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Study of Slotting Machine in Lab Experiment


Study of Slotting Machine in Lab Experiment


A slotting machine or slotter is used for cutting different types of slots and it certainly proves to be most economical. Its other uses are in machining irregular shapes, circular surfaces and other premarked profiles. Its construction is similar to that of a vertical shaper. Its ram moves vertically and the tool cuts during the downward stroke only.

Type of Slotter

Puncher SlotterThe puncher slotter is a heavy rigid machine designed for removal of large amount of metal from large forgings or castings. The length of stroke of a puncher slotter is sufficiently large.

Precision SlotterThe precision slotter is a lighter machine and is operated at high speeds. The machine is designed to take light cuts giving accurate finish. The precision machines are also used for general purpose work and are usually fitted with whit worth quick return mechanism.

Slotter SizeThe size of a slotter like that of a shaper is specified by the maximum length of stroke of the ram expressed in mm. The size of a general purpose or precision slotter usually ranges from 80 to 900 mm. To specify a slotter correctly the diameter of the table in mm, amount of cross and longitudinal travel of the table expressed in mm, number of speeds and feeds available, h.p of the motor, floor space required etc. should also be stated.

Slotting Machine Parts

Base or BedThe base is rigidly built to take up all the cutting forces and entire load of the machine. The top of the bed is accurately finished to provide guide ways on which the saddle is mounted.

ColumnThe column is a vertical member which is cast integral with the base and houses driving mechanism of the ram and feeding mechanism.

The front vertical face of the column is accurately finished for providing ways on which the ram reciprocates.


Figure: Slotting Machine

1. Base, 2. Feed gear, 3. Cross-slide, 4. Table, 5. Cross feed handle, 6. Longitudinal feed Handle, 7. Circular feed handle, 8. Tool, 9. Ram, 10. Crank disc, 11. Lever for counterbalance weight, 12. Bull gear, 13. Cone pulley, 14. Column, 15. Feed shaft, 16. Pawl actuating crank.

SaddleThe saddle is mounted upon the guide ways and may be moved towards or away from the column either by power or manual control to supply longitudinal feed to the work. The top face of the saddle is accurately finished to provide guide ways on the base.

Cross SlideThe cross slide is mounted upon the guide way of the saddle and may be moved parallel to the face of the column.

Rotary TableThe ram is the reciprocating member of the machine mounted on the guide ways of the column. It supports the tool at its bottom end on a tool head. A slot is cut on the body of the ram for changing the position of stroke.

Ram Drive MechanismA slotter removes metal during downward cutting stroke only whereas during upwards return stroke no metal is removed. The usual types of ram drive mechanisms are

  1. Whitworth quick return mechanism
  2. Variable speed reversible motor drive mechanism
  3. Hydraulic drive mechanism.

Feed Movements

Ram Drive MechanismA slotter removes metal during downward cutting stroke only whereas during upwards return stroke no metal is removed. The usual types of ram drive mechanisms are

In a slotter, the feed is given by the table. A slotting machine table may have three types of feed movements.

  1. Longitudinal
  2. Cross
  3. Circular

If the table is feed perpendicular to the column towards or away from its face, the feed movements termed as longitudinal. If the table is feed parallel to the face of the column the feed movement is termed as circular

Work Holding DevicesThe work is held on a slotter table by a Vise, T-bolts and clamps of by special fixtures. T-Bolts and clamps are used for holding most of the work on the table. Before clamping packing pieces are place below the work so as to allow the tool to complete the cut without touching the table.

Slotter OperationsThe operations performed in a slotter are

  1. Machining flat surfaces:
  2. Machining cylindrical surfaces
  3. Machining irregular surfaces and cam machining
  4. Machining slots, keyways and grooves.

Slotter ToolsThe tool in a slotter removes metal during its vertical cutting stroke. This changed cutting condition presents a lot of difference, in the tool shape. In a slotter the cutting pressure acts along the length of the tool. The rake and the clearance angle of a slotter tool apparently look different from a lathe or a shaper tool as these angles are determined with respect to a vertical plane rather than the horizontal. Slotter tools are provided with top rake front clearance and side clearance, but no side rake is given. The-nose of the tool projects slightly beyond the shank to provide clearance.


There are many accessories and fittings, which, if provided greatly improve the performance and range of work which can be carried out on a Slotting machine.