Introduction to Machine Tools
Machine Tools: Machining equipment that cuts, shears, punches, presses, drills, grinds.
Machine tools are generally the power driven metal cutting or metal farming machines used to alter/change the workpiece to the required shape and size by:
1. Cutting away the unwanted sections
2. Pressing, drawing, punching or shearing
3. Controlled electrical machinery process
Generation of Machine Tools
1. Machine tools are operated manually or with automatic control. The earlier machines used flywheels to stabilize their motion and had complex system of gears and levers to control the machine and the piece being worked on.
2. Machines continued to be improved and soon after World War II, the numerical controlled (NC) machine was developed. The NC machines used a series of numbers punched on paper tape or punch cards to control their motion.
3. Lately computers have been added and the Computerized Numerical Control (CNC) machines have allowed industry to produce parts quickly and accurately. The same part can be reproduced to the exact accuracy, any number of times if the part programme has been properly prepared. The operating commands that control the machine tool are executed with amazing speed, accuracy, efficiency and reliability.
For becoming the finished product, various operations such as turning, drilling, milling, threading, reaming, grinding etc., have to be performed. A variety of machine tools to perform these operations and the choice of a particular machine essentially depends on:
1. Material of the workpiece
2. Nature of metal cutting operations
3. Number of parts to be machined
4. Degree of accuracy desired
Any machine tool chosen will have the capability to:
1. Hold and support the workpiece and cutting tool
2. Impart suitable reciprocating or rotary movement to the cutting tool or workpiece
3. Regulate the cutting speed and feeding movement between the tool and workpiece so that the desired cutting actions, accuracy and repeatability can be achieved.
Basic machine tools are the machines that are used for general purpose metal cutting operations within their range and these include engine lathe machine, drilling lathe machine, shapers lathe machine, milling machines, grinder lathe machine and power hacksaws lathe machine, Planer lathe machine, Sloter lathe machine etc.