What are injection molded parts?
Injection molded parts refer to various injection molded products produced by injection molding machines, collectively referred to as injection molded parts, including various packaging, parts, etc. It is mainly made of materials such as polyethylene or polypropylene and added with a variety of organic solvents.
Process parameters of injection molded parts
The main process parameters of injection molded parts include:
1. Cylinder temperature: The temperature of the melt is very important, and the temperature of the injection cylinder used is only a guideline. Melt temperature can be measured at the nozzle or air jet method. The temperature setting of the injection cylinder depends on the melt temperature, screw speed, back pressure, injection volume and injection molding cycle. If you have no experience in processing a specific grade of plastic, please start with the lowest setting. In order to facilitate control, the shooting cylinder is divided into zones, but not all are set to the same temperature. If the operation time is long or the operation is at high temperature, please set the temperature of the first zone to a lower value, which will prevent the plastic from melting and shunting prematurely. Before starting the injection molding, make sure that the hydraulic oil, hopper closure, mold, and injection cylinder are all at the correct temperature.
2. Melt temperature: Melt temperature plays a major role in the flow properties of the melt. Since plastic has no specific melting point, the so-called melting point is a temperature range in the molten state. The structure and composition of the plastic molecular chain are different, so it flows. The influence of temperature is also different. Rigid molecular chains are more obviously affected by temperature, such as PC, PPS, etc., while flexible molecular chains such as: PA, PP, PE, etc. The fluidity is not obvious by changing the temperature, so it should be adjusted according to different materials. Correct the temperature of injection molded parts.
3. Mold temperature: Some plastic materials require higher mold temperature due to high crystallization temperature and slow crystallization speed, and some require higher temperature or lower temperature due to the need of controlling size and deformation, or demoulding, such as PC It is required to be above 60 degrees. In order to achieve better appearance and improve fluidity, the mold temperature of PPS sometimes needs to be above 160 degrees. Therefore, the mold temperature has an inestimable effect on improving the appearance, deformation, size, and rubber mold of the product.
4. Injection pressure: The melt overcomes the resistance required to advance and directly affects the size, weight and deformation of the product. Different plastic products require different injection pressures. For materials such as PA and PP, increasing pressure will make them fluid. Significantly improved, the injection pressure determines the density of the product, that is, the appearance of gloss. It has no fixed value, and the more difficult it is to fill the mold, the pressure of the injection molded part will increase.
Common problems and solutions for injection molded parts (lack of glue)
Lack of glue in the injection molding process is a relatively common problem, and there are many reasons for the lack of glue in injection molding. Based on the editor¡¯s years of experience in the injection molding plant, the reasons and improvement measures are summarized as follows:
1. Material temperature, mold temperature is too low, can be increased, material tube temperature and mold temperature.
2. The size of the nozzle and the glue inlet point is too small, so appropriately enlarge the nozzle and glue inlet point.
3. Poor venting of molds, vent holes can be added.
4. The nozzle is cold or blocked, which can be solved by removing debris from the nozzle and increasing the temperature of the nozzle
5. If the injection speed and pressure are not enough, the shooting speed can be increased and the shooting pressure can be solved.
Guangzhou Aote Engineering Plastics Co., Ltd. is a Guangzhou plastic company. Our company focuses on high-performance plastics and engineering plastics injection molding, PEEK injection molding, PEEK plastic parts, PFA injection molding, PPS injection molding, PVDF injection molding, and PSU injection molding.
