date：2020-05-13view：453
1. advantages of hot runner system:
save plastic material: in the pure hot runner mold because there is no cold runner, so there is no production waste. this is especially important for expensive plastic applications. in fact, in an era of high world oil and plastic prices, major international manufacturers of hot runner have grown rapidly. because hot runner technology is an effective way to reduce material cost.
characteristics of hot runner system:
(1) plasticizing: namely, glass state, high elastic state (rubber state), viscous flow dynamics (plasticizing state) and decomposition state.
glass state: 0 ~ t1, molecules in the frozen state, hard and brittle, easy to break under pressure.
viscous flow state (plasticizing state) : t2 ~ t3, can be shaped at will.
decomposition state: at t3, the plastic begins to crack, the gas decomposes, and even becomes charred.
(2) forming conditions: after the hot runner mold is formed, the parts are finished, and there is no need to repair the gate and recycle the cold runner. promote production automation. many foreign manufacturers combine hot runner with automation to greatly increase production efficiency.
molding cycle: since there is no cooling time limit in the runner system, the parts can pop out in time after molding and curing. the forming cycle of many thin-walled parts produced by hot runner molds can be less than 5 seconds.
hanoi expansion: many of the most advanced plastic molding processes are based on hot-road technology. for example, pet preforming, multi-color co-injection in the mold, multi-material co-injection process, stack mold, etc.
