In injection molded products, local stress state is different everywhere, and degree of deformation of product will be determined by stress distribution. If product is cooling. In presence of a temperature gradient, this type of stress will develop, so this type of stress is also called "forming stress".
Tag: injection temperature
In injection molded products, local stress state is different everywhere, and degree of deformation of product will be determined by stress distribution. If product is cooling. In presence of temperature gradients, such stresses will develop, so these stresses are also referred to as "forming stresses".
Electroplated PC/ABS parts are widely used in automobiles, home appliances and IT industries due to their beautiful metallic appearance. Material formulation design and electroplating process are usually considered to be main factors affecting electroplating performance of PC/ABS. However, few people pay attention to impact of injection molding process on electroplating performance.
Materials with medium comprehensive mechanical properties-general engineering plastics refer to those engineering plastics used in engineering to make various product shells and shells for non-load bearing purposes. It is mainly plastic and plexiglass with styrene as main monomer. It is mainly formed by modification of PS. After synthesis of PS in engineering, it is found that PS has two major characteristics, one is transparent; the other is fragile, surface is easily scratched. In order to solve its shortcomings and retain its transparency, it has been modified in two ways. On the one hand, it produced a transparent AS MBS; on the other hand, it produced an opaque HIPS ABS AAS ACS
Before molding, plastic must be fully dried. After material containing moisture enters mold cavity, silver ribbon-like flaws will appear on the surface of workpiece, and even hydrolysis will occur at high temperatures, resulting in material deterioration. Therefore, material must be pretreated before molding process, so that material can maintain appropriate moisture.
PC has excellent performance, high transparency, good impact toughness, creep resistance, and wide operating temperature range. Process characteristics of PC: melt viscosity is less sensitive to shear rate, but is sensitive to temperature, has no obvious melting point, high melt viscosity, resin is easy to hydrolyze at high temperature, and product is easy to crack. For these characteristics, we must pay special attention to different treatments: 1. To increase fluidity of melt, not by increasing injection pressure but by increasing injection temperature; 2. Runner and gate of mold are required to be short and thick to reduce pressure loss of fluid, and at the same time to have a higher injection pressure;
Spray-free materials are more and more widely used, such as rice cookers, pressure cookers, electric kettles, soymilk machines, washing machines, air conditioners and other household appliances shells; automobile pedals, glove boxes, sun visors, pillar trims, side skirts and other interior and exterior trims are increasing using spray-free materials, and spray-free materials are therefore favored by manufacturers.
1. Select proper sprue and gate according to fluidity. 2. Select appropriate fusion state corresponding to gate position. 3. Due to high pressure forming, retraction inclination must be more than 2°. 4. Forming shrinkage must be around 0.5%.
1. High mechanical strength, good toughness, high tensile and compressive strength. Specific tensile strength is higher than that of metal, and specific compressive strength is comparable to that of metal, but its rigidity is not as good as that of metal. Tensile strength is close to yield strength, more than twice as high as ABS. Ability to absorb shock, stress and vibration is strong, impact strength is much higher than that of general plastics, and is better than acetal resin.
Temperature control system design:1. In design of automotive injection molds, each mold needs to use Moldflow software for cooling deformation analysis during design process, then adjust temperature control design system for areas with large product deformations or areas with high molding temperatures.2. Design cooling water circuit for fixed mold as far as possible in accordance … Continue reading 8 precautions for mold design: temperature control system design
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