Designing plastic parts is a complex task that involves many factors and a range of requirements for the application program. How to use this part? "" How does it match with other parts in the component? "" What load will it bear during use? "In addition to functional and structural issues, injection molding problems also play a significant role in the design of injection molded plastic parts in Shijiazhuang. How molten plastic enters, fills, and cools the mold cavity to form a part largely determines the characteristics that the part must possess. Adhering to some basic rules of injection molded part design will result in parts that are typically more robust in use, in addition to being easier to manufacture and assemble. Dividing parts into basic groups will help you build them in a reasonable way while minimizing molding issues. When a component is developed, remember how it is formed and what you can do to reduce pressure.

Plastic injection molding is a good process for manufacturing plastic parts. Injection molding is used to manufacture many things, such as electronic casings, containers, bottle caps, car interiors, combs, and most other plastic products today. It is an ideal choice for producing large quantities of plastic parts, as using multi cavity injection molds can produce multiple parts in each cycle. Some advantages of injection molding are high tolerance accuracy, good repeatability, multiple material choices, low labor costs, minimal waste loss, and almost no need to complete parts after molding. Some drawbacks of this process are expensive upfront tool investment and process limitations.

Most polymers can be used, including all thermoplastics and some elastomers. There are thousands of different materials available for injection molding. The mixture of available materials with alloys or previously developed materials means that product designers can find a material with the correct performance from a wide range of material choices. Select materials based on the required strength and functionality of the parts; And each material has different molding parameters that must be considered. Common polymers such as nylon, polyethylene, and polystyrene are thermoplastic.

An injection molding machine, also known as a press, consists of a hopper, an injection head or screw plunger, and a heating device. The injection mold in Shijiazhuang is clamped on the pressure plate of the molding machine, and plastic is injected into the mold through the injection port. Pressure machines are evaluated based on tonnage, which is the calculated clamping force that the machine can apply. This force keeps the mold closed during the injection molding process. Tonnage can range from less than 5 tons to 6000 tons, although higher tonnage presses are rarely used. The total clamping force required is determined by the projected area of the customized molded part. Multiply the projected area by a clamping force of 2 to 8 tons per square inch of projected area. Based on experience, 4 or 5 tons/inch can be used for most products. If the plastic material is very hard, more injection pressure will be required to fill the mold, thus requiring more fixture tonnage to keep the mold closed. The required force can also be determined by the material used and the size of larger plastic parts that require higher clamping force.

A mold refers to a tool used in the molding process to produce plastic parts. Traditionally, the manufacturing cost of injection molds is high and they are only used for mass production applications that produce thousands of parts. Molds are typically made of hardened steel, pre hardened steel, aluminum, and/or beryllium copper alloy. The material selection for manufacturing molds is mainly based on economic factors. Steel molds generally have a higher cost, but a longer service life, which offsets the higher initial cost of manufacturing more parts before wear and tear. Pre hardened steel molds have poor wear resistance and are mainly used for lower volume requirements or larger components. The hardness of pre hardened steel is usually 38-45 on the Rockwell hardness table. Hardened steel molds undergo heat treatment after processing to improve their wear resistance and lifespan. The typical hardness range is between 50 and 60 Rockwell hardness.

The cost of aluminum molds is significantly lower than that of steel molds, and when using better quality aluminum such as QC-7 and QC-10 aircraft aluminum and processed with modern computer equipment, they can economically form hundreds of thousands of parts. Aluminum molds also provide fast turnover and faster cycles due to better heat dissipation. They can also be coated with wear-resistant coatings made of glass fiber reinforced materials. Beryllium copper is used in areas of plastic molds in Shijiazhuang that require rapid heat dissipation or generate high shear heat.

By injection molding, granular plastic enters the heating bucket from the hopper under the action of gravity. When the particles are slowly pushed forward by the spiral piston, the plastic is pushed into a heating chamber called a barrel, where it melts. As the plunger advances, the melted plastic is forced to pass through the nozzle on the mold sprue sleeve, allowing it to enter the mold cavity through the sprue and runner system. The mold is kept at a set temperature, so the plastic can solidify almost immediately after the mold is filled.

The sequence of events during the injection molding process of plastic parts is called the injection molding cycle. When the mold is closed, the cycle begins, and then the polymer is injected into the mold cavity. Once the cavity is filled, maintain pressure to compensate for material shrinkage. In the next step, the screw rotates to feed the next lens into the front screw. This causes the screw to retract when preparing for the next injection. Once the parts have cooled sufficiently, the mold opens and the parts are pushed out.