Shaping

SHAPIN G

FABRICATION AND MACHINING TECHNIQUES

PRESENTED BY : OJASVITA OSHMA NAWIN NITHIN NUPUR

ACKNOWLEDGEMEN T This presentation on SHAPING incorporates all our research on the topic including the information that we collected by the visit to the INDUSTRIAL TRAINING INSTITUTE. We bid our thanks to our esteemed faculty Mr Sharan for his inevitable guidance and support. Any suggestions for the improvement of our presentation will be whole-heartedly accepted.

FABRICATION AND MACHINING Fabrication applies to the building of machines, structures and other equipment, by cutting, shaping and assembling components made from raw materials. It also involves the metal preparation, welding and assembly aspects. Machining is one of the most important material removal methods and is a collection of material-working processes in which power-driven machine tools, such as lathes, milling machines, and drill presses are used with a sharp cutting tool to mechanically cut

SHAPING Shaping is a material removal process in which a cutting tool takes mass and shapes a stationary object to produce a sculpted or plane surface.

THE SHAPING MACHINE

A shaping machine is used to machine surfaces. It can cut curves, angles and many other shapes. It is a popular machine in a workshop because its movement is very simple although it can produce a variety of work.

TYPES OF SHAPERS 1. According to the TYPE of mechanism used 2. According to the POSITION and TRAVEL of ram 3. According to the type of DESIGN of the table 4. According to the type of CUTTING STROCK stroke

CRANK SHAPER • Single point cutting tool is given reciprocating motion equal to the length of the stroke. • Bull gear is used to change the motion of crank to circular path. •

GEARED TYPE • The reciprocating motion of the ram in some type of shaper is effected by mean or rack and pinion. • Speed and the direction in which the machine will transverse depend on the number of gears in the gear train.

HYDRAULIC SHAPER • The reciprocating movement of the ram is obtained by hydraulic power. Piston speed is changed according to the amount of liquid delivered by the pump. • Advantages- constant speed, flexibility of speed and feed control, eliminates shock, machine doesn’t make much

HORIZONTAL SHAPER • The ram holding the tool reciprocates in a horizontal axis. • Horizontal shaper are mainly used to produce flat surface.

VERTICAL SHAPER • The ram holding the tool reciprocates in vertical axis. • In some, vertical position of the ram can be changed about 10 degree. • Very convenient for machining internal surfaces, keyways, slots or grooves. • •

TRAVELLING HEAD SHAPER • The ram carry the tool while it reciprocates moves crosswise • It is static on the basement while the ram moves.

UNIVERSAL SHAPER • In addition to the two movement, the table can be tilted on an angle parallel to thePUSH ram. TYPE • SHAPER • •The metal is removed when the ram is moved away from the column.

DRAW TYPE SHAPER • the metal is removed when the ram is moves towards the column of the machine. • The cutting pressure acts to take a deep cut.

PRINCIPAL PARTS

BASE It is necessary for support required for all machine tools. The base may be bolted to the floor or on the bench according to the size. It is designed that it can take up the entire load of machine and the forces set up by cutting tools. It is made of cast iron.

The column is a box like thing which is mounted upon the base. It encloses the ram deriving mechanism. Two guideways are provided on the top of the column on which the ram reciprocates. The front vertical face serves the guideways for the crossrail. These all are

CROSS RAIL The cross rail is mounted on the front vertical guide ways of the columnIt has two parallel guide ways that perpendicular to the ram axis it can be pulled up and down by elevating screw.

SADDLE The saddle is mounted on the cross rail which holds the table firmly on top. Crosswise movement of the saddle by rotating the cross feed screw by hand or by power

TABLE it is a box like casting having Tslots both on the top and the sides for clomping the work.

RAM The ram is the reciprocating member of the shaper. This is semi cylindrical in the form and heavily ribbed inside to make it more rigid. It slides accurately on well machined guide ways on the top of the column. It houses a screwed shaft for altering the position of the ram with respect to the work. It holds the tool head at the extreme forward end.

TOOL HEAD The tool head of shaper holds the tool rigidly, provides vertical and angular feed movement to the tool and allows the tool to have an automatic relief during its return stroke

Shaper mechanism

In a shaper ,rotary movement of the drive is converted into reciprocating Movement by the mechanism contained within the coloumn of the machine. The ram holding the tool gets the reciprocating movement.

Task: to remove the punched area

The tools used to cut the material

Tools used to adjust these cutting tools So that it is in contact with the material

The shavings or crap

Slotted Link Quick Return Shaper Drive Mechanism - The slotted link quick returns mechanism. Slotted link mechanism Principle of mechanism

Slotted link mechanism is very common in mechanical shapers. The mechanism is simple and compact. It converts the rotary motion of the electric motor and gearbox into the reciprocating motion of the ram. The slotted link mechanism gives the rain a higher velocity during the return non cutting stroke than The slotted link mechanism gives the rain a higher velocity during the return non cutting stroke than during its forward cutting stroke thereby reducing the time wasted during the return stroke. The bull gear is driven by a pinion which is connected to the motor shaft through a gearbox with four, eight or more speeds available. The bull wheel has a slot. The crank pin A is secured into this slot; at the same time it can slide in the slotted crank B. When the bull wheel rotates, the crank pin A also rotates and side by side slides through the slot in the slotted crank B. This makes the slotted crank to oscillate about its one end C. This oscillating motion of slotted crank (through the link D) makes the ram to reciprocate. The intermediate link D is necessary to accommodate the rise and fall of the crank.

