GB/T 17421.3

📋 Scope / 适用范围 ai_extracted

This part of GB/T 17421 specifies the inspection and evaluation methods for circular hysteresis, circular deviation, and radius deviation of the circular trajectory generated by the simultaneous movement of two linear axes. For relevant inspection tools, refer to the description in 6.6.3 of GB/T 17421.1-1998. The purpose of this part is to provide a method for inspecting the contouring characteristics of numerically controlled machine tools.

📝 Foreword / 前言 ai_extracted

GB/T 17421 "Test Code for Machine Tools" is divided into the following parts: — Part 1: Geometric accuracy of machines operating under no-load or finishing conditions; — Part 2: Determination of accuracy and repeatability of positioning of numerically controlled axes; — Part 3: Evaluation of thermal effects; — Part 4: Circular tests for numerically controlled machine tools; — Part 5: Evaluation of noise emission; — Part 6: Determination of positioning accuracy on body and face diagonals (Diagonal displacement tests). This part is Part 4 of GB/T 17421, identical to ISO 230-4:1996 "Test Code for Machine Tools — Part 4: Circular Tests for Numerically Controlled Machine Tools" (English version). For ease of use, the following editorial modifications have been made to ISO 230-4:1996 (English version): — Prepared in accordance with the provisions of GB/T 1.1-2000, with the addition of "Table of Contents" and "Foreword"; — In the chapter "Normative References," the names of national standards listed are followed by the corresponding international standard numbers and consistency degree codes; — The "Bibliography" in the original international standard, which was an informative Annex D, has been changed to a subsequent element after Annex A, Annex B, and Annex C in accordance with GB/T 1.1; — The foreword of ISO 230-4:1996 has been deleted; — Some expressions applicable to international standards have been modified to those applicable to Chinese national standards. Annex A, Annex B, and Annex C of this part are informative annexes. This part is proposed by the China Machinery Industry Federation. This part is under the jurisdiction of the National Metal-Cutting Machine Tool Standardization Technical Committee (SAC/TC22). This part is drafted by: Beijing Machine Tool Research Institute. Main drafters of this part: Xu Guangwu, Li Xiangwen. GB/T 17421.4-2003/ISO 230-4:1996 Test Code for Machine Tools — Part 4: Circular Tests for Numerically Controlled Machine Tools

📚 References & Relations / 引用与关联

📖 Terms & Definitions / 术语和定义 ai_extracted

实际轨迹

actual path 按编程的名义轨迹运动时机床产生的轨迹。

actual path The trajectory generated by the machine tool when moving according to the programmed nominal trajectory.

圆滞后H

circular hysteresis H 两实际轨迹的最大半径差，其中一个轨迹是顺时针轮廓运动，另一个是逆时针轮廓运动(见图1)e 注:评定基准是两个实际轨迹的最小二乘方圆的圆心 o. 02 mm + 两个实际轨迹的最小二乘方圆的圆心 0 起始点; 1— 实际轨迹，顺时针方向; 2— 实际轨迹，逆时针方向。 圆滞后，H-=0.008 mm 图1 圆滞后H 的评定 GB/T 17421. 4-2003八SO 230-4:1996

circular hysteresis H The maximum radial difference between two actual trajectories, one of which is a clockwise contour motion and the other is a counterclockwise contour motion (see Figure 1). Note: The evaluation reference is the center of the least squares circle of the two actual trajectories. O — Center of the least squares circle of the two actual trajectories; 0 — Starting point; 1 — Actual trajectory, clockwise direction; 2 — Actual trajectory, counterclockwise direction. Circular hysteresis, H = 0.008 mm Figure 1 — Evaluation of circular hysteresis H GB/T 17421.4-2003 / ISO 230-4:1996

