- Mold Design: The first step is to create a mold design that outlines the shape and specifications of the desired plastic part. The mold design includes details such as the part geometry, cooling channels, and ejection mechanisms.
- Material Selection: The appropriate plastic material is chosen based on the part’s requirements, such as strength, flexibility, and temperature resistance. Common plastic materials used in injection molding include ABS, PP, PE, and PC.
- Material Melting: Plastic pellets or granules are fed into the injection molding machine’s hopper and melted in the heated barrel. The molten plastic is then ready for injection.
- Injection: The molten plastic is injected under high pressure into the mold cavity through a nozzle and runner system. It fills the mold’s cavities, taking the shape of the desired part.
- Cooling: After injection, the mold remains closed, and the plastic cools and solidifies within the mold cavity. The cooling process determines the part’s final structure and minimizes defects.
- Ejection: Once the plastic has sufficiently cooled and solidified, the mold opens, and ejector pins or plates push the finished part out of the mold cavity.
- Trimming: The part may have excess material or flash along its edges due to the molding process. Trimming removes these excesses and ensures the final part meets the desired specifications.
- Quality Inspection: The finished parts undergo thorough inspection to check for defects, dimensions, and other quality parameters. Defective parts are discarded, and only approved parts are prepared for assembly or distribution.
In summary, plastic injection molding involves designing the mold, selecting the appropriate material, melting and injecting the plastic, cooling and solidifying the part, ejecting and trimming it, and finally inspecting the quality to ensure the production of high-quality plastic parts efficiently and accurately.
Injection molding, also known as injection molding, is a common plastic processing method. It works by injecting molten plastic material into a mold, then cooling and solidifying to finally form the desired plastic product. Injection molding has many advantages, making it a widely used technology in modern manufacturing.
First, injection molding has fast production speed and high efficiency. Compared with traditional manual manufacturing methods, injection molding can complete a large number of production tasks in a short time. This is because the injection molding process is automated. The entire production process can be completed automatically by simply heating the plastic material to the appropriate temperature and injecting it into the mold. This efficient production method greatly improves production efficiency and saves time and costs.
Secondly, injection molding can achieve many different patterns and shapes. Whether it is a simple geometric shape or a complex structural design, it can be realized through injection molding. This makes injection molding broadly applicable in manufacturing a variety of products. Whether it is automobile parts, home appliance casings, or medical devices, they can all be produced using injection molding.
In addition, injection molding can also realize the production of large and small size products. Due to the design flexibility of injection molding molds, products of different sizes can be manufactured as required. Whether it is large industrial equipment or small consumer products, they can be produced through injection molding. This flexibility allows injection molding to meet the needs of different industries and markets.
In addition, injection molding also features precise product dimensions and easy updates. Due to the precision control of the mold during the injection molding process, the dimensions of the products produced are very accurate. This makes injection molding very advantageous when manufacturing products that require high precision requirements. In addition, if the product needs to be updated or improved, only the mold needs to be replaced instead of redesigning and manufacturing the entire product.
Finally, injection molding can also create parts with complex shapes. Thanks to advances in the design and manufacturing of injection molding molds, it is now possible to manufacture parts with complex shapes and structures. This is very important for some parts that require special shapes, such as automotive engine parts, electronic equipment casings, etc.
To sum up, injection molding, as a common plastic processing method, has the characteristics of fast production speed, high efficiency, multiple patterns and shapes, production capacity of large and small size products, precise product size and easy update. It is widely used in mass production, complex shape products and other mold processing fields.
What are the steps of plastic injection molding?
- Heating and pre plasticizing
Driven by the drive system, the screw conveys and compacts the materials from the hopper forward. Under the shearing and friction of the heater outside the barrel, the screw and the barrel, the materials gradually melt. A certain amount of molten plastic has accumulated at the head of the barrel. Under the pressure of the melt, the screw slowly retreats. The retreating distance depends on the amount required for one injection of the metering device. When the predetermined injection amount is reached, the screw stops rotating and retreating.
- Mold closing and locking
The mold locking mechanism pushes the template and the mold moving part installed on the moving template to close and lock with the mold moving part on the moving template, so as to ensure that sufficient clamping force can be provided to lock the mold during molding.
- Injection device moves forward
When the mold closing is completed, the entire injection base is pushed forward to make the nozzle of the injection machine fully fit with the main runner of the mold.
- Injection and pressure maintaining
After the mold locking and nozzle fully fit the mold, the injection pressure cylinder enters the high-pressure oil to push the screw forward relative to the barrel, injecting the melt accumulated at the head of the barrel into the mold cavity with sufficient pressure. The plastic volume shrinks due to the temperature drop. In order to ensure the compactness, dimensional accuracy and mechanical properties of the plastic parts, it is necessary to maintain a certain pressure on the melt in the mold cavity to supplement materials.
- Pressure relief
When the melt at the mold gate freezes, the pressure can be relieved.
- Injection device retreats
Generally speaking, after the pressure relief is completed, the screw can rotate and retreat to complete the next feeding and pre plasticizing process. (In general, the action that the injection base withdraws from the main gate of the mold has been canceled for existing injection molding. This action is performed for materials with serious salivation, such as PA).
- Mold opening
After the plastic parts in the mold cavity are cooled and shaped, the clamping mechanism opens the mold and pushes out the plastic parts in the mold.