CNC Flashcards

1
Q

Work pieces made by EDM are submerged in what?

A

Dielectric Fluid

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1
Q

Where are the CNC programs created and stored?

A

The Machine Control Unit (MCU)

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2
Q

Which quadrant of the coordinate plane is positive in the Y axis and negative in the X axis?

A

2

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3
Q

Which quadrant of the coordinate plane is negative in both the X and Y axis?

A

3

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4
Q

What code causes the cutter to move directly to the specified coordinates without cutting?

A

G00

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5
Q

What code would move a cutter from Point A to Point B through a clockwise curve?

A

G02

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6
Q

What code would move a cutter from Point A to Point B through a counterclockwise curve?

A

G03

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7
Q

What is the difference between G00 and G01?

A

G00 moves the cutter as fast as the machine will allow, G01 requires a Feed Rate for cutting

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8
Q

How would you specify a clockwise curve with a radius of 8, traveling at less than half a circle at 500 inches per minute?

A

G02 R8 F500

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9
Q

How would you specify a counterclockwise curve with a radius of 6, traveling at more than half a circle at 300 inches per minute?

A

G03 R-6 F300

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10
Q

Point A is X5, Y0, Point B is X5, Y5. Feed Rate is 700 inches per minute. Rank all 5 methods of cutting from point A to point B from lowest to highest X value, using N in place of the radius.

A
  1. G02 Y5 R-N F700
  2. G02 Y5 RN F700
  3. G01 Y5 F700
  4. G03 Y5 RN F700
  5. G03 Y5 R-N F700
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11
Q

What function does a CNC machine do when prompted with an N-Code?

A

None. N-codes are for the user to identify which set of instructions they are looking at, and are ignored by the program.

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12
Q

What is a “Dog Leg”?

A

In a G00, the machine reaches one axis of its destination before it reaches the others.

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13
Q

How do you calculate Inches Per Minute for a Spot Drill or Split Point Drill?

A

Rotations per Minute x Inches per Revolution = Inches per Minute

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14
Q

How are Inches per Revolution calculated?

A

Diameter of cutting tool / 0.0625 x 0.001

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15
Q

How are rotations per minute calculated for aluminum?

A

3.82 x 300 / diameter of cutting tool

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16
Q

How are inches per minute calculated for an end mill?

A

Rotations per Minute x Number of Flutes x Chip Load

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17
Q

Define the following set of commands:
N05 G00 X0 Y0
N10 G01 X1 Y8 F500

A

Step 1: Set point A to 0,0
Step 2: At 500 inches per minute, proceed in a straight line to point B at 1,8

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18
Q

Define the function of M30

A

End the program and reset to starting point

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19
Q

What is G54 used for?

A

Defining the 0 point

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20
Q

What is the easiest way to crash a CNC machine?

A

Incorrectly set tool length

21
Q

What is the recommended RPM for an Edge Finder?

A

750

22
Q

How does G90 work?

A

Use absolute coordinates for all subsequent moves

23
Q

What is the difference between G20 and G21?

A

G20 sets the program to run in Inches, G21 sets the program to run in Millimeters.

24
Q

Which G-Code sets the active plane for circular motion along the X and Y axis?

A

G17

25
Q

Which G-Code sets the active plane for circular motion along the X and Z axis?

A

G18

26
Q

Which G-Code sets the active plane for circular motion along the Y and Z axis?

A

G19

27
Q

If the cutting tool has a diameter of 10, and the cutter is to the right of the stock, how would you define that in G-Code?

A

G42 P5.0

28
Q

If the cutting tool has a radius of 4, and the cutter is to the left of the stock, how would you define that in G-Code?

A

G41 P4.0

29
Q

The sequence G0 G20 G17 G40 G80 G90 M05 is known as a Safety Line. What does it do, and what is it’s purpose?

A

The safety line resets and cancels all functions in the event that a program is interrupted and needs to start over

30
Q

Where does a Safety Line go in sequences?

A

At the beginning of every program

31
Q

What is the function of M06?

A

Switching between tools

32
Q

Explain the function of S2292 M03

A

Run the cutting tool clockwise at 2292 RPM

33
Q

Explain the function of S3667 M04

A

Run the cutting tool counterclockwise at 3667 RPM

34
Q

Which M-Code turns off all Coolant?

A

M09

35
Q

What does M05 do?

A

Stops the rotation of the cutting tool

36
Q

What is the difference between M07 and M08?

A

M07 uses light misting coolant, M08 uses heavy flooding coolant

37
Q

Tool Length Offset is defined by which G-Code?

A

G43

38
Q

What does G28 do?

A

Returns the tool to its 0 position

39
Q

What does G91 do?

A

Uses incremental coordinates for all subsequent moves

40
Q

What is the purpose of G80?

A

It cancels all canned cycles to ensure no axis motion will occur

41
Q

What are canned cycles?

A

Canned cycles are a shortened code for a repetitive action such as drilling multiple holes of the same size

42
Q

What operation is performed under G81?

A

Canned drilling Cycles

43
Q

What does G99 do, and why is it necessary?

A

It returns the cutter to the rapid plane in order to avoid obstacles such as the vice clamps

44
Q

What does G98 do?

A

It returns the cutter to the initial start plane

45
Q

What symbol must all programs begin and end with?

A

%

46
Q

Describe the formula for calculating the RPM for a mild steel workpiece with a 1/4 inch drill.

A

(3.82 x 100) / .250
382 / 0.250 = 1528 RPM

47
Q

Describe the formula for calculating the RPM for an aluminum workpiece with a 5/8 inch end mill.

A

(3.82 x 300) / (5/8)
1146 / 0.625 = 1833 RPM

48
Q

Describe the formula for calculating the RPM for a cast iron workpiece with a 3/8 inch reamer.

A

( (3.82 x 70) / (3/8) ) x 0.5
(267.4 / 0.375) x 0.5
713.07 x 0.5 = 357 RPM

49
Q

Describe the formula for calculating the Feed Rate for a 1/4 inch diameter drill.

A

( (1/4) / (1/16) ) x 0.001
(0.25/0.0625) x 0.001
4 x 0.001 = 0.004 Feed per Revolution