INTRODUCTION TO COMPUTER NUMERICAL CONTROL • The variety being demanded in view of the varying tastes of the consumer calls for a very small batch sizes. Small batch sizes will not be able to take advantage of the mass production techniques such as special purpose machines or transfer lines. Hence, the need for flexible automation is felt , where you not only get the benefits of rigid automation but are also able to vary the products manufactured thus bringing in the flexibility. Numerical control fits the bill perfectly and we would see that manufacturing would increasingly be dependent on numerical control in future.
Numerical control a. Starting and stopping of machine tool spindle. b. Controlling the spindle speed. c. Positioning the tool tip at desired locations and guiding it along desired paths by automatic control of motion of slides. d. Controlling the rate of movement of tool tip ( feed rate) e. Changing of tools in the spindle.
Functions of a machine tool a. Able to hold the work piece and cutting tool securely. b. Endowed the sufficient power to enable the tool to cut the work piece material at economical rates. c. Capable of displacing the tool and work piece relative to one another to produce the required work piece shape. The displacements must be controlled with a degree of precision which will ensure the desired accuracy of surface finish and size.