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Insert Moulding / Over Moulding / Injection Molded (Plastic) Sintered Neodymium Magnets:Is it possible to insert mould a sintered neodymium magnet inside a plastic injection moulded part?

If you’re looking for an assembly of round magnets into an ABS housing, then you’ll LOVE this article.

What technique do you use to stick the magnet on the ABS part?

One solution is using 3M double sided tape, Loctite glue s or AB glue. But this is not a fixed component. Even you try many different glues and sometimes it will fail.

If you need permanent fixation, the other good solution is INSERT MOUDING. The sintered NdFeB magnet manufacturerd by injection molded technique is also called plastic coated magnet. It is colorful, weatherproof and more durable than uncoated magnet or normal coated NiCuNi, Zn magnets, avoiding gluing the magnet as a secondary process. You may have a tooling charge (if a existing tool cannot be used or modified) and depending on the magnetic assembly, a magnetising fixture may be required as well.

Why overmolding would work with N42 or N45 grade magnet as I know the injection temperature of ABS is over 200°C ?

It is true that all magnets are affected by heat. And the maximum working temperature of sintered neodymium from N to AH series is among 80℃-220 ℃ which is lower than injection molding. That’s why, generally, when it comes to injection molded magnet, you’ve heard enough about bonded ndfeb magnet, samarium cobalt magnet and ferrite magnet for one lifetime.

Because of 250 degree celsius high temperature of the plastic mold, only these ferrite, smco and bonded ndfeb magnets which can work under higher temperature environment are suitable for injection molding manufacture. Why we insist on using sintered ndfeb magnet here even it’s hard to make: super power magnetic force is the most important factor and no other magnet in the world can take the place of sintered ndfeb magnet.

Okay, how N42 Sintered NdFeB magnet work here? When overmold process is fast, like about 10-40 seconds. This short time has few influence on magnetic force. Because the outside of the magnet expose all the heat but the inner volume may not get so hot. Meanwhile, you may have to choose a stronger magnet or higher working temp. Magnet than your original design to avoid any demagnetization during overmolding process.

All options you can choose for permanent SINTERED NDFEB magnet overmolding:

1. Overmold 80 ℃ sintered neodymium magnet (unmagnetized), and then magnetize the full component (depends on the size of assembly).
2. Overmold a standard 80℃ sintered NdFeB magnet (magnetized), and then fully re-charged the assembly (depends on the size of assembly).
3. Overmold a higher Hci NdFeB magnet (magnetised), but it cost more.
4. Put sintered NdFeB in plastic housing, add plastic cap, and then ultrasonic weld seal.

China Magnets Source Material Limited is a professional plastic magnet manufacturer for many years. We also manufacture magnetic assembly according to your special requirements.

Contact information
China Magnets Source Material Limited
Tower B, Qiongzhu Building,
Huawang Rd,Longhua District,
Tel: +86 755 28174720
Fax: +86 755 28174720