Difference Between Single Point and Multi Point Cutting Tool

Cutting Tool is a wedge shaped device that actually removes (shears off) excess material from a preformed blank (workpiece) in order to obtain desired shape, size and accuracy. Geometry, orientation and material are three important factors that influence performance of a cutting tool. Every conventional machining operation employs a physical cutting tool. Although basic shape of cutting tool varies greatly with the type of operation it is intended to perform, every cutting tool must possesses a wedge shaped portion with a sharp cutting edge, which can cut material smoothly and efficiently.

A cutting tool may contain one or more main cutting edges, and accordingly, it can be classified into three categories—single point, double point and multi-point cutting tools. A single point cutting tool contains only one main cutting edge, a double point cutting tool contains two cutting edges while multi-point cutting tool contains more than two main cutting edges. Important similarities and differences between single point and multi point cutting tools are discussed in the following sections.

Note: Sometime cutters are classified in two groups only (single point and multi-point), so double-point cutters are also considered as multi-point cutters. After all, drill (only example of double point cutter) may not necessarily have two cutting edges only (for example, wood cutting drills). For the sake of difference double point cutter is not considered separately; instead, it is subsumed into multi-point cutter group.

Difference between single point and multi point cutting tool

Similarities between single point and multi point cutting tool

  • Both are employed in conventional machining operations to remove excess material from workpiece.
  • Sharp cutting edge is present in both types of cutter; however, number of cutting edges is different.
  • Geometry and material are influencing factors for both types of cutter.

Differences between single point and multi point cutting tool

Single Point Cutting Tool Multi Point Cutting Tool
These cutting tools contain only one main cutting edge. Multi point cutting tools contains more than one up to hundreds of cutting edges.
While machining with single point cutting tool, only one main cutting edge continuously remains in contact with workpiece. While machining with multi point cutting tool, more than one cutting edge simultaneously engage in material removal action in a pass.
Chip load per tooth is usually high. Due to presence of multiple cutting edges, effective chip load per tooth reduces.
Since one cutting edge continuously remains in contact with the workpiece, so rate of rise in tool temperature is high. Due to successive engagement and disengagement, heat in cutter dissipates when it is not in contact with workpiece. Consequently rate of rise in tool temperature is low.
In case of unplanned breakage of cutting edge, entire process is required to pause until the broken tool is replaced by a new one. If one cutting edge breaks, cutting action can be continued using other cutting edges without much problem.
Design and fabrication of single point cutting tools are comparatively easy. Design and fabrication of multi point cutting tools are quite difficult.
Usually single point cutting tools are given low feed rate, so Material Removal Rate (MRR) and thus productivity are low. Higher feed rate can be employed with multi point cutting tool, which increases MRR and productivity. So machining operation becomes economic.
Examples of single point cutters—

  • Turning tool
  • Shaping tool
  • Planing tool
  • Slotting tool
  • Boring tool, etc.
Examples of single point cutters—

  • Milling cutters
  • Hobs
  • Broach
  • Grinding wheels, etc.

 

References

  • Book: Machining and Machine Tools by A. B. Chattopadhyay (Wiley). Buy this book
  • Book: Metal Cutting: Theory And Practice by A. Bhattacharya (New Central Book Agency). Buy this book
  • Book: Manufacturing Process for Engineering Materials by S. Kalpakjain and S. Schmid (Pearson Education India). Buy this book
  • Book: DeGarmo’s Materials and Processes in Manufacturing by J. T. Black and R. A. Kohser (Wiley). Buy this book