(1) Improper feeding adjustment, lack of material or excessive material. Incorrect feeding measurement or abnormal operation of feeding control system, abnormal injection cycle caused by injection molding machine or mold or limited operation conditions, small pre plastic back pressure or small particle density in the barrel may cause material shortage. For granular materials with large particles and many voids and plastics with large specific volume change of crystallinity, such as polyethylene, polypropylene, nylon, etc And plastics with high viscosity, such as ABS, should be adjusted to a higher amount. When the material temperature is high, the amount should be increased. When there is too much material stored at the end of the barrel, the screw consumes extra injection pressure to compress and promote the excess material stored in the barrel during injection, which greatly reduces the effective injection pressure of the plastic entering the mold cavity and makes the product difficult to fill.—molding of tape carrier

(2) The injection pressure is too low, the injection time is short, and the plunger or screw returns too early. The molten plastic has high viscosity and poor fluidity at low working temperature, so it should be injected at a higher pressure and speed. For example, when making ABS color parts, the high temperature resistance of the colorant limits the heating temperature of the barrel, which should be compensated by higher injection pressure and longer injection time 。

(3) The injection speed is slow. The injection speed is of great significance for some products with complex shape, large thickness change and long process, as well as plastics with high viscosity, such as toughened ABS. When the products cannot be filled with high pressure, high-speed injection should be considered to overcome the problem of dissatisfaction.—molding of tape carrier

(4) The material temperature is too low. The temperature at the front end of the barrel is low, and the viscosity of the molten material entering the cavity rises too early to flow due to the cooling effect of the mold, which hinders the mold filling at the far end; the low temperature at the rear section of the barrel and the difficult flow of plastic with high viscosity hinder the forward movement of the screw. As a result, it seems that the pressure displayed by the pressure gauge is sufficient, but in fact, the molten material is under low pressure and low speed Enter the cavity; If the nozzle temperature is low, it may be that the nozzle loses heat by contacting with the cold die for a long time during fixed feeding, or the material temperature is low due to insufficient heating or poor contact of the nozzle heating ring, which may block the feeding channel of the die; If the mold does not have a cold charging well, use a self-locking nozzle and adopt the post charging procedure, so that the nozzle can maintain the necessary temperature; The nozzle is too cold at the beginning of startup. Sometimes, the flame gun can be used for external heating to accelerate the temperature rise of the nozzle. —molding of tape carrier