Common problems in profile production

1、Mold plugging

At the exit of the die,if the average speed of each part of the parison is equal,and the influence of self weight is not considered,the parison uniformly extruded will also be affected by three aspects:

(1)Melt off mold expansion;

(2)Parison draft contraction;

(3)Parison cooling shrinkage.

When the drawing speed of the parison at the exit of the die is less than the extrusion speed of the parison under the action of the tractor,the phenomenon of die plugging will occur.

The main reasons for mold plugging are as follows:

1.The tractor slips and the traction force is too small.(water on the surface of the profile,adjust the positive pressure of the upper and lower tracks)2 The speed of the tractor is unstable,fast and slow.(check the tractor)3 The material is too plastic,and the parison cannot support the traction force(reduce the barrel temperature)4 The temperature is out of control,and the discharge on one side is too fast.(check thermocouple)5 The vacuum degree of the setting mold or water tank is too large,and the resistance of the profile is large.(adjust vacuum)6 The lubricant in the formula is excessive,the fluidity is too strong,and the extrusion speed is unstable.(adjust lubricant proportion)7 The feeding slope at the jaw opening of the feeding end of the setting die is too small and too short.(lengthen the feeding slope*)8 The discharge at the jaw mouth is too fast(blowing air for cooling or stopping the machine to repair the discharge*)9 The gap at the jaw opening of the setting die is larger in front and smaller in rear(check whether the positioning system of the setting die and the template are installed incorrectly)