When the injection molding parts are processed, there will be insufficient filling in many cases, which will eventually lead to the unqualified quality of the injection molding products, which often causes a lot of economic losses to the injection molding plant. Therefore, injection molding operators need to know how to do a good job of filling. Solutions for insufficiency.
1. Improper adjustment of the feed, lack of material or too much.
Improper feed measurement or improper feed control system operation, abnormal injection cycle due to injection molding machine or mold or operating condition limitations, low preform back pressure or low particle density in the barrel may cause material shortages. For particles with larger particles and larger porosity, plastics with large crystallinity ratio changes, such as polyethylene, polypropylene, nylon, etc., and plastics with high viscosity, such as ABS, etc., should be carried out when the material temperature is high. Adjust, adjust the amount of material.
When there is too much material stored at the end of the barrel, the screw will consume additional injection pressure during the injection process to compress and push the excess material stored in the barrel, thereby greatly reducing the effective injection pressure of the plastic into the mold cavity. Product is difficult to fill.
2. The injection pressure is too low, the injection time is short, and the plunger or screw returns too early.
Molten plastic has high viscosity and poor fluidity at low temperature, so high pressure and high speed injection should be used. For example, in the manufacture of ABS colored parts, the high temperature resistance of the colorant limits the heating temperature of the barrel, which should be compensated by using a higher injection pressure and longer injection time than usual.
3. The material temperature is too low.
The temperature at the rear end of the barrel is low, and the melt entering the mold cavity rises to a level that is difficult to flow due to the cooling effect of the mold, which hinders the filling of the distal mold; the low temperature and high viscosity at the front of the barrel are difficult to flow and prevent the screw from flowing. Forward movement, causing the pressure indicated by the pressure gauge to be sufficient, but the melt enters the cavity at low pressure and low speed
When the injection molding parts are underfilled, it is very important to take corresponding measures in time. Insufficient filling is one of the problems often encountered in the injection molding process. Therefore, large injection molding manufacturers will conduct real-time training for injection molding operators.
Post time: Mar-15-2022