圆偏差G

circular deviation G 包容在实际轨迹上的两个同心圆(最小区域圆)的最小半径差，如图2所示，还可用最小二乘方圆的 最大半径范围来评定。 注1:圆偏差不包括安装误差，即检验工具的定心误差。 注2;圆偏差的测量不需要带标定长度的检验装置，而半径偏差需要。圆偏差G和半径偏差F之间的区别参照附 录A. 注3:当一个平面内的一条线上的所有点都包含在半径差不超过给定值的两个同心圆内时，则认为这条线是圆的 (见图2和GB/T 17421. 1-1998中的6.6.1 ), + 最小区域圆的圆心; 0 起始点; 1— 最小区域圆; 2- 实际轨迹 圆偏差，Gxy=0.012 mm 图2 回偏差G的评定

circular deviation G The minimum radial difference between two concentric circles (minimum zone circles) that enclose the actual trajectory, as shown in Figure 2, can also be evaluated using the maximum radius range of the least squares circle. Note 1: Circular deviation does not include installation errors, i.e., the centering error of the inspection tool. Note 2: The measurement of circular deviation does not require a test device with calibrated length, whereas radius deviation does. For the distinction between circular deviation G and radius deviation F, refer to Appendix A. Note 3: When all points on a line within a plane are contained within two concentric circles whose radial difference does not exceed a given value, the line is considered to be circular (see Figure 2 and 6.6.1 of GB/T 17421.1-1998). + Center of the minimum zone circle; 0 Starting point; 1— Minimum zone circle; 2— Actual trajectory Circular deviation, Gxy=0.012 mm Figure 2 Evaluation of circular deviation G

半径偏差F

radial deviation F 实际轨迹与名义轨迹间的偏差，名义轨迹的圆心有下列两种: a) 机床上检验工具的圆心; b) 最小二乘方圆的圆心。 注1:从圆心向外测量为正偏差，反之为负偏差(见图3).半径偏差用最大差值F,和最小差值Fm,表示。 注2:当适用于上述a)的情况时，半径偏差F包括安装误差。 注3:半径偏差F和圆偏差G的区别参照附录A. 0.02- 卜~~~~~州 名义圆的圆心; 起始点; I— 名义轨迹 2— 实际轨迹 半径偏差，F.~ 一 F...,=+0 -0008 006mm 图3 半径偏差F的评定 GB/T 17421. 4-2003/ISO 230-4:1996

Radial deviation F The deviation between the actual trajectory and the nominal trajectory. The center of the nominal trajectory is defined in the following two ways: a) The center of the inspection tool on the machine tool; b) The center of the least-squares circle. Note 1: Deviation measured outward from the center is positive, while deviation measured inward is negative (see Figure 3). The radial deviation is expressed by the maximum difference F₊ and the minimum difference F₋. Note 2: When applicable to case a) above, the radial deviation F includes installation errors. Note 3: For the distinction between radial deviation F and circular deviation G, refer to Appendix A. 0.02- ┌─────┐ │ │ │ ──── │ │ │ │ │ │ │ │ │ │ ──── │ └─────┘ Center of the nominal circle; Starting point; I— Nominal trajectory 2— Actual trajectory Radial deviation, F₊ = +0.008 mm F₋ = -0.006 mm Figure 3 — Evaluation of radial deviation F GB/T 17421.4-2003/ISO 230-4:1996

轴线标志identification / axis identification

of axes 产生实际轨迹的运动轴线的标示符号。

of axes Symbol for the designation of the actual motion axes that generate the trajectory.

轮廓方向sense

of contouring(I Il时针或逆时针的轮廓线，适用于圆偏差G和半径偏差F) 以运动轴线标志顺序表示方向，即运动方向是从第一个下标所表示的轴线正向移动到第二个下标 的轴线正向;例如:X轴和Y轴顺时针运动所产生的圆偏差G，记为G-，逆时针运动时则记为Gxv.

of contouring (I Clockwise or counterclockwise contour lines, applicable to circular deviation G and radius deviation F) The direction is indicated by the order of the motion axis symbols, i.e., the motion direction is from the positive direction of the axis represented by the first subscript to the positive direction of the axis represented by the second subscript. For example: the circular deviation G generated by clockwise motion of the X-axis and Y-axis is denoted as G-, while for counterclockwise motion, it is denoted as Gxv.

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