CNC Machines

Computer numerical control machines are an important machine for mechanical engineers. All the basic numerical control functions can be performed by these machines. Here programmes can be entered through some mechanism in a computer which can be used again and again. Any change in the programme can be done easily. The input information can reproduced and development of sub programmes also possible to undertake. Thus any operation like drilling holes, cutting etc. can be developed in the form of programs and can be stored in the computer memory. The CNC machines have the facility for proving the part programme without actually running it on tyhe machine tool. It also allows the compensation for any changes in the dimensions of the cutting tool. Direct numerical control (DNC) is a manufacturing system in which a large number of machines (all linked to a main frame computer) are controlled by a computer through direct connections. Reduced lead time, elimination of operator errors, less operator activity, lower labour cost, longer tool life, elimination of special jigs and fixtures, flexibility in changes of component design, less scrap, accurate costing and scheduling, reduced inspection etc. are some advantages of CNC machines. But more money have to be spent as investment cost, maintenance cost, man power cost and support facility cost.