abdômen, comumente conhecido como acrilonitrila butadieno estireno, é feito por copolimerização de acrilonitrila butadieno estireno. Devido às diferentes proporções dos três monômeros, ABS com diferentes propriedades e temperatura de fusão pode ser expandido para ABS com diferentes usos e propriedades, such as impact grade, heat resistance grade, flame retardant grade, transparent grade, reinforced grade, electroplating grade, etc., if it is blended with other plastics or additives.
The fluidity of ABS is between PS and PC. the fluidity of ABS is related to injection temperature and pressure. The influence of injection pressure is slightly greater. Portanto, higher injection pressure is often used to reduce melt viscosity and improve filling performance.
1. Treatment of plastics
The water absorption rate of ABS is about 0.2% – 0.8%. For general grade ABS, bake in oven at 80-85 ℃ para 2-4 hours or in drying hopper at 80 ℃ para 1-2 hours before processing. For heat-resistant ABS with PC component, the drying temperature should be adjusted to 100 ℃, and the specific drying time can be determined by extrusion. The proportion of recycled materials should not exceed 30%, and the recycled materials should not be used for electroplating ABS.
2. Selection of injection molding machine
The standard injection molding machine of Ramada can be selected (the length diameter ratio of screw is 20:1, the compression ratio is greater than 2, and the injection pressure is greater than 1500bar). If the color masterbatch is used or the appearance of the product is high, the screw with a smaller diameter can be selected. The clamping force is determined according to 4700-6200t / m2, which depends on the plastic grade and product requirements.
3. Mold and gate design
Mold temperature can be set at 60-65 ℃. The channel diameter is 6-8mm. The gate width is about 3 milímetros, the thickness is the same as the product, and the gate length is less than 1 milímetros. The exhaust hole is 4-6mm wide and 0.025-0.05mm thick.
4. Temperatura de fusão
It can be accurately determined by air injection. According to different grades, the melt temperature is also different. It is suggested to set as follows:
Impact grade: 220 ℃ – 260 ℃, 250 ℃ is better
Electroplating grade: 250 ℃ – 275 ℃, 270 ℃ is better
Heat resistant grade: 240 ℃ – 280 ℃, 265 ℃ – 270 ℃
Flame retardant grade: 200 ℃ – 240 ℃, 220 ℃ – 230 ℃ is better
Transparent grade: 230 ℃ – 260 ℃, 245 ℃ is better
Glass fiber reinforced grade: 230 ℃ – 270 ℃
For products with high surface requirements, higher melt temperature and mold temperature are used.
5. Injection rate
The fire grade should use slow speed, and the heat grade should use fast speed. If the surface requirement of the product is high, the shooting speed of high-speed and multi-stage injection should be controlled.
6. Contrapressão
Em geral, the lower the back pressure is, o melhor. The commonly used back pressure is 5bar. The dyeing material needs higher back pressure to make the color mixing uniform.
7. Residence time
Desnecessário perguntar 265 ℃, the residence time of ABS in the melt can not exceed 5-6 minutes at most. The flame retardant time is shorter. If the machine needs to be stopped, the set temperature should be lowered to 100 ℃ first, and then the general-purpose ABS can be used to clean the glue cartridge. The cleaned mixture should be put into cold water to prevent further decomposition. If you need to change from other plastics to ABS material, you need to use PS, PMMA or PE to clean the glue cartridge. Some ABS products have no problem when they are just demoulded, and they will change color after a period of time, which may be caused by overheating or too long residence time of the plastic in the melt cartridge.
8. Post treatment of products
General ABS products do not need post-treatment, only electroplating grade products need to be baked (70-80 ℃, 2-4 horas) to passivate the surface traces, and the products that need to be electroplated can not use mold release agent, and the products should be packed immediately after they are taken out.
9. Matters needing special attention during molding
There are several grades of ABS (especially flame retardant grade). After plasticization, the adhesive force of the melt on the screw surface is very large, and it will decompose after a long time. When the above situation occurs, it is necessary to pull the homogenizing section and compression screw out for wiping test, and regularly clean the screw with PS, etc.
Sobre JasonMould Industrial Company Limited
Jasonmould é um Fabricante de moldes da china de moldes de plástico- molde de injeção, moldes de fundição sob pressão, moldagem por sopro de plástico, moldagem rotacional, médico moldagem por injeção de plástico, dois tiros moldagem por injeção de plástico, inserir moldagem, sobremoldagem, moldagem por injeção de metal, moldagem por micro injeção, moldagem por injeção de pó, moldagem por injeção de cerâmica, moldagem por injeção de líquido, moldagem por injeção husky, molde doméstico, molde de fundição, ferramenta de molde, moldes personalizados, moldes da china, ferramentas de prototipagem rápida, ferramentas de prototipagem de plástico, ferramentas de punção, matriz e ferramentas para peças móveis / celulares, partes automotivas, aspirador de pó, ferramentas recarregáveis, telefones, copiadoras, computadores, alto-falantes multimídia, e muitos outros produtos eletrônicos e eletrodomésticos. E também um fabricante de produtos de plástico, fabricante de moldes China- peças de plástico, tanque de água de plástico, bolas de plástico, recipientes de plástico, fivela de plástico, âncora de plástico, cabide de plástico, colher de plástico, encaixe de tubo de plástico, tombo de plástico, talheres de plástico, copos de plastico, garrafas plásticas, bandeja de plastico, recipiente plástico de cosmético, caixa de plástico, recipiente de plástico para comida, cadeiras de plástico, tampas de plástico, tampa de plástico, tubos de plástico, canos de água de plástico, maçanetas de plástico, tubo de plástico, caixas utilitárias de plástico, prateleiras de plástico e assim por diante.
Contato:
Pessoa: James Yuan
Empresa: JasonMould Industrial Company Limited
Adicionar: LongGang Village,LongXi Town,BoLuo County,Cidade de HuiZhou,Província de Guangdong, China
Tel: 86-752-6682869
E-mail: [email protected]
Local: https://www.jasonmolding.com/custom-injection-molding/
