Tool Wear and Its Compensation in Screw Rotor Manufacturing

Since screw compressor rotors are of a helical shape and tool points engaged in their manufacturing pass different cutting length, the tools do not wear uniformly along the rotor profiles. The nonuniformity depends on a difference between the rotor point angle and pressure angle and on the rotor helix angle. A difference in relative movement between the tool and the rotors with and without the cutting stock is used to quantify a relative wear of the tool. This is now in counterpart used as a basis for calculation of a variable rotor stock distribution, which results in a uniform wear of the finishing tool when it is applied. Finally, the roughing or semi-finishing tool is generated which cuts the rotors with such a variable distributed stock. Application of this procedure can substantially improve the overall tool economy.