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How To Use Tool Length Compensation In CNC Machining

The concept of tool length compensation.

Tool length compensation is the tool position compensation when the tool nose reaches the programmed position. The tool length compensation command is generally used for tool axial compensation, so that the actual displacement of the tool in the Z-axis direction is greater or less than the given amount in the program, so that the tool end face and different lengths reach the same actual position in the Z-axis direction.

For example, we have to drill a hole with a depth of 50mm and then tap to a depth of 45mm using a 250mm long drill and a 350mm long tap. First drill to a depth of 50mm with a drill bit. At this point, the machine tool has set the workpiece zero point.

When tapping the tap, if both knives start machining from the set zero point, the tap is too long and cannot be longer than the tapping of the drill bit, and the tool is damaged. and artifacts. At this point, if tool compensation is set, the length of both the tap and drill will be compensated. After the zero point of the machine tool is set, even if the tap and bit length are different, due to the existence of compensation, the Z zero coordinate has automatically compensated the tap length to Z+ (or Z) during the tap operation to ensure the correct machining of the zero position.

Tool length compensation work

The tool length compensation is realized by executing G43 (G44) and H commands. We give a Z coordinate value to make the tool move to the Z point away from the workpiece surface after compensation. Another command G49 cancels the G43 (G44) command. In fact, we don’t have to use this command because each tool has its own length compensation. When changing the tool, use the G43 (G44) H command to compensate the length of the tool itself. The length compensation of the previous cut is automatically canceled.

Tool length compensation in CNC machining

Use the actual length of the tool as a tool length compensation (recommended). Tool length compensation is to measure the length of the tool by tool-to-tool, and then input the value into the tool length compensation register as the tool length compensation. The reasons for using tool length as tool length compensation are as follows:

First of all, using the tool length as tool length compensation can avoid constantly modifying the tool length offset during the machining of different workpieces. This tool is used for different workpieces without modifying the tool length offset. In this case, each tool can be archived according to a certain tool numbering rule, and a small symbol is used to write the relevant parameters of each tool, including the length and radius of the tool.

In fact, many large machining enterprises use this method to manage the tool of CNC machining equipment. For those companies that specialize in tool management, there is no need to tell the parameters of the tool and the tool in person, even if the tool is removed due to the capacity of the tool magazine, it will be installed next time.

Secondly, using the tool length as tool length compensation allows the machine tool to perform machining operations while measuring the length of other tools during tool setting, instead of taking up the running time of the machine tool due to tool setting on the machine tool, so that the machining can be fully utilized. . efficiency of the center. When the spindle moves to the programmed Z coordinate point, the Z coordinate value after tool length compensation is added (or subtracted) to the spindle coordinate.