Purpose and method of radius compensation for the

2022-08-04
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Purpose and method of tool radius compensation

(1) purpose of tool radius compensation

when contour machining is performed on a milling machine, because the milling cutter has a certain radius, the tool center (tool center) path does not coincide with the workpiece contour. If the NC device does not have the function of automatic tool radius compensation, it can only be programmed according to the tool center path (dotted line in figure ()), and its numerical calculation is sometimes quite complex. Especially when the tool diameter changes due to tool wear, regrinding, replacement of a new tool, etc., it is necessary to recalculate the tool center path and modify the program, which is cumbersome and difficult to ensure the machining accuracy. When the NC system has the tool radius compensation function, the programming only needs to be carried out according to the workpiece contour line (the thick solid line in figure ()), and the NC system will automatically calculate the tool center path coordinates to make the tool deviate from the workpiece contour by a radius value, that is, radius compensation

figure () tool radius compensation

a) outer contour b) inner contour

(2) tool radius compensation method

NC tool radius compensation is to hand over the process of tool center path to the NC system for execution. When programming, it is assumed that the tool radius is zero, and programming is directly carried out according to the contour shape of the part, while the actual tool radius is stored in a programmable tool radius offset register. In processing engineering, The CNC system automatically calculates the tool center path according to the part program and the tool radius of carbon fiber composite in 3D printing, and completes the machining of parts. When the tool radius heater: screw in heater changes, it is not necessary to modify the part program, just modify the radius value stored in the tool radius offset register or select a tool testing machine in another tool radius offset register to detect a variety of tools with radius

g41 refers to tool radius left compensation (left tool compensation), G42 refers to tool radius right compensation (right tool compensation), and G40 refers to canceling tool radius compensation. This is a set of modal commands, which defaults to G40

usage format:

Description: (1) tool radius compensation G41, G42 discrimination method, as shown in figure (), it is specified that if the tool is located on the left of the workpiece contour (programming track) along the moving direction of the tool, it is the left tool compensation (G41), otherwise, it is the right tool compensation (G42)

figure () tool radius compensation discrimination method

(2) work planes (G17, G18, G19) must be selected when using tool radius compensation. If work plane G17 command is selected, when G17 command is executed, tool radius compensation only affects the movement of X and Y axes, but has no effect on Z axis

(3) when the spindle rotates clockwise, use G41 to command the milling mode to be forward milling; on the contrary, use G42 to command the milling mode to be reverse milling. In order to improve the surface quality of NC machine tools, forward milling, namely G41 command, is often used

(4) when creating and canceling tool compensation, it must be combined with G01 or G00 command. If it is used in conjunction with G02 or G03 command, the machine tool will alarm. It is recommended to use combination with G01 command in actual programming. The process of establishing and canceling tool compensation is shown in figure (), so that the tool moves from point O without tool radius compensation to compensation start point a in cooperation with G01 command, and tool radius compensation is established. After the workpiece contour processing is completed, the tool compensation process should be canceled, that is, from the tool compensation end point B to the point O without tool compensation in cooperation with the G01 command

figure () establishment and cancellation process of tool radius to detect and compensate the mechanical properties of steel used in steel structure

a) establishment and cancellation of left tool compensation b) establishment and cancellation of right tool compensation

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