CNC 4 Constructional features and working of CNC

CNC 4. Constructional features and working of CNC machines co: -Carryout job production on CNC Lathe machine by Setting tool offsetand tool wear compensation. Identify CNC tooling and use as per operation. Visit for more Learning Resources

Different Mechanical Elements • Machine structure • Guideways • Ball screw • Transmission elements -Couplings/Pulley • Power chuck • Auto Tool changer • Auto pallet changer

Machine Structure • Load carrying and supporting member of the machine • Subjected to static and dynamic loads • Structure should not deform or vibrate under the loads beyond limits

Machine structure Safty and precaution v. Flow arrangment v. Impotanse of levelling v. How lift the machine 4 3/11/2021

Guide Way Guideways are used to • Control the direction of carriage or the table on which a workpiece/tool is held • To absorb all static and dynamic forces

Guide Way Table / Carriage Guideway Ball screw

Guide Way CNC machines use antifriction guideways to • Reducing friction • Improve smoothness of movement • Reduce amount of wear • Reduce heat generation Rolling elements are used between moving and stationery elements of machine Ex: Linear recirculating LM guides

Anti friction Guide Way. LM bearings

Mechanical Transmission System Components which are in the force and motion transmission paths from drive motor to the slide • Elements to convert rotary to linear motion Ball screw , Rack and pinion • Torque transmitting elements Timing belt pulley , Gear box, Coupling

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Recirculating Ball screws A ball screw is a mechanical device for translating rotational motion to linear motion. A threaded shaft provides a spiral raceway for ball bearings which act as a precision screw. As well as being able to apply or withstand high thrust loads they can do so with minimum internal friction. They are made to close tolerances and are therefore suitable for use in situations in which high precision is necessary. The ball assembly acts as the nut while threaded shaft is the screw.

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Flexible Variable lead. Couplings thread cutting These couplings are used when the driver and driven shaft are coaxial Flexibility built into the couplings compensate misalignment errors like radial, angular and axial

Flexible Contd. Variable. Couplings lead thread-cutting

Timer Belt and Pulley Variable lead thread cutting Endless toothed belts. Used when shafts are not coaxial Advantages: • Low cost • Less noise • No lubrication • Less maintenance • Higher efficiency Set initial tension properly For more detail contact us