JB/T 8772.7-1998 Inspection conditions for precision machining centers Part 7: Accuracy inspection of precision machined test pieces
Some standard content:
JB/T8772.7—1998
This standard is formulated based on JB/T8771.7 "Inspection Conditions for Machining Centers Part 7: Precision Inspection of Finished Test Pieces" (this standard is equivalent to ISO/DIS10791-7 "Inspection Conditions for Machining Centers Part 7; Precision Inspection of Finished Test Pieces"). It is the same as JB/T8771.7 in terms of inspection items, inspection methods, inspection tools, etc., and the tolerance is compressed on the basis of this standard (generally the compression ratio is about 1.6, and the individual compression ratio is about 1.25). This standard is one of the standards in the series of inspection conditions for precision 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 attached spindle head machine tools (horizontal B axis); Part 2: Geometric accuracy inspection of vertical machining centers; Part 3: Geometric accuracy inspection of integral universal spindle head machine tools with horizontal main rotary axis (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 fine-machined test pieces, Part 8: Spherical evaluation using the 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, Qian Wenming, Chen Mingsheng. 665
1 Scope
Machinery Industry Standard of the People's Republic of China
Test conditions of precision machining centres
Part 7: Accuracy of a finished test piece
Test conditions of precision machining centresPart 7 :Accuracy of a finished test pieceJB/T8772.7—1998
This standard specifies the characteristics, dimensions and cutting tests of standard test pieces under finishing conditions, which are used to evaluate the cutting accuracy of machine tools. This standard is applicable to precision machining centres with linear axis travel up to 2000 mm. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were valid. All standards are subject to revision. 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 GB5342-85 Indexable Face Milling Cutters
3 General Requirements
3.1 In this standard, all linear dimensions, deviations and corresponding tolerances are expressed in millimeters (mm); angular dimensions are expressed in degrees (°). 3.2 When using this standard, reference must be made to GB/T17421.1, especially the installation before machine tool inspection, the idle running temperature rise of the spindle and other moving parts, the measurement methods and the recommended accuracy of the inspection tools. 3.3 The order of the inspection items in this standard does not represent the actual inspection order. In order to facilitate the installation and disassembly of the inspection 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 inspection items that he is interested in, but these items must be clearly stated when ordering the machine tool. 3.5 The inspection tools specified in this standard are only examples. Other inspection 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 This standard only uses precision cutting for processing tests. 3.7 When the measured length is different from the length specified in this standard, the specified tolerance value should 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 is still calculated as 0.003mm. 4 Number of test pieces
This standard provides two types, and each type of test piece has two specifications. The type, specification and mark of the test piece are shown in Table 1. In principle, only one piece of each type should be processed during acceptance. In the case of special requirements, such as statistical evaluation of machine tool performance, the number of processed test pieces shall be determined according to the agreement between the manufacturer and the user. Approved by the State Bureau of Machinery Industry on July 17, 1998 666
Implementation on December 1, 1998
Contour processing test piece
End milling test piece
Test piece positioning
JB/T 8772. 7—1998
Table 1
Test piece type, specification and mark
Nominal specification
Test piece JB/T8772.7-A160
Test piece JB/T8772.7-A320
Test piece JB/T8772.7-B80
Test piece JB/T 8772.7-B160
The specimen shall be located approximately in the middle of the travel of the X axis and placed along the Y and Z axes at a suitable position for the specimen and fixture positioning and tool length.
When there are special requirements for the specimen positioning, they shall be specified in the agreement between the supplier and the buyer. 6 Fixing of the specimen
The specimen shall be mounted on a special fixture to achieve maximum stability of the tool and fixture. The mounting surfaces of the fixture and the specimen shall be straight. The parallelism between the specimen mounting surface and the fