Single Point Cutting Tool

Single point cutting fits in the category of machining as a manufacturing process. It involves the removal of metal from a workpiece using cutting tools that only have one primary cutting edge. Single point cutting using standard tools and equipment is a good option for the production of small batches and 1 off items such as prototypes. Machines are flexible and can be used for the production of a large range of components without the need for dedicated tooling. Basic set up costs are relatively low.

Characteristics of Single Point Cutting Tools

• Hardness even at high temperatures
• Toughness
• Chemical
• Resistant to wear

These characteristics have traditionally been found through the adoption of carbon and low alloy steels, although they did have a tendency to wear a little too easily. Being relatively easy to sharpen offset this problem to an extent but there was a clear need for further development  of tooling which could perform better.
High speed steels provided an initial solution to the wear problem, which was mainly brought about as a result of high temperatures being present while machining that would have an adverse affect on the low alloy steels. The high speed steels are still considered to be an affordable and effective choice for cutting most materials, but more recently there has been an adoption of cemented carbide inserts.
Cemented carbide tips are used in conjunction with tool holders and are normally supplied in a triangular geometry which can now be rotated in the holder to provide a new cutting tip when it does wear simply by loosening a retaining screw and clamp. Early designs used brazing to secure the carbide tip in its holder which, for obvious reasons, made continued use of the tip after wear impractical.
Further improvements in wear resistance came in the form of ceramic coatings that could be used on both high speed steels and cemented carbide tools. Diamond is another cutting tool material but is pretty much limited to low temperature applications, despite it being the hardest known material available.

Nomenclature of Single Point Cutting Tool

The single point cutting tool has only one cutting point or edge. These tools used for turning, boring, shaping or planning operations. These tools used on lathe, boring and shaper machines.

A single point cutting tool consists of a sharpened cutting part and the shank and main parts or elements which are:
1: Shank
It is the main body of the tool.
2: Flank:
The surface or surfaces below the adjacent to the cutting edge is called flank of the tool.
3: Face
The surface on which the chip slides is called the face of the tool.
4: Heel
It is the intersection of the flank and the base of the tool.
5: Nose
It is the point where the side cutting edge and end cutting edge intersect.
6: Cutting Edge
It is the edge on the face of the tool which removes the material from the work piece. The cutting edge consists of the side cutting edge(major cutting edge) and cutting edge(minor cutting edge) and the nose.

Single Point Cutting Tool Angles

The single point cutting tool mainly focus at their angles. The angle in cutting tool is following

• Side rake angle :This angle has major effect on the power efficiency as well as on the tool life. The value of this angle lies between 15° to 25°.
• Back rake angle : This angle controls the flow of chips, thrust force of the cut and the power of cutting tool edge. The value of this angle lies between 4° to 8°.
• Side cutting edge angle :This angle can reduce the thickness of chips. The value of this angle lies between 10° to 15° and is also called as lead angle.
• True rake angle :This angle has prime importance in metal removal process. All three angles which are discussed above are directly affected by this angle. If we have high positive true rake angle then less force, power and heat generate. The value of true rake angle can either be positive or negative but it totally depends upon the cutting tool material, machine rigidity and some other variables.
• End cutting edge angle :This angle provides us some clearance between cutter and finished surface of the work piece. If the value of angle is very close to zero then the tool strength will increase and if we take a larger value then it weakens the tool. The value of this angle lies between 8° to 15°.
• Nose radius:This angle gives us the strength to cutting edge, improves finish and also put some stress on the life factor of the tool. If we take a large value then it produces large radial force .But if we take too small value then it stops proper distribution of heat and reduces cutting tool material properties.
• Primary clearance angle :This angle is below cutting edge angle and is used to prevent tool from rubbing.
• Secondary clearance angle :This angle is on the tooth forms of shank and has a large value so it can permit chips to escape easily. But if we take too large value then it weakens the tool, so to avoid this problem we take economical value.