Slotter machines are reciprocating machines that are designed to create horizontal, vertical, and flat surfaces. They are often used to cut planes, and keyways, and form surfaces. They are suitable for single and small-batch production.
The slotter machine is one of the oldest machine tools that exists and was invented for BRUNE. It is very similar to the vertical shaper machines, as the ram carrying the slotting tool reciprocates in a vertical guideway of the machine. Also, this machine can produce flat and contour surfaces, slots, and internal grooves.
Well, in this reading, we’ll explore what a slotting machine is, its applications, parts, diagrams, types, specifications, operations, and how it works. We’ll also explore the advantages and disadvantages of slotting machines.
Let’s begin!
What is a Slotting Machine?
Slotting machines are reciprocating machines that are primarily employed to produce horizontal, vertical, or flat surfaces. The slotting machine is primarily employed for the purpose of carving planes, forming surfaces, and creating keyways, among other tasks. It is appropriate for both single-use and small-scale production.
A slotter machine is a machine tool that is used to remove unwanted material from the workpiece in order to create lines, channels, and other features. In this instance, the Ram (tool affixed) is transported in a reciprocating motion, while in a shaper, the Ram is transported horizontally.
These machine tools can shape regular and irregular surfaces on internal and external path especially for profiles and gears. They can used on any tools where vertical tool movement will occur.
Applications
Just as earlier mentioned, slotting machines are used in various manufacturing units for cutting keys, slots, metal sheets, and grooves of various shapes. They are versatile and can be used in any workshop where vertical tool movement is needed.
They are used for light cuts, splines, inside keyways, spur gears, curved faces of circular sections, internal oil grooves, internal recesses of circular, concave, and convex surfaces. They are also used in machining of internal and external gears, enlarging and finishing noncircular holes bordered by flat surfaces, internal grooves and slots of rectangular with curved sections, and internal machining of blind geometrical holes.
Related: What is Shaping Machine? Its Diagram and How it Works
Components of Slotter Machine
A slotter machine consists of the following parts:
Base: The base is a rigid component on a slotter machine that takes the entire load of the machine. They are made of cast iron. The bed top is a smooth and finished surface for the saddle guideways which are perpendicular to the face of the column.
Column: The column is a vertical and integral rigid part made of cast iron; it serves as a housing for the feeding mechanism of the table. It also houses the driving mechanism of the ram, which reciprocates on its front vertical face. The column also played an important role as it moved on guideways on the base to provide a longitudinal feed of the table. This longitudinal feed may be given either manually or by power.
Cross-slide: The component of a slotter machine is mounted on the guideways of the saddle, allowing cross-feeding to be achieved on the table.
Circular Table or Rotating Table: This part is designed to rotate on a crop slide to provide circular feeding to the work. Other devices like clamp, fixtures, and fixing vice can be use to perform different operations on the machine. Some slotter table are design to be graduated in degrees and has the structure of rotary feeding by power or hand.
Ram and Tool Head: The ram slides on the guideways mounted on the front vertical face of the column, and it provides a slot for changing the position of the stroke. The tool is then mounted to the ram at the bottom end of the toolhead.
Ram Drive: This slotter machine part produces a circular motion of the motor to the reciprocating motion of the ram in a vertical plane. The ram drive also provide slower speed during the cutting or forward stroke and higher speed at the return stroke which help to reduce the idle time.
Feed Drive: This slotting machine part produces the arrangement of longitudinal and cross-feed of the table either manually or by power. The feed drive also allow the arrangement of circular or rotary feeding of the table on a vertical axis. The forward stroke of the ram or cutting allows intermittent feeding of the table.
Diagram
How Does A Slotter Machine Work?
The working of the slotter machine is very similar to the shaper machine. Their major difference is that shaper machines work horizontally, whereas slotter machines work vertically. The ram is connected to the crank, and the crank is connected to the gears. This allows the increase or decrease of the gear speed and takes effect on the rotation of the crank speed. It also allows the ram to move up and down.
The workpiece is attached to the workable, and the ram will be manually taken to the workpiece. The worktable is designed to be adjusted and has the workpiece clamp on it. The crank rotates as soon as power is supplied to the machine, and the crank is connected to the ram, which moves up and down.
During the up and down movement of the ram, the cutting stroke occurs in the upstroke and there is no cut in the return stroke.
Slotter Machine Mechanism
The following are the two different slotter machine mechanisms:
- Hydraulic Drive (greater speed flexibility, smoother operation, stroke length can be adjusted)
- Variable Speed Motor Drive (multi-speed arrangement)
Hydraulic Drive:
In this mechanism, a speed motor is driven by a hydraulic pump, which delivers oil at a constant pressure to the line. It also contains a regulating valve that pushes oil under pressure to each end of 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 the 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 reverse. 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
With this mechanism, the speed of a slotter machine is obtained by different gears present in the gearbox, while the shaft rotates with the aid of an electric motor. It is used in modern large slot machines.
Types of Slotter Machines
The following are types of slot machines:
Punch Slotting Machine
The machine tool is heavy and rigid, designed for removing large amounts of metal from forged or cast material. The puncher slotter’s length is as long as 1800 to 2000 mm. It works similarly to other types, but the ram is usually driven by a special pinion mesh with the rack teeth cut on the underside of the ram. A reversible electric motor with a variable speed is used to drive the pinion, and the feed is controlled by an electrical gear.
Precision Toolroom Slotter
These slotter machine types have a good machine speed, create light cuts, and offer an accurate surface finish. These types of slotter machines are capable of taking light cuts and give accurate finishing. Also, special jigs, makes the machine to handle various tasks easily.
Special Purpose Slotter Machine
This machine offers a high volume of production at a low cost and gives greater accuracy. Keyseaters are one of the special purposes of slotting machines, used for machining keys on the wheel and gear hub.
Production Slotter Machine
Manufacturing Slotter is a heavy-duty slotter that often comes in two parts and has a heavy cast base and frame. Its application is in general production work. The ram’s action is reciprocated by a slotted disc with a connecting rod. In order to prevent stroke at the end of the stroke, flywheel is incorporated.
Specification of Cutting Machines
The specifications of a slotting machine depend on several factors, which include:
- Power input.
- Maximum table drive.
- Type of drive.
- The maximum length of ram stroke.
- A number of feeds.
- Table feed.
- A number of speeds.
- Floor space requirement.
- kW of the motor.
- The diameter of the worktable in MM.
Slotter Machine Operations
Slotting machines can be used to produce various operations like:
- Internal and external circular surfaces.
- Bling holes internal machining.
- Internal and external flat surface machining.
- Shaping internal and external forms of profiles.
- Internal recess of circular, semi-circular, concave, and convex surfaces.
- Irregular surface machining.
- Dies and punches operation.
- Slots, grooves, splines, and internal and external keyways surface.
- Internal and external gear teeth.
Related: What is Milling Machine? its Diagram & How it Works
Advantages and Disadvantages of Slotter Machine
Advantages
The following are pros of a slotter machine:
- The single-point cutting tool is used.
- Low-cost machine.
- Accurate surface finish.
- High machine efficiency.
- Low maintenance.
- The machine is light.
Disadvantages
The following are cons of a slotter machine:
- It requires a skilled person to operate it.
- Rigid in construction.