44Magnet AssembliesOur definition of a magnet assembly is a “product”that has become a customised “magnet system” byfurther processing of sintered and plastic bondedpermanent magnets.We complement the magnetswith other precision components, such as gearwheels, impellers, and shielding cans, that makemounting much easier for the customer. The handlingand processing of permanent magnets is verycritical, because they are so brittle and the magneticforces often enormous. We have various machinerysetups that are required for working with magnets,and we develop and build special arrangementsas needed in our special machine manufacturingsection. Through our many years of experience, weare in a position to offer economical package solutions.Production begins at Magnetfabrik SchrambergBeginning of the 1990sManufacturing process- Overmoulding or injection moulding- Multiple component injectionmoulding technology- Gluing technology- Various joining technologies, such asultrasound welding and hot caulking
46 Magnet assembliesParts/componentsThe Path from Magnetto the Magnet AssemblyOutgoing goods inspectionIn the Magnet Assemblies business area, permanentmagnets are converted into custom finished solutions.The customising processes include:• Overmoulding or injection moulding• Multiple component injectionmoulding technology• Adhesive technology• Various joining technologies,such as ultrasound welding, clippingMagnetising, marking, coatingto customer specifications
Magnet assemblies 47Magnets from our own productionHard ferrite magnets, rare earth magnets,plastic bonded magnetsInspection of incoming goodsSurface treatments to customer requirements(such as cleaning, sand blasting)Extrusion coating or injection mouldingMultiple componentinjection moulding technologyGluing technologyOther joining technologies(such as ultrasound welding, clipping)
48 Magnet assembliesOvermoulding or injection mouldingBy overmoulding inserts with magnetic material and/or technicalplastic, magnets can be combined with axles, bushings, or other functionalelements.This can be done by direct injection moulding, overmoulding, or injectionof magnetic material (plastic bonded magnets) or using technicalplastics.Injection technology: plastic bonded magnets• Injection moulding on axles, shafts, and bushings.• Injecting or overmoulding of technical plastics with the magnetmaterial.Injection technology: technical plastic• A sintered or plastic bonded magnet is overmoulded with technicalplastic.• Technical plastic joins sintered or plastic bonded magnets with otherprecision piece parts. Inserts like magnet and axle are solidly bondedtogether by the plastic.
Magnet assemblies 49Multiple component injection moulding technologyMultiple component injection moulding technology offers the capabilityof safely connecting together several plastics of different materialproperties in a single injection moulding process.Multiple component injection moulding technology offers definiteadvantages over conventional processes:• High precision, since all components are injected in thesame die, in one manufacturing step, and thus withoutany fitting tolerances.• Possibility to combine different properties in one part.• Wide range of shaping possibilities, such as miniaturisation.• Better connection quality because the components arefused together.• Reduction in material use, less magnet compound needed.• Fewer manufacturing stages.• Elimination of expensive handling.• Lower cost for manufacturing large numbersof complicated assemblies.For years, we have successfully worked with multiple componentinjection moulding technology.
50 Magnet assembliesGluing TechnologyOver recent years, gluing precision components has been gaining inpopularity. Currently, the airplane and automotive industries, forexample, use gluing in serial production.We have years of experiencein the area of industrial serial production. Employees especially trainedin these adhesive technologies guarantee a professional treatmentand thus stable, enduring quality.Quality control of the glued connections includes:• Tension and compression test (random samples).• Adhesive quantity monitoring by SPC.• Surface tension test.• Surface roughness measurements.Our modern facilities manufacture cost-effectively to exacting standards:• Water-based industrial cleaning.• Sand blasting and plasma facilitiesfor pretreatment of parts.• Curing ovens for temperatures up to +250 °C.• Facilities for UV adhesive curing.• Automatic dosing units; insertion and placement machines.• Complete production lines for fully automatic mass production.
Magnet assemblies 51Other joining technologiesFor certain assemblies, there are economic or technical advantagesto using other joining technologies, such as ultrasound welding, clipping,hot caulking, or mounting, rather than adhesives. Users canprofit directly from the know-how that we have developed from ourmany diverse projects. You can always rely on us for an optimal productand finishing recommendation for your specific requirements.