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Introduction Roe (1916) credits James Nasmyth with the invention of the shaper in 1836. But the basic function of a shaper is still sound; tooling for them is minimal and very cheap to reproduce; and they are simple and robust in construction, making their repair and upkeep easily achievable.

Thus they are still popular in many machine shops, from jobbing shops or repair shops to tool and die shops, where only one or a few pieces are required to be produced and the alternative methods are cost- or tooling-intensive. Shaper A shaper is a type of machine tool that uses linear relative motion between the work piece and a single-point cutting tool to machine a linear tool path. Its cut is analogous to that of a lathe, except that it is (archetypal) linear instead of helical. Types

Shapers are mainly classified as higher, draw-cut, horizontal, universal, vertical, geared, crank, hydraulic, contour and traveling head. The horizontal arrangement is the most common. Vertical shapers are generally fitted with a rotary table to enable curved surfaces to be machined (same idea as in helical). The vertical shaper is essentially the same thing as a slitter (slotting machine), although technically a distinction can be made if one defines a true vertical shaper as a machine whose slide can be moved from the vertical. A slitter is fixed in the vertical plane. Small shapers have been successfully made to operate by hand power. As size increases, the mass of the machine and its power requirements increase, and it becomes necessary to use a motor or other supply of mechanical power. This motor drives a mechanical arrangement (using a pinion gear, bull gear, and crank, or a chain over sprockets) or a hydraulic motor that supplies the necessary movement via hydraulic cylinders. 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. 2

Figure – shaper machine 3

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. 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. Operation A shaper operates by moving a hardened cutting tool backwards and forwards across the work piece. On the return stroke of the ram the tool is lifted clear of the work piece, reducing the cutting action to one direction only. The work piece mounts on a rigid, box-shaped table in front of the machine. The height of the table can be adjusted to suit this work piece, and the table can traverse sideways underneath the reciprocating tool, which is mounted on the ram. Table motion may be controlled manually, but is usually advanced by automatic feed mechanism acting on the feed screw. The ram slides back and forth above the work. At the front end of the ram is a vertical tool slide that may be adjusted to either side of the vertical plane along the stroke axis. This tool-slide holds the clapper box and tool post, from which the tool can be positioned to cut a straight, flat surface on the top of the work piece. The tool-slide permits feeding the tool downwards to deepen a cut. This adjustability, coupled with the use of specialized cutters and tool holders, enable the operator to cut internal and external gear tooth profiles, spines, dovetails, and keyways. 4

The ram is adjustable for stroke and, due to the geometry of the linkage, it moves faster on the return (non-cutting) stroke than on the forward, cutting stroke. This action is via a slotted link or Whitworth link. Specification of shaper

The size of a shaper is determined by the maximum length of stroke or cut it can make. The usual size ranges from 175 to 900 mm. The length of stroke indicates, in addition to the general size of the machine, the size of a cube that can be held and planed I the shaper. Thus in a 250 mm shaper the length of stroke may be adjusted from 0 to 250 mm, the cross feed adjusted of the table will be 250 mm and the extreme bottom position of the cross rail will permit the table to accommodate a work piece 250 mm high. The length of stroke of a shaper merely indicates the overall size of the shaper other particulars, such as the type of drive : belt or individual motor drive, power input, floor space required, weight of the machine, cutting to return stroke ratio, number and amount of feed etc. are also sometimes necessary.

Mechanism in shaper

In order to reduce the time wasted during the return non-cutting stroke, shaping machines are fitted with a quick-return mechanism, usually of the crank and slotted-link design. 5

This is shown diagrammatically in Figs. . The ram is driven by a slotted link which pivots at its lower end and is attached to the ram by a loose connecting link at its upper end. The slotted link engages with the crank pin mounted on the driving wheel which rotates at constant speed and causes the link to oscillate and the ram to reciprocate. A gearbox controls the speed of the driving pinion, thus providing a range of speeds for the ram. A shaper is analogous to a planer, but smaller, and with the cutter riding a ram that moves above a stationary work piece, rather than the entire work piece moving beneath the cutter. The ram is moved back and forth typically by a crank inside the column; actuated shapers also exist. 6

Assuming the driving wheel is rotating in a clockwise direction, then with the ram at the start of the cutting stroke the centre-line of the slotted link is tangential with the path of the crank pin shown at point 2 on diagram. As the wheel rotates the ram moves forward until the link again becomes tangential, shown at point 10. Further rotation of the driving wheel withdraws the ram to its starting position at point 2. Hence the rotation from point 2 to 10 in this example, 240°, is the cutting stroke, and that from 10 to 2 in this example, 120°, is the return stroke, giving a 2:1 ratio. As the length of the stroke is increased or decreased the ratio of the cutting time to the return time varies

As the driving disc is connected to the bull gear the table feed movement is effected when the bull gear or the diving disc rotates through half of therevolution, i.e., during return stroke only. Rotation through other half imparts no feedmoveme nt. To reverse the direction of rotation of ratchet wheel and consequently the feed, a knob / on the top of the pawl 4 after removing the pin 2 is rotated through 180 degrees. The amount of feed may be altered by shifting the position of crank pin 9 with respect to the centre. Greater the throw of eccentricity, more will be the rocking movement of the arm and the pawl will pass through three or four teeth on the wheel at a time imparting greater feed movement.

Uses

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.

4. It is even possible to obviate wire EDM work in some cases. Starting from a drilled or cored hole, a shaper with a boring-bar type tool can cut internal features that don't lend themselves to milling or boring (such as irregularly shaped holes with tight corners)

Conclusion

So the shaper machine is very needed Producing a flat or plane surface which may be in a horizontal, a vertical or an angular plane

Reference

 Www.shaper machine. wiki  en.wikipedia.org/wiki/Shape  seminarprojects.com/s/shaper-machine-pdf-file 7

 www.alibaba.com/showroom/advantages-of-shaping-machine.html  wiki.answers.com › Wiki Answers › Categories › Uncategorized

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