This document discusses computer aided manufacturing (CAM) and computer numerical control (CNC) machines. It covers the main components of CNC machines which include the program of instruction, machine control unit, and machine tool. The machine control unit consists of a central processing unit, memory, and input/output interface. Direct numerical control (DNC) is also discussed, along with advantages and types of CNC machines. Elements of CNC machines like slide ways, screws, and feedback devices are described.

1. TSSM’S
BHIVARABAI SAWANT COLLEGE OF ENGINEERING AND
RESEARCH , POLYTECHNIC, NARHE,PUNE-41
Department Of Mechanical Engineering
Course : Advancedmanufacturingprocess(22563)
Unit 4 : Fundamental of Computer Aided
Manufacturing (CAM)
( 12 Marks)
C563.1 : Maintain CNC machine to produce components
effectively.

2. Introduction To CAM

3. Numerical Control

4. Application of NC Machine

5. Advantages of NC Machine

6. Disadvantages of NC Machine

7. Problems with Conventional NC

8. Features of CNC Machine
• Storage of more than one part program
• Various forms of program input
• Program editing at the machine tool
• Fixed cycle and programming subroutines
• Cutter length and size compensation
• Acceleration and deceleration calculations
• Communication interface
• Diagnostics

9. Advantages of CNC Machine

10. Disadvantages of CNC Machine

11. Applications of CNC Machine
• Industries for removing metal
• Industries for fabricating Metals
• Electrical Discharge Machining
• Other Industries where CNC machines are used

12. Main Components of CNC Machine
CNC will consist of the following basic elements
• Program of instruction
• Machine control unit
• Machine tool
Program of instruction
• The part program is called as program of instruction.
• It is prepared by the part programmer.
• It is the detail step-by-step set of instructions which tells the machine tool what
to do
• The part program is a combination of numbers and letters and is fed to the
controller.
• It is generally input to through the keyboard manually.

13. The Machine Control Unit (MCU)
The MCU consists of the following components and subsystem
1. Central Processing Unit
2. Memory
3. Input/ Output Interface
Central Processing Unit:
• The central processing unit (CPU) is the brain of the MCU
• It manages the other components in the MCU based on software contained in
main memory
The CPU can be divided into three sections:
a) Control section
b) Arithmetic-logic unit
c) Immediate access memory
Memory:
a) Primary memory:
b) Secondary memory:
Input / Output Interference

14. Machine Tool

15. DIRECT NUMERICAL CONTROL
Components of DNC System
• Central computer
• Bulk memory, which stores the NC part programs
• Telecommunication lines
• Machine tools
• Behind-the-tape-Reader (BTR) System
Fig. DNC machine Fig. Special Machine Control Unit

16. Function Of DNC

17. Advantages of DNC

18. Types of CNC Machines
1. CNC Milling Machine
2. CNC Lathe Machine
3. CNC Router Machine
4. CNC Plasma Cutting Machine
5. CNC Laser Cutting Machine

19. Classification of CNC Machines

20. Based on control system characteristics
1. Point – to – Point System

21. Straight Line System

22. Contouring System
Fig. Continuous Path Control System

23. Based on Feedback System
1. Open Loop Control System

24. 2. Closed Loop Control System

26. Selection Criteria
1. Current Machine Tool Set-up
2. Part Difficult and Complexity
3. Material to be Machined
4. Linear Motion Guide Ways or Box Guide ways
5. Types of CNC control system
6. Cost per part
7. Available Space At Factory
Elements of CNC Machines
Slide ways
Types of Slide ways
1. Hydrostatic Type Slide ways
2. Anti-friction type slide ways

27. Hydrostatic Type Slide Ways

28. Anti-friction Type Slide Ways

29. Re-circulating Ball Screw

30. Feedback Devices-Transducers
Synchro Resolver

31. Inductosyn

32. Feedback Devices- Encoders

33. Incremental encoders