The 'Whitworth' quick return mechanism converts rotary motion into reciprocating motion, but unlike the crank and slider, the forward reciprocating motion is at a different rate to the backward stroke. At the bottom of the drive arm, the peg only has to move through a few degrees to sweep the arm from left to right, but it takes the remainder of the revolution to bring the arm back. This mechanism is most commonly seen as the drive for a shaping machine.

Shaper vises :

A vise is a quick method of holding and locating Relatively small and regular shaped work pieces. It consist of base, table,screw,f ixed,and movable Jaws. the base has a projection or tongue which Fits into the slots of the machine table.

Parallel s:

When the height of the job is less than the height of the jaws of the vise, parallels are used To raise and seat the work piece above the vise jaws and parallels with the wise bottom. Parallels are square or rectangular bars of steel or cast iron , hardened and ground with opposites sides Parallel. they are available in different heights…

Hold downs:

Hold downs or grippers are used for holding thin pieces of work in a shaper vise. Hold downs are also used for holding work of smaller height than the vises jaws where Suitable parallels are not available.

Clamping work on the table: When the work piece is too large to be held a visit must be fastened directly on the shaper table. in holding work on the table ,clamping bolts should not be unduly Tightened to produce distortion of the work. Different methods are applied : T-bolts and clamp: T-bolts having tea heads are fitted in the t-slots of the table. The length of the threaded Portion is sufficiently long in order to accommodate different heights of work.

Stop pins and toe dogs: While holding thin work on the table stop pins in conjuntion with toe dogs are used. A toe dog is similar to that of a center punch or a cold chisel. The end of the to dogis slightly drilled so that I end of the stop pin screw may fit into it A large number of stops pins dogs are placed all round the work. when of the stop pin Is tightened ,the work is gripped down on the table.

Stop and strip pins: Work having sufficient thickness is held on the table by strip and stop pins. A strip is a long bar having a toungue with holes of fitting the t-bolts The stopping screws are then tightened from the other end of the work so that the work may be clamped between stop pins and strip plate V-block: For holding round rods v-block are used. Work may be supported on two V-blocked at its two ends and is clamped to the table by t-bolts and clamps

SHAPING OPERATIONS The different operations which a shaper can perform are as follows : §Machining horizontal surface §Machining vertical surface §Machining angular surface §Cutting slots, grooves and keyways §Machining irregular surface §Machining splines and cutting gears

MACHINING HORIZONTAL SURFACE A shaper is mostly used to machine a flat, true surface on a work piece held in a vise or other holding devices. After the work is properly held on the table, a planing tool is set on the tool post with minimum overhang. The table is raised till there is a clearance of 25 to 30 mm between the work piece and the tool. Proper cutting speed and feed is then adjusted. Depth of cut is adjusted by rotating the down feed screw of the tool head. The amount of depth of cut is adjusted by a

MACHINING VERTICAL SURFACE

A vertical cut is made while machining the end of a work piece, squaring up a block or cutting shoulder. The work is mounted in the vise or directly on the table and the surface to be machined is carefully aligned with the axis of the ram. A side cutting tool is set on the tool post and the position and length of the stroke is adjusted. The vertical slide is set exactly at zero position and the apron is swivelled in a direction away

MACHINING ANGULAR SURFACE An angular cut is made at any angle other than a right angle to the horizontal or to the vertical plane. The work is set on the table and the vertical slide of the tool head is swivelled to the required angle either towards left or towards right from the vertical position. The apron is then further swivelled away from the work so that the tool will clear the work during the return stroke. The

CUTTING SLOTS, GROOVES AND KEYWAYS

With the suitable tools shaper can very conveniently machine slots or grooves on a work or cut external keyways on shafts and internal keyways on pulleys or gears. For cutting slots or keyways a square nose tool similar to a parting tool is selected. External keyways are cut on a shaft by first drilling a hole at the blind end of the keyway. Internal keyways are cut by holding the tool on a special tool holder so that the tool post

MACHINING IRREGULAR SURFACE A shaper can also produce a contoured surface that is a convex or concave surface or a combination of any of the above surfaces. To produce a small contoured surface of forming tool is used. If the curve is sufficiently large, power-cross feed is conjunction with manual down feed is so adjusted that the tool will trace the required contour. If the contour has too many ups and downs both the feeds are operated by hand. A round nose tool is selected for machining irregular surfaces.

MACHINING SPLINES AND CUTTING GEARS The work is mounted between two centres and a spline is cut similar to the cutting of a keyway. After the first spline is cut the work is rotated through a predetermined amount by using index-plate and index-pin. The periphery of a gear blank is divided, and equally spaced grooves are cut by using an index-plate having proper whole circles. While cutting gear a formed tool is used.

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