The bending deformation of PVC profile is a common problem in the extrusion process. The main reasons are: uneven discharge of the die; insufficient cooling of the material during cooling and shaping, and inconsistent shrinkage; equipment and other factors.
It is recommended to solve the problem from the following aspects:
①Ensure the concentricity and levelness of the entire extruder line, and correct the concentricity and levelness of the extruder, die, shaping die, water tank, etc. every time the die is changed.
②Assemble the die carefully before starting the machine so that the gaps of all parts are consistent. If the die output is found to be uneven when the machine is turned on, adjust the die temperature according to the bending deformation direction of the parison to ensure uniform output of the die, such as adjusting the die. The temperature is invalid, and the plasticization degree of the material can be appropriately increased.
③Adjust the cooling system of the sizing mold, and increase the amount of cooling water on the side of the large material that bears the tensile stress.
④Adopt the method of mechanical offset center adjustment, that is, adjust the positioning bolt in the middle of the shaping mold while producing, and make reverse micro-adjustment according to the bending direction of the profile (this method should be used with caution and the adjustment amount should not be too large).
⑤ Pay close attention to the work quality of the mold, pay attention to the maintenance of the mold, and maintain and maintain the mold at any time according to the actual situation.