Plastic injection molding process flow:

Preparation before plastic injection molding—feeding—plasticization—injection into the mold—pressure cooling—demolding—trimming—post-processing

Preparation before plastic injection molding:

Pretreatment of raw materials or inserts (not all raw materials or inserts need to be pretreated – drying, preheating, depending on the degree of product technical requirements, raw material types, and temperature conditions, for metal inserts, generally in winter Requires preheating.)

Raw material drying (baking material) process attention.

There must be clear drying process documents and operating procedures.

Detection and control of moisture content in injection molding before use.

The baking material equipment has a status mark, and the equipment is in good condition.

The records of incoming and outgoing raw materials are clear and clear, and implemented in accordance with regulations, without confusion.

Moisture-proof conditions during the use and turnover of raw materials after baking (conditions for turnover packaging and temporary storage in the factory).

The temperature control instruments and vacuum instruments on the drying equipment have been measured and verified, have verification marks, and are in a valid period of use.

Supplementary instructions for raw material drying:

The drying time is different from the humidity of the raw material itself, the thickness of the material during drying, the drying temperature, and the drying method. The time can be extended or shortened appropriately. The key is to control the moisture content of the raw material before use after drying. Some types of plastics cannot be dried in hot air for a long time, otherwise, they will cause oxidative degradation and discoloration, which will seriously affect the quality of products. **Excessive moisture in the raw material will lead to defects such as silver threads, streaks, and bubbles (internal or external) on the surface of the product, and even cause degradation during the plasticizing process.

Several types of plastics are common for plastics to be dried before processing:

Preparation before molding:

Cylinder cleaning attention: When changing the type of raw material or changing the color, the barrel must be cleaned, and the cleaned material should be marked. Misuse is strictly prohibited! ! The material to be cleaned is *PC, and ABS or PA is not allowed; the material to be cleaned is POM, and PVC is not allowed.

Plastic injection molding process (feeding, plasticization, injection into the mold, cooling under pressure, demolding, (and trimming)

Focus on:

1. The use of recycled materials.
2. Selection of release agent.
3. Injection molding (process parameters)
4. Process products: mold cavity (quantity and runner status), testing means, testing items, and frequency.
5. Whether there is any obvious deformation during the ejection process of the parts.
6. Trimming
7. Parts turnover and circulation identification.