Shanghai Daoqin Plastics Co., Ltd.

BMC is glass fiber reinforced saturated and poly hot solid property plastics 简称, is currently use amount most large type reinforcement hot solid property plastics.

(l)BMC features and application

BMC tool has good physical properties, electrical property can and force property can, therefore it application separation 广泛, can made as 诸如变 speed parts, gas tube/pipe, gas cover/cap, 保险杠 and other machine parts; in requirements resistant

震, flame retardant, 美观, resistant use aviation, construction, furniture and other 方面也 to application; in it electrical appliances field/area inner, its applications 也越 越广泛.

(2)BMC injection molding equipment in BMC申, due to add glass fiber, therefore use equipment and usually hot solid property plastics injection molding molding equipment has different, use injection molding machine, 柱塞式 and screw can;

1) add material system "不论 is screw also is 柱塞式, must add 一 挤 pressure add material plant/unit, strong/high material material material 筒, add material plant/unit more using/adopting 柱塞式 add - pressure material.

2) injection molding system. due to 柱塞式 injection molding machine injection amount 准确而恒定, make glass fiber (GF) less loss dispersion material in, therefore, 柱塞式 injection molding machine use relatively more, gas 不便.

3) add hot system. in BMC injection molding in, control material temperature degree separation important, must has sleeve/set control system control temperature degree, ensure add material to nozzle temperature degree is most 佳. currently more using/adopting temperature water or 恒

temperature 油进行 add hot. can using/adopting electrical add hot.

4) clamping plant/unit. more using/adopting machine 械, liquid pressure and full liquid pressure and other types clamping plant/unit.

5) mold. BMC injection molding and usually thermoplastic property, hot solid property injection molding has different, main/primary is BMC shrinkage rate relatively low, therefore in design mold cavity dimensions has 变化.

(3)BMC injection molding process

1) material temperature degree and mold temperature degree. injection molding processing 时, requirements BMC in material temperature degree lower, relatively long time maintain low viscosity flow 态; generally material temperature degree can meet/satisfy BMC low value. material temperature degree generally separation is 两
段 or control, material relatively low, nozzle temperature degree relatively high. generally versus 差20-60C, mold temperature degree generally control in 135~185C;.
2） injection pressure. due to BMC flow property 差, solid fast, mold structure complex injection pressure selection relatively high pressure, generally is 80~16OMPao
3) injection speed degree. injection speed degree improve/increase, has improve/increase parts surface quality, shrink short solid time, 但不利于排 gas, increase glass fiber (GF) orientation degree. -故应 in ensure parts surface quality front lower 采
use relatively low injection speed degree, usually is 1.8-3.5m/min.
4) screw speed and back pressure. using/adopting screw injection molding machine, in injection BMC时, screw for glass fiber (GF) loss relatively large, is amount decrease/reduce glass fiber (GF) loss 伤, screw speed low value, generally is 20~5Or/
min. according to BMC viscosity, using/adopting low back pressure is 宜, generally is 1.4-2.0MPa.
5) molding cycle. due to parts large small and complex degree different, process time different, generally injection time is 2~20s, temperature time is 10-20s/mm(thick degree).