What needs to be considered for screw wear

Update:01 Sep 2021

The geometry of the screw is designed according to the specific application. If the operating conditions are normal and meet the operating requirements, it should be able to achieve gentle processing of different materials and a long service life of the screw and barrel. In order to reduce the wear of the screw and barrel, corresponding measures have been taken in the design and manufacture of the machine. Through continuous improvement, the geometric design of the screw can be adapted to different, newer and higher requirements.

For the guided-rotating twin screw, the material is conveyed in the axial direction, similar to the situation of a pair of calender rolls (calendering effect). The screw is subjected to upward and outward forces, and the screw is pushed to the barrel, causing the screw and barrel to wear. This is a common phenomenon, but it is more prominent when processing materials. It is conceivable that the above-mentioned force is proportional to the size of the recycled material (hard particles) and the particle size is the main influencing factor for the degree of wear of the screw and barrel. The larger the particles, the more severe the wear. When processing recycled materials, the particle size of recycled materials should be as small as possible.

The particle size of the pellets has basically the same effect as the particle size of the recycled materials. The main difference between the two is that the shape and size of the pellets are more uniform than the recycled materials, and the "hard particle effect" brought by the similar density and geometry is basically the same. Therefore, the particle size of the processed pellets should also be as small as possible.

Good plasticization of the material can reduce any unfavorable factors that cause the screw and barrel to wear to a minimum. Therefore, all measures that can promote and optimize the degree of plasticization of materials are worth recommending and adopting.