MILLING MACHINE OPERATIONS - OD1644 - LESSON 1/TASK 1
2.
Milling Machines
a.
General.
The milling machine removes metal with a revolving cutting
tool called a milling cutter.
With various attachments, milling machines
can be used for boring, slotting, circular milling dividing, and drilling.
This machine can also be used for cutting keyways, racks and gears and for
fluting taps and reamers.
b.
Types. Milling machines are basically classified as being horizontal
or vertical to indicate the axis of the milling machine spindle.
These
machines are also classified as knee-type, ram-type, manufacturing or bed-
type, and planer-type milling machines. Most machines have self-contained
electric drive motors, coolant systems, variable spindle speeds, and power-
operated table feeds.
(1)
Knee-type Milling Machines.
Knee-type milling machines are
characterized by a vertical adjustable worktable resting on a saddle
supported by a knee. The knee is a massive casting that rides vertically on
the milling machine column and can be clamped rigidly to the column in a
position where the milling head and the milling machine spindle are properly
adjusted vertically for operation.
(a)
Floor-mounted Plain Horizontal Milling Machine (figure 1 on the
following page).
1
The floor-mounted plain horizontal milling machine's column
contains the drive motor and, gearing and a fixed-position horizontal
milling machine spindle. An adjustable overhead arm, containing one or more
arbor supports, projects forward from the top of the column. The arm and
arbor supports are used to stabilize long arbors, upon which the milling
cutters are fixed. The arbor supports can be moved along the overhead arm
to support the arbor wherever support is desired. This support will depend
on the location of the milling cutter or cutters on the arbor.
2
The knee of the machine rides up or down the column on a rigid
track.
A heavy, vertical positioned screw beneath the knee is used for
raising and lowering.
The saddle rests upon the knee and supports the
worktable.
The saddle moves in and out on a dovetail to control the
crossfeed
2
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