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Introduction to machine tool / Single point cutting tool

The tool is wedge shape object of hard material. It is usually made from H.S.S. Beside H.S.S. machine tool is also made from High Carbon Steel, Satellite, Ceramics, Diamond, Abrasive, etc. The main requirement of tool material is hardness. It must be hard enough to resist cutting forces applied on work piece. Hot hardness, wear resistance, Toughness, Thermal conductivity, & specific heat, coefficient of friction, are other requirement of tool material. All these properties should be high.

Classification of cutting tools
A] According to number of cutting edge.

Single point cutting tool
It is simplest from of cutting tool & it have only one cutting edge.
Examples – shear tools, lathe tools, planer tools, boring tolls etc.

Multi point cutting tool
In this two or more single point cutting tools arranged together as a unit. The rate of machining is more & surface finish is also better in this case.
Example- milling cutter, drills, brooches, grinding wheels, abrasive sticks etc.

B] According to motion

Linear motion tools – lathe tools, brooches
Rotary motion tools – milling cutters, grinding wheels
Linear & rotary motion tools – drills, taps, etc.

 

Single point cutting tool geometry
The single point cutting tool mainly consist of tool shank & cutting part called point. The point of cutting tool is bounded by cutting face, end flank, side/ main flank, & base. The chip slide along the face.
The side / main cutting edge ‘ab’ is formed by intersecting of face & side / main flank
The end cutting edge ‘ac’ is formed by the intersection of end flank & base.
The point ‘a’ which the intersection of end cutting edge & side cutting edge is called nose
Mainly the chip cuts by side cutting edge.

Terminology of single point cutting tool

Shank – It is main body of tool. The shank used to gripped in tool holder.
Flank – The surface or surface below the adjacent of the cutting edge is called flank of the tool.
Face – It is top surface of the tool along which the chips slides.
Base – It is actually a bearing surface of the tool when it is held in tool holder or clamped directly in a tool post.
Heel – It is the intersection of the flank & base of the tool. It is curved portion at the bottom of the tool.
Nose – It is the point where side cutting edge & base cutting edge intersect.
Cutting edge – It is the edge on face of the tool which removes the material from work-piece. The cutting edges are side cutting edge (major cutting edge) & end cutting edge ( minor cutting edge)
Tool angles-Tool angles have great importance. The tool with proper angle, reduce breaking of tool, cut metal more efficiently, generate less heat.
Noise radius –It provide long life & good surface finish sharp point on nose is highly stressed, & leaves grooves in the path of cut.Longer nose radius produce chatter.