Reparos em plástico

501-25-53 Body Repairs - General Information 501-25-53 DESCRIPTION AND OPERATION As with all other welding processes, only certain material combinations can be joined together using plastic welding. NOTE: Basic and in-depth training is offered on the following topics. You will find an overview of the complete range listed in the Training brochure published by the Ford Service Organization. NOTE: The manufacturer's data must be taken into account when choosing welding materials and the correct temperature setting of the hot air gun. Repair sequence during plastic welding: ‡ To prepare the location for welding, remove paint residues and sand the weld area. ‡ If parts of the material have been pushed in by an impact, the damaged area can be brought back to shape by heating. ‡ Drill out the ends of the split to stop it spreading further. Machine the location of the weld into a 90° V-shaped groove, to accept the welding rod. ‡ Lay the welding rod in the groove. ‡ Perform the welding. Hot air draw welding or hot air fanning welding. ‡ Rework the weld seam. After cooling, sand the raised weld seam. ‡ Clean the sanded repair surface using plastic cleaner. Apply plastic primer thinly to the repair surface and paint it. Despite good preparation and the correct choice of welding materials, weld faults may occur. The following points must be noted when welding plastic: ‡ Weld together like with like: œ With very few exceptions, only the same materials can be welded together, e.g. PP with PP. ‡ Correct temperature: œ The correct choice of temperature is important for the success of the repair. The plastic must be warmed until it plasticizes (dough-like, soft). Guideline values for welding temperature: Brief Plastic Temperat descrip- ure WLRQ ABS Acrylonitrile butadiene 360° styrene copolymer PA Polyamide 400° Brief Plastic Temperat descrip- ure WLRQ 3& Polycarbonate 370° 33 Polypropylene 280° PP/EPDM Polypropylene/ethylene 280° propylene diene copolymer 385 Polyurethane 300° Hard PVC Polyvinylchloride 340° Soft PVC Polyvinylchloride 370° ‡ Even pressure: œ When rod welding, the pressure is applied by pressing on the welding rod. ‡ Steady speed: œ To achieve a good weld, care must be taken that the working speed is steady. Possible causes of weld faults: ‡ Deformation caused by overheating of the repair area or tensions in the material while welding the component. ‡ Plastic material too thin. ‡ Poor weld joint because the weld temperature was too low or the welding speed was too fast. ‡ Welding different materials together. ‡ Weld seam dropped because the split gap was too wide or the welding temperature was too high. A good weld is recognized by a slightly raised, smooth and even weld bead on the surface of the component. The weld bead must only be worked once it has fully cooled down. Plastic adhesive bonding Adhesive bonding of plastics has some advantages over welding methods: ‡ Within the group of thermoelastic plastics, all semi-rigid ancillary components (such as bumpers, front grilles, etc.) can be repaired without identification. ‡ A two-component polyurethane based adhesive is used for all thermoplastic parts. ‡ Reinforcement strips can be attached behind splits (split length up to max. 100mm) and