Shaper: working principles, classification, Construction, Machining time, MRR ~ MECHTECH GURU

Shaper: working principles, classification, Construction, Machining time, MRR

Shaper: working principles, classification, Construction, Machining time, MRR

The shaper

Ø In a shaper , the work piece is held stationary during cutting,  while the tool reciprocates horizontally.
Ø Producing a flat or plane surface which may be in a horizontal, a vertical or an angular plane.
Ø Making slots, grooves and keyways
Ø Producing contour of concave/convex or a combination of these
Ø Machine tool used for shaping operation is called shaper
Ø   Designed for machining flat surfaces on small sized jobs. If the size of the job is large, then planning is used.
Ø The feed and depth of cut are normally provided by moving the work. Such shaper is called a horizontal shaper.

The basic principle of shaping machine is generation of flat surface by. The cutting motion provided by the linear forward motion of the reciprocating tool and the intermittent feed motion provided by the slow transverse motion of the job along with the bed result in producing a flat surface by gradual removal of excess material layer by layer in the form of chips. The vertical in feed is given either by descending the tool holder or raising the bed or both. Straight grooves of various curved sections are also made in shaping machines by using specific form tools. The single point straight or form tool is clamped in the vertical slide which is mounted at the front face of the reciprocating ram whereas the work piece is directly or indirectly through a vice is mounted on the bed.

The main parts of the Shaper machine are
  • Base
  • Body (Pillar, Frame, Column)
  • Cross rail
  • Ram and tool head (Tool Post, Tool Slide, Clamper Box Block)

  •   Base is a heavy cast iron casting which is fixed to the shop floor.
  •  It supports the body frame and the entire load of the machine.
  •  Base absorbs and withstands vibrations and other forces which are likely to be induced during the shaping operations.

Body (Pillar, Frame, Column):

  •   It is mounted on the base and houses the drive mechanism compressing the main drives, the gear box and the quick return mechanism for the ram movement.
  •  The top of the body provides guide ways for the ram and its front provides the guide ways for the cross rail.

Cross rail:

  •  Mounted on the front of the body frame and can be moved up and down.
  •  The vertical movement of the cross rail permits jobs of different heights to be accommodated below the tool.
  •   Sliding along the cross rail is a saddle which carries the work table.

 Ram and tool head:
  •   Ram is driven back and forth in its slides by the slotted link mechanism.
  •  The back and forth movement of ram is called stroke and it can be adjusted according to the length of the work piece to be-machined.

Working principle:

·        Job is rigidly fixed on the machine table.
·         Single point cutting tool held properly in the tool post is mounted on a reciprocating ram.
·        Reciprocating motion of the ram is obtained by a quick return motion mechanism.
·         As the ram reciprocates, the tool cuts the material during its forward stroke.
·         During return, there is no cutting action and this stroke is called the idle stroke.
·         Forward and return strokes constitute one operating cycle of the shaper.
In shaper, rotary movement of the drive is converted into reciprocating movement by the mechanism contained within the column of the machine. The reciprocating movement of the ram and the quick return mechanism of the machine are usually obtained by any one of the following methods:

1. Crank and slotted link mechanism:


2. Whitworth quick return mechanism:

Ram moves at a comparatively slower speed during the forward cutting stroke. During the return stroke, the mechanism is so designed to make the tool move at a faster rate to reduce the idle return time. This mechanism is known as quick return mechanism. As the ram moves at a faster rate during return stroke, the time taken becomes less. The total machining time decreases and the rate of production increases. 

3. Hydraulic shaper mechanism

Types of shaper

• Machining horizontal surface
• Machining vertical surface
• Machining angular surface
• Cutting slots, grooves and keyways
• Machining irregular surface

• Machining splines or cutting gears

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