling for tougher, thicker material; flexibility to handle higher- and lower-gauge product; and more.
BY LOUIS A. KREN, SENIOR EDITOR
TThe centerpiece of any press line, the press itself, gets all the press, so to speak. Most of us probably are familiar with stamping-machine technology advancements and the advantages they bring, from the introduction of servo- driven units to the use of simulation to construct more robust presses to controls advances that allow for flexibility in speed, line integration and process-monitoring functions. But it all starts with the feed. Material must enter the press straight and true, and in synch with every other line component. If not, be prepared for scrap, lower quality and increased down- time, and their negative impacts on the bottom line.
To be sure, coil feeding has evolved to deal with newer breeds of material, and the increasing needs of metalformers and their customers. To take stock of the evolution, Metal- Forming spoke with David Hui, senior manager-controls engineering for Colt Automation (www.coltauto.com), Mis- sissauga, Ontario, Canada.
Built to Feed Stronger Material
Robust material demands robust equipment and new ways to route it through the press. To handle heavy-gauge material, a power uncoiler with tension control, reinforced straightener and beefed up rolls, and a servo feeder with holding brake are must-have configurations.
“A 15-30-hp uncoiler motor, for example, often is specified for uncoiling such material,” Hui says. “It has the power to keep the coil tight to ensure proper material feed. Unwinding force is so high when feeding heavy-gauge material that the coil can unwind by itself if the tension is too low, and the straightener can be damaged if not engineered properly. The regenerative power of the uncoiler will feed back to straightener through a shared DC bus, instead of dissipated on a dynamic-braking resistor.”
Absolute encoders accurately track rolls, guides and pass- line positions, and information in job recipes enable moni- toring and control of position and other variables to keep machinery operating efficiently and effectively.
Do not, Hui stresses, attempt to run higher-gauge material on feed equipment not rated for such use. For example, the tension created via an uncoiler with an air brake does not even approach the tension created by a 5-hp motor.
“Such equipment cannot accurately hold this material,” explains Hui, “and trying to do so will increase scrap pro- duction, damage equipment and lead to expensive down- time.”
Whereas feed equipment once could only handle high- er- or lower-gauge material, on the scene today are systems that can feed both. Hui notes Colt-installed feed equipment that can adjust to material gauge ranges through the flick of a switch, which reconfigures the machinery. For heavy- gauge material, the uncoiler operates in tension mode and material is pulled off from the mandrel by pinch roll, while for light-gauge material, the uncoiler, in speed-control mode, offers less tension and the pinch roll is bypassed.
22 MetalForming/January 2018
www.metalformingmagazine.com
Trends
Trends
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Coil
Coil
Feeding
Feeding