How to set the tool compensation of a CNC lathe

The tool compensation for CNC lathes is divided into two types: tool position compensation and tool tip arc radius compensation. The setting method is clear and can be operated step by step ‌, as follows:

Ⅰ. Basic Explanation of Tool Compensation

The tool compensation of CNC lathes includes two types, each with different functions:

1. tool position compensation ‌ : It is used to correct the deviation of tool installation position, compensate for tool wear, and solve the problem of dimensional deviation after tool setting;

2. tool tip arc radius compensation ‌ : It is used to eliminate the contour processing error caused by the tool tip arc, mainly for fine turning of conical surfaces and arc surfaces.

Ⅱ. Steps for Setting Tool Position Compensation (Most Common Scenarios)

Tool position compensation is bound to the tool setting process. The basic value is automatically generated after the trial cutting and tool setting, and can be adjusted subsequently according to the dimensional deviation.

1. Basic Settings (Tool setting stage)

After completing the trial cutting of the X and Z axes according to the aforementioned trial cutting tool setting method, open the ‌ tool compensation/tool offset setting ‌ page of the machine tool;

For the current tool, enter the measured outer diameter after trial cutting (such as X29.6) in the X column corresponding to the tool compensation number, and enter Z0 (the origin is on the right end face) in the Z column. Click "Enter" to confirm, and the system will automatically calculate the position compensation value and store it in the corresponding memory.

2. Dimensional adjustment after processing (daily correction)

After trial cutting and processing, measure the dimensions. If there is a deviation, simply modify the compensation value directly

In the X direction: after turning the outer circle, if the actual size is 0.2mm‌ larger than the required ‌, subtract 0.2mm‌ from the original X tool compensation value by ‌. If the size is 0.2mm smaller, add 0.2mm.

Z direction: If the end face position is 0.1mm‌ to the left of the required ‌, subtract 0.1mm‌ from the original Z tool compensation value by ‌. If the deviation direction is opposite, adjust in the reverse direction.

Ⅲ. Steps for Setting the Radius Compensation of the Blade Tip Arc

When precisely turning conical surfaces and arc surfaces, the arc at the tool tip will cause contour errors, and it is necessary to set the tool tip arc radius compensation:

1. Pre-parameter Settings

Determine the radius of the tool tip arc: The packaging box of the turning tool will indicate the size of the tool tip R. For common cylindrical turning tools, the R is generally 0.4mm or 0.8mm. Enter this radius value in the "R" column of the corresponding tool supplement page.

Determine the tool tip position number: According to the cutting position of the tool, input the tool tip position number corresponding to 0-9 (the theoretical direction of the tool tip as seen from the R center of the tool tip, determined by the cutting direction) :

Outer circle turning tool, the tip position is generally ‌3 no. ‌;

Internal hole turning tool, the tip position is generally ‌ no. 2 ‌;

Left-cut outer circle knife, the tip position is generally ‌4 ‌.

2. Compensation is called in the program

Add compensation instructions before the processing program cuts into the contour and cancel them after processing is completed:

G41: Left compensation for the radius of the tool tip arc; G42: Right compensation for the radius of the tool tip arc;

G40: Eliminate the compensation for the radius of the tool tip arc.