CNC Machine

1. CNC
Mechanical Element of
CNC Machine.

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

3. •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

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Machine structure
Safty and precaution
Flow arrangment
Impotanse of levelling
How lift the machine

5. 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

6. Guideway Ball
screw
Table /
Carriage
Guide Way

7. 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
Guide Way

8. Anti friction Guide Way-
LM bearings

9. 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
Mechanical Transmission System

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Ball Screw

11. 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 the threaded shaft is the screw.

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16. Variable lead thread cuttingFlexible Couplings
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

17. Variable lead thread cuttingFlexible Couplings - Contd.

18. Variable lead thread cuttingTimer Belt and Pulley
Endless toothed belts .Used
when shafts are not coaxial
Advantages:
• Low cost
• Less noise
• No lubrication
• Less maintenance
• Higher efficiency
Set initial tension properly

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Electronics