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1. Content of Today’s Lecture
Unit 1 : Fundamentals of CNC Machine
 Systems of CNC machines
 CNC Tooling
 DNC machine tools
Production Processes- 314340

2. Reference Books :
1) Manufacturing Processes - II by H.S. Bawa, Tata
McGraw Hill
2) Manufacturing Science and Technology by Rao &
K. Vara Prasada, New edge publication,
New Delhi.
3) Production Technology, HMT Banglore, McGraw
Hill Education, New Delhi

3. Systems (Elements) of CNC Machines:
1) Structure -
i) Bed ii) Saddle iii) Column iv) Table
2) Spindle and Feed drives –
i) Stepper motors
ii) DC servo motors
iii) AC servo motors
iv) Fluid motors

4. 3) Actuator Support Bearings -
i) Re-circulating ball screw systems
ii) Linear motion guideways
4) Feedback devices –
i) Rotory Encoders
ii) Linear Encoders
5) Automatic Tool changers (ATC)
i) Magazine Type
ii) Turret Head

5. 6) CNC Tooling –
i) Tools
ii) Tool Holders
7) Material Handling System –
i) Bar feeder
ii) Parts catcher
iii) Robot loaders
iv) Chip conveyor

6. 8) Pallet Changer system –
i) Linear pallet changer system
ii) Rotory pallet changer system
9) Lubrication system –
10) Coolant System

7. DNC Machine Tools :
 DNC i.e. Direct Numerical Control machine tools is
a manufacturing system in which a number of
machines are controlled through a central computer
by direct connection.
 The central computer provides the programming
instructions to each machine tool as well as receive
the data from the machine tools.
 DNC computer is providing instructions and
commands instantly to the individual machine tools.

9. DNC Machine Tools with Satellite computers:
 If the network of machine tools is large, then use is
made of intermediate computers known as satellite
computers.
 Each satellite computer is a minicomputer and
controls smaller groups of machine tools by receiving
the instructions from the central computer.

11. Basic Elements of DNC Machine Tool system:
1) Main computer
2) Memory for storing part program listing
3) Communication network and Interfaces
4) Machine tools

12. Functions of DNC machine tool :
1. To control the machine tools placed at different
locations from a single computer.
2. To facilitate the storage and editing of part
programs of all machine tools by a single central
computer.
3. To maintain the data base of all machine tools
centrally by receiving the data from the machine
tools.
4. To integrate CAM with CAD.

13. Advantages of DNC machine tools :
1. It eliminates punched tapes and tape readers
2. Large memory of DNC allows it to store a large
amount of part programs.
3. Central DNC computer can keep close control over
the complete machine shop.
4. Individual machine performance report can be
obtained on demand.
5. DNC uses a central computer, which can be easily
isolated from the machine shop.

14. Limitations of DNC machine tools :
1. In the event of failure of central DNC
computer, the complete activities of the
machine shop will come to standstill.
2. DNC is expensive and its use is justified where
high automation is required.

15. Assignment :
Q. (1) Explain the systems of CNC machines.
Q. (2) Give in detail DNC machine tool.
Q.(3) Give advantages & limitations of DNC
machine tool.

16. Summary:
 So, In this Lecture we have studied
- Systems of CNC machines
- CNC Tooling
- DNC machine tools

17. Next Lecture Contents :
 CNC Turning centres
 CNC Machining centres

18. THANK YOU !!
AMP - 22563