# CNC MACHINIST KNOWLEDGE ASSESSMENT.



## HMF (Feb 25, 2018)

Questions and Answers

1. 
When referring to CNC programming, which of the following is the command coed to move the tool in the clockwise direction?
A. 
G01
B. 
G02
C. 
G03
D. 
G17

2. 
When referring to CNC programming, which of the following is the program format for circular interpolation in a counter clockwise direction?
Discuss
A. 
G90 G01 X_Y_R_F_;
B. 
G17 G02 X_Y_R_F_;
C. 
G90 G01 X_Y_Z_F_;
D. 
G17 G03 X_Y_I_J_F_;

3. 
When referring to CNC programming, which of the following is the command coed to move the tool in the counter clockwise direction?
A. 
G01
B. 
G02
C. 
G03
D. 
G17

4. 
When referring to the elements of word address CNC programming, a "1" bit is a representation of an _________ condition.
A. 
On
B. 
Emergency
C. 
Off
D. 
Ultimate

5. 
Calculate the feed per minute when an 8 tooth CNC cutter is rotating at 700 rpm and the chip load is 0.008 inch. The feed per minute will be _______ inches.
A. 
56.0
B. 
44.8
C. 
5.6
D. 
0.7

6. 
Which of the following operations will produce a hole with 45 degree chamfers?
A. 
Blind hole drilling.
B. 
Spot drilling.
C. 
Center drilling.
D. 
Counter sinking.

7. 
The most common type of feed drives used on CNC machines is the:
A. 
Electric servo motor.
B. 
Hydraulic drive.
C. 
Manual crank.
D. 
Manual/hydraulic system.

8. 
When referring to CNC tapping operations, what does the acronym TDS stand for?
A. 
Tap Drilling Speed
B. 
Total Diameter Size
C. 
Tap Drill Size
D. 
Tap Down Speed

9. 
When referring to CNC operations, an excessive surface cutting speed will result in:
A. 
Extended tool life.
B. 
A longer time to machine the workpiece.
C. 
Rapid tool wear.
D. 
A decreased use of coolant.

10. 
When referring to common CNC programming structures, which of the following is the best example of an end of block character?
A. 
;
B. 
G
C. 
G00
D. 
%

11. 
What is a major disadvantage of the vertical spindle machining centers?
A. 
They can handle heavy workpieces.
B. 
Chips accumulate on top of the workpiece.
C. 
Some of the spindles have vertical motion.
D. 
The crosslide can move transversally.

12. 
When referring to CNC programming, which of the following multiple hole patterns is typically the simplest to program?
A. 
An arc hole pattern.
B. 
A bolt hole circle.
C. 
A linear hole pattern.
D. 
An angular hole pattern.

13. 
The coolant system of a CNC machine would most commonly be a __________ pump.
A. 
Low pressure
B. 
Medium pressure
C. 
High pressure
D. 
Gravity

14. 
What does the X and Z relate to with a CNC faced can cycle having a G94X__Z__F__; code?
Discuss
A. 
It is the program feed rate.
B. 
It is the incremental dimensions from park location to cutting start and end points.
C. 
It is the absolute dimensions of the cutting start and end points.
D. 
It is the facing canned cycle command.

15. 
Which of the following statement is true with respect to CNC multiple repetitive machining cycles?
A. 
It is not possible to program tool nose radius compensation when using repetitive cycles G70-72.
B. 
When programming TNR inside the cycle, you must cancel the compensation inside the cycle.
C. 
It is not possible to program and cancel TNR outside the repetitive cycle
D. 
For pattern repeating cycle G 73 the operator programs the number of rough cuts and the DOC workpiece.

16. 
With CNC repetitive cycle programming, what does the D stand for in the code G71P__Q__U__W__D__S__F__; (rough turning and boring repetitive cycle)
Discuss
A. 
The ratio of cut from the far to near surface.
B. 
The depth of cut for the roughing pass.
C. 
It is a block number immediately following the G71.
D. 
It tells the CPU how the X value must be adjusted.

17. 
Which of the following CNC codes relates to "spindle on" counter clockwise at constant surface speed?
A. 
N020 T0101
B. 
N 030 G50 X8.500 Z7.500 S3000
C. 
N040 M04 S500 G96
D. 
N200 M05

18. 
With CNC programming it is good practice to program a rapid motion in ____ axis at a time.
A. 
4
B. 
3
C. 
2
D. 
1

19. 
When should a CNC linear interpolation command never be used?
A. 
For programs longer than 27 lines
B. 
Outside the work area.
C. 
For canned programs
D. 
With projects using 4 quarter addressing.

