Object:To calculate DTCR and make a radar chart.
DTCR is made for evaluating machinability of the workpiece from material properties without conducting machining tests.
The conventional method to evaluate machinability is machinability rating.
Machining test is required to calculate machinability rating.

- How to obtain machinability rating
When AISI B1112 is machined, the cutting speed \( V_0 \) is researched under the condition which the tool life is 20 minutes.
And then, when target workpiece material is machined, the cutting speed \( V_1 \) is researched under the condition which the tool life is 20 minutes.
Machinability is calculated according to the equation \( 100 \cfrac{V_1}{V_0} \).

However, when you would like to know the machinability, it is the time when you have to machine the workpiece material which you machine first time.
It takes time and effort to conduct the machining tests to calculate the machinability rating.

The machinability rating is affected by heat treatments and so on.
Thus, the machinability rating is not perfect.

DTCR is made to predict the machinability easily without conducting machining tests.
Radar chart is made by hardness, tensile strength, elongation, thermal conductivity, density and specific heat.
The shape of radar chart shows trends of cutting force, chip breakability and cutting temperature.
The area of radar chart is DTCR.

It is effective to stack radar charts of the target workpiece material and the known workpiece material.
Thus, 11 workpiece material data are already input.

Reference:
・Yasuo YAMANE and Katsuhiko SEKIYA:An Evaluation of Difficulty in Machining DIfficult-to-Cut Materials by using Difficult-to-Cut-Rating, Journal of the Japan Society for Precision Engineering, Vol.70,No.3(2004),pp.407-411.(in Japanese)