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Bme

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Bme

  1. 1. Introduction: The shaper is a machine tool used primarily for: 1. Producing a flat or plane surface which may be in a horizontal, a vertical or an angular plane. 2. Making slots, grooves and keyways 3. Producing contour of concave/convex or a combination of these
  2. 2. Working Principle: The job is rigidly fixed on the machine table. The single point cutting tool held properly in the tool post is mounted on a reciprocating ram. The 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. The forward and return strokes constitute one operating cycle of the shaper.
  3. 3. BLOCK DIAGRAM OF A SHAPER
  4. 4. Construction: The main parts of the Shaper machine is Base, Body (Pillar, Frame, Column), Cross rail, Ram and tool head (Tool Post, Tool Slide, Clamper Box Block). Base: The 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. The base absorbs and withstands vibrations and other forces which are likely to be induced during the shaping operations.
  5. 5. 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: The cross rail is 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: The 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.
  6. 6. CONSTRUCTION OF A SHAPER
  7. 7. OPERATIONS PERFORMED ON A SHAPER
  8. 8. Types of shapers Shapers are classified according to various aspects. 1) Based on type of mechanism employed for the movement of the cutting tool i.e. tool carrying ram the shapers are classified in to three types a. Crank type b. Gear type c. Hydraulic type
  9. 9. 2) According to position and movement of ram the shapers are classified in to three types a. Horizontal type b. Vertical type c. Travelling head type 3) Shapers are classified in to two types based on design of the work table a. Standard shaper b. Universal shaper 4) Based on type of cutting stroke employed these are classified in to a. Push type b. Draw type
  10. 10. Crank type shaper In these shapers the reciprocating ram is driven by crank mechanism. In this a single point cutting tool is employed to do the operation. A crank is connected to the ram and the bull gear to which the power is given through an individual motor. These are most common type of shapers being used. The reciprocating length of tool will be always is equal to the length of stroke. Gear type shaper These are the rarely used shapers. In these shapers a rack and pinion are employed the rack is attached to the lower part of the ram and on which the pinion moves. The power is transmitted from the bull gear. A grain train is engaged for the transfer of power from the bull gear to pinion.
  11. 11. Hydraulic type shaper These shapers run on hydraulic power. The end of the ram is connected to a piston fitted in to a cylinder. Oil is fed in to the cylinder initially the oil acts in one direction and the ram moves in one direction. A varying pressure is applied on the oil so as to obtain the reciprocating motion of the ram. One of the main advantage of this shaper is a constant speed can be obtained from the starting of the machining operation. There will be no fluctuations in the cutting speed and stroke of the ram. Another important advantage of this shaper is no sound will be produced hence a noise free environment can be obtained. Horizontal shaper As the name indicates these shapers have the motion of ram along the horizontal axis. This type of shapers is generally used for generation of fine and flat surfaces.
  12. 12. A quick return mechanism is used where there is a need to convert rotary motion into reciprocating motion. As the disc rotates the black slide moves forwards and backwards. Many machines have this type of mechanism and in the school workshop the best example is the shaping machine.  

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