Wuhan Handern One two-component (or multi-component) injection molding
DATE：2020/11/25 9:14:13 / READ： / SOURCE：This station
One two-component (or multi-component) injection molding
Two-component injection molding includes two-color, two-component, and double-layer compound injection molding. The equipment structure is roughly the same. www.handern.net Spunbond Non-woven Fabric Making Machine
1. Two-color injection molding
Two different colors of the same plastic are simplified and plasticized by two materials and then injected into the same nozzle at the same time or one after another. A control valve is installed between the barrel and the nozzle, which acts simultaneously with the plasticizing screw (plunger) , Subject to program control. Another type is that the nozzle is equipped with a rotatable mandrel to produce a radial pattern. The resulting product is mixed colors, with all kinds of flowers. It is also possible to use two parallel or opposite injection devices to combine two mold systems. The mold can be rotated 180° to obtain a mixed color product with obvious color separation.2. Two-component structural foam plastic injection molding
The molding equipment is similar to that shown in Figure 10-13. First, the foaming agent-free material (surface material) is injected into the mold cavity, and then the same nozzle. Inject the core layer material containing foaming agent, and while foaming, the surface layer material is squeezed and compacted to the cavity wall. At this time, the cavity is full. Due to cooling and shrinkage, a small amount of foaming agent-free The material fills and closes the gate to obtain a product with no surface shrinkage. www.handern.net Spunbond Non-woven Fabric Making Machine
(1) Equipment characteristics The injection molding equipment is basically the same as the ordinary injection molding machine, but two sets of plasticizing and French plastic devices are required. The nozzle used has a special structure and a closed nozzle to ensure that the two components can be completely separated when passing through the nozzle.
(2) Process characteristics ①The material should be dried in advance, and then the foaming agent should be added; ②The injection temperature of the core layer is related to the foaming agent. When the exothermic foaming agent is used, the barrel temperature should be 10-20 lower than the ordinary injection temperature. Suction foaming agent should be increased by 10-20℃; ③The mold temperature should not be too low, so as to prevent the surface material from freezing faster and not conducive to the core material filling, usually ABS is 35~45℃, and modified PPO is 80~90℃; ④The amount of surface layer and core layer is based on the use requirements (strength, etc.), product shape and size, molding process conditions, etc., usually based on the ability to fully cover the core material; ⑤Injection speed, injection molding and mold structure and other factors Related, usually a slower injection speed is used to ensure the laminar flow of the body, so that the cooling time of the two-component structural foam of a product with good surface quality is related to the wall thickness, dimensional accuracy, mold temperature and foaming agent consumption of the product. The time cannot be too short, but the gate setting of the mold that can be quickly demolded and immediately put into the cold water should ensure that the two components are evenly filled. The vent hole can use the gap of the parting surface to vent, and the main runner of the center gate is close to The diameter of the cone at the product should be greater than the wall thickness at the flange to avoid free jetting. If split gate or film gate is used, it should be greater than 2mm.
(3) Product features It has the following features: ①The core layer material is completely covered by the surface layer material; ②Light weight, good sound insulation and shockproof effects ③It can form large products, the general thickness can be 8-10mm, bending strength, rigidity Good, ④Products with sudden thickness changes can be formed without shrinkage or collapse on the surface. ③The surface of the product is smooth and can be post-processed and machined. ③Conductive fillers (such as throat black, carbon fiber, aluminum powder, etc.) can be added to the core material to provide shielding efficacy. ⑦Waste materials can be used as core materials to reduce costs. www.handern.net Spunbond Non-woven Fabric Making Machine
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