Planning machine (Planner)

    

Planer Machines

 

Introduction to Planer Machines

 Planing is one of the basic
operations performed in machining work and generally preferred for machining
large flat surfaces.
 These surfaces may be vertical, horizontal or inclined. The workpiece that can be machined
on the planer machine cannot be machined on the shaper machine, due to
limitation of size. 
 Also, Planing machine is most economical for
machining for large flat surfaces. 
The workpiece is rigidly held on the work-table, which can slide on the groovesprovided on the base ofthe planer. The tool is held vertically in the
tool-head mounted on the cross-rail which can travel ina direction at right
angle to the direction of motion of the work-table.
    Cutting action is achieved by
applying the linear primary motion to the workpiece and feeding the tool at
right angle to this motion.


Working principle of planar machine
Working principle of planar machine


   
Types of Planing Machines

Following are
the types of Planing machines which are generally used

  1.   Double housing or standard planer 
  2. Open side planer 
  3.  Pit planer 
  4. Edge or plate planer 
  5. Divided table planer

1. Double housing planer


 Double housing or standard planer is the most
commonly used type of planer.
 It consists of two vertical columns i.e. one on each
side of the bed.  Between these two columns
(housings) the cross-rail is fitted which carries one or two vertical tool heads. 
These machines are heavy
duty type and carry a very rigid construction.
 In these machines, cutting speed is
very high, but the size of workpiece is limited because of the width of the table. 
Due to long table and larger table
travel, on either side of the columns, a number of workpiece in a series can be
held over the bed length and machining is
done. This will result in a substantial saving in
machining time Also, because of high rigidity of
the machine and robust design of cutting tools, heavier cuts can be easily
taken, which leads to quicker metal removal and a reduced machining time. 
Components machined on these
machines are, extremely large and heavy castings such as machine beds, tables,
plates, slides and
columns.

2. Open side planer


 This type of machine consists of
only one housing i.e. vertically on one side of the bed and the other side is
left open without any obstruction.
 The cross-rail is suspended from the housing as a cantilever. Open side planer is similar to
double housing planer, but the former carries three tool heads and latter
carries four tool heads. 
As one side is open, the components
which are difficult to machine on double housing planer can be easily machined
on these
machines. As there is only one housing, the
machine is subjected to severe twisting forces during the
operation. Hence, during designing of the machine special care
is needed.

Open side planar
Open side planar

3. Pit planer

Pit planer is a special type of Planing machine. It is specially designed for
machining 1ong, heavy and tall workpiece, which can not machined on the
conventional types of planer.
 The workpiece is mounted on a stationary plate or on
the floor inside a pit. 
For clamping of workpiece, T-slots are provided on
the table. The machine is provided with two short vertical
housings which carry a cross-rail. One or two toolheads are
mounted on the cross-rail and if required, two side tool posts on the housings. For machining the surface of the
workpiece, the whole unit travels along the horizontal guide ways.


Pit Planer

Pit Planer


 4. Edge or plate planer


  This machine is completely
different from conventional planer machine in construction as well as working.
  In this machine, the bed and table,
is a fixed unit and the workpiece is mounted on the table. 
The toolhead is mounted on a
movable carriage, which can travel longitudinally along the bed. 
While machining, the operator can
stand on a platform which is attached to the carriage and travels along with
it. Hence during the operation, the
workpiece remains stationary, while the tool moves to and
fro. It is a single purpose machine
constructed for special works such as boiler plates, ship plates, for pipelines
and for welding.

5. Divided table planer

In this machine, the table is
constructed in two or more parts which can be joined together to hold long
workpiece or used separately, as
required. This machine is mainly used for
those components for which more machine setting time is required, because of
their heavy weights. 
For such items, particularly when
identical parts are to be machined on large scale, this machine with divided
table is used such that when the workpiece on one table is being machined; the
same is being simultaneously set-up on the other table, for replacing the
former after the operation is
over. This will result in a
considerable saving in setting time. 

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