Technological process of twin screw equipment

Twin screw extruder is developed on the basis of single screw extruder. Due to its good feeding performance, mixing and plasticizing performance, exhaust performance, extrusion stability and other characteristics, it has been widely used in the processing of extrusion products.

Twin screw extruder process flow:

The curved surface of twin-screw is a spiral surface, which can be machined by the methods of form milling, form turning and form grinding

1. Form milling method: the cutter is a form milling cutter, which is used to process the external formed surface on various milling machines. The shape of the blade is designed and calculated according to the profile of the formed surface of the workpiece, which belongs to the use of cutter. In disk forming milling, there is an included angle between the cutter axis and the workpiece axis, and there is the shortest distance between the axes, that is, the center distance angle. For the helicoid workpiece with symmetrical end section, the disk milling cutter with symmetrical axial section can be designed, and the disk milling cutter is a kind of finishing cutter; In finger shaped milling, the axis of finger shaped milling cutter is orthogonal to the workpiece, the milling cutter rotates according to its own axis, the screw moves in spiral according to the specified lead, and the cutter surface and the spiral surface are enveloped in the mutual movement. Due to the particularity of the spiral surface, this kind of cutter can only be used as the constant pitch spiral surface roughing cutter.

2. Forming turning method: the tool is forming turning tool. Forming turning tool is used to process the forming surface of inner and outer revolving body on various lathes. The shape of the blade is designed according to the profile of the workpiece, which belongs to the cutting tool. A profile template cutter is installed on the common lathe tool holder, and the cutter is turned to a helix angle to make the front edge of the cutter contact with the normal section of the helix. The screw rotates for a circle, and the cutter moves a lead to cut the helix easily. The manufacturing of the forming cutter and the principle of the forming turning method determine that the surface quality of the helix machined by this method is difficult to improve.

3. Form grinding method: the cutter is a form grinding wheel, and its processing principle is similar to that of a disc-shaped milling cutter. The high-precision grinding technology improves the accuracy of the spiral surface, and is used in the processing of twin-screw to improve the meshing accuracy and efficiency of the screw. However, there are few reports on the application of this method in the processing of screw.