JB/T 8771.5-1998 This standard is equivalent to the draft international standard ISO/DIS 10791-5 "Test conditions for machining centers Part 5: Test of positioning accuracy and repeat positioning accuracy of workpiece holding pallets". This standard specifies the requirements and test methods for the positioning accuracy of a group of workpiece holding pallets (hereinafter referred to as pallets) on machine tools and the repeat positioning accuracy of each pallet. This standard is applicable to pallets of ordinary precision single-stage machining centers for general purposes. JB/T 8771.5-1998 Test conditions for machining centers Part 5: Test of positioning accuracy and repeat positioning accuracy of workpiece holding pallets JB/T8771.5-1998 Standard download decompression password: www.bzxz.net

JB/T8771.5--1998
This standard is equivalent to the draft international standard ISO/DIS10791-5 "Test conditions for machining centers Part 5: Positioning accuracy and repeatability of workpiece holding pallets". This standard is equivalent to the draft international standard in terms of technical content. There are the following main differences between this standard and ISO/DIS10791-5: The "Preamble" part is cancelled because its main content is already included in the "Preamble" and "Scope". This standard is one of the series of standards for inspection conditions for machining centers. This series of standards includes the following 13 parts, which can be used simultaneously or separately:
Part 1: Geometric accuracy inspection of horizontal and machine tools with additional spindle heads (horizontal B axis) Part 2: Geometric accuracy inspection of vertical machining centers Part 3: Geometric accuracy inspection of machine tools with integral universal spindle heads with horizontal main rotary axes (vertical Z axis) (to be formulated) Part 4: Positioning accuracy and repeatability inspection of linear and rotary axes Part 5: Positioning accuracy and repeatability inspection of workpiece clamping pallets Part 6: Feed rate, speed and interpolation accuracy inspection (to be formulated) Part 7: Precision inspection of finished test pieces
Part 8: Spherical evaluation by circular test method (to be formulated) Part 9: Evaluation of tool change and pallet change action time (to be formulated) Part 10: Evaluation of thermal deformation (to be formulated) Part 11: Evaluation of noise emission (to be formulated) Part 12: Evaluation of vibration intensity (to be formulated) Part 13: Evaluation of safety measures (to be formulated) This standard is proposed and managed by the National Technical Committee for Standardization of Metal Cutting Machine Tools. The drafting units of this standard are: Beijing Machine Tool Research Institute, Beijing Milling Machine Research Institute, Shenyang Boring and Drilling Machine Research Institute, Shanghai Fourth Machine Tool Plant, Tianjin First Machine Tool Plant.
The main drafters of this standard are: Zheng Tingjuan, Liu Dequan, Mao Sili. 564
JB/T 8771. 5—1998
ISOForeword
ISO (International Organization for Standardization) is a federation of national standards organizations (ISO members) worldwide. The work of developing international standards is usually done by ISO technical committees. Each ISO member interested in a topic established by a technical committee has the right to express its opinion in the technical committee. International organizations, official or non-official bodies associated with ISO may also participate in this work. ISO cooperates closely with the International Electrotechnical Commission (IEC), which is responsible for electrical standards. Draft international standards accepted by the technical committee are sent to the members for comments and then voted on. Publication of international standards requires approval by at least 75% of the members voting.
ISO10791-5 was prepared by ISO/TC39
Technical Committee for Machine Tools
1 Scope
Standards for the Machinery Industry of the People's Republic of China
Machining centers
Test conditions
Part 5:
Positioning accuracy and repeatability test of workpiece holding pallets
Test conditions of machining centresPart 5: Tests for accuracy and repeatability ofpositioning of work-holding palletsJB/T8771.5—1998
This standard specifies the requirements and test methods for the positioning accuracy of a set of work-holding pallets (hereinafter referred to as pallets) on machine tools and the repeatability of each pallet.
This standard is applicable to pallets of single machining centres of ordinary accuracy for general use. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T17421.1-1998 General rules for machine tool inspection Part 1: Geometric accuracy of machine tools under no-load or finishing conditions ISO230-2:1997 General rules for machine tool inspection Part 2: Determination of positioning accuracy and repeatability of CNC machine tools JB3051-82 Nomenclature of coordinates and movement directions of numerically controlled machine tools JB/T7447.1-94 Common machine tool parts - Travelling pallets for workpieces with nominal dimensions up to 800 mm JB/T7447.2-94 Common machine tool parts - Travelling pallets for workpieces with nominal dimensions greater than 800 mm 3 General requirements
3.1 All linear dimensions in this standard are expressed in millimeters (mm) and angular deviations are expressed in ratios. The conversion relationship is as follows: 0.010/1 000=10×10-610 μrad2\3.2 When using this standard, reference must be made to the provisions of GB/T17421.1, especially the measurement methods of geometric accuracy and the recommended accuracy of inspection tools.
For the inspection conditions for evaluating positioning accuracy and repeatability, reference should be made to ISO230-2. The indicator should have a resolution of 0.001mm.
