Position that acts as the origin in each part program.

Position that acts as the origin in each part program.

• A. Program zero
• B. Machine zero
• C. Work zero
• D. Global zero

Answer: (A)

In CNC part programming, every program has its own starting reference point called program zero. All coordinates within the program are measured from this point unless another coordinate system is actively selected. This makes the program portable and reusable—you can position the workpiece differently using work offsets (like G54) without changing the program’s geometry. Machine zero is the machine’s home position, and work zero is the origin of the current work coordinate system. Global zero is not the standard origin for a single part program. So, the origin in a part program is program zero.

In CNC part programming, every program has its own starting reference point called program zero. All coordinates within the program are measured from this point unless another coordinate system is actively selected. This makes the program portable and reusable—you can position the workpiece differently using work offsets (like G54) without changing the program’s geometry. Machine zero is the machine’s home position, and work zero is the origin of the current work coordinate system. Global zero is not the standard origin for a single part program. So, the origin in a part program is program zero.