Reasons for Neodymium Magnet Insert-Molding
In consumer products, electronics, automotive, and various other industries, neodymium magnets find wide-ranging applications. Despite their versatility, these magnets are delicate and prone to breakage and corrosion. Encasing them in plastic or rubber materials serves the dual purpose of protection and enhancing aesthetics.
However, not all magnet companies possess expertise in plastic injection molding, and vice versa. This is where Tengye comes in.
Dealing with High Temperatures when Insert-molding Neodymium Magnets
Insert molding is a plastic injection molding technique wherein an insert is placed into the mold cavity and molded with plastic to form a single solid piece. Neodymium magnets are susceptible to high temperatures, which can cause demagnetization. This risk is particularly pronounced during plastic injection molding processes. The extent to which the magnet’s surface is exposed to the molten plastic at high temperatures determines whether the magnets are pre-magnetized or magnetized after injection molding. In the latter case, the entire insert-molded piece is placed into a magnetizing coil for magnetization.
Insert Molding with Non-Magnetic Mold Steel
If the neodymium magnet being insert molded is sufficiently thick along its magnetization direction, or if temporary exposure to the plastic flow does not cause demagnetization, another concern arises: the magnets may be attracted to the mold steel, which is often ferromagnetic. In cases where we need to insert mold neodymium magnets in a magnetized state, we opt for non-magnetic mold steel, even though it typically has a shorter mold life. This choice is particularly common for irregularly shaped products that are challenging to place in a magnetizing coil.
