Page 20 - MetalForming May 2009

Compact Feed Lines
When considering investing in a compact feed line, compared to a more conventional long-loop line, metalformers should carefully consider the application-specific guidelines discussed here.
BY ROBERT ALLRED
Every few years a new catch phrase floats around the industry until it becomes a bit generic, such as “servo feed” in the early 1980s and “servo press” more recently. Not long ago, no one had heard much of the “compact feed,” introduced in the early 1990s and many years later becoming another of those catch phrases.
Years ago, when a metalformer required additional space to make room for a traditional long-loop line, it would construct an addition to its building. Things have changed a bit, and now companies strive to make as much use of their existing space as possible. This increase in the value of space has always been a consideration in Europe, and explains why much of the technology for compact feed lines has come out of
Robert Allred is sales and marketing man- ager, The Minster Machine Co., Automa- tion Div., Minster, OH: tel. 419/628- 2331, www.minster.com.
Spec your feed line with optional straightener-head opening action to allow for easy access to the rolls, for cleaning. This proves particularly useful to stampers that switch from forming hot-rolled scaly material to cold-rolled steel or aluminum on the same machine.
Europe, and now has spread to the Unit- ed States.
However, a compact line does not always represent the best solution. What factors should metalformers consider?
1) Strokes per minute. If your job requires high speeds or very long feed lengths, a long-loop line offers the best solution. Applications where feed length exceeds 30 in. and exceeds 30 to 35 strokes/min. tax a compact feed line. For example, a motor-lamination stamper never would be able to attain the speeds needed—500 strokes/min. with a 4-in. feed length—with a compact system.
2) Surface-critical material. Since a compact line stops at each stroke, feed and straightening rolls also stop. During this stop time, the machinery might leave a witness or shadow mark across the width of the material. This might be acceptable when stamping nonsurface-
critical parts, but when running pre- polished material that becomes the fin- ished product, these marks likely will be visible, and unacceptable. In these cases, applying a long-loop line—where the material continues to travel through the straightener without stopping until the line stops—offers the optimum solution. Also important is the addition of a variable-speed drive on the straight- ener, to eliminate unnecessary starts and stops. The loop control provides a more fluid speed output to the straight- ener, eliminating the start/stop problem. Also add a good ultrasonic or laser loop sensor.
Cradle or Reel? Single or Dual?
Once the above-mentioned criteria are understood and a metalformer remains a candidate for a compact line, the next consideration is coil handling.
18 METALFORMING / MAY 2009
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