Cnc Machines Flashcards
1
Q
3 basic motion types for cnc
A
Rapid motion
Linear interpolation
Circular interpolation
2
Q
3 different compensation types on turning centers
A
Wear offset
Geometry offset/work shift
Tool nose radius comp
3
Q
Origin from which you specify your coordinates
A
Program zero point
4
Q
Provides a way to size in workpiece attributes during set up or production runs as cutting tools wear
A
Wear offset
5
Q
Used to specify program zero assignment values
A
Geometry offsets and work shift
6
Q
Let’s you program the work surface tool path, ensures that small radius om cutting edge stays in contact
A
Tool nose radius compensation
7
Q
Provides the approach and retract motions for cutting tools when they are not cutting
A
Rapid motion
8
Q
Ways to control feed rate on lathe and mill (turning centers)
A
Per revolution on lathe
Sfpm for mill
9
Q
Cnc programs must be structured for 3 reasons
A
Helps familiarize with the program
Provides consistency with the program
Allows cutting tools to be re-run on their own
10
Q
Minimizes the commands needed to program machining operations
A
Canned cycle
11
Q
Keeps you from repeating redundant commands in cnc programs, if you need to machine multiple identical workpiece attributes
A
Sub programming
12
Q
Three basic modes of operation
A
Manual mode
MDI
Program operation mode
13
Q
4 types of format for programming
A
Program start up format
Tool ending format
Tool start up format
Program ending
14
Q
What is g99
A
Inch per revolution feed rate mode
15
Q
What is G20?
A
Imperial measurement mode
16
Q
What is G23?
A
Cancel stored stroke limit
17
Q
What is G50?
A
Spindle limiter
18
Q
What is M41 and M42?
A
Low and high spindle range
19
Q
Gives the operator a choice between one of two conditions
A
Block delete
20
Q
Means the cnc machine does its best to provide the intended motion based upon a limited amount of program data
A
Interpolation
21
Q
What is G0, G01 and G02/G03
A
Rapid motion, Linear and circular interpolation
22
Q
Brings cutting tool well above largest diameter of workpiece after a cut
A
Escape distance
23
Q
Rule of thumb for rapid approach distance and escape distance
A
0.1 for approach and 0.05 for escape distance
24
Q
Most important application for linear interpolation
A
To machine straight surfaces
25
Preffered method between absolute and inceremntal
Absolute
26
What is g98 and g99 for feed?
G98 is ipm
G99 is ipr
27
What word or letter to use to specify size of the arc radius being machined
R word
28
Does feed rate carry over from linear to circular interpolation?
Yes
29
2 ways to specify arc size
R word and directional vector
30
Is g28 considered a canned cycle?
Yes
31
Does feed rate get carried over from precious canned cycles?
Yes
32
What canned cycle is G94
One pass facing
33
What canned cycle is G90?
One pass turning cycle
Or boring cycle for ID
34
What is G71?
Rough turning/boring
35
What is G70?
Finishing for g71/72/73
Turningboring/facing/pattern
36
What is G75?
Peck drill and face groove
37
What is G74?
Radial grooving
38
What is P and Q command words on a repetitive cycle?
First and last sequence number of repetitive cycle
39
What is U command word on g71
How much stock left on diameter of part
40
What is W command word in g71/72
How much material is left on face
41
What is D and F word command in g71/72
Depth of cut and feed rate
42
2 limitations of G71 command
Machining recesses and efficiency
43
Limitation of g73 (pattern repeating)
Cutting air time
44
For G73 what is D, I and K word command for
D- # of roughing passes
I- amount of raw material left on diameter
K- material left on face
45
Limitation of G74 (radial grooving)
Doesn't break sharp edges
46
How much overlap do you move grooving tool when width is bigger than tool
Atleast 0.100 to avoid witness marks
47
All single point tools have a small radius in its cutting edge, t or f?
