JB/T 9871-1999 This standard is a revision of JB/Z 276-86 "Precision Classification of Metal Cutting Machine Tools". During the revision, only editorial changes were made according to relevant regulations, and the main technical content remained unchanged. This standard specifies the precision levels of various types of metal cutting machine tools. This standard is applicable to general-purpose machine tools. This standard was first issued in December 1986. JB/T 9871-1999 Precision Classification of Metal Cutting Machine Tools JB/T9871-1999 Standard Download Decompression Password: www.bzxz.net

ICS25.080
Machinery Industry Standard of the People's Republic of China
JB/T9871-1999
Metal Cutting Machine Tools
Published on 1999-05-20
Accuracy Classification
Implemented on 2000-01-01
National Bureau of Machinery Industry
JB/T9871-1999
This standard is a revision of JB/Z276-86 "Accuracy Classification of Metal Cutting Machine Tools". The original version was formulated based on the actual situation of current machine tool products and the use requirements of users. Its technical content can still meet the current scientific and technological level and meet the needs of production and use. This standard is consistent with the technical content of JB/Z276-86, and has only been re-edited in accordance with relevant regulations. This standard replaces JB/Z276-86 from the date of implementation. This standard is proposed by the National Technical Committee for Standardization of Metal Cutting Machine Tools. This standard is under the jurisdiction of the National Technical Committee for Standardization of Metal Cutting Machine Tools. The responsible drafting unit of this standard is Beijing Machine Tool Research Institute. This standard was first issued in December 1986. 1 Scope
Machinery Industry Standard of the People's Republic of China
Precision Classification of Metal Cutting Machine Tools
This standard specifies the precision levels of various types of metal cutting machine tools (hereinafter referred to as machine tools). This standard is applicable to general-purpose machine tools. 2 Referenced Standards
JB/T 9871-1999
Replaces JB/Z276—86
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 are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T 1184—1996
GB/T1800.3—1998
GB/T23631990
GB/T 10095—1988
3 Principles of machine tool accuracy classification
Form and position tolerances Unindicated tolerance values
Basics of limits and fits Part 3: Numerical tables of standard tolerances and basic deviations Accuracy system for small module involute cylindrical gears
Accuracy of involute cylindrical gears
3.1 According to the machining accuracy requirements of the workpiece, machine tools are divided into six absolute accuracy grades according to the absolute classification method, represented by Roman numerals VI, V, IV, I, I, and 1 respectively. Grade V has the lowest accuracy and grade I has the highest accuracy. 3.2 For each type of machine tool, it should be divided into three relative accuracy levels based on the absolute accuracy level according to the relative classification method, represented by the Chinese phonetic letters P, M, and G respectively:
P--ordinary accuracy (pronounced as "Pu", P omitted in the model); M-precision level (pronounced as "Mi");
G-high accuracy level (pronounced as "Gao"). 3.3 Each type of machine tool can determine one, two or three relative accuracy levels according to the specific situation and the requirements of the series spectrum. 3.4 The accuracy indicators of P-level accuracy machine tools should be equivalent to the technical level of the current international standards or foreign advanced standards. For cylindrical surface processing machines with a relative accuracy level of P, if they can achieve the IT6 to IT7 dimensional tolerance specified in GB/T1800.3, and the roundness and cylindricity can reach the 8-level processing accuracy specified in GB/T1184, they should generally be placed in the position of absolute accuracy level V (such as horizontal lathes).
