It still may seem alien, but more molders are exploring - and buying - electropermanent magnet systems to hold molds onto the platens of injection molding machines. The reason? Fast and simple mold changes. The magnetic system is bolted to a base plate, which is attached to the platen.
Here are some answers to often-asked questions about electropermanent magnets for clamping molds:
Q. How does the mold remain clamped to the magnet, even when the power goes out?
A. Electrical power is only used to turn the magnets on, or turn them off, when the mold is being attached or taken down. Magnetic force, not electricity, holds up the mold.
Q. How long does it take to magnetize or demagnetize the system?
A. Two seconds or less, with a short burst of electricity.
Q. Will the magnetic force influence the working of moving parts inside the mold, such as core pulls?
A. No. The magnetic field extends less than 1 inch from the surface of the magnetic platen into the mold. Existing ejectors will work, since the platens have holes in industry-standard positions.
Q. What maintenance does it require?
A. Only periodic cleaning of the mold and magnetic surfaces. Magnets have no moving parts.
Q. How much mold daylight do I have to give up? How thick are the magnetic platens?
A. It depends on the supplier, but the thickness of each magnet system runs from 49-55 millimeters. To calculate the total loss of daylight, double that number.