Magnetic approach proves attractive for reducing automotive parts scrap

Plastics processor IPL Inc., a $220 million/yr company with four processing facilities in Canada, is one of many in the industry doing all it can to reduce its environmental footprint while also giving its bottom line a boost. Some recent environmentally friendly initiatives have included installing an independent water supply at two of its plants, decreasing the shipment of waste material to the landfill by more than 11% and significantly reducing its hydraulic oil consumption.

Recently, the company turned to Eriez Magnetics (Erie, PA) for help in reducing the amount of scrap generated during processing of a two-piece assembly for a sport utility vehicle. IPL molds the two parts using a glass reinforced polypropylene (GFR-PP), then magnetically induction welds them together to form a single assembly. Scrap assemblies were being thrown away; the welding material meant these could not be reused for these parts.

Norman Asselin, manager of technical products at IPL, turned to Eiez and its PolyMag process for assistance. The supplier's PolyMag additive is incorpo¬rated into one of the GFR-PP grades prior to molding, making this resin susceptible to the magnetic field produced in Eriez's Erium rare earth roll separator. Scrap parts are run through a standard granulator and the PolyMag separator can then separate the mixed plastic regrind.

Savings start to add up

John Collins, Eriez' plastics market manager, says that for the IPL project the PolyMag Separator was supplied with a thicker cleated belt to remove the magnetic welding material from the regrind. The welding material ranges from 5-20% of the regrind weight. The magnetic roll generates a magnetic flux density up to 24,000 gauss, which Collins says is more than enough to remove the welding material.

IPL's Asselin estimates his company has been able to use the new kit to clean about 160,000 pounds (about 73,000 kg) of material that would otherwise have been wasted. Collins notes that, with a belt change, IPL can potentially use the traditional thin belt and PolyMag process to separate mixed resin regrind, containing the PolyMag additive, for other two-shot and overmolded applications.