Injection Molding for Other Plastic Products

What is Injection Molding?

In the plastic mold industry, injection molding for other plastic products is defined as a crucial plastic processing technique that involves heating plastic raw materials (typically in granular or powdered form) to a molten state within an injection molding machine. Under high pressure, this molten plastic is then injected into a pre-designed mold. As the plastic cools and solidifies within the mold, it takes on the specific shape and dimensions of the mold cavity. Once the process is complete, the mold opens, and the formed plastic product is ejected or removed for subsequent handling (such as trimming, assembly, etc.), ultimately becoming a finished product.

What is the Process of Injection Molding ?

● Raw Material Preparation: Selecting the appropriate plastic raw material and performing preliminary treatments like drying and mixing.

● Heating and Melting: Feeding the plastic raw material into the injection molding machine's barrel, where it is heated and sheared by the screw to melt into a viscous and flowable melt.

● Injection Molding: Injecting the molten plastic under high pressure through the nozzle of the injection molding machine and into the mold cavity via the gate system.

● Cooling and Solidification: Allowing the plastic to cool and solidify within the mold, acquiring the desired shape and dimensions.

● Ejection: Opening the mold and ejecting or removing the formed plastic product.

● Post-Processing: Trimming, assembling, inspecting, and other post-processing steps to transform the ejected plastic product into a finished good.

What is the key points do we need to pay attention to, during the Injection Molding?

1.Raw Material Handling

● Drying Treatment: Raw materials must be thoroughly dried according to process requirements to prevent moisture content that can lead to silver streaks or other defects on the finished product's surface.

● Formulation and Mixing: Select suitable plastic raw materials and perform preliminary treatments such as formulation and mixing to ensure material quality and stability.

2.Injection Molding Machine Operation

● Plasticizing: Feed the plastic raw materials into the hopper of the injection molding machine, where they are heated and plasticized into a molten state by the rotating screw.

● Injection Pressure and Speed Control: The injection pressure and speed are crucial for product quality. These parameters must be adjusted according to the plastic material and mold structure. Injection speed should be carefully controlled to avoid issues caused by excessive or insufficient speed.

● Holding Pressure and Cooling: After the plastic fills the mold cavity, a holding pressure is maintained to prevent shrinkage and deformation. Simultaneously, the mold cooling system solidifies the plastic rapidly.

3.Molding Process Control

● Temperature Control: Temperature, pressure, and time parameters must be precisely controlled to ensure plastic flowability, filling, and curing. Close attention should be paid to mold temperature and injection speed variations during the process.

● Internal Stress Control: Products must not exhibit significant internal stresses, which can lead to deformation or cracking. Internal stress testing should be performed after molding.

4.Post-Processing

● Deburring and Trimming: After molding, the product surface may have burrs or flash, which require removal and trimming.

● Painting and Assembly: Products requiring painting or assembly undergo additional post-processing steps.

Production Environment

● Air Quality

● Noise Control

● Temperature and Humidity Control