Final answer:
The statement is true; during demonstrations of CNC machinery or programming, it's shown that the tool diameter must be entered in the tool register for precise machining.
Step-by-step explanation:
True or False. During a demo, it was shown that for each tool used in the program, its diameter must be entered in the tool register. This statement is generally true. In CNC programming and machinery, tools used in machining processes have their parameters, including diameters, lengths, and possibly specific cutting properties, stored in a tool register or library.
This is important because the machine needs to compensate for these variables to achieve precise movements and cuts. For example, when the tool paths are being calculated by software, the diameter of the tool affects the offset and is critical for ensuring that the work piece is machined correctly to the desired dimensions.