What is metal cutting process?

Metal cutting process
Fig. 1 Metal cutting process

Metal cutting process is also known as conventional machining processes.
These processes are normally done in machine shops or tool room for producing cylindrical or flat jobs to a desired shape, size and surface finish.
The cutting tool moves in such a way that a layer of metal is removed in the form of a chip.

What is machine tools?

Machining processes are carried out with the help of machine tools (single or multi-point).
A machine tool is a cutting machine which helps in managing the motion between cutting tool and the job.
This creates various shapes and sizes as per the requirement.
In metal cutting (machining) process, the mechanisms of machine tool creates the necessary action for the workpiece and tool to travel relative to each other and machine the material in the form of chips.

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Turning operation

What are the different types of cutting?

Types of cutting operations
Fig. 2 Types of cutting operations

In this process, the cutting operation is classified as orthogonal cutting and oblique cutting.
Orthogonal cutting which is also known as two dimensional metal cutting has the cutting edge perpendicular to the work piece.
In orthogonal cutting there is no force acting in perpendicular direction to the tool and work piece which are in the relative motion.
Oblique cutting which is also known as three dimensional cutting is used in various metal cutting operations.
In this operation, the cutting action is inclined with the job by a certain angle which is also known as the inclination angle.

What is a cutting tool?

Cutting tools are classified as single point cutting tool or multipoint cutting tools.
The cutting phenomenon takes place with the help of teeths and cutting edges.
A single point cutting tool (such as a lathe, shaper and planner and boring tool) has one cutting edge, whereas a multi-point cutting tool (such as milling cutter, drill, reamer and broach) has a number of cutting edges on its periphery.

What is a single point cutting tool?

Single point cutting tool
Fig. 3 Single point cutting tool

Single point cutting tools are classified into two types:
(a) solid type.
(b) tipped type.
The materials used for making solid type single point tool are high speed steel and cast alloy.
Brazed tools are used in tool holders.
The tipped type of tool is made from a good shank steel on which is mounted a tip of cutting tool material.
High speed steel or cemented carbide is used for making a tipped tool.
Inserts are also used as a cutting tool which removes the material as and when required.
The Insert type tool are basically held in the tool holder.
The inserts are purchased which are ready for use.
Inserts are not reusable once the cutting edges have lost their sharpness.

Describe the geometry of a single point cutting tool?

Geometry of single point cutting tool
Fig. 4 Geometry of single point cutting tool

Back rake angle
Back rake is the angle between the face of the tool and a line parallel with base of the tool.
It is measured in a perpendicular plane through the side cutting edge.
negative back rake angle is created when the slope face is downward toward the nose and a positive back rake angle us created when the slop face is upward.
The main function of this angle is to remove the chips away from the work piece.

Side rake angle
Side rake angle has the face of tool inclined side ways.
This angle is used to determine the thickness of the tool behind the cutting edge.
Due to this angle a clearance is generated between work piece and tool so as to prevent the rubbing of workpiece with end flake of tool.

End relief angle
The main function of this angle is to allow the tool to cut without rubbing on the workpiece.
It is defined as the angle between the portion of the end flank immediately below the cutting edge and a line perpendicular to the base of the tool.
Extra end clearance is provided on the tool which is also known as end clearance angle.
It is basically a secondary angle directly below the end relief angle.

Side relief angle
The main function of this angle is to prevent the interference of the tool that enters the material.
It is an angle between the side edge and a line perpendicular to the base of the tool.
It is incorporated on the tool to provide relief between its flank and the workpiece surface.
Side clearance angle is basically an extra side clearance provided on the tool.
It is basically a secondary angle directly below the side relief angle.

End cutting edge angle
The angle between the cutting edge at the end and a line perpendicular to the shank of the tool is called as end cutting edge angle.
A clearance is maintained between tool cutting edge and work piece.

Side cutting edge angle
The angle between straight cutting edge on the side of tool and the side of the shank is known as side cutting edge angle.
In industry, this angle is also called as lead angle.
The main function of this angle is to turn the chip away from the finished surface.

Nose radius
It is the nose point connecting the side cutting edge and end cutting edge.
The main function of nose radius is to create good surface finish on the workpiece.

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