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 from the following aspects:
1. Ensure 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.
2. Carefully assemble the die before starting the machine to make single screw and barrel the gap between all parts consistent. If the die is found to be
unevenly discharged when starting up, adjust the temperature of the die
according to the bending and deformation direction of the parison to
ensure uniform discharge of the die, such as adjusting the mouth The
mold temperature is invalid, and the plasticization degree of the
material can be appropriately increased.
3. Adjust the cooling system of the shaping die and increase the amount
of cooling water on the side of the large material that bears the
tensile stress.
4. Use the method of mechanical offset center adjustment, that is,
adjust the positioning bolt in the middle of the shaping die while
producing, and make reverse micro-adjustment according to the bending
direction of the profile (the method should be used with caution and the
adjustment 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