JB/T 8772.4-1998 JB/T 8772.4-1998 Test conditions for precision machining centres Part 4: Test of positioning accuracy and repeatability of linear and rotary axes JB/T8772.4-1998 Standard download decompression password: www.bzxz.net

JB/T8772.4—1998
This standard is formulated based on JB/T8771.4-1998 "Testing conditions for machining centers Part 4: Positioning accuracy and repeatability of linear and rotary axes" (this standard is equivalent to ISO/DIS10791-4.2 "Testing conditions for machining centers Part 4: Positioning accuracy and repeatability of linear and rotary axes"), and is the same as JB/T8771.4 in terms of test items, test methods, test tools, etc., and the tolerance is compressed on the basis of this standard (the compression ratio is about 1.6). This standard is one of the standards in the series of test conditions for precision machining centers. This series of standards includes the following 13 parts, which can be used simultaneously or separately: www.bzxz.net
Part 1: Geometric accuracy test of horizontal and attached spindle head machine tools (horizontal B axis); Part 2: Geometric accuracy test of vertical machining center, Part 3: Geometric accuracy test of machine tools with integral universal spindle head with horizontal main rotary axis (vertical Z axis) (to be formulated); Part 4: Positioning accuracy and repeatability test of linear and rotary axes; Part 5: Positioning accuracy and repeatability test of workpiece clamping pallet; Part 6: Feed rate, speed and interpolation accuracy test (to be formulated); Part 7: Precision test of fine-machined test pieces; Part 8: Spherical evaluation using 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, Kunming Precision Machine Tool Research Institute, Ningjiang Machine Tool Factory. The main drafters of this standard are: Tang Qishou, Xie Ling, Xie Hong, Ren Diao, Ji Xiangwen. 654
1 Scope
Machinery Industry Standard of the People's Republic of China
Test conditions of precision machining centres
Part 4: Accuracy and repeatability of positioningof linear and rotary axes
JB/T 8772.4—1998
This standard specifies the tolerances for positioning accuracy inspection of linear and rotary axes of precision machining centres. This standard is applicable to precision machining centres with linear axis travel up to 2000mm and rotary axis. 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 principles for machine tool inspection Part 1: Geometric accuracy of machine tools under no-load or finishing conditions ISO230-2:1997 General principles for machine tool inspection Part 2: Determination of positioning accuracy and repeatability of coordinate axes of CNC machine tools 3 General requirements
3.1 In this standard, all linear dimensions and corresponding tolerances are expressed in millimeters (mm); angular dimensions and corresponding tolerances are expressed in degrees (\), microradians (μrad) and seconds (\). The conversion relationship is as follows: 0.010/1 000=10×10 6=10 μrad～2(\)3.2 When using this standard, reference must be made to ISO230-2, especially the test conditions, test procedures and evaluation of results. 3.3 The order of test items in this standard does not represent the actual test order. In order to facilitate the installation and disassembly of test tools and the inspection, the inspection can be carried out in any order.
3.4 ​​When inspecting a machine tool, not all items in this standard must be inspected according to the structure. When inspection is required for acceptance purposes, the user may obtain the manufacturer's consent to select some of the test items he is interested in, but these items must be clearly stated when ordering the machine tool. 3.5 The test tools specified in this standard are only examples. Other test tools with the same indication and at least the same accuracy can be used. The indicator should have a resolution of 0.001mm or higher. 3.6 When the measured length is different from the length specified in this standard, the specified tolerance value shall be converted according to the measurable length in accordance with the provisions of 2.3.1.1 of GB/T17421.1-1998. When the conversion result is less than 0.003mm, it shall still be calculated as 0.003mm. 3.7 During the axis inspection process, the moving parts on the non-detection axis of the three basic axes should be placed in the middle of their working stroke as much as possible, or kept in a position that minimizes the measurement deviation of the shadow element. Sliding spindles, rams, etc., when they are auxiliary axes, should be kept in the retracted position.
