Cnc Machinist
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CNC MACHINIST KNOWLEDGE ASSESSMENT.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- A.
The block number.
- B.
The type of offset.
- C.
The value of the tool nose radius.
- D.
The tool orientation number.
- 31.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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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