common questions in plastic injection 1

common questions in plastic injection （1）

1. When the machine is just started, the product runs on the edge (flying edge), and the reason and solution for the lack of glue after a period of production.

When the injection molding machine is just started, due to the long heating time, low viscosity and good fluidity of the melt glue in the material pipe, the product is easy to run around. After a period of production, the heat is constantly taken away by the melt glue, resulting in insufficient melt glue, high viscosity and poor fluidity, which makes the product lack of glue. After a period of production, gradually increase the temperature of the material pipe to solve the problem.

2. In the production process, when the product is short of glue, sometimes increasing the glue injection pressure and speed is invalid. Why?

After a period of production, due to the continuous heat taken away by the melt glue, the melt glue is insufficient, with high viscosity and poor liquidity, resulting in the lack of glue in the product. Raise the temperature of the material pipe to solve the problem.

3. Causes and solutions of product ellipse.

 The product ellipse is caused by uneven glue injection, which causes uneven pressure around the product and makes the product ellipse. Three points of glue injection are used to make the product even.

4. Requirements of precision products on mould.

 It is required that the die material has good steel property, small elastic deformation and small thermal expansion coefficient.

5. Purpose of acid resistance test.

 The purpose of acid resistance test is to detect the internal stress of the product and the position of the internal stress point, so as to eliminate the internal stress of the product.

 6. The reason and solution of metal insert cracking easily under stress.

Inserts are placed in the product. When the hot tear filled melt adhesive meets the cold inserts during injection molding, internal stress will be formed, which will reduce the strength of the product and make it easy to crack. During production, the inserts are preheated.

7. rationality and selection method of mold exhaust point.

 The unreasonable exhaust point of the mould can not achieve the exhaust effect, but will cause product deformation or dimensional change, so the exhaust point of the mould should be reasonable. Select the mold exhaust point, should be in the product last go full of rubber and product trapped gas burning place open exhaust.

8. Causes and solutions of product embrittlement.

 The product is easy to crack, which is caused by too many materials and secondary materials used in the product, or the material stays in the material pipe for too long, which causes the aging of the rubber material and makes the product easy to crack. Increase the proportion of new materials, reduce the number of times of recycling of nozzle materials, generally not more than three times, to avoid the rubber material staying in the material pipe for a long time.

9. The reasons and solutions for the easy occurrence of PAN fiber in glass fiber products.

 It is due to the low temperature of the melt glue or the mold and the insufficient injection pressure that the glass fiber cannot be well combined with the plastic in the glue, so that the PAN fiber appears. Increase melt temperature, mold temperature and injection pressure.

10. Effect of feed port temperature on the product.

 Too high or too low temperature at the feed inlet will cause unstable material return of the machine and unstable feeding quantity, which will affect the size and appearance of the product.