What is Whirling?
Whirling is a machining operation in which a series of profiled cutters remove material by passing over the workpiece moving at cutting speeds of 350-650SFM and advancing at “Lead” to produce a helical form.
Whirling removes material similarly to milling; however, in whirling the carbide cutters are arranged along the inside of a ring to a predetermined cutting circle diameter calculated from the thread data. (Outer Diameter, Pitch, Lead, etc.)
The whirling head is tilted to the nominal helix angle of the worm. Material removal is the result of the whirling ring rotating at high speed around a slowly rotating workpiece. The rotating workpiece combined with the advancement of the longitudinal slide produces the required pitch of the thread.
The tangential cutting action of the whirling process leaves the tool in contact with the workpiece for a much longer time along the arc of the “cutting circle” of the inserts.
Thread whirling process:
Five movements willl be finished when the whirling process:
(1) The whirling ring with carbide forming tools rotates at high speed (main movement)
(2) The lathe spindle with workpiece rotates at slow speed (subsidiary movemetn)
(3) The whirling head forwards axially with the workpiece according to the thread pitch or lead(feed movement)
(4) The cross slide of lathe with whirling head feed radially (cutting movement)
(5) The whirling head could be titled exactly according to the helical angle.