The steering wheel is a composite material made of metal as skeleton material and plastic by injection.
(1)Raw materials and the typical formula. Polypropylene modified with thermoplastic elastomer SBS can be used as special material for automobile steering wheel.
(2) Main production equipment. A screw right-angle injection machine with an injection capacity of 2000g, with a locking force of about 4000 kN. The injection capacity of 2000g can meet the needs of various automobile steering wheel production. 9 The choice of screw type is to ensure the plastic plasticizer and uniform coloring.
(3) Preparation process.The metal frame of the steering wheel is made for the metal processing process, which is omitted here. The hygroscopicity of the modified polypropylene automobile steering wheel is not high (less than 0.02%), but in order to ensure quality stability, it is still advisable to dry at 90 ~ 100 ^ for 3-4h in advance. The steering wheel is shaped by injection. Because this product has a metal skeleton, the plastic in the mold flow channel is longer, the plastic cooling speed is faster, so the injection speed should be slightly faster (40~80. ^/8). The injection pressure should be appropriate. When the product is too large, it is easy to overflow edge, and the internal residual stress is large; the thick wall is easy to shrink and dent, so about 49MPa is generally selected. The temperature of the injection material is slightly lower than that of the pure PP powder, because the processing temperature of SBS is lower (160~190)