Part programming and CNC Machine | Interview Question and Answers

Part programming and CNC Machine | Interview Question and Answers

Part programming and CNC Machine | Interview , viva ,oral Question and Answers

1. Define numerical control machine.

Numerical control can be defined as a form of programmable automation in which the process is controlled by numbers, letters and symbols.

2. List out any 3 Basic component of NC system

1.Program of instruction 2.Controller unit 3.Machine tool

3. Classify NC Motion Control Sysem

1.Point to point 2. straight Cut 3.Contouring

4. Mention any 3 Application of Numerical control

1 .Milling 2.Drilling 3 .Boring

5. What is NC part programming

NC part programming is the procedure of by which the sequence of processing steps to be performed on the NC machine is planned and documented

Read more ; Standard G Code and M Code | CNC programming basicsOpens in a new tab.

6. What is tape reader?

The tape reader feed the data from the tape to the buffer in blocks.

7. What are the responsibility in computer assisted part programming

1 .Defining the work part geometry, 2. Specifying the operation sequence and tool path.

8. What is APT language?

APT is not only a NC language it is also the computer program that performs the calculations to generate cutter positions based on APT statement.

9. Classify statements in APT

1. Geometry statement 2. Motion statement 3.Post processor statement 4. Auxilary Statement

10. Define Check surface.

This is the surface that stops the movement of the tool in its current direction.In a sense,the forward movement of the tool.

11. Write general form of Motion Statement

motion command/descriptive data example:GOTO/Pl

12. Mention any 4 Post processor statement in APT


13. Write any 3 Contouring Motion words


14. What are the merits of CAD/CAM IN NC programming

• Savings in geometry definition
• Immediate visual verification
• Use of automatic programming routine

15. What is CNC

CNC is an NC system that utilizes a dedicated,stored program computer to perform some or all of the basic numerical control functions

16. What are functions of CNC?

1. Machine tool Control
2. In Process compensation
3. Improved Programming and operating feauters

Read more : Classification of Numerical Control CNC MachinesOpens in a new tab.

17. List out any 3 merits of CNC.

1. Part program tape and tape reader are used only once
2. Tape editing at machine site
3. Greater flexibility

18. What is FTP NC?

The objective of machine tool control system to move the cutting tool to a predefined location.

19. What do you mean by machining centre ?

The machining centre in a control machines is an automatic tool changing arrangement that is designed to perform a variety of machining operations, with large number of cutting tools and provided with a continuous path CNC system.

20. Where is the common path contouring used?

Common path contouring is used in grinding machine and routes.

21. What is a part program ?

Part program is a high level language program containing the instructions for-machining a part on sheets with respect to various standard words / codes and symbols.

bobcad cam - cnc programming software
bobcad cam – cnc programming software

22. What is post processing?

Post processing is a computer program that takes a generalized part program output and adopts it to a particular machine control unit/ machine tool combination. It is the basic intelligence required to change the program into computer language.

23. Name the language used in CNC programming.

The language used in CNC programming is APT(Automatically Programmed Tool).

24. Write the various types of tape readers.

The various types of tape readers are:
a) Electromagnetic tape reader. b) Magnetic tape reader.
c) Photo eletrical tape reader. d) Pneumatic tape reader.

25. Write the order of the instructions in a part program.

The order of the part program is
1. Preparatory function, 2.Feed function, 3.Tool function, 4.End of block

26. What is meant by manual part programming?

Manual part programming is a process of writing programs which consist of a set of instructions to carry out the machining of the work.

27. Write the disadvantages of manual part programming.

The disadvantages of manual part programming are:
a) It is difficult to perform several co-ordinate calculation for complex shapes.
b) Setting of the tool can be done to an approximate dimension and the difference is adjust by suitable external switches set.

28. What is preparatory function ?

It is word address format represented by the letter G ,followed by a numerical code for the operation of the control unit to instruct the machine tool.

29. What is tool length offset?

When tools with different length are used, then the difference in their lengths with respect to a datum is known as offset of each tool.

30. Give a brief note on Canned Cycle.

The canned cycle simplifies and shortens the programming in such way whenever any one of the above operation is required.

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Sachin Thorat

Sachin is a B-TECH graduate in Mechanical Engineering from a reputed Engineering college. Currently, he is working in the sheet metal industry as a designer. Additionally, he has interested in Product Design, Animation, and Project design. He also likes to write articles related to the mechanical engineering field and tries to motivate other mechanical engineering students by his innovative project ideas, design, models and videos.

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