The injection molding machine is also called injection molding machine or injection molding machine, injection molding machine It is the main molding equipment for making thermoplastic or thermosetting plastics into plastic products of various shapes by using plastic molding molds. It is divided into vertical, horizontal and all electric. The injection molding machine heats the plastic and applies high pressure to the molten plastic to make it eject to fill the mold cavity. Next, let's take a look at the factors that affect the molding failure of the injection molding machine.
The influencing factors of injection molding machine non molding are as follows:
1、 Slow injection speed
Injection speed is of great significance for some plastics with disordered shape, large thickness change, long process flow and high viscosity, such as drag ABS. When the finished product cannot be filled under high pressure, high-speed injection molding should be considered to solve the problem of dissatisfaction. Improper feed adjustment, shortage or excess of materials. The amount of the feeder is prohibited or the feeding control system is abnormal. Due to the limitations of the injection molding machine or mold or operating conditions, the injection cycle is abnormal, the back pressure before 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 more. 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 of the barrel during injection molding, which greatly reduces the effective injection pressure of the plastic entering the mold cavity and makes it difficult for the finished product to overflow. The injection pressure is too low, and the plunger or screw retracts too early during the injection period. 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 barrel, which needs to compensate for the higher injection pressure than usual and extend the injection time.
2、 Material temperature too low
The temperature of the front end of the barrel of the injection molding machine is low, and the viscosity of the molten material entering the cavity rises too early to move due to the cooling effect of the mold, which hinders the filling of the mold at the far end; The plastic with low temperature and high viscosity in the rear section of the barrel is difficult to move, which prevents the screw from moving forward. As a result, it seems that the pressure displayed by the pressure gauge is satisfied, but in fact, the molten material enters the cavity at low pressure and low speed, which may block the feeding channel of the mold; If the mold does not have a cold well, use a self-locking nozzle and select a post feeding program. The nozzle can better maintain the necessary temperature; When the nozzle is too cold at the beginning of start-up, sometimes the flame gun can be used for external heating to speed up the temperature rise of the nozzle.
