Lathe Operations: Facing

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Facing Operations Facing is the process of removing metal from the end of a workpiece to produce a flat surface. Most often, the workpiece is cylindrical, but using a 4-jaw chuck you can face rectangular or odd-shaped work to form cubes and other non-cylindrical shapes.

When a lathe cutting tool removes metal it applies considerable tangential (i.e. lateral or sideways) force to the workpiece. To safely perform a facing operation the end of the workpiece must be positioned close to the jaws of the chuck. The workpiece should not extend more than 2-3 times its diameter from the chuck jaws unless a steady rest is used to support the free end. Cutting Speeds

If you read many books on machining you will find a lot of information about the correct cutting speed for the movement of the cutting tool in relation to the workpiece. You must consider the rotational speed of the workpiece and the movement of the tool relative to the workpiece. Basically, the softer the metal the faster the cutting. D…

Purpose, Importance and Functions of Slotting Machine

A Slotting machine may also be known as heavy-duty shaper. Slotting machine resembles a shaping machine in all respect except that the ram instead of reciprocating to and fro in the horizontal plane, moves up and down in the vertical plane. Therefore, the slotting machine is some times called as vertical shaper.


Slotting Machine



Purpose of Slotting Machine


It is very useful for making keyways, machining square holes, cutting of internal and external teeth on big gears, machining of dies, punches, etc. The job is generally supported on a round table, which has rotary feed in addition to the usual table movement in cross direction.



Importance of Slotting Machine


It is very useful for making keyways, machining square holes, cutting of internal and external teeth on big gears, machining of dies, punches, etc. The job is generally supported on a round table, which has rotary movement in addition to the usual table movement in cross direction. The stroke of slotting machine ranges from 8” to 12”.  Slotter does not need to have such a large travel of the ram as shaper. The ram can be either crank driven (slotted disc type) or hydraulically driven. Ram speed usually ranges from 2 to 4 m/min in longitudinal and transverse power feed ranges from 0.05 to 2.5mm/stroke. Cutting action takes place in down ward position (stroke).


Slotted Disc Mechanism



Functions of Slotting Machine


The main function of a slotting machine is to remove metal from a piece of a work to bring it to the required shape and size. This is accomplished by holding the work rigidly on the machine and a reciprocating single point tool mounted on tool head. The single point tool moves along a vertical axis over the work piece. The pinion which is in mesh with the main gear gets its drive from a pulley through a belt by motor. The gear is coupled to the slotted disc. The circular motion of slotted disc is converted into the reciprocating one with the help of connecting rod. The crank pin can be formally set in the slot of slotted disc at different distances from the centre for verifying the length of the ram stroke. The position of the stroke is adjusted with the help of hand lever provided for the stroke adjustment. Slotting machine is usually provided with horizontal circular worktable, but coordinate tables are also provided some times.  The table is mounted directly over a bed casting and heavy work may be placed on it. The circular table can be revolved by hand or power fed. It is graduated around its outer edges and work can thus be mounted and turned to a predetermined position, depending upon the function for which slotter is designed.

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