Lab Injection Molding Machine

Email Us

The Reason Why Injection Molding Machine Can Not Be Molded

Desktop injection molding machine is the main molding equipment which uses plastic molding mold to make thermoplastic or thermosetting plastics into various shapes of plastic products. It is divided into vertical, horizontal and all-electric. The injection molding machine heats the plastic, applies high pressure to the molten plastic, and ejects it to fill the mold cavity. So what are the factors that the desktop injection molding machine does not form?

1. Injection speed is slow

Injection speed is of great significance for some plastics with disordered shape, large thickness change, long process flow and high viscosity, such as ABS. When high pressure is not available to fill the finished product, high speed injection molding should be considered to address the unsatisfactory shortcomings. Improper feeding adjustment, lack of material or excessive material.The amount of the feeder is prohibited or the feeding control system operates abnormally. Due to the limitation of the injection molding machine or mold or operating conditions, the injection cycle is abnormal, the back pressure in front of the mold is too small, or the material density in the barrel is small. Granular materials with more voids and plastics with large changes in crystalline specific volume, such as polyethylene, polypropylene, nylon, etc., and plastics with high viscosity, such as ABS, should be used in a larger amount. Adjust when the material temperature is high.

When there is too much material at the end of the barrel, the screw needs to use the rated injection pressure to compress and push the excess material in the barrel during injection molding, which greatly reduces the effective injection pressure of plastic entering the mold cavity and makes it difficult for the finished product to overflow. Injection pressure too low, injection time, plunger or screw retraction too early. Molten plastic has high viscosity and poor fluidity at low working temperature, so it should be injected under high pressure and high speed.For example, when making ABS color parts, the high temperature resistance of the colorant limits the heating temperature of the cartridge, which requires compensation for higher injection pressure and longer injection time than usual.

2. Material temperature is too low

The temperature at the front end of the machine barrel of the desktop injection molding machine is low, and the viscosity of the molten material entering the mold cavity rises prematurely to the point that the molten material is difficult to move due to the cooling effect of the mold, so that the temperature at the rear section of the far-end filling machine barrel is low, and the plastic with high viscosity is difficult to move, so that the screw is prevented from moving forward, and as a result, it seems that the pressure displayed by the pressure gauge is satisfied, but in fact, the molten material enters the mold cavity It may block the feeding channel of the mold. If the mold does not have a cold well, use a self-locking nozzle.After the selection of feeding procedures, the nozzle is more able to adhere to the necessary temperature, when the nozzle is too cold, sometimes you can use a torch to do external heating to speed up the temperature rise of the nozzle.

Injection Molding Machine