For plane machining machines with relative accuracy level P, if the flatness and verticality can reach the machining accuracy of the form and position tolerances of level 6 to 7 specified in GB/T1184, they should generally be placed at the position of absolute accuracy level V (such as lifting table milling machines). For gear profile machining machines with relative accuracy level P, if they can reach the machining accuracy of the gear tolerances of level 6 to 7 specified in GB/T2363 or GB/T10095, they should generally be placed at the position of absolute accuracy level V (such as gear shaping machines). 3.5 For machine tools with accuracy levels from VI to V, V to IV, IV to III, III to I, and II to I, the tolerance values ​​of the working accuracy inspection items in their accuracy standards should be determined according to the requirements of the accuracy of the processing object, and the common ratio between the accuracy levels should be determined. For items in the geometric accuracy inspection that have a direct impact on the working accuracy, the compression ratio of the tolerance value should be the same as the common ratio of the corresponding tolerance grades (generally 1.6); for items in the geometric accuracy inspection that have a small impact on the working accuracy, the compression ratio of the tolerance value can be smaller than the common ratio of items that have a direct impact on the working accuracy (generally 1.25). 4 Classification of machine tool accuracy The accuracy classification of various types of machine tools should generally comply with the provisions of Tables 1 to 4. Table 1 Cylindrical surface machining machine tools
Absolute accuracy level of machine tools
Machine tool type
Single-axis longitudinal cutting automatic lathewww.bzxz.net
Single-axis turret automatic lathe
Multi-axis automatic and semi-automatic lathe
Vertical lathe
Floor-type lathe
Horizontal lathe
Profiling lathe
Multi-tool lathe
|Chuck multi-tool lathe
Horizontal milling and boring machine
Floor-type boring machine
Planing table horizontal milling and boring machine
Floor-type milling and boring machine
Horizontal fine boring machine
Vertical fine boring machine
Centerless external cylindrical grinder
External cylindrical grinder
Internal cylindrical grinder
Radial drilling machine
Vertical drilling machine
Bench-type Drilling machine
Relative accuracy grade of machine tools
Type of machine tools
Guide grinder
Universal tool grinder
Horizontal spindle and rectangular table surface grinder
Vertical spindle and rectangular table surface grinder
Horizontal spindle and rotary table surface grinder
Vertical spindle and rotary table surface grinder
Gantry milling machine
Surface milling machine
Profiling Milling machine
Lift table milling machine
Arm milling machine
Bed milling machine
Universal tool milling machine
Cantilever and gantry planer
Shaper
Machine tool type
Gear hobbing machine
Gear shaving machine
Gear shaping machine
Spline shaft milling machine
Dish wheel gear grinding machine||tt| |Conical grinding wheel gear grinding machine
Worm grinding wheel gear grinding machine
Forming grinding wheel gear grinding machine
Large flat grinding wheel gear grinding machine
Cycloidal gear gear grinding machine
JB/T9871-1999
2 Plane processing machine tools
Absolute accuracy level of machine tools
Relative accuracy level of machine tools
Tooth profile and thread surface processing machine tools
Absolute accuracy level of machine tools
Relative accuracy level of machine tools
Machine tool type
Curved bevel gear grinding machine
Curved bevel gear milling machine
Straight bevel gear planing machine
Shoveling lathe
Thread grinder
Screw lathe
Machine tool type
Side broaching machine
Vertical internal broaching machine
Horizontal internal broaching machine
Vertical external broaching machine
Jig boring machine
Jig grinding machine
Circular scoring machine
Long scoring machine
JB/T9871-1999
Table 3 (end)
Absolute accuracy grade of machine tools
Relative accuracy grade of machine tools
Table 4 Other processing machine tools
Absolute accuracy grade of machine tools
Relative accuracy grade of machine tools
1 Machine tools not listed in the table, as well as new machine tools developed due to technological progress, can be graded for accuracy according to the accuracy grading principles in this standard. For machine tool products with accuracy lower than the ordinary grade or higher than the high grade, they can be developed according to user needs. People's Republic of China
Mechanical Industry Standard
Precision Classification of Metal Cutting Machine Tools
JB/T9871-1999
Published and distributed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry Printed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry (No. 2 Shouti South Road, Beijing
Format 880×1230
Postal Code 100044)
Sheet 1/2
Word Count 10,000
First Edition July 1999
First Printing July 1999
Print Quantity 1-500
Price 5.00 Yuan
99-187
6661_86 /1
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