Effect of Vibration on Surface Roughness in Finish Turning: Simulation Study

This paper presents the results of simulation analyses carried out to investigate the effect of adding controlled vibration of varying amplitudes and frequencies onto simulated workpiece profiles on surface roughness. The surface profiles were generated using the nose edge image of a real cutting tool insert at various stages of wear. The invariant moment sub-pixel edge detection method was used to extract the precise tool nose profile. The extracted nose profile was duplicated 20 times to generate the simulated workpiece profile. Vibration signals in the form of sine waves of amplitudes 0 to 50 % of the peak-to-valley height of the original workpiece profile and various frequencies were added to the simulated profile. Noise signals emanating from real machining were also added to the original profile to investigate their effect on roughness. The simulation study has shown that average roughness may increase continuously or fluctuate randomly depending on the magnitude of vibration added to the vibration-free workpiece profile. In the absence of vibration, the surface roughness of the workpiece decreases due to flattening effect of the tool nose during early stages of tool wear.

Specialized Screw for Clamping of Cutting Tool Inserts

The paper presents the design of easy-to-use and sophisticated cutting tool insert clamping that is applied for turning tools. The simplified analytical calculation and von Mises stress fields obtained by Finite Element Method are provided. The technical solution of clamping screw is based on the specialized screw head that is of hexagonal-conical shape. The higher axial force in screw arising from the tightening, higher contact pressure clamping the cutting tool insert. The frictional force between screw head and the insert surfaces presses the cutting tool insert into its seating when tightening and helps to get out the insert when un-tightening. The design of clamping specialized screws gives the possibility to use them in integrated cutting tools with two or more cutting tool inserts.