Simplified Guide to Tool Offset, Radius, and Wear Compensation on CNC Vertical Lathes
Ensuring the tools function properly in CNC vertical lathes is crucial for achieving accurate machining. This involves ensuring the tool offset (length), cutter tip radius, and other types of adjustment are correct. Below is a detailed overview:
I. Tool Offset (Length) Compensation: What It Means and What It Does
Tool offset compensation adjusts for the length difference between the cutter you are using and the one you are comparing it to. In CNC vertical lathes, different tools may have different lengths. If you don’t compensate for the length, the machining may result in incorrect sizes. Tool offset compensation ensures each cutter reaches the correct position during machining.
How to do it: Enter the tool position deviation value into the CNC system’s tool offset register to adjust the tool offset. To activate adjustment in the program, simply call the cutter number and compensation number. For example, in the FANUC system, use positive or negative compensation commands together with the cutter length adjustment register number command to implement tool length compensation.
Notes: The tool offset compensation values should be based on actual measurements and checked and adjusted regularly. When changing tools, ensure that the new tool compensation values are set correctly to avoid issues.
II. Tool Tip Radius Compensation: What It Is and How It Works
During machining, the tool tip of a turning tool often wears down into a smaller arc due to tool wear and the need for finishing. To maintain the workpiece’s shape, the centerline of the tool tip arc’s movement path should not cross the workpiece’s shape. Instead, the movement path should offset by a radius value. This offset is called tool tip arc radius offset.
Tool tip arc radius compensation corrects the problems caused by the tool tip arc radius.
How to do it: Use the left or right offset commands to apply the tool tip arc radius compensation. In the program, specify the tool tip arc radius offset adjustment number and the tool offset adjustment number. The process involves three steps: first, establish the compensation; second, perform the compensation; and third, cancel the compensation.
Notes: Tool tip arc radius offset can only work in the movement command mode. Pay attention to the difference between the front and rear tool holders when selecting the tool tip radius offset direction and tool edge position. To prevent the cutter from cutting too much during the process of setting up and removing cutter radius compensation, it’s best for the start and finish points of the program segment to be on the same side as the compensation direction when setting up and removing the compensation.
III. Tool Wear Compensation: What It Is and How It Works
Tool wear offset fixes errors caused by worn tools. As the tool wears down, it changes the dimensions of the material being processed. Tool wear offset adjusts the cutter to maintain consistent dimensions.
How to do it: You usually perform tool wear offset through the CNC system’s cutter parameter interface. If the machine detects a discrepancy between the workpiece’s dimensions and theoretical values, measure the difference and enter the corresponding compensation value into the tool compensation interface. For example, if the outer diameter is too large, you can subtract a negative X value to compensate. Similarly, if the length is too long, subtract a negative Z value for compensation.