Red Seal Machinist Practice Exam

In a CNC machine, what aspect is primarily controlled by the computer?

1. The speed of the operator

2. The programming of machining commands

3. The selection of materials

4. The formation of chips

The correct answer is: The programming of machining commands

The primary function of a CNC (Computer Numerical Control) machine involves the programming of machining commands, which is why the selected answer is accurate. In CNC machining, operators write programs using specialized software or codes (such as G-code) to dictate how the machine should move and operate to achieve the desired part specifications. These commands include details on the movement paths, feed rates, spindle speeds, and tool changes necessary for the machining process. While the speed of the operator and the selection of materials may impact the overall efficiency and effectiveness of the machining process, they are not directly controlled by the CNC system itself. The machine operates autonomously, executing pre-programmed instructions rather than relying on the operator's immediate actions. Similarly, the formation of chips occurs as a result of the machining process dictated by these commands, but it is not something that the computer specifically controls; instead, it is a byproduct of the machining operations prescribed by the programmed instructions. Thus, the essence of a CNC machine lies in how it uses complex programming to perform precise, automated machining, making the programming of machining commands the key aspect controlled by the computer.