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What are the influencing factors of the injection molding machine not forming?
In the plastic processing industry, the injection molding machine is the most used injection molding equipment. The output of vertical injection molding products accounts for more than 30% of the total plastic products. It is characterized by easy production automation, short production cycle, strong adaptability, High-end production power. However, when the vertical injection molding machine has problems at work, it is generally a process problem. So what are the influencing factors of the vertical injection molding machine not forming?
1. The injection speed is slow. The injection speed has a very prominent meaning for some finished products with messy shapes, large changes in thickness, and long processes, as well as plastics with high viscosity such as resistance-enhancing ABS. When the high pressure can not fill the finished product, it should be considered to use high-speed injection to solve the shortcoming of dissatisfaction.
2. The injection pressure is too low, the injection time is short, and the plunger or screw is retracted too early. Molten plastic has high viscosity and poor mobility at low operating temperature, and should be injected with high pressure and speed. For example, when making ABS colorful parts, the high temperature resistance of the colorant limits the heating temperature of the barrel, which should be compensated by higher injection pressure and extended injection time than usual.
3. Improper feeding conditioning, lack of material or more material. Feeding metering prohibition or abnormal operation of feeding control system, abnormal injection cycle due to vertical injection molding machine or mold or operating conditions, low pre-molding back pressure or small particle density in the barrel may cause material shortage. , The amount of pellets with a lot of open space and plastics with a large change in crystalline specific volume such as polyethylene, polypropylene, nylon, etc. and plastics with high viscosity such as ABS should be adjusted to a higher amount, and a larger amount should be adjusted when the material temperature is high. . When there is too much material at the end of the barrel, the screw will consume a rated injection pressure to compress and push the excess material in the barrel during injection, which greatly reduces the effective injection pressure of the plastic entering the mold cavity. Make it difficult for the finished product to overflow.
4. The material temperature is too low. The temperature of the front end of the barrel of the vertical injection molding machine is low, and the viscosity of the molten material entering the cavity rises prematurely to the point where it is difficult to move due to the cooling effect of the mold, which hinders the filling of the far end; the temperature of the rear part of the barrel is low , The plastic with high viscosity is difficult to move, which hinders the advance of the screw. As a result, it seems that the pressure displayed by the pressure gauge is satisfactory, but in fact the melt enters the cavity at low pressure and low speed; the low temperature of the nozzle may be due to the long-term relationship between the nozzle and the fixed feeding. The cold mold loses heat when it touches, or the heating ring of the nozzle is not heated enough or the contact is poor, resulting in low material temperature, which may block the feeding channel of the mold; if the mold does not have a cold material well, use a self-locking nozzle, and select the post-feeding program. It is more able to maintain the necessary temperature; the nozzle is too cold when it is just turned on, and sometimes a flame gun can be used for external heating to speed up the heating of the nozzle.
1. The injection speed is slow. The injection speed has a very prominent meaning for some finished products with messy shapes, large changes in thickness, and long processes, as well as plastics with high viscosity such as resistance-enhancing ABS. When the high pressure can not fill the finished product, it should be considered to use high-speed injection to solve the shortcoming of dissatisfaction.
2. The injection pressure is too low, the injection time is short, and the plunger or screw is retracted too early. Molten plastic has high viscosity and poor mobility at low operating temperature, and should be injected with high pressure and speed. For example, when making ABS colorful parts, the high temperature resistance of the colorant limits the heating temperature of the barrel, which should be compensated by higher injection pressure and extended injection time than usual.
3. Improper feeding conditioning, lack of material or more material. Feeding metering prohibition or abnormal operation of feeding control system, abnormal injection cycle due to vertical injection molding machine or mold or operating conditions, low pre-molding back pressure or small particle density in the barrel may cause material shortage. , The amount of pellets with a lot of open space and plastics with a large change in crystalline specific volume such as polyethylene, polypropylene, nylon, etc. and plastics with high viscosity such as ABS should be adjusted to a higher amount, and a larger amount should be adjusted when the material temperature is high. . When there is too much material at the end of the barrel, the screw will consume a rated injection pressure to compress and push the excess material in the barrel during injection, which greatly reduces the effective injection pressure of the plastic entering the mold cavity. Make it difficult for the finished product to overflow.
4. The material temperature is too low. The temperature of the front end of the barrel of the vertical injection molding machine is low, and the viscosity of the molten material entering the cavity rises prematurely to the point where it is difficult to move due to the cooling effect of the mold, which hinders the filling of the far end; the temperature of the rear part of the barrel is low , The plastic with high viscosity is difficult to move, which hinders the advance of the screw. As a result, it seems that the pressure displayed by the pressure gauge is satisfactory, but in fact the melt enters the cavity at low pressure and low speed; the low temperature of the nozzle may be due to the long-term relationship between the nozzle and the fixed feeding. The cold mold loses heat when it touches, or the heating ring of the nozzle is not heated enough or the contact is poor, resulting in low material temperature, which may block the feeding channel of the mold; if the mold does not have a cold material well, use a self-locking nozzle, and select the post-feeding program. It is more able to maintain the necessary temperature; the nozzle is too cold when it is just turned on, and sometimes a flame gun can be used for external heating to speed up the heating of the nozzle.
