CNC CNC G-Code and Programming 2

Question 1

What is the purpose of a G54 command in CNC programming?

Accepted Answer

Selects work coordinate system 1

Answer

G54 selects Work Coordinate System 1, which tells the machine where the workpiece origin is located on the table.

Question 2

Which canned cycle code is used for a standard drilling operation in CNC?

Accepted Answer

G81

Answer

G81 is the standard drilling canned cycle that drills to a specified depth and retracts at rapid feed rate.

Question 3

What does the R-value represent in a canned drilling cycle?

Accepted Answer

Retract plane height above the work surface

Answer

The R-value in a canned cycle specifies the retract plane, which is the height the tool returns to between drilling operations.

Question 4

In CNC programming, what does G96 activate?

Accepted Answer

Constant surface speed (CSS) mode

Answer

G96 activates Constant Surface Speed (CSS) mode, which automatically adjusts spindle RPM as the tool diameter changes.

Question 5

Which character is used to indicate a program end and rewind in a CNC program?

Accepted Answer

M30

Answer

M30 ends the CNC program and rewinds it to the beginning, resetting the program pointer for the next run.

CNC - Cutting Practice Test