CNC Questions and Answers – NC Part Programming

This set of CNC Multiple Choice Questions & Answers (MCQs) focuses on “NC Part Programming”.

1. Part programming can be done by which of the following methods?
a) Virtual data input
b) Manual data input
c) Symbolic data input
d) Real time input
View Answer

Answer: b
Explanation: The various methods for part programming are manual programming, computer-assisted part programming, CAD/CAM part programming, manual data input. Manual data input is also known as conversational programming.

2. In manual part programming the part program is prepared using _________
a) Low level machine language
b) High level language
c) Algorithmic language
d) Business oriented programming language
View Answer

Answer: a
Explanation: Numerical control code in manual part programming is written using low-level machine language. The coding system is based on binary numbers. The Numerical Control system uses a binary coded decimal system.

3. What is the name given to the organization of words within a block?
a) Program format
b) Instruction
c) Word format
d) Block format
View Answer

Answer: d
Explanation: The block format which is used in modern Numerical Controllers is word address format. Word address format uses spaces to separate words within a block and a letter prefix for identifying the type of word. A word denotes operation details like x/y position, feed rate, etc.

4. G-words are also called _________
a) Preparatory words
b) Miscellaneous words
c) Sequential prefix
d) Axial words
View Answer

Answer: a
Explanation: G words are known as preparatory words because the prefix G is followed by two numerical digits that prepare the machine control unit for the instructions contained in the block. M words are used for miscellaneous functions.

5. Which of the following word prefixes indicate rotational axes?
a) X Y Z
b) A B C
c) S T N
d) G F M
View Answer

Answer: b
Explanation: A-, B-, C- words are used for rotational axes and X-, Y-, Z- words for linear axes coordinates. N-words are used to denote sequence number, S- words are used for spindle speed, F- words are used for feed rate, and T- words are used for tool selection.

6. Which of the following software is used for CNC part programming?
View Answer

Answer: d
Explanation: MASTERCAM is a CAD/CAM software package that is widely used for part programming. The CAD model of the part to be machined can be developed or can be imported from another CAD package. The output of the MASTERCAM program is a part program in the word address format.

7. Which word is used to stop the spindle in manual part programming?
a) M05
b) M09
c) M02
d) M03
View Answer

Answer: a
Explanation: In word address format, M09 is written to turn cutting fluid off. M02 is written at the end of the program to stop the machine. M03 is used to start spindle in the clockwise direction for a milling machine and forward for a turning machine.

8. In manual part programming, which word is used for point to point rapid traverse movement between the previous point and end point in the current block?
a) G03
b) G02
c) G01
d) G00
View Answer

Answer: d
Explanation: G01 is a preparatory word for linear interpolation movement. G02 is written for circular interpolation in the clockwise direction. G03 is written for circular interpolation in the counter-clockwise direction.

9. In _________ the operator directly feeds part geometry data and commands into the machine control unit before performing operations on the job.
a) Manual part programming
b) Computer-assisted part programming
c) Manual data input
d) Cad/cam part programming
View Answer

Answer: c
Explanation: In manual data input, the machine operator performs part programming work at the machine tool directly. In manual data input, the operator can visualize the operation through tool path display and tool path sequence animation.

10. Which of the following word prefixes are used to indicate coordinates of the center of arc in circular interpolation?
a) R,F
b) U,W
c) X,Y,Z
d) I,J,K
View Answer

Answer: d
Explanation: R is used for specifying arc radius in circular interpolation. F indicates feed rate per minute/per revolution. In turning, U and W denote incremental moves in x and z directions. X, Y, Z are used for defining coordinates for three linear axes.

Sanfoundry Global Education & Learning Series – CNC.

To practice all areas of CNC, here is complete set of Multiple Choice Questions and Answers.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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