Compensation of the length of cutters for CNC machining

1. The concept of CNC CNC machining tool length Tool length is a very important concept. When we are programming a part, we must first specify the programming center of the part, then we can establish the workpiece programming coordinate system, this coordinate system is only a workpiece coordinate system, the zero point is generally on the workpiece. The length compensation is only related to the Z coordinate. It is like the programmed zero point in the X Y plane. Since the tool is positioned by the spindle taper hole does change, the zero point about the Z coordinate is different. The length of each knife is different. For example, we want to drill a hole with a depth of 50mm then tap a depth of 45mm. Use a drill with a length of 250mm a tap with a length of 350mm. First drill a hole with a depth of 50mm. At this moment, the machine tool has set the workpiece zero point. When tapping is replaced, if both tools are processed the set zero point, the tap is too long to be tapped because it is longer than the drill bit. Artifacts.

2. The work of tool length compensation The use of tool length compensation is accomplished by executing instructions containing G43 (G44) H. At the same time, we give a Z coordinate value so that the tool moves to a local distance the surface of the workpiece after compensation. In addition, a command G49 cancels the G43 (G44) command.In fact, we do need to use this command.Because the sea tool has its own length compensation, when changing the tool, the G43 (G44) H command is used to give its own tool length. The compensation automatically cancels the length compensation of the previous tool.

3. Two methods of tool length compensation

1) The actual length of the CNC machining tool is used as the tool length compensation (this method is recommended). Using tool length as compensation is to measure the length of the tool with a tool setting instrument, then enter this value into the tool length compensation register as tool length compensation. The reasons for using tool length as tool length compensation are as follows:

By using the tool length as the tool length compensation, it can avoid constantly modifying the tool length offset in different workpiece processing. Such a tool is used on different workpieces without modifying the tool length offset. In this case, it is possible to file each tool in accordance with certain tool number regulations, write a small label with the relevant parameters of each tool, including the length radius of the tool, many other large-scale tools. Mechanical processing enterprises choose this method for tool management of CNC machining equipment. For those companies that have a tool management department, it is necessary to tell the parameters of the tool face-to-face with the operation I. At the same time, even if the tool is removed due to the capacity of the tool magazine, the next time you reinstall it, you only need to The tool length value on the label is used as tool length compensation no further measurement is required.

Secondly, using the tool length as the tool length compensation allows the CNC machining machine to perform the measurement operation while measuring the length of other tools on the tool setting instrument, instead of occupying the machine tool operating time due to tool setting on the machine tool, which can fully Give full play to the power of the machining center. In this way, when the spindle moves to the programmed Z coordinate point, it is the spindle coordinate plus ( minus) the Z coordinate value after tool length compensation.