SHAPER to Teach

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SHAPER


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SHAPING MACHINE

The Main Function of shaper is to generate a flat

surface by combination of linear movement of

cutting tool and work pieces.

A shaping machine is used to machine surface. It

can cut curves, angles and many other shapes. It is

a popular machine in a workshop because itsmovement is very simple although it can produce a

variety of work.


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Advantages

Set up of shaper is easy & quick

Work can be held easily

Single point tools are inexpensives Tools can be grounded easily to any desired

shape

Low intial cost Thin & fragile jobs can be conveniently

machined.


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Limitations

Shaper is a slow machine

Tool requires a number of strokes for

machining a work

Cutting speeds are slow

Not adaptable for assembly & production line


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Applications

Small & medium sized work

Tool room jobs

Job shop production Die & jig making


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CLASIFICATION OF SHAPERS

Shapers are classified in a number of ways as :

1) According to the type of mechanism used for giving reciprocating motionto the ram :

Crank type

Geared type

Hydraulic type2)According to the position and travel of the ram:

Horizontal type

Vertical type

Travelling head type

3) According to the type of design to the table: Standard shaper

Universal shaper

4)According to the type of cutting stroke:

Push type

Draw type


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SHAPING MACHINE


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PRINCIPLE PARTS OF SHAPER

Base

Column

Ram

Cross-rail

Table

Tool Head :-The Tool head assembly is located on thefront of the ram casting. The tool head can be rotated

on its mounting. It can be moved vertically. Theforward stroke of the tool is used for the cuttingoperation. The backward stroke is return stroke.


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Specifications

Length, breadth and depth of the bed

Maximum axial travel of the bed and verticaltravel of the bed / tool

Maximum length of the stroke (of the ram / tool) Range of number of strokes per minute

Range of table feed

Power of the main drive Type of quick return mechanism

Space occupied by the machine


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Shaper operations

The different operations can be performed onshaping machine. They are listed as.

Machining horizontal surface

Machining vertical surfaceMachining angular surface

Machining an irregular surface

Machining an curved surfaceMachining a slots, grooves or keyways

Cutting splines or gears


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Machining horizontal surface

1) Set the vice jaws length perpendicular

to the ram movement.2) Hold the job length-wise parallel to

the tool stroke so that maximumstroke of the tool may be utilized.

3) Adjust the cutting speed and feeddepending upon the surface finishrequired, rough or finish.

4) Hold the appropriate tool in toolhead. Set the proper inclination of thetool and depth of cut.

5) Give cross feed to the tool initially by

hand till the cut start and thenemploy power feed.

6) After the tool has cut the full width ofthe job, stop the shaper, inspect thejob and set another depth of cut.

7) Repeat the above steps.


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Machining vertical surface

1) The tool is fed downward invertical cutting so swivel theclapper box from the face of thework to be cut .

2) The tool is fed downwards byrotating the downfeed screw byhand at the end of return stroke.

3) On the return stroke the toolswings away from the work andgives clearance, which prevents

the work from being scored.4) Start cutting from highest point

towards the bottom.

5) Repeat the procedure for anothercut.


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Machine angular surfaces

1) Set the swivel head to therequired angel for shaping angularfaces as shown in Fig. 6.4.6.(c).

2) The clapper box is to be swung

away from the face to bemachined.

3) The tool is to be fed by the slidehand wheel.

4) The apron top is also swiveled inthe direction away from thesurface to be machined.

5) Feed the tool during return stroke.

6) Repeat the procedure to finish thework.


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Crank shaper

This is the most common type of shaper. In this a single point

cutting tool is given a reciprocating motion equal to the length

of stroke desired and the work is a clamped on the table.

The crank shaper employs a crank mechanism for converting a

circular motion of a large gear called a bull gear to

reciprocating motion of the ram.


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Hydraulic shaper

In hydraulic shaper, reciprocating movement of the ram isobtained by the hydraulic power. Oil under pressure is

pumped into the operating cylinder fitted with piston.

The piston speed is varied by varying the amount of liquiddelivered by the pump.


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Geared shaper

In this shaper rack and pinion is used to

convert the circular motion of electric motor

into reciprocating motion of the ram. The rack

teeth which are cut directly below the rammesh with a spur gear. the pinion meshing

with the rack is driven by gear train. This type

of shaper is not widely used.


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HYDRAULIC SHAPER MECHANISM

The constant discharge from the oil pump develops moderate oilpressure. This pressure is then transmitted through piping and areversing valve to an operating cylinder. This pressure acts on thepiston and moves the shaper ram forward on its cutting stroke. thesame movement expels the oil from the other side of the cylinderand returns it to the sump through the piping and the throttle valve.

At the end of the stroke, a limit switch actuates the reversing leverwhich pulls the reversing valve towards the lever side and thusdirects the oil under pressure to the other end of the operatingcylinder.

The stroke of the shaper is controlled by adjusting the limit switches.

The discharge rate of gear pump is constant. The same volume of oilis delivered to both the sides of the piston.


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HYDRAULIC SHAPER MECHANISM


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Advantages of hydraulic shaper

1) The cutting and return speeds are constant

throughout the stroke practically.

2) The reversal of the ram is obtained quickly

without any stroke as the oil on the other side ofthe cylinder provides cushioning effect.

3) The relief valve ensures safety to the tool and

the machine, when the machine is over loaded.But it is costly and difficult for service and

maintenance.


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SHAPER to Teach

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