Detailed explanation of a case of injection molding machine adjustment

During the production of this product, such defects will occur every three or two molds. The surface of normal products is bright; This is a bad picture, with the gate as the center and fan-shaped white outward.
The method of countermeasure is much simpler from the result, that is, to change the backward loosening (ejection) from 1.0MM to 5.2MM, but why?
Now let me say that from the surface trace, I preliminarily determined it as "cold material trace", and there are many reasons, such as:
1. Low mold temperature, as shown in the figure;
2. The injection position is not set properly, and the difference between the high and low pressure/speed values is too large, which is similar to the slope on the Elida machine platform. There is a creeping phenomenon, one meal at a time;
3. The heating ring is abnormal (or broken), or the internal heating buffer value of the system is too large, and the heating is unstable, which is easy to produce cold glue at the gate;
4. The operation cycle of employees is unstable, and there are 1 and 3 man-made;
5. The temperature of the first section is too high, and cold glue is produced after overflow;
6. The back pressure is too high, resulting in cold glue after overflow;
7. The nozzle deviates from the mold nozzle, resulting in the "material handle" that cannot be pulled out and cold glue;
8. The mold cold well is too small to accommodate large cold glue;
From so many reasons, eliminate them one by one in your mind, and you are left to confirm. The same is cold material, different mold structures, different injection molding machines, different materials, and different countermeasures. There is no fixed magic weapon for machine adjustment. Only by checking all the possibilities of occurrence can we find out the real abnormal points.