Which of the following is not the characteristics of cutting tool material? 

Explanation:

Cutting Tool Material Characteristics

• Cutting tool materials are specially engineered materials designed to withstand extreme conditions during the machining process, such as high temperatures, mechanical stresses, and friction. The selection of an appropriate cutting tool material is critical to achieving efficient and precise machining performance.

Coefficient of friction between chip and tool should be very high.

• This option is incorrect because the coefficient of friction between the chip and the tool should ideally be as low as possible, not high. High friction between the cutting tool and the chip would result in several adverse effects during the machining process, such as:
• Increased Heat Generation: High friction leads to excessive heat at the tool-chip interface, which can cause thermal softening of the cutting tool material and reduce its service life.
• Tool Wear: High friction accelerates tool wear, including abrasive wear, adhesion, and diffusion wear, leading to more frequent tool changes and increased operational costs.
• Poor Surface Finish: High friction can cause irregularities on the workpiece surface, leading to poor dimensional accuracy and surface quality.
• Increased Cutting Forces: High friction results in higher cutting forces, which place additional strain on the machine tool and can lead to vibrations and chatter.