The parameters of screw:(1)screw diameter,outside screw diameter,often use 60-150mm,the diameter increase ,conveyor capacity increase(2)the screw length to diameter ratio L/D:the effective L/D when working,usually 20-40,L/D is larger,can reduce current and leakage flow,need plasticizing time is long ,such as rigid plastics,powder,or crystalline plastics.
Heat-sensitive plastics,when temperature increase easy decomposition,L/D is smaller,
(3)the spiral groove depth is smaller,generate high shear force ,is benifit plasticizing
But the productivity may decrease.