Introduction to Slotting Machine :
The slotter or slotting machine is also a reciprocating type of machine tool similar to a shaper. It may be considered as a vertical shaper. The machine operates in a manner similar to the shaper, however, the tool moves vertically rather than in a horizontal direction. The job is held stationary. The slotter has a vertical ram and a hand or power operated rotary table.
Common types of slotting machine
1. Puncher slotting machine
2. General production slotting machine
3. Precision tool room slotting machine
4. Keyseater slotting machine
This puncher slotter is a really rigid and heavy machine that has been designed for removing a large percentage of metal from castings and forgings. The stroke length of the puncher slotter is large sufficiently. It can be anywhere ranging between two thousand to eighteen hundred meters. The Ram of the puncher slotter is driven usually by the meshing of the spiral pinion with cut rack teeth on the ram’s underside. Pinion here gets driven by reversible electric variable speeds motor that is very similar to a planer. Electrical gears control the feed.
This slotter is a machine that is lighter when compared to puncher plotters. They can operate at really high speeds. The machine has been designed for taking the light cuts which present an accurate finish. Using the special jigs, the machine is capable of handling a large number of tasks on a production basis.
Classification of slotting machine:
1.Punch slotting machine
- Heavy duty
- Large casting frame
- Large stroke
2.Production slotting machine
- General production machine
- Common type
- Mechanism – Slotted disc, Connecting ram
3.Precision Tool Room slotting machine
- Light duty machine
- High speed
Slotter Machine Diagram :
Principal parts of a Slotting machine :
The figure shows a slotter and its various parts. The main parts of a slotter are discussed as under:
1. Bed or Base
It is made up of cast iron. It supports columns, tables, ram, driving mechanisms, etc. The top of the bed carries horizontal ways along which the worktable can traverse.
It holds the workpiece and is adjustable in longitudinal and crosswise directions. The table can be rotated about its center.
They are provided for rotating the table and for the longitudinal and cross traverse. The column is the vertical member. They are made up of cast iron and it houses the driving mechanism. The vertical front face of the column is accurately finished for providing ways along which the ram moves up and down.
It is provided to reciprocate vertically up and down. At its bottom, it carries the cutting tool. It is similar to the ram of a shaper; but it is more massive and moves vertically, at right angle to the worktable, instead of having the horizontal motion of a shaper.
It can be moved parallel to the face of the column. The circular work-table is mounted on the top of the cross-slide.
Working Principle of the Slotting machine:-
The slotting machine is a reciprocating machine tool in which, The vertical slide holding the cutting tool is reciprocated by a crank and connecting rod mechanism, The job, to be machined, is mounted directly or in a vice on the work table. Like shaping machines, in the slotting machines also the fast cutting motion is imparted to the tool and the feed motions to the job. In the slotting machine, in addition to the longitudinal and cross feeds, a rotary feed motion is also provided in the work table.
The mechanism of the slotting machine can be available in two forms which include:
In this mechanism, a speed motor is a drive-by a hydraulic pump that delivers oil at a constant pressure to the line. It also contains a regulating valve that pushes oil under pressure to each end on the piston alternately and allows oil from the opposite end of the piston to return to the reservoir. The piston pushed is connected to the ram by piston rod as the ram carries the cutting tool. Trip dogs and pilot valves aid the distribution of oil to each end of the piston.
The ram moves a complete stroke (forward and return) by a trip dog which will trip the pilot valve that operates the regulating valve. The regulating valve will push the oil to the other side of the piston and the motion of the ram will reversed. The ram stroke length will depend upon the position of the trip dogs which can be changed. This is done by unclamping and moving the trip dogs to the desired position.
Variable speed motor drive:
Slotter machine with this mechanism, the speed is obtained by different gear present in the gearbox whilst, the shaft rotates with the aid of an electric motor. It is basically used in modern large slotting machines.
Application of slotting machines
1. It is used for machining vertical surfaces
2. It is used angular or inclined surfaces
3. It is used to cut slots, splines, keyways for both internal and external jobs such as machining internal and external gears
4. It is used for works as machining concave, circular, semi-circular, and convex surfaces
5. It is used for shaping internal and external forms or profiles
6. It is used for machining of shapes which are difficult to produce on a shaper
7. It is used for internal machining of blind holes
8. It is used for machining dies and punches
Slotting machine operations
Operations which can be performed on the slotting machine are, cutting of:
1. Internal grooves or keyways
2. Internal gears
4. Concave, circular and convex surfaces etc
Types of slotter tools
A typical set of slotter cutting tools includes the following:
3. Right hand
4. Left hand
Specifications of slotting machine
It is given by
1. Maximum length of stroke of slotter ram (mm) e.g 400mm
2. Diameter of rotary table (mm) e.g.915mm
3. Longitudinal movement of the table(mm) e.g 762 mm
4. Cross Movement of the table (mm) e.g 559 mm
5. Motor power (H.P) e.g 7.5 HP
6. Number of speed 9
7. Floor space required 3050 mm x 1800mm
1. Maximum length of stroke of slotter ram (mm)
2. Diameter of the work table
3. Type of drive
4. Maximum table travel
5. Power input required
6. Floor space required
7. No.of speeds available
8. No.of feeds available
Advantages and disadvantages of a slotting machine:
Advantages of Slotting machine
The following stated below represent the benefits of a slotter machine:
- A single-point cutting tool is used.
- Low-cost machine.
- Accurate surface finish.
- High machine efficiency.
- Low maintenance.
- The machine is light.
Disadvantages of slotting machine
The following stated below are the disadvantages of slotting machines:
- Required a skillful person to operate it.
- Rigid in construction.
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