How to overcome the process of incomplete injection molded products?

Question.
The injection molded product is incomplete, how can the process be overcome?

The answer is.
Slow injection speed
Injection speed is of great significance for some products with complex shapes, large thickness, long process flow, and high viscosity plastics such as tough ABS. When high pressure is not enough to fill the product, high speed injection should be considered to overcome the unsatisfactory problem.
Improper feed adjustment, missing or overfilled material
Inaccurate measurement or improper operation of feed control system, injection molding machine or mold or operating conditions, resulting in abnormal injection cycle, small pre-molding back pressure or small density of material in the barrel may cause lack of material. For large particles, large voids, special changes in crystallography, such as polyethylene, polypropylene, nylon, etc., and higher viscosity plastics, such as ABS, the dosage should be adjusted higher. When the temperature is high, the amount of material should be adjusted.
When too much material is stored at the end of the barrel, the screw consumes additional injection pressure to compress and push the excess material in the barrel during the injection process, which greatly reduces the effective injection pressure of the plastic entering the mold cavity. The product is difficult to fill.
Material temperature is too low
The temperature at the front of the barrel is low, and the melt entering the cavity is prevented from filling distally by the cooling effect of the mold, causing the viscosity to rise prematurely to a point where it is difficult to flow; the plastic at the rear of the barrel is low in temperature and high in viscosity. Difficulty in flow impedes the advance of the screw, causing the pressure gauge to appear adequate to actually enter the cavity at low pressure and low velocity.
If the nozzle temperature is low, the nozzle may be in contact with the cold mold for a long time, with insufficient heat, or the nozzle heating coil may not be heated sufficiently, or the contact temperature may be low, which may block the feed passage to the mold; if the mold is not cold Wells, use a self-locking nozzle with a post-feed procedure, the nozzle can maintain the necessary temperature; when the nozzle is too cold, the nozzle can be heated externally to accelerate the nozzle temperature.
Injection pressure is too low, injection time is too short, plunger or screw returns too early
Molten plastics have higher viscosity and poor flowability at lower working temperatures and should be injected at higher pressures and speeds. For example, in the case of ABS colored parts, the high temperature resistance of the colorant limits the heating temperature of the barrel, which is compensated by a higher injection pressure and longer injection time than usual.