Design of injection mould for medical shadowless lamp holder
Based on the injection molding requirements of a medical shadowless lamp holder,30%glass fiber reinforced poly-butylene terephthalate(PBT)acrylonitrile acrylate styrene(ASA)material was selected for its molding.In response to the difficulty of opening gates due to the disc+double cylindrical structure of the plastic part,two hot gates were designed for the pouring of the plastic part mould cavity,ensuring the reliability of mould cavity filling.In response to the difficulty of automatic demolding of plastic parts with deep walled cylindrical cylinders on both sides,a step-by-step demolding method was adopted.Firstly,a fixed mold top rod pushed by a spring was used to assist in demolding the plastic part from the cavity insert when the mould was first opened.Then,the second opening of the mould drived and pulled the cylindrical core on the mould side to extract it from the plastic part.Finally,the top rod of the injection molding machine was used to push the top needle to eject the plastic part,achieving complete automatic demolding.The mould cavity layout was the first mock examination and one cavity,and the mould was opened twice.A clip sequence controller was designed to control the opening sequence of the mould.The reset spring had also been applied and improved,in addition to being used for resetting the push plate,it was also used for controlling the sequential opening of the mould template.The installation of wear-resistant pads at the top of the reset rod and rubber pads at the bottom are beneficial for improving the mould life.The mould manufactured under this design scheme ensures that the molding accuracy of the plastic parts is MT3 level,and the yield rate is above 95.6%.
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