Principle Parts of Column and Knee Type Milling Machines

Principle Parts of Column and
Knee Type Milling Machines
 

 The main parts of all column and
knee type milling machines are similar but, only the movements 
are different. All
these machines consist of following
main parts

 Base

Column

Knee  

Table

Saddle 

Overarm

Arbor

1. Base


 Base is a heavy casting and provided at the bottom
of the machine.
On both the top and bottom surfaces, it is
accurately machined.
 It acts as a load taking member for
all other parts of the machine and a reservoir for the coolant.
Column of the machine is secured to the base.
Also, the base carries a screw jack which supports
and moves the knee.

2. Column


Column is very important part of a
milling machine and produced under careful attention because on the column many
parts and controls are fitted.

Vertical parallel guide ways are
provided on front face of the column in which knee slides up and down.
Also, on the top of the column overarm is supported.

3. Knee

Knee is a rigid casting which is
capable of sliding up and down 
along the guide ways provided on front face of
the
column. 

With the movement of the knee, the
table height or distance between the cutter and work piece can be
adjusted. 

By operating the screw jack
with the help of hand wheel or Powel feed, the height can be adjusted.

For cross movement of the saddle
and table, horizontal guide ways are provided the top surface of the
knee.
Two bolts are usually provided on front face of the
knee for securing the braces
it.

4. Table

Table acts as a support for the work piece.
Table is generally made of cast iron with its top
surface accurately machined.
To accommodate the clamping bolts
for fixing the work piece, the top surface of the table carries longitudinal T-slots.
Also, the cutting fluid after it is
used drains back to the reservoir through slots these and for this purpose pipe
is fitted.
Longitudinal feed is provided to
the table by using hand wheel fitted on one side of the feed screw.
Vertical feed is provided by
raising or lowering the knee and cross feed by the moving saddle.
Also, in case of universal milling
machine, the table can be swiveled in a horizontal plane around the center of
its base.

3. Saddle

Saddle is the intermediate part
between the table and knee which acts as a support for the
table.
To provide cross feed to the table,
the saddle can be adjusted crosswise along the guide ways provided on the top
of the
knee.
Also, horizontal guide ways are
provided at the top of the saddle along which the table can be moved in a
longitudinal
direction.

4. Overarm 

 It is the heavy support provided on
the top of the milling machine (in plain and universal milling machines).
To support the projecting arbor, it
can slide horizontally, forward and backward and adjusted at required position.

5. Arbor

Arbor is used for holding the milling cutters during
the operations.
It is a common method of mounting
the cutters, although they are mounted on the machine spindle directly too.
The arbors are mainly of two types i.e. standard
arbor and stub arbor.
Standard arbor is provided with a
set of spacing collars, which helps in adjusting the cutter position.
The slots are provided on the
flange of the arbor to engage the driving dogs of the spindle.
Stub arbors are used to hold face
and side milling cutters, which do not need a large overhang.


Milling Arbor
Milling Arbor

0 thoughts on “Principle Parts of Column and Knee Type Milling Machines”

  1. The principle parts of column and knee type milling machines are the column, the knee, the headstock, the spindle and the table.

    The column is a vertical support that provides stability to the machine. It is usually made from cast iron or steel. The knee is a horizontal pivoting support that provides stability to the machine. The headstock is used for mounting and rotating cutting tools in relation to workpiece. The spindle is used for mounting cutting tools in relation to workpiece.

    The table provides surface on which workpieces can be positioned during machining process.

    Reply

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