Views:4 Author:Site Editor Publish Time: 2021-05-12 Origin:Site
In the plastics processing industry, the vertical 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, a short production cycle, and adaptability. Robust and high-end production power, but the vertical injection molding machine has a problem working, which is generally a process problem. What are the influencing factors of the vertical injection molding machine not forming?
1. The injection speed is slow, and the injection speed has a very prominent meaning for some of the shape messy, the thickness change, the finished product with a long process, and the high viscosity plastic such as the resistant ABS. When the high pressure can not be used to fill the finished product, a high-speed injection can be considered to solve the shortcomings of filling dissatisfaction.
2. The injection pressure is too low, the injection time is short, the plunger or the screw is returned too early, the molten plastic has a higher viscosity at a low operating temperature, and the mobility is poor. The injection should be injected at a higher pressure and speed, such as in ABS colorful parts. When the colorant is not resistant to high temperatures, it limits the heating temperature of the barrel, which must be compensated by higher injection pressure and extended injection time than usual.
3. Improper feed conditioning, lack of material, or excessive material. Feeding metering is forbidden, or the feeding control system is not operating normally, the vertical injection molding machine or mold operating conditions are restricted to cause the injection cycle to be abnormal, the pre-plastic back pressure is too small, or the material particle density in the barrel is small, which may cause a material shortage.
Regarding the large particles and a large amount of open space, and the plastics with significant changes in the specific volume of crystallinity, such as polyethylene, polypropylene, nylon, etc. higher viscosity plastics such as ABS, the amount of material should be increased. The amount. When there is too much material at the end of the barrel, the screw will consume more than the rated injection pressure to compress during injection, pushing the excess stock of the barrel, greatly reducing the useful injection pressure of the plastic entering the mold cavity, so that The finished product is difficult 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 melt entering the cavity is too early to rise 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 section of the barrel is too high The low, high-viscosity plastic is difficult to move forward, hindering the advancement of the screw, and the result is that the pressure displayed by the pressure gauge is satisfied, but in fact the melt enters the cavity under low pressure and vulgarity.
If the nozzle temperature is low, it may be that the nozzle loses heat due to the long-term contact with the cold mold during the fixed feeding. Perhaps the nozzle heating ring lacks heat or touches badly, resulting in a low temperature of the material, which may block the feeding channel of the mold. The mold does not have a cold material well. , With a self-locking nozzle, after selecting the feeding program, the nozzle can better maintain the necessary temperature, and the nozzle is too cold when it is just turned on. Sometimes a flame gun can be used for external heating to speed up the temperature of the nozzle.
The vertical injection molding machine uses the thrust of the screw (or plunger) to inject the plasticized plastic in the molten state (that is, the viscous flow state) into the closed mold cavity and obtain the product after solidification and shaping.