CNC Programming & Machine Operation 3

Question 1

What is the purpose of the M03 command in a CNC program?

Accepted Answer

Start the spindle in a clockwise direction

Answer

M03 starts the spindle in the clockwise (forward) direction, which is the standard direction for most milling and turning operations.

Question 2

Which M-code is used to activate flood coolant in most CNC controllers?

Accepted Answer

M08

Answer

M08 activates flood coolant, while M07 activates mist coolant, and M09 turns all coolant off.

Question 3

A programmer writes 'S1200 M03' in a CNC block. What does the S-word value represent?

Accepted Answer

Spindle speed in RPM

Answer

The S-word sets the spindle speed in revolutions per minute (RPM) when the machine is in direct RPM mode.

Question 4

What does G96 mode do in CNC turning?

Accepted Answer

Activates constant surface speed (CSS) control

Answer

G96 activates Constant Surface Speed mode, automatically adjusting RPM as the tool moves to maintain a consistent surface speed.

Question 5

When using G97 in a CNC lathe program, what is being commanded?

Accepted Answer

Direct RPM spindle speed mode

Answer

G97 sets the spindle to direct RPM mode, canceling any G96 constant surface speed that may have been active.

(CNC) Computer Numerical Control Machinist Technical Practice Test