The screen diameter is dependent on the equipment you use. No matter what equipment you use, the diameter of your extruder screens will most likely is within the average diameter range of 30 to 200 millimeters.
The extruder screens should have a filter element that ranges from a mesh count of 240 (60 micron) to a mesh count of 180 (1,000 micron).
In terms of the outer supportive layering of the screen, 16 to 20 mesh is commonly used for the back end while 30 to 40 mesh is generally used for the face end.