CNC Assignments Flashcards
Which style of V-flange tool-holder is most commonly used in North America?
- CAT 40
List two ( 2 ) types of 40 size tapers for machining centers.
- CAT ( Caterpillar )
- BT
What is the most obvious difference between CAT and BT V-flange tool holders?
- Size of the width V-groove around the flange
What ensures that the tool-holder and cutting tool remain concentric with the spindle in a milling machine?
- Smooth internal tapered surface within spindle engages matching external taper on tool-holder shank
What is the purpose of the dimple in the keyway of a tool-holder?
- Helps with orientation
( Helps with identifying deeper drive slot )
If tool station number 2 is not currently in the spindle, what command must be used to place tool number 2 in the spindle?
- T02 M06
What command makes the spindle rotate to the orient position?
- M19
What codes are used to initiate tool length compensation?
- G43 and an H-word
List 4 available safety functions, used when verifying a program.
- Dry run
- Single block
- feed hold
- distance to go
What feature allow you to ignore milling cutter size when calculating coordinates?
- Cutter radius compensation
Most machining centers require feed rate, feed rate in IPM ( inches per minute). What G-code specifies IPM?
- G94 = Inches per minute ( IPM )
- G95 = Inches per revolution ( IPR )
What is the preferred positioning method, absolute or incremental?
- Absolute
What G-codes are used to specify Absolute and Incremental positioning?
- Absolute = G90
- Incremental = G91
When programming an arc using directions vectors, what do the I and J values specify?
- ” I “ specifies X-axis components
- ” J “ specifies Z-axis components
What are the 3 G-codes related to plane selection?
- G17 = XY plane
- G18 = XZ plane
- G19 = YZ plane
List and describe the 2 G-codes used to instate cutter compensation. ( For Milling )
- G41 = cutter on left
- G42 = cutter on right
What code cancels cutter compensation?
- G40
How does G28 work?
- Zero return command causes two motions to their intermediate points.
What is G80?
- Cancels Canned cycle
What is G81 for milling?
- Standard drilling cycle
( G81 G99 Z-0.375 R0.1 F9. )
What is G73?
( Milling )
- Chip-breaking peck drilling cycle
( G73 G99 Z-2.15 Q0.2 R0.1 F9. )
What is G83?
( Milling machines )
- Deep hole peck drilling cycle
What is G84?
( Milling machines )
- Right hand tapping cycle
( 7/16 - 14 @ 500 RPM )
( G84 G99 Z-.065 R 0.1 J3 F3.5.7143 )
( J3 = Retract speed )
What is G74?
( Milling machines )
- Left hand tapping cycle
( G74 G99 Z-.065 R0.1 J3. F35.7143 )
( J3 = Retract speed )
What is G86 for milling?
- Standard boring cycle
( G86 G99 Z-0.54 R0.1 F4.5 )
What is G89?
- Counter-boring cycle
( G89 G99 Z-0.375 P0 )
What type of tap holder is required on older machines?
- Special Tension/Compression tap holder
What is rigid tapping and what are the advantages?
- Allow perfect synchronization between spindle reversal at hold bottom and Z-axis motion.
How are G86 and G76 different?
- G86 ( Standard Boring mill ) Leaves drag-line mark
- G76 ( Fine Boring mill ) Leaves no marks
What is the difference between G85 ( Reaming ) and G81 ( Drilling ) ?
- G85 = Feeds to bottom of hole and retracts at the same feed-rate
- G81 = Standard drilling cycle for reaming to save time
Explain the difference between the Initial Plane and the R Plane.
- ( G99 ) = R-plane, Position just above work surface
- ( G98 ) = Initial-plane, Above obstruction in Z-Axis
To avoid clamps and other obstructions with the Initial and the R plane specify G99 for ___ plane and G98 for the ___ plane.
( G99 ) R-plane / ( G98 ) Initial plane
The G code used to instate the Polar Co-ordinate system mode is.
- G16
- G15 ( Cancels )
When using polar co-ordinates the letters X and Y specify:
- X specifies radial co-ordinates
- Y specifies angular co-ordinates
The G code used to specify a temporary shift of the program zero is.
- G52
What is M97?
- Local sub-routine call
What is M98?
- Invoke sub-program
What is M99?
- End of sub-program
What are the 2 benefits of using sub-programs?
- Series of commands can be repeated when machining holes.
- Simplifies programming for manual programmers.
What word has to be included in a program to allow all hole locations to be specified within a sub-program?
- The L word
What is the difference between Polar co-ordinates and Co-ordinate rotation?
- Polar co-ordinates give you the ability to rotate one coordinate.
- Coordinate rotation lets you rotate the whole series while maintaining relationships among coordinates.
Explain the term Helical Interpolation.
- Combination of linear and circular interpolation. X and Y-axis moves along a circular path while the Z-axis moves linearly.
Name two ( 2 ) types of rotary devices.
- Indexer
- Rotary axis
What is Limits of Size?
- Actual upper and lower limit of size.
Which of the following types of information does a “ go / no-go gauge “ provide?
a) type of material
b) SPC data
c) variable date
d) Attribute data
d) Attribute Data
What materials are gauge blocks made from?
- Hardened steel
- Carbide ( Expensive, wears less faster )
- Ceramic ( Expensive, wears less faster )
Why would we use wear blocks in a gauge block set-up if we purchased them?
- To prevent corrosion on the contact face
- Placed on either ends to protect blocks from damage and abrasion
What G code is used to specify a counter-boring cycle?
( Lathes )
a) G80 b) G81
c) G82 d) G83
e) G84 f) G73
g) G76
c) G82
What G code is used to specify a standard drilling cycle?
a) G80 b) G81
c) G82 d) G83
e) G84 f) G73
g) G76
b) G81
What G code is used to specify a chip-breaking peck drilling cycle?
( Lathes )
a) G80 b) G81
c) G82 d) G83
e) G84 f) G73
g) G76
f) G73
What G code is used to specify a deep-hole peck drilling cycle?
a) G80 b) G81
c) G82 d) G83
e) G84 f) G73
g) G76
d) G83
What G code is used to specify a tapping cycle?
( Milling - machines )
a) G80 b) G81
c) G82 d) G83
e) G84 f) G73
g) G76
e) G84
