Read the program. Predict the motion. Then run it.

Start with state and intent

A CNC block may change motion, units, positioning mode, spindle state, feed, coolant, or tool selection. Students should identify which words are modal, what remains active, and what the machine is expected to do before pressing Cycle Start.

Short exercises with G0, G1, G2/G3, G20/G21, G90/G91, F, S, T, and common M codes create a foundation for reading longer CAM-generated programs.

• Confirm units and positioning mode
• Identify the active work coordinate
• Check spindle, feed, coolant, and tool commands
• Predict the next X/Y/Z motion
• Separate rapid positioning from feed motion

Use MDI for focused practice

MDI lets an instructor isolate a concept without hiding it inside a long file. Learners can enter a safe move, observe the result, correct syntax, and compare absolute with incremental positioning.

The length of an MDI exercise should follow the learning objective, not an arbitrary limit. Complex work is usually easier to manage as a saved program, while MDI remains valuable for direct commands and targeted practice.

Prove out before continuous execution

External programs should be inspected for units, coordinates, tool calls, feeds, spindle commands, coolant, and required stock dimensions. Single Block and Feed Hold help learners observe state changes one step at a time.

Simulation is especially useful for connecting code with runtime indicators and visible material removal before the same habits are applied under an instructor's machine-specific procedures.