Cutting speed- The cutting speed for cutting operation is speed at which the cutting edge passes over the material. It is specified in meters/min. For turning operation the cutting speed is the surface speed of bar being turned.

Depth of cut- The advancement of the tool against material cut. In case of turning it is double.

Feed- Advancement of the tool per revolution. Cutting time & MHR estimations -

Let the cutting speed for machining the above component is 80m/min. Let the feed is 0.3mm 2 cuts are required. One is rough cut and another is finish cut. One is required to calculate the time required for machining the component and MHR.

First we need to calculate the RPM of machine. It can be calculated by using formula-Cutting speed = π∗D∗N60

After calculating N (RPM of machine), time required for machining the job can be calculated by formula-Time=

Lengthof jobRPM∗Feed

Points to remember-The life of a machine as per norms is 10yrs and that of a building is 25yrs.

Calculation of MHR-Let the CNC turning machine was purchased for Rs.10LacsNow the depreciation of machine in 1 Hr.- Rs.41It is assumed that the motor of the machine runs at 80% of its capacity. Let the machine is powered by a 5HP motor. So actual rating of motor is 4HP.Hence the electricity bill for 1 Hr.- Rs.15Now the depreciation of building in 1yr-Rs. 80000Therefore depreciation of building in 1Hr.- Rs. 33.3Operator charges for 1Hr. if the operator gets Rs.6000 p.m. = Rs.30Tooling cost (for 2 bits consumed in 8Hrs and each bit costs Rs.140)= Rs.35Hence total cost= Rs.154For inefficiency, multiply the cost by 1.1%. Hence total cost is Rs.169.4Lubrication costs .5%.Maintenance costs .5%. If the machine is on loan the multiply the bank interest.Keep a minimum of 10% profit.After calculating total MHR is Rs. 216.43Hence cost of component= Rs. 28