Operations of Milling
Milling Process:
Gear Cutting:
The gear cutting operation is performed during a miller by
employing a form-relieved cutter. The cutter could also be a cylindrical type
or end mill type. The cutter profile fits exactly with the tooth space of the
gear. Equally spaced gear teeth are cut on a gear blank by holding the work on
a universal diving head and then indexing it.
Helical Milling:
The helical milling is that the operation of manufacturing
helical flutes or grooves round the periphery of a cylindrical or conical
workpiece. The operation is performed by rotating the table to the required
helix angle. And then by rotating and feeding the workpiece against rotary
cutting edges of a milling cutter. Production of the helical milling cutters,
helical gears, cutting helical grooves or flutes on a drill blank or a reamer.
Cam Milling:
The cam milling is that the operation of manufacturing cams
during a miller by the utilization of universal dividing head and a vertical
milling attachment. The cam blank is mounted at the end of the dividing head
spindle and an end mill is held in the vertical milling attachment. The axis of
the cam blank and the end mill spindle should always remain parallel to each
other when setting for cam milling. The dividing head is geared to the table
feed screw so that the cam is rotated about its axis while it is fed against
the end mill. The axis of the cam can be set from 0 to 90° in reference to the
surface of the table for obtaining a different rise of the cam.
Thread Milling:
The thread miller operations are wont to produce threads by
employing a single or multiple threads milling cutter. Thread milling operation
is performed in special thread milling machines to supply accurate threads in
small or large quantities. The operation requires three driving motions in the
machine. One for the cutter, one for the work and the third for the
longitudinal movement of the cutters. When the operation is performed by a
single thread milling cutter, the cutter head is swivelled to the exact helix
angle of the thread. The cutter is rotated on the spindle and the workpiece is
revolved slowly about its axis. The thread is completed in one cut by setting
the cutter to the full depth of the thread and then feeding it along the entire
length of the workpiece. When the thread is cut by multiple threads milling
cutter, the cutter axis and the work spindle are set parallel to each other
after adjusting the depth of cut equal to the full depth of the thread. The
thread is completed by simply feeding the revolving cutter longitudinal through
a distance equal to the pitch length of the thread while the work is rotated
through one complete revolution.
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