Shaper Machine: Types, Working and operation

Shaper machine: Types, Working and Operation:

Principle of shaper machine:

Shaper Machine diagram
Shaper Machine

Shaper is used generally to get flat surfaces on small to medium-size workpieces. In 1836 an English man James Naismith developed a metalworking shaper. In shaper the tool is provided reciprocating motion by ram and cutting takes place only during forward stroke, the workpiece remains stationary. The workpiece is mounted on the table and is held in a vice. Both horizontal and vertical feed can be provided to the workpiece by moving the table, the modern shaper can prepare curve surfaces also.

Classification and types of shaping machines:

The classification of shaper may be carried out in different ways as under:

(1) According to the driving mechanism:
(a) Crank type shaping machine
(b) Gear type shaping machine
(c) Hydraulic type shaping machine.

(2) According to the direction of travel of ram:
(a) Horizontal shaper
(b) Vertical shaper
(c) Travelling head shaper

(3) According to the design of the table:
(a) Standard shaper
(b) Universal shaper

(4) According to nature of cutting stroke:
(a) Push type shaper
(b) Draw type shaper

Main Parts of shaping machine:


  • Base: To support the complete machine tool and is made of cast iron.
  • Column: A big box type casting mounted on the base and carrying all mechanism.
  • Cross rail: Mounted on the front vertical guideways of the column. It carries a table. Cross rail may go up and down. A horizontal cross feed screw is fitted within the cross rail.
  • Ram: Reciprocating member of the shaper.

  • Tool head:  It is a device in which the cutting tool is caught and the cut position and the depth of the shaft are set.

A Horizontal shaper is shown in fig. has a horizontal ram that reciprocates at cutting speed. A cutting tool is carried on the tool head in the front of the ram. The length and position of the stroke of the ram are adjustable so that the tool can be set to cover any part of the maximum stroke of the shaper and need not travel any more than necessary for each job. The slide that carries the tool on the tool head can be swivelled to and clamped at any angle in a vertical plane on the front of the ram. An application of the adjustment is illustrated in fig. The slide can be adjusted by a micrometre dial or fed by hand or automatically in the direction to which it is swivelled.

The available movement is limited because the slide is short. The cutting tool, normally in a tool post, is fastened to a clapper box on the front of the tool slide. The clapper box is pivoted and swings to allow the tool to lift and ride loosely over the work on the return stroke. This eases the pressure on the tool and prevents marring the work surface.

A cross-rail mounted on ways on the front of the column of a horizontal shaper is adjustable up or down. The work table rides crosswise on the rail and can be adjusted or fed manually or automatically. Feed takes place just before the beginning of each stroke. The power feed is activated by the ram driving mechanism.

Bench shapers run at high speeds for small work. Others are floor mounted. A plain, utility, or tool room shaper is a light shaper. Standard industrial, heavy-duty, or production shapers are heavy and rugged for large pieces and fast and deep cuts. A universal shaper has a table that can be swivelled around two horizontal axes in addition to horizontal and vertical adjustments. In addition, special shapers have been made with such features as two or more heads on one ram for multiple cuts and two tables for loading and cutting alternately.

All the shapers described so far push the tool away from the column to cut. In contrast, a draw cut shaper cuts towards the column. It can be built with a long stroke and take heavy cuts and is made in the larger sizes. Draw cut shapers are intended for heavy-duty and are correspondingly expensive.

Different operations performed on shaping machine:

Basically, shaping machine designed to prepare flat surfaces with the help of single point cutting tool but the following operations can also be performed:


  1. Machining horizontal surface
  2. Machining vertical surfaces
  3. Machining angular surface
  4. Cutting slots, grooves and keyways
  5. Machining irregular surface
  6. Machining splines or cutting gears.

(l) Machining horizontal surface:

Fig shows thin operation, Workpiece is held in the wise or clamp or the table. The tool is held in the tool post. The table is then adjusted in such a way that a distance of 25 to 30 mm is obtained between the upper surface of the workpiece and the bottom of the cutting edge of the tool. The stroke length and the position are then adjusted according to the dimension of the workpiece required. Then by selecting suitable speed and feed screw handle. During each stroke, the table is moved by a distance equal to half the width of the cutting tool edge. This can be done manually or power-operated feed mechanism.

(2) Machining vertical surface:

Fig shows the machining operation. For this operation side cutting tool is used to get a feed at right angles the tool head slide is located at 0 degree. The apron is kept slightly inclined in the opposite direction of the machining surface.

(3) Machining angular surface:
Fig shows the operation. Here the vertical slide of the tool head is adjusted at a required angle either to the right or to the left. The apron is always kept inclined in the opposite direction of the machining surface.

(4) Cutting slots, grooves and keyways:
Fig shows respectively cutting of external and internal key-ways. Here parting tool having square nose is used to provide relief to the tool at the end of stroke a hole is drill on the external surface of the shaft having diameter larger than 0.5 to 0.8 mm and depth larger than 1.5 mm. The position of the stroke and the length of stroke is so adjusted that when the tool reaches the hole drilled on the shaft the cutting stroke gets completed. It can be seen that for internal key-way cutting a special type of tool holder is used.

(5) Machining irregular surfaces:
Fig shows the operation. Form tools are used for getting concave, convex and mixed curvature on the workpiece surface. For larger dimension surfaces the table is provided automatic crossfeed and the tool is down fed manually to get the desired shape. Sometimes both cross and down feeds are given manually. A nose tool is used for machining.

(6) Machining irregular surface:
Machining splines or cutting gears: Fig illustrates the method. An indexing mechanism is used for cutting escaped teeth of splines. The workpiece is held between the centres. The splines are cut like keyways and the work is rotated with the help of indexing mechanism for gear cutting form tools are used.


Comparison between hydraulic shaper and mechanical shaper:

In hydraulics shaper following advantages are obtained:
(I) Constant cutting speed.
(2) Faster return stroke
(3) More number of stroke per minute, more production.
(4) Unlimited feed and
(5) Feed control is independent of ram drive.

Disadvantages:
(1) They are very costly.

(2) Suitable for high speed and fine feed. 
  
Application of Shaper Machine:
  1. It is regularly utilized for the electric discharge machining.
  2. In the blind holes, gear tooth cutting is accomplished with this machine.
  3. It is likewise utilized for dovetail sliders.
  4. It is also a prominent device with the assistance of which we can increase the smoothness of a rough surface.
  5. Gear teeth as well as for internal splines.
  6. Irregularly shaped holes having the tight corners can't be made utilizing the milling or some other machining process. Just a shaper machine can make such holes.

Shaper Machine: Types, Working and operation Shaper Machine: Types, Working and operation Reviewed by Harish on July 06, 2020 Rating: 5

No comments:

Powered by Blogger.