Hours become minutes on changeover of stamping dies
By Kip Hanson, Contributing Editor
Article from May 2014 issue of Shop Metalworking (Canada).
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Shop Metalworking’s web site
(Partial article. Use this link to read it in full): For years, those familiar with Single Minute Exchange of Die (SMED) have been hearing how efficiency expert Shigeo Shingo helped automaker Toyota reduce setup time on its 1000-ton presses, going from four hours to just three minutes. An admirable achievement, but is it really necessary to change dies faster than you can pick up a happy meal at the local drive-thru?
Probably not, but it’s a sad fact that many shops waste time during set-up, and best measure their machine downtime in hours rather than minutes. This leads to oversized production runs and long lead times for finished goods, bloated inventory, product obsolescence and machine utilization figures that would have Shingo rolling in his grave.
Hilma Div. of Carr Lane Roemheld Mfg. Co. offers a complete line of quick die change and handling solutions. “With smaller presses, say 100 tons and below, there’s less clamping hardware to deal with, fewer nuts and bolts, less weight to jockey into position,” said David Fischer, Hilma Engineering manager. “This means shops feel less pressure to go with quick change clamping systems.” That doesn’t mean, however, that they shouldn’t do it.
Fischer offers an example of a 100-ton press with a one-hour setup—implementing quick change could easily lop 50 per cent off that time. True, that only saves half an hour, but with frequent changeover environments, every minute adds up. But the real benefit, Fischer argues, is consistency. “Quick change systems mean easier standardization, and more consistent processes overall. For example, you don’t get caught out at the machine missing a bolt or a strap, and end up wasting time walking to the tool crib for a part that cost a couple of bucks. Set-up times become very predictable.”
Carr Lane Roemheld offers hydraulic and magnetic die clamp systems. “It’s all about what’s best for the application. For example, magnetics are very fast. We recently worked with a company making furnace components, and the ability to quickly switch from one length to the next was important—in this case, magnetics were the best choice. They’re also flexible, and work great where a company still has some work to do on the standardization of their die sets—thickness is basically irrelevant. You must have a clean, flat surface for safe clamping, a way to locate the die, and you’re up and running.”
Read the full article on
Shop Metalworking’s web site