4 Positioning of linear axes
4.1 The tolerances for positioning accuracy of different measuring strokes for precision machining centers with a stroke of up to 2000mm are shown in Table 1. Approved by the State Bureau of Machinery Industry on July 17, 1998 and implemented on December 1, 1998
Bidirectional positioning accuracy
Unidirectional positioning accuracy
Inspection items
Bidirectional repeat positioning accuracy
Unidirectional repeat positioning accuracy
Reverse difference of axis
Average reverse difference
Bidirectional positioning system deviation
Unidirectional positioning system deviation
JB/T 8772.41998
Tolerance of linear axis positioning accuracy
Measurement stroke of axis
A+ and A+
R+ and R★
E and E+
Average bidirectional position deviation range of axis M
>500~800
>800~1250
>1 250~~2 000
Inspection generally uses laser interferometers, and other measuring systems with similar accuracy can also be used. When using laser interferometers, 4.2
Appropriate protective measures should be taken in accordance with A13 of GB/T17421.1-1998. 4.3 Regarding the execution of inspection, the process specified in 4.3.2 of ISO230-2:1997 should be followed, especially all inspections up to 2000mm.
4.4 The format of the calculated deviation
statistical analysis results of measured data is recommended to be in the form of Table 2. Table 2 Format of all inspection results of positioning accuracy of linear axis up to 2000mmAxis name and corresponding measuring stroke
Bidirectional positioning accuracy
Positioning accuracy (positive)
Positioning accuracy (negative)
Bidirectional repeat positioning accuracy
Repeat positioning accuracy (positive)
Repeat positioning accuracy (negative)
Reverse difference of axis
Average reverse difference
Bidirectional positioning system deviation
Positioning system deviation (positive)
Positioning system deviation (negative)
Average bidirectional position deviation range M of axis
Positioning of rotary axis
JB/T8772.4—1998
The tolerance of positioning accuracy of precision machining center with measuring stroke up to 360° is shown in Table 3. Table 3 Tolerance of the positioning accuracy of the rotary axis
Bidirectional positioning accuracy
Unidirectional positioning accuracy
Bidirectional repeat positioning accuracy
Unidirectional repeat positioning accuracy
Maximum reverse difference
Average reverse difference
Bidirectional positioning system deviation
Unidirectional positioning system deviation
Average bidirectional position deviation range of the axis
A+ and A+
R+ and R+
E+ and E+
5.2 During the inspection, a laser angle interferometer with a dividing table, an autocollimator with a polygon mirror, or other measuring systems with similar accuracy can be used. When using an autocollimator, appropriate protective measures should be taken in accordance with A11 of GB/T17421.1-1998. 5.3 Regarding the execution of the inspection, 4.3 of ISO230-2-1997 should be followed.4. The calculated deviation
The format of the statistical analysis results of the measured data is recommended to be in the form of Table 4. Table 4 Format of the complete inspection results of the positioning accuracy of the rotary axis to 360°Axis name and corresponding measuring stroke
Bidirectional positioning accuracy
Positioning accuracy (positive)
Positioning accuracy (negative)
Bidirectional repeated positioning accuracy
Repeated positioning accuracy (positive)
Repeated positioning accuracy (negative)
Reverse difference of axis
Average reverse difference
Bidirectional positioning system deviation
Positioning system deviation (positive)
Positioning system deviation (negative)
Average bidirectional position deviation range M() of the axis
Recommended information to be recorded
The inspection report is recommended to contain the following information.
Information for identifying the machine tool:
Name of manufacturer:
Design year (if available);
Model and serial number;
JB/T 8772. 4—1998
Machine tool structure type in accordance with 3.11 and 3.12 of JB/T8772.1—1998JB/T8772.2—1998 or JB/T8772.3--1998 (if possible).
6.2 Information for identification inspection:
Serial number.
Date and place of inspection;
Name of company and inspector;
List of inspection equipment used, including manufacturer's name, model of components (e.g. laser head, optical components, temperature sensors) and information on 6.3 inspection conditions:
Machine tool parts moving along or around the axes under inspection; feed rates;
Position of axis slides or moving parts on axes not under inspection; Position of measuring lines;
Number and location of temperature sensors;
Readings of temperature sensors immediately before and after the inspection; coefficient of expansion used for material compensation;
Temperature, pressure and humidity of the air before and after the inspection (if relevant); Type of compensation applied to the machine tool axes;
Type of compensation applied to the measured data.
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