True
48
4 nose radius sizes on single point tools
1/64
1/32
3/64
1/16
49
Pros and cons of larger tool nose radius
Pros: better finish
Cons: less stable which could lead to chatter/vibration
50
The larger the TNR, the greater the deviation between the programmed path and work surface, t or f?
True
51
TNRC is only required for single point cutting tools, like turning tools and boring bars, t or f?
True
52
Only use TNRC for finishing operations only when angular and circular surfaces are critical to quality of work piece, t or f?
True
53
What is G41, G42 and G40?
G41- instate TNRC with a tool left condition
G42 - TNRC with a tool right condition
G40- cancel TNRC
54
When do you use G42?
When external machining, turning in a direction toward the chuck
55
When do you use G41?
When internal machining, boring towards the chuck or when facing towards center
56
G code for program data entries
G10
57
What does API stand for?
American petroleum institute
58
Popular thread for applications involving the flow of gas or liquids
Tapered thread
59
Most popular thread form
V thread
60
Type of thread for application when normal usage may cause components fastened with right hand threads to loosen
Left hand thread
61
The distance between one thread to the next determines the threads ______?
Coarseness
62
What are the 6 classes of fit for threads?
1a,2a,3a are male threads
1b,2b,3b are female threads
Higher the number the tighter/snugger fit
63
Does the root and crest change to opposite on internal threads? Y or no
Yes
64
What does UNC and UNF on threads stand for?
Unified coarse and unified fine
65
3 ways to produce threads on a cnc turning center
Chasing, tapping and roll forming
66
How the threading tool is positioned for each pass is called
Infeed method
67
When cutting threads, depth of cut per pass is called
Infeed amount
68
Limitation of a v shaped threading tool
It doesn't cut the major dia for external threads and doesn't cut minor dia for internal
69
Cresting tool or topping tool machines the entire thread form, t or f
True
70
3 infeed methods
Compound indeed
Radial indeed
Alternating compound (also known as incremental infeed)
71
Infeed method when using engine lathes compound rest between passed
Compound infeed
72
Type of threading tool that can machine on both sides of the cutting tool
Cresting tool
73
Type of infeed that causes the threading tool to simultaneously machine on both sides of the thread
Radial infeed
74
Type of infeed method that tends to prolong cutting tool life while still providing a good surface finish
Alternating compound infeed
75
Decreasing infeed amount per pass is recommended for threading tools that have more of a square shaped t or f?
False
76
Preferred method between angular retract and straight retract
Straight retract. Especially when thread relief is present
77
When machining a 1 start thread, the motion rate per spindle revolution is?
Equal to the thread pitch
78
How to calculate feed for threading in inches per minute
Multiply the leads (pitch) times the rpm
79
Rule of thumb for approach when threading
4x the thread lead or 0.2in, whichever is smaller
80
F word when threading specifies ___?
Thread lead or pitch
81
Cnc lathe spindle directions
M03 forward ( ccw)
M04 reverse (cw)
82
To determine tool handedness, right cutting edge is right hand and left cutting edge is left handed, t or f?
True
83
Three major components of a threading tool
Shank, insert and clamping mechanism
84
What is M03 for threading?
Spindle forward (towards you)
85
What is M04 in threading?
Spindle reverse direction (away from you)
86
What is G32?
Threading motion cycle
87
What is G92?
One pass canned cycle for threading
88
What is G76?
Multiple repetitive cycle for threading
89
What is recommended when programming Z axis on a threading tool, extreme leading edge or center of threading form?
Extreme leading edge
90
2 versions of G76?
One line g76 command and two line g76 command
91
What is D, I, P, K and A for threading
D- first pass depth
I- taper amount
P- infeed method
K- thread depth
A- tool angle
92
What is P1,P2,P3 and P4 for threading
P1- compound infeed, reduced doc
P2- alternating compound infeed reduced doc
P3- comp infeed, constant doc
P4- alternating comp infeed, constant doc
93
For radial infeed, do you just leave P and A out of G76 command? Y or n
Yes
94
Is low range and rpm mode recommended for cutting threads? Y or n
Yes
95
Do machines that DO NOT have live tooling, have tapping canned cycles? Y or n
No
96
What G feed method do you use when tapping on a lathe?
