Why does the temperature of the injection molding machine exceed the set temperature?

After the temperature of the injection molding machine is set, it will always exceed the set temperature after a period of time.

1) After reaching the set temperature, the relay is disconnected, and the temperature is still high:
The control of this circuit is normal. The reason is that the friction between the raw material, the screw and the material tube heats up naturally. You can use a fan beside the material tube to improve this phenomenon.
In addition, if the set temperature of a certain section is high, heat conduction will also cause the temperature of other sections to be high.
The other is to open the computer temperature buffer screen and modify the buffer value to be smaller.
2) The relay is still not cut off if the set temperature is exceeded:
First check the 8PMOLEX cable on the CPU, and unplug it, and measure whether the electric heating coil has electricity. If there is no electricity, check the heating relay board or temperature board. If there is still electricity, check the wiring.
3), display temperature lock does not change with temperature:
Use a multimeter to measure the impedance of all AC/DC power supplies and the machine (should be above 1MΩ).
Check it again and check the short-circuit strip on the temperature board (6000) or main board (S260), which should be removed.
If it has been removed, replace the 6000 temperature board CPU board and the 260 host CPU board.