Abstract:

A hot runner two plate mold was designed for injection molding of plastic parts for an automotive glove box body. In this mold， a hot runner + cold runner composite gating system was adopted for gating according to the non⁃equilibrium characteristics of the plastic mold cavity. There were three cold gates at the beginning of the mold cavity， which were fed in a timely and sequential manner by two hot nozzles， ensuring the filling balance of the mold cavity. In terms of a difficulty in implementing automated demolding for plastic parts with multiple demolding directions， an integrated classification design method was applied for demolding directions. Based on the determination of the main demolding direction， 14 secondary demolding directions were obtained， and corresponding 4 sliders and 11 lifters were set up for the side core demolding of these difficult demolding models. This design method is effective to solve the problems in automated demolding for complex plastic parts in automobiles. There were 11⁃lifter mechanisms， and three different types of lifter mechanisms were set up according to the design space， including a square top rod mechanism， a cylindrical lifter rod + lifter block mechanism， and a cylindrical lifter rod + inclined guide column extended range lifter mechanism. In the extended range lifter mechanism， the inclined guide column was used to extend the range of the lifters seat plate on the basis of the cylindrical lifter rod+lifter block mechanism， thus realizing the lateral core pulling stroke extension of the lifters block. For the formation of plastic part skin patterns， a skin pattern depth of 30μm and a draft angle of 2.4 ° were adopted as a solution. The forming material was S136 alloy steel， and the skin pattern was polished with a 1000 ^# sandpaper.

Key words: automobile glove box, injection mould, leather texture, sloping roof, sliding block, hot runner, cold runner