G97 /rpm
97
Which direction should you rotate the chuck then tapping a RH Tap on a lathe
M03/forward direction
98
Recommended tap holder when tapping on a lathe
Floating tap holder
99
Recommended G code command when tapping a lathe that disables feed hold,feed rate and spindle speed
G32
100
Problem with go/no go gauge
Doesn't give you deviation amount
101
2 causes of incorrect thread lead
Maximum feed rate and spindle speed.
Machine can't keep up
102
Manual function to move axis for rough positioning
Jog mode
103
Manual function mode that provides precise control of a manual motion
Hand-wheel mode
104
Some, mostly older, method that require that you manually send the machine to its zero return position in each axis
Zero return mode
105
The program zero are specified by what other names? 3 of them
Work zero, part zero, workpiece origin
106
Name the 3 position display screen pages
Absolute position
Machine position
Relative position
107
X and Z axis geometry offsets are usually positive or negative on lathe turning centers?
Negative
108
Rotating tools for turning centers/lathes are called?
Live tools
109
A mill/turn machine has atleast one additional axis, what axis is it?
C axis
110
Mill/turn machines have 2 main spindle modes, what are they?
Lathe mode and live tooling mode.
M154 for live tooling
M155 for lathe mode
111
2 types of live tooling holders
Face work and diameter work
112
Can you machine work attributes that are off center on a mill/turn machine with 3 axis? Y or n
No
113
What axis do you need for off center live tooling operations on a mill/turn machine?
Y axis
114
For machining motions involving x,y and z, you specify feed rate in....
Inches per minute feed rate mode (g98)
115
What is m14 for mill/turn machine when using c axis
Clamp main spindle
116
What is G28 H0?
Send C axis to its zero return position
117
What letters when choosing absolute and incremental positioning on C axis
C for absolute
H for incremental
118
Does the C axis have an over travel limit? Y or n
No
119
Where is the Y axis zero point located
Workpiece center
120
Letters for absolute and incremental positioning for Y axis
Y for absolute
V for incremental
121
For any machining motion that involves the C axis, you must specify feed rate in ...
Degrees per minute (dpm)
122
Plane selection. What is g18 and g19
G18- cutting tool is pointing in the Z axis
G19- pointing in the X axis
123
G codes for face work canned cycles on G18
G80 cancel canned cycle
G81 drilling
G82 counterbore
G83 deep hole peck drill
G95 rh tapping
G186 lh tapping
124
G codes for diameter work canned cycles on G19
G241 drilling
G242 counterbore
G243 deep hole peck drill
G195 rh tapping
G196 lg tapping
G80 cancel canned cycle
125
3 Steps for hole machining canned cycle
Rapid to hole location
Machine the hole
Retract from the hole
126
The live tool retracts from the hole and to a clearance post, what is the position called
Rapid plane or R plane
127
What is P and Q for live tooling canned cycles
P is pause for counterboring
Q specifies peck depth for peck drilling
128
If your mill/turn machine has a Y axis, do you still need to use polar coordinate interpolation. Y or n
No
129
You use this with z axis facing end mills, it allows you to program the milling of unique shapes, flats, comtours and pockets into workpiece faces
Polar coordinate interpolation
130
What G code instate and cancels polar coordinate interpolation?
G112 to instate
G113 to cancel
131
When you run thr first end of the workpiece, turn wp around and reactivate the cycle on the other end is called..
Flip job
132
3 popular types of two spindle turning centers
-Twin/dual spindle turning centers
-fixed headstock sub spindle tc
-sliding headstock sub spindle tc
133
Turning center that has 2 matching spindles, can be horizonral/vertical spindles and commonly have matching capabilities related to spindles speed, hp and axis travels
Twin/dual spindles turning centers
134
Sometimes called a Swiss style turning center
Sliding headstock sub spindle tc
135
Axis used for workpiece transfer for sub spindle turning centers
W Axis
