What is Slotting Machine?
Slotting machines are reciprocating machines that are mainly used to manufacture horizontal, vertical, or flat surfaces. The slotting machine is mainly used for cutting planes, forming surfaces and keyways, etc., and is suitable for single or small batch production.
A Slotter machine is defined as a machine tool uses for removing unwanted material chips from the workpiece to make splines, grooves, and more. Here the Ram (Tool attached) moves reciprocating, whereas In shaper the ram moves horizontally.
Slotter machines can be considered vertical shaper machines because both are very similar in many ways. The slotting machine is a very old type of machine and was invented by BRUNEL. The tool we use in this is the Single Point cutting Tool which is made up of High-Speed Steel.
The slotting machine is used for cutting grooves, keys, and slots of various shapes making regular and irregular surfaces both internal and external cutting internal and external gears and profiles The slotter machine can be used on any type of work where vertical tool movement is considered essential and advantageous.
Working Principle of Slotting Machine
The working of the slotting machine is similar to that of the shaper machine, but the main difference between them is that the shaper machine works horizontally, while the slotting machine works vertically
Now the ram is attached to the crank and the crank is connected to the gears. So, what occurred here is when we increase or decrease the gear speed, the rotation of the crank increases and decreases. And as by these, the ram goes up and down.
We have combined the workpiece to the work table and manually we bring the ram near to the workpiece and according to the ram we adjust the worktable and then we have to clamp it. Now we provide the power as per gear the crank turns and the crank is attached to the ram so the ram moves up and down.
During the down (RAM goes down) there is a cutting stroke and there is no cut while going up or returning the stroke. If we have to cut it into several sections, we manually feed it to the work table, and as per demand, it cuts.
Parts of Slotting Machine
A slotter machine consists of the following different parts:
- Rotating or Circular table
- Ram and tool head
- Ram drive
- Feed drive mechanism
- Base: The base is built rigidly for taking up all cutting forces and the machine’s entire load. The bed top is finished accurately for providing guideways on where the saddle was mounted. These are perpendicular to the face of the column. Generally, it is made of Cast Iron.
- Saddle: It is always mounted upon guideways and can be moved towards or away from the column either with manual control or power for supplying longitudinal feed.
- Cross-Slide: Cross slide is always mounted upon saddle’s guideways and may even be moved right parallel to column’s face.
- Ram and Tool Head: Ram drives on the guideways installed on the front vertical face of the column. It gives a slot for adjusting the position of the stroke. Ram provides the tool, which is attached at the bottom end of the tool head.
- Ram Drive: It provides the circular motion of the motor to the reciprocating motion of the ram in a vertical plane. It also provides the arrangement of slower speed during the cutting or forward stroke and greater speed during the return stroke to reduce the idle time.
- Column: The right vertical cast integral rigid portion of the base is the column; it serves the following purposes: It houses the driving device of the ram, which reciprocates on its front vertical face. It also houses the feeding mechanism of the table.
- Circular table or Rotating Table: It can turn on cross-slide to produce circular feeding of the work. And it can continue the work by clamping, using fixtures, fixing vice, etc. It has the structure of rotary feeding either by hand or by power. On some machines, the table may be graduated in degrees for indexing.
- Feed Drive: It gives the arrangement of longitudinal and crosses a feed of the table either by power or manual. It also gives the arrangement of circular or rotary feeding of the table on a vertical axis. Intermittent feeding of the table is supplied at the beginning of each cutting or forward stroke of the ram.
Types of Slotting Machine
Different types of slotting machines are:
- Puncher Slotting machine
- Toolroom Sloting machine
- Production Sloting machine
- Keyseater Slotting machine
1. Puncher Slotting Machine
It is 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 sufficiently large. It can be anywhere from two thousand to eighteen hundred meters.
The ram of the puncher slotter is usually powered by the meshing of a spiral pinion with cut rack teeth on the underside of the ram. The pinion is driven here by a reversible electric motor with variable speed, which is very similar to a planer. Electric gears control the feed.
2. Toolroom Slotting Machine
It is a lighter machine and is operated at high speed. It is made for very precise machining. This machine takes light cuts and gives accurate finishing. You can work at very high speeds. With the special jigs, the machine can handle a variety of tasks on a production basis.
3. Production Slotting Machine
Production Slotter is a heavy-duty slotter consisting of a heavy cast base and heavy frame and is generally made in two parts. Its mainly used for general production work. A slotted disc with a connecting rod is used for reciprocating the action of the ram. A flywheel is used in this slotter to prevent stroke at the end of the stroke.
4. Key seater Slotting machine
The key seater slotter additionally recognized as a key seating machine is a special type of slotter designed to cut keyways.
The key seater is related to vertical shapers, the variation is that the cutting tool on a key seater enters the workpiece as of the bottom and cuts on the down-stroke, as the tool on a shaper enters the workpiece as of the top and cuts downward.
Mechanism of Slotting Machine
- Hydraulic Drive
- Variable Speed Motor Drive
A speed motor operates a hydraulic pump that delivers oil at a constant pressure on the line. A regulating valve considers oil under pressure at each end alternately on the piston.
At the same time releasing oil from the different ends of the piston to return to the reservoir. The piston is pushed with oil and attached to the piston rod with the ram, moving the ram forward while carrying the tool.
Oil penetration at each end of the piston is accomplished alternately, with the help of travel dogs and pilot valves. As Ram moves forward and completes his stroke (forward and return), a trip dog pilot will trip the valve which will operate the regulating valve.
The regulating valve will accept the oil on the other side of the piston and the ram speed will be reversed. The length of the ram stroke will depend on the position of the trip dogs. The length of the ramp stroke can be changed by moving the trip dogs to the desired position.
Variable Speed Motor Drive:
In this type of slotter, the speed is achieved by various gears present in the gearbox and the shaft rotates with the help of an electric motor. Originally, it is used in modern large slotting machines.
Specification of Slotting Machines
The specifications of Slotting Machines depend on several factors some of these are:
- Power Input
- Type of drive
- Maximum table drive
- Number of feeds
- Table feed
- Floor space required
- The maximum length of ram stroke
- Number of speeds
- The diameter of the Work Table in MM
- kW of motor
Application of Slotting Machine
The main applications of slotting machines are
- To cutting keys, slots, metal sheets, grooves of various shapes and forming regular or irregular shapes used in many manufacturing units. It can be used in any workshop where vertical tool movement is necessary and required to manufacture different metal objects.
- It is used for light cuts, splines, inside keyways, the straight dagger of internal spur gears, inside curved face of circular section, internal oil grooves and etc.
- The internal recess of circular, concave & convex surfaces.
- It is also used for the Machining of internal and external gears.
- Enlargement and finishing noncircular holes bordered by a number of flat surfaces.
- Internal grooves and slots of rectangular with curved sections.
- Internal machining of blind geometrical holes similar to the hexagonal socket.
- Internal flat surfaces.
Advantages of Slotting Machines
The advantages of Slotting Machines are:
- This is a light machine.
- Low-cost machine.
- Low Maintenance.
- Accurate surface finish.
- The tool uses here is a single-point cutting tool.
- Machine efficiency is more.
Disadvantages of Slotting Machines
The disadvantages of Slotter Machines are:
- Skilled worker requires to operate.
- Rigid in construction.