How to set the relative coordinates for tool setting in a CNC lathe?

Relative coordinate tool setting ‌ in a CNC lathe is not achieved by directly "setting" the relative coordinate system. Instead, it is realized by ‌ taking the current tool position as the reference point, measuring and inputting the tool offset value ‌. Its essence is to use relative displacement to complete the tool setting compensation for multiple tools. This method is often used in multi-tool machining. After establishing the workpiece coordinate system with one reference tool, the remaining tools complete tool setting by measuring their relative deviations from the reference tool.

The specific operation steps are as follows

Reference tool setting (establishing the workpiece coordinate system) ‌

First, use the first tool (such as an external cylindrical turning tool) for trial cutting and tool setting to determine the origin of the workpiece:

Test cutting of the outer circle: Gently cut a section of the outer circle surface, keep the Z-axis stationary, and retract the tool along the Z-direction. After the spindle stops rotating, measure the diameter of the outer circle (e.g., Φ28.5mm).

Input X offset: Enter the "Tool Offset" interface, input the measured diameter value into the X item corresponding to the tool number, and the system will automatically calculate the X origin in the workpiece coordinate system.

Trial cutting of the end face: Cut the right end face of the workpiece to the center, keep the X-axis stationary, and withdraw the tool along the X-direction.

Input Z-offset: Set the Z-coordinate to 0 (or program the origin Z value) to complete the tool setting of the reference tool.

Switch the tool and measure the relative deviation (relative coordinate tool setting core) ‌

Switch to the second knife (such as the cutting knife) and repeat the trial cutting action:

Manually change the tool to T02 and start the spindle.

When lightly cutting the same outer circular section, after retracting the tool, the ‌ input values of X/Z are not changed ‌. Record the ‌ relative offset ‌ between the tool tip and the reference tool's trial cutting position at this time.

Enter the "Tool Offset" interface, select the compensation number corresponding to T02, and press the "‌ measure ‌" function key. The system will automatically calculate and fill in the tool compensation value ‌ relative to the reference tool at ‌, thus completing the relative tool setting.

Explanation of the ‌ principle ‌

The core of the relative tool alignment method is to ‌ not repeatedly set the workpiece origin ‌, but to ensure that the tool compensation values of all tools are compensated relative to the reference tool. After tool changing, the system automatically calculates the relative offsets in the U (ΔX) and W (ΔZ) directions by comparing the coordinate differences of each tool when it attempts to cut at the same position, and stores them in the corresponding tool supplement number. This approach simplifies the multi-tool setting process and avoids the repetitive setting of workpiece coordinate systems such as G54.