Imagine using magnets to secure an injection mold — a big hunk of steel that weighs thousands of pounds — inside a molding machine. To the uninitiated, it sounds like a science fair project.
But magnets are for real. As Plastics News reported in our May 27 issue, magnets already have grabbed the attention of automotive molders. Now other sectors are finding out.
Electropermanent magnets are compelling. They offer fast and simple mold changes. Also, magnets are versatile. According to advocates, magnetic systems can handle a wider variety of mold sizes than mechanical mold-holding methods, including both traditional clamps and bolts and quick-disconnect systems.
“Electropermanent” means just what it says. First, you position the mold half into the platen and give it a quick shot of electricity to turn on the magnetism. That's it: The magnets stay magnetized with no further need for electrical power. To turn them off again, after safely securing the mold, you apply another burst of electricity.
Prices for injection molding magnets have come down as volumes have risen. As long as the magnets are safe, it seems like a no-brainer that they deserve serious consideration by processors that change molds frequently. Today, that's nearly everybody.
For anyone who works around molds, it's an awesome sight, that mold hanging there. Changing molds will never be the same. Yes, the sky's the limit. Everything's rosy - except for the unfortunate old-school business practice of magnet competitors bashing one another.
Tecnomagnete Inc. and StÃ¤ubli Corp. are taking pot shots at each other — and not just in the Plastics News story (May 27, Page 1, “Magnets getting grip on molders”). Several injection molding officials interviewed for that story said they hear the trash-talking. To its credit, the third magnet supplier, EAS Mold & Die Change Systems Inc., seems to be showing more restraint.
Some of that is normal, of course. Sales people in every industry get a little down and dirty. They make claims about their products and criticize the other company´s. But when it comes to magnets, we're not talking about dueling cell-phone kiosks at the mall. There are real safety issues at stake.
For the record, nobody has been hurt by a mold falling off the magnets, according to industry officials. The metalworking industry has used electropermanent magnets for years for work-holding applications. Even so, the technology is so new to most people in the plastics industry that safety remains a major concern.
Tecnomagnete and StÃ¤ubli can tweak each other all they want, but if some plastics worker gets crushed under a magnetically held mold, well, you can kiss that giant injection molding market goodbye.
We hope magnet suppliers can act in a more professional manner. One way to start: working together to create safety standards through the Society of the Plastics Industry Inc.'s Machinery and Moldmakers divisions. Currently, there are no SPI standards for magnetic mold holding.
Pressure for standards is sure to build in coming months as injection press manufacturers start to promote magnets on new machines. Machinery makers know the value of industrywide standards.
Agreed-upon standards would give magnets a seal of approval — and take away one reason for molders to hold off on switching to magnets.