2. MILLING is the process of machining flat, curved, or
irregular surfaces by feeding the workpiece against a
rotating cutter containing a number of cutting edges. The
milling machine consists basically of a motor driven
spindle, which mounts and revolves the milling cutter,
and a reciprocating adjustable worktable, which mounts
and feeds the workpiece.
3. Milling machine may be define as the type of machine in
which the metal is removed by causing the job to be fed
against a revolving cutting tool called the milling cutter.
Milling Cutters
5. 1. BASE
The base serves as the
foundation of all other parts of
the milling machine. It is the
platform that sits on the
ground to support the
machineโs weight.
2. COLUMN
The column is a box shape
frame that is mounted
vertically to support the
machine. It is connected
directly to the base. It serves
as the housing of all the
driving mechanisms of the
table feed and the spindle.
PRINCIPAL PARTS AND
FUNCTIONS
6. 3. SADDLE
The saddle is a flat surface
that supports the table in a
longitudinal motion. It caters to
the horizontal motion in the Y-
direction of the work piece.
4. KNEE
The knee is the part of the
milling machine that supports
the table and saddle. It caters
to the vertical motion in the Z-
direction of the work piece.
The knee serves as the
housing of the table feed
mechanism and controls.
PRINCIPAL PARTS
AND FUNCTIONS
7. 5. Table
The table is located horizontally on top
of the saddle. It has T-slots for
clamping the material to be used, such
as steel and aluminum. The
longitudinal motion of the table is
limited to avoid or lessen mistakes
with the work piece. However,
universal machine tables can move
both vertically and horizontally.
6. SPINDLE
The spindle is located on the
upper part of the column. The
accuracy of machining depends
on the rigidity, strength and
accuracy of the spindle. The
power transmits to the spindle
through clutches, gears and belts.
PRINCIPAL PARTS AND
FUNCTIONS
8. 7. ARBOUR
The arbour is the spindleโs
extension that secures
rotating and mounting. It is
made with taper shanks with
7:24 value to ensure proper
alignment. It is placed
parallel to the spindle.
8. OVER HANGING ARM
The over-hanging arm is
located on top of the
column. It serves as the
support to the cutter and the
arbour.
PRINCIPAL PARTS AND
FUNCTIONS
9. TYPES MILLING MACHINE
1. BED TYPE MILLING MACHINE
โข This type of milling machine has vertical adjustment in
the spindle.
a. Simplex milling machine
b. Duplex milling machine
c. Triplex milling machine
2. COLUMN AND KNEE TYPE MILLING MACHINE
โข This type of milling machine has vertical adjustment of
the worktable.
a. Hand milling machine
b. Plain milling machine
c. Universal milling machine
d. Omuniversal milling machine
e. Vertical milling machine
10. COMMON USED MILLING MACHINES
KNEE-TYPE:
Knee-type mills are characterized by a vertically adjustable worktable
resting on a saddle which is 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 milling
machine spindle are properly adjusted vertically for operation.
UNIVERSAL HORIZONTAL MILLING MACHINE
The basic difference between a universal horizontal milling machine and a plain
horizontal milling machine is the addition of a table swivel housing between the table
and the saddle of the universal machine. This permits the table to swing up to 45ยฐ in
either direction for angular and helical milling operations. The universal machine can
be fitted with various attachments such as the indexing fixture, rotary table, slotting
and rack cutting attachments, and various special fixtures.
12. RAM-TYPE MILLING MACHINE
The ram-type milling machine is characterized by a spindle mounted
to a movable housing on the column to permit positioning the milling cutter
forward or rearward in a horizontal plane. Two popular ram-type milling
machines are the universal milling machine and the swivel cutter head ram-
type milling machine.
UNIVERSAL RAM-TYPE MILLING MACHINE
The universal ram-type milling machine is similar to the universal
horizontal milling machine, the difference being, as its name implies, the
spindle is mounted on a ram or movable housing.
SWIVEL CUTTER HEAD RAM-TYPE MILLING MACHINE
The cutter head containing the milling machine spindle is attached to
the ram. The cutter head can be swiveled from a vertical spindle position to a
horizontal spindle position or can be fixed at any desired angular position
between vertical and horizontal. The saddle and knee are hand driven for
vertical and cross feed adjustment while the worktable can be either hand or
power driven at the operator's choice.
13. GENERAL MILLING OPERATIONS
Setup
๏ฑ Before setting up a job, be sure that the workpiece, table,
the taper in the spindle, and the arbor or cutter shank are
free from chips, nicks, or burrs.
๏ฑ Do not select a milling cutter of larger diameter than is
necessary.
๏ฑ Check the machine to see if it is in good running order and
properly lubricated, and that it moves freely, but not too
freely in all directions.
๏ฑ Consider direction of rotation. Many cutters can be
reversed on the arbor, so be sure you know whether the
spindle is to rotate clockwise or counterclockwise.
14. ๏ฑ Feed the workpiece in a direction opposite the rotation of
the milling cutter (conventional milling).
๏ฑ Do not change feeds or speeds while the milling machine
is in operation.
๏ฑ When using clamps to secure a workpiece, be sure that
they are tight and that the piece is held so it will not
spring or vibrate under cut.
๏ฑ Use a recommended cutting oil liberally.
๏ฑ Use good judgment and common sense in planning every
job, and profit from previous mistakes.
๏ฑ Set up every job as close to the milling machine spindle
as circumstances will permit.
Editor's Notes
Knee type and universal milling machine
Ram type milling machine
Universal ram type milling machine
Swivel cutter head ram type millling machine