Design engineers at Tengam Engineering, Inc. have developed injection molding techniques that allow injection molded magnet material to be more effective when used as a replacement for sintered ferrite or NdFeB magnet arcs. This process will allow the injection molded magnet industry to be expanded.
Weight loss reductions for the magnets have been estimated to be as much as 60% while keeping magnetic requirements at the same level as sintered ferrite. Magnet assemblies have proven to be reduced by 45% but could also go as high as 60%. Assembly processes, which are somewhat typical within the motor industry, can be reduced by significant amounts when multiple molding operations are incorporated into the process and air gaps can easily be reduced to .020″ (.5mm) with gaps between magnet arcs completely eliminated.
This process was first tested on a ½ HP brushless DC (BLDC) motor. Preliminary analysis indicated that weight reduction, assembly processes and tolerances would all be greatly improved while retaining the original parts magnetic requirements. Part quality and consistency would also be greatly affected. All of these areas were proven after the testing of a completed prototype assembly.
Molded magnet sizes examples for sintered ferrite replacements range from .75″ x .375″ x 4.0″ (19 x 10 x 100mm) and could be as large as 6.0″ x 5.50″ x 2.5″ (150 x 140 x 65mm) although Tengam engineers admit that larger sizes may not be as cost effective. Parts can be molded onto back irons (yokes) or directly onto motor shafts. Other concepts regarding part size and configuration have also been discussed with great interest and are achievable in manufacturing processes. Please call or email to discuss your unique applications. (269) 694-9466 or firstname.lastname@example.org