Why are injection molded magnets weaker than compression molded magnets?
Compression molded magnets have much more magnet material in them than injection molded magnets, so they are inherently stronger. Compression molded magnets are made from a mixture with a high concentration of magnet powder and a small amount of epoxy as a binder. This mixture is then compressed to a high density before curing the epoxy. Injection molded magnets are made by mixing the magnet powder with a plastic that is liquid enough to inject into a mold, and pressures are lower, so injection molded parts have a much lower concentration of magnetic powders and are therefore weaker.
