What is single point cutting tool?

Short Answer:

A single point cutting tool is a type of cutting tool that has only one main cutting edge used to remove material from a workpiece. It is mainly used in turning, shaping, and planing operations where the tool removes material in the form of chips. The tool cuts the workpiece by moving relative to it under controlled speed, feed, and depth of cut.

These tools are generally made from high-speed steel (HSS), carbide, or ceramic materials. A single point cutting tool is designed with specific angles such as rake angle, relief angle, and cutting edge angle to perform smooth cutting and achieve good surface finish.

Detailed Explanation :

Single Point Cutting Tool

A single point cutting tool is the simplest and most commonly used tool in metal cutting operations. It has only one main cutting edge that performs the actual cutting work. This type of tool is widely used in machining processes like turning on a lathe, shaping, and planing, where material is removed from the workpiece in the form of chips. The tool is held rigidly, and the workpiece rotates or moves against the tool to produce the desired shape and size.

Construction of Single Point Cutting Tool

A single point cutting tool is made up of two main parts:

  1. Shank: The shank is the main body or the holding portion of the tool. It is clamped into the tool post or tool holder.
  2. Head: The head of the tool contains the cutting part. It has the cutting edge and different angles designed for effective machining.

The head of the tool includes the following important parts:

  • Face: The surface over which the chip flows during cutting.
  • Flank: The surface below and adjacent to the cutting edge that faces the finished workpiece surface.
  • Cutting Edge: The edge formed by the intersection of the face and flank, responsible for shearing the material.
  • Nose: The curved portion at the tip of the tool joining the side and end cutting edges, which helps to improve surface finish and tool strength.

Angles of Single Point Cutting Tool

To perform effective cutting, a single point cutting tool is designed with specific angles. These angles reduce friction, control chip flow, and improve tool life. The main angles are:

  1. Rake Angle:
    It is the angle between the tool face and a line perpendicular to the work surface. It helps in controlling chip flow and cutting forces. A positive rake angle reduces cutting force but weakens the tool, while a negative rake angle increases strength but needs more cutting power.
  2. Relief Angle:
    It is the angle between the flank and the surface being cut. It prevents rubbing between the tool and workpiece and allows smooth cutting.
  3. Side Cutting Edge Angle:
    It is the angle between the side cutting edge and the longitudinal axis of the tool. It helps distribute cutting forces and control chip direction.
  4. End Cutting Edge Angle:
    It is the angle between the end cutting edge and a line perpendicular to the tool axis. It prevents rubbing between the tool and the workpiece.
  5. Nose Radius:
    The rounded portion at the tool tip that improves surface finish and tool life by avoiding sharp corners.

Materials Used for Single Point Cutting Tools

The material of the tool must be harder than the workpiece and able to resist wear, heat, and pressure. Common materials used include:

  1. High-Speed Steel (HSS): Most common for general machining, tough and economical.
  2. Cemented Carbide: Used for high-speed machining, with good wear resistance.
  3. Ceramic Tools: Used for high-temperature and high-speed cutting operations.
  4. Cubic Boron Nitride (CBN): Suitable for hard materials like hardened steel.
  5. Diamond Tools: Used for very hard or non-metallic materials, giving excellent surface finish.

Working Principle of Single Point Cutting Tool

When the single point cutting tool is fed against a rotating workpiece, its sharp edge penetrates the material and shears it off in the form of chips. The tool cuts due to relative motion between the workpiece and the cutting edge. During this process, a large amount of heat is generated at the cutting zone, which must be controlled using coolants or lubricants.

The effectiveness of the cutting depends on three main factors:

  • Cutting speed
  • Feed rate
  • Depth of cut

Proper selection of these parameters ensures better surface finish, higher tool life, and efficient metal removal.

Applications of Single Point Cutting Tool

Single point cutting tools are mainly used in:

  1. Turning operations on lathe machines to produce cylindrical parts.
  2. Shaping and planing operations to produce flat surfaces.
  3. Boring operations to enlarge or finish holes.
  4. Thread cutting operations to form screw threads.

These tools are essential for producing precise and smooth surfaces in mechanical manufacturing industries.

Advantages of Single Point Cutting Tool

  1. Simple design and easy to manufacture.
  2. Low cost and easy to sharpen or regrind.
  3. Can be used for both roughing and finishing operations.
  4. Easy to set up and replace in the tool holder.
  5. Suitable for various cutting operations with different materials.

Limitations of Single Point Cutting Tool

  1. Cannot be used for very high-speed cutting.
  2. Limited tool life compared to multi-point tools.
  3. Generates more heat during cutting.
  4. Not suitable for cutting very hard materials without advanced tool materials.
Conclusion:

A single point cutting tool is a fundamental and widely used tool in machining processes. It has one main cutting edge that removes material in the form of chips to shape and finish the workpiece. With proper geometry and tool material, it provides accuracy, good surface finish, and efficiency. Though simple in design, it plays a vital role in various machining operations and forms the foundation of modern manufacturing processes.