3.3 The schematic diagrams of this standard use some letters with general meanings that must be understood in all situations. The meanings of these letters are as follows (the naming of the actual axis of the machine tool is in accordance with the provisions of JB3051): -M and N represent the horizontal axis of the machine tool. In the approach direction function of the pallet, X and Z (or Z and X) should replace M and N for horizontal machining centers; X and Y (or Y and X) should replace M and N for vertical machining centers; -P represents the vertical axis of the machine tool. Y should replace P for horizontal machining centers and Z should replace P for vertical machining centers; -R represents the rotation of the pallet. Axis, for horizontal machining centers, B should replace R, and for vertical machining centers, C should replace R; i is the sequence number related to the approach (the first and second approach); State Machinery Industry Bureau approved 566 on July 17, 1998, implemented on December 1, 1998, JB/T8771.5-1998, is the sequence number related to the pallet (the first pallet); k is the common letter representing each axis M, N, P and R in the formula. 3.4 When inspecting machine tools, not all items in this standard must be inspected depending on the structure. When inspection is required for acceptance purposes, the user may obtain the manufacturer's consent to select some inspection items of interest, but these inspection items must be clearly stated when ordering the machine tool. 3.5 The inspection tools indicated below are only some examples. Other inspection tools with the same indication and at least the same accuracy and resolution can be used.
4 Repeatable positioning accuracy of each pallet on the machine tool 4.1
Installation of inspection tool
The installation of inspection tool is shown in Figure 1. Put the gauge block into the reference groove of the pallet and put a square on the pallet close to the gauge block. If the pallet is used to fix the workpiece or fixture with different references (such as the positioning holes or side positioning blocks shown in JB/T7447.1 and JB/T7447.2), then the inspection tool must be placed in the same reference position. tN
Figure 1 Inspection tool installation position diagram
4.2 Formula for calculating deviation from individual readings
α is the total reading of the indicator, W is the repeat positioning accuracy of the pallet along (or around) each axis, and the required value is calculated from each reading in the following way:
an=α2 (the position of indicator 2 closer to the rotation axis of the pallet)apα
ar (αz —ag)/d
W# =aijkmax-ajkmin
4.3 Tolerance
L≤500
L>500~～800
L≥>800~1250
L>1250～2 000
Any L length
The shorter side of the pallet.
4.4 Inspection tools
JB/T8771.5—1998
W..yz=0,008
Wx.y.=0.010
Wxyz=0. 013
Wx.yz=0.016
Wr=0.013/1 000
Indicator, gauge block, angle ruler or special fixture, or other inspection tools that can provide the same measurement results. 4.5 Inspection method
Except for the axis of motion of the pallet, all other axes shall be locked. On the positioning datum for the pallet fixture, a special fixture or a square or any other inspection tool shall be fixed so that the inspection tool is fixed at the same position for each pallet. The indicator shall be fixed in a position that does not affect the loading and unloading of the pallet. To prevent the probe from coming into direct contact with the inspection tool, the reading may be taken with a gauge block placed between the inspection tool and the probe each time. When the first pallet is positioned for the first time, the indicator shall be zeroed. Each pallet shall be loaded and unloaded 5 times without re-adjusting the indicator, and the indicator reading shall be recorded each time. The total deviation α in different directions shall be calculated from each reading separately according to the provisions of 4.2. The error shall be measured as the maximum repeatability of each axis in each pallet. www.bzxz.net
Note: The aR deviation can also be measured with the aid of an autocollimator, provided that the reflector is placed at exactly the same position of the different pallets relative to the positioning datum for the workpiece holding fixture.
4.6 Error evaluation
In this standard, the repeatability is not expressed in the range of the estimated 4s standard deviation in ISO230-2, but in the range W between the maximum and minimum readings.
4.7 Measured deviation
Table 1 gives an example of recording the readings and determining the required deviation. The first row of the table, M, N, P and R axes, can be represented by the actual X, Y, Z, B and C axes shown in Figure 1 and described in 3.3. Table 1 Repeatability of each pallet
aikmax
ajimin
Positioning accuracy of a group of pallets associated with a machine tool 5.1 Installation of inspection tools
JB/T8771.5—1998
Table 1 (end)
42二a
Because the result of this inspection is determined by the readings taken during the above inspection, the placement of the inspection tools should refer to Figure 1. 5.2 Formula for calculating deviation from individual readings
α is the total reading of the indicator, A is the positioning accuracy of a group of pallets along (or around) each axis, and the required value is calculated from the individual readings in the following way:
A =ajmax —aimin
Usually the two i values ​​and the two values ​​are different. In particular, if the maximum value of α and the minimum value of a in the above formula belong to the same pallet, then for a specific axis it means: As=W
5.3 Tolerance
L500~800
L>800~1 250
L>12502000
Any L length
The shorter side of the L pallet.
5.4 Inspection tool
Ax.y0.016
Ax.y.0.020
Ax.y.0. 025
Ax.yz=0.032
Ar =0. 025/1 000
Indicator, gauge block, angle square or special fixture, or other inspection tool that can provide the same measurement result. 5.5 Error evaluation
This standard does not use the statistical calculation in ISO 230-2 to determine the positioning accuracy, but instead expresses it as the difference between the maximum and minimum readings of the group of pallets.
5.6 Measured deviation
Table 2 gives an example of recording the individual readings and determining the required deviation. The first row of the table, the M, N, P and R axes, can be represented by the actual X, Y, Z, B and C axes shown in Figure 1 and described in 3.3. The individual values ​​of aumax and aumin in Table 2 should be taken from the M, N, P and R columns corresponding to the pallet in Table 1. 569
aijMmax
aijMmar
JB/T 8771. 5-1998
Table 2 Positioning accuracy of a set of pallets
ajNmax
aijNmax
aijPmax
agRmix
aijRmax
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