20. 
With CNC linear interpolation programming what does the U refer to in G01U__W__F__; (incremental feed motion)?
A. 
The coordinate along the X axis.
B. 
The coordinate along the Z axis.
C. 
The program feed code.
D. 
The linear interpolation code.

21. 
When applying tool measurement using a master reference tool and work shift, all Z values can be set to a pre-machined workpiece or the:
A. 
Reference point of the machine.
B. 
Face of the chuck.
C. 
X0 point.
D. 
Base of the tool turret.

22. 
Which of the following statement is true with respect to CNC multiple repetitive machining cycles?
A. 
For boring or internal facing the tool must be located above the cored diameter.
B. 
Only absolute values may be used for co-ordinate positions.
C. 
The starting point should be as far away from the workpiece as possible to assist with tool movement.
D. 
For external turning and facing the tool must be located above and in front of the workpiece.

23. 
Which of the following CNC codes deals with a multiple repetitive, rough cutting cycle used for facing operations?
A. 
G94
B. 
G76
C. 
G72
D. 
G68

24. 
Refer to the program format of the following canned cycle for threading. G92 X__Z__F__ The value X indicates:
Discuss
A. 
The lead of the thread to four decimal places.
B. 
The length of the thread including the deceleration distance.
C. 
The minor diameter of the thread for external threads.
D. 
The depth of cut for the threading pass.

25. 
With CNC repetitive cycle programming, what does the P stand for in the code G71P__Q__U__W__D__S__F__; (rough turning and boring repetitive cycle)
A. 
The block number of the first tool motion from tool park location for machining the finish profile.
B. 
The block number of the last tool motion completing the part profile and closing the repetitive cycle loop.
C. 
The amount of material left on the diameter for the finish cut.
D. 
The amount of material that is left on the Z faces for the finish cut.

26. 
Which of the following CNC codes cancels the mirror image coordinates for double turret turning centres?
A. 
G94
B. 
G76
C. 
G72
D. 
G69

27. 
How are CNC "G" codes grouped?
A. 
According to their bit size.
B. 
According to their function.
C. 
Based on their sequence.
D. 
Based on the number of significant digits.

28. 
When programming a multiple-start threading operation for a CNC machine, the shift amount is always equal to the ________ of the thread.
A. 
Lead
B. 
Depth
C. 
Pitch
D. 
Lag

29. 
With CNC linear interpolation programming what does the W refer to in G01U__W__F__; (incremental feed motion)?
A. 
The coordinate along the X axis.
B. 
The coordinate along the Z axis.
C. 
The program feed code.
D. 
The linear interpolation code.

30. 
In the following typical G10 command block for a Fanuc control, what does the letter "L" stand for? N____G10L___R___T___:
Discuss
A. 
The block number.
B. 
The type of offset.
C. 
The value of the tool nose radius.
D. 
The tool orientation number.

31. 
With CNC turning machines and preparatory codes what does a "G01" represent?
Discuss
A. 
A code that allows the tool to dwell at a location.
B. 
It instructs the control to move rapidly to specific X and Z locations.
C. 
It is a linear interpolation feed rate code.
D. 
It directs the machine control to use to use workpeice coordinate values stored in memory.

32. 
What diameter must be used when doing spindle calculations for threading operations with a CNC machine?
A. 
The diameter of the bit.
B. 
The major diameter of the thread being cut.
C. 
The outside diameter of the headstock.
D. 
The inside major diameter of the thread being reamed.

33. 
With respect to CNC turning centres which of the following is true with respect to multiple spindle-multiple turret arrangements?
A. 
It is used where work must be machined on both ends.
B. 
It is designed for work that must be machined from both sides at the same time.
C. 
It is the most common arrangement.
D. 
It is used in high production machining.

34. 
When using the right hand rule for identifying an axis, what does the index finger represent?
A. 
The Z axis.
B. 
The Y axis.
C. 
The X axis.

35. 
What type of transducer is a resolver?
A. 
Transitional
B. 
Positional
C. 
Modulated
D. 
Direct

36. 
What angle of bed decline do most CNC turning machines have to assist with chip management?
A. 
70-85
B. 
50-65
C. 
30-45
D. 
18-28

37. 
In which of the following CNC program preparation systems is the program prepared off line then stored on a disc or hard drive ?
A. 
Text editor.
B. 
MDI.
C. 
CAM software.
D. 
MMI configuration.

38. 
With CNC turning machines, the programmed speed for tapping is generally 25 to ____ % of that used for drilling.
A. 
50
B. 
46
C. 
33
D. 
27

39. 
Which of the following is true with respect to a Preparatory (G) code?
A. 
They turn various functions of the machine on or off.
B. 
They are modal or non modal.
C. 
They follow EIA/ASC11 guidelines.
D. 
It controls directly tool, speed and feedrate functions.

40. 
What principle of measurement does a rotary encoder use?
A. 
Transitional
B. 
Positional
C. 
Indirect
D. 
Direct

41. 
What does the semicolon symbol represent with CNC machines and basic addresses?
Discuss
A. 
It is used for comments and messages in front of the program.
B. 
It is used to skip program blocks.
C. 
It is used to indicate program number for ISO standard.
D. 
It is used at the end of each program block.

42. 
With CNC turning machines and Miscellaneous (M ) codes what does a "M03" represent?
A. 
Program stop and ends program execution.
B. 
Optional stop used when occasional part inspection may be required.
C. 
Spindle on in clockwise rotation.
D. 
Spindle on in counter clockwise rotation.

43. 
Which of the following is true with respect to CNC machines and program storage that uses hard drives?
Discuss
A. 
The tape has to be fast forwarded or reversed to locate the required program.
B. 
It is historically the only medium for program storage and transfer
C. 
They can be used for storage large amounts of program data in a compressed form.
D. 
They can be affected by viruses but have the largest storage capacity.

44. 
What is the common rotary resolution for most CNC machines in degrees?
A. 
0.0001
B. 
0.001
C. 
0.01
D. 
0.1

45. 
Which of the following best describes a PLC.
Discuss
A. 
RAM connecting directly to binary logic allowing machining logic.
B. 
It is a type of ROM that allows a programmed feedback loop.
C. 
Its function is to develop signals from program data for driving servo motors.
D. 
It allows a CNC machine to be programmed.

46. 
When using the right hand rule for identifying an axis, what does the middle finger represent?
A. 
The Z axis.
B. 
The Y axis.
C. 
The X axis.

47. 
Which of the following is true with respect to CNC machines and program storage that uses perforated or punched tape?
A. 
The tape has to be fast forwarded or reversed to locate the required program.
B. 
It is historically the only medium for program storage and transfer
C. 
They can be used for storage large amounts of program data in a compressed form.
D. 
They can be affected by viruses but have the largest storage capacity.

48. 
With CNC repetitive cycle programming and boundaries which of the following describes park location D?
Discuss
A. 
The position of the tool clear of the work piece after the profile is machined.
B. 
The last location on the work piece defining the profile to be machined.
C. 
The first location chew off the work piece before defining the part profile to be machined
D. 
The XZ position of the tool before the repetitive cycle G71 is activated.

49. 
What is zero suppression when dealing with CNC machines?
Discuss
A. 
It allows dimensions to be written without the zeros in front of the decimal point.
B. 
It is used to reduce the number of zeros in the full format dimensions.
C. 
It allows dimensions to be written without the zeros after the decimal point
D. 
Where eight digits are required for each dimension.

50. 
What does odd parity mean in reference to CNC terminology?
Discuss
A. 
Each program character is represented in rows containing odd number holes.
B. 
The number of wires from the controller to the hardware is always odd.
C. 
The RAM is sectored off in odd divisions.
D. 
The hard drive is mathematically tuned to mathematical operations thst result in odd numbers.


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## JimDawson (Feb 25, 2018)

Fun


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## spumco (Feb 27, 2018)

I got grumpy because I didn't know most of the G-codes or Words.

Then I got happy because I understood:
a) There are many different code dialects, and that the two I'm familiar with aren't Fanuc
b) Many of the questions have multiple correct answers, depending on the machine, language, and other variables
c) I've only been doing this for 18 months and none of the questions were Greek to me.
d) The middle finger on my right hand is for when I crash a tool in the X- direction on a vertical mill, and Z- on a lathe. 

A question about paper tape drives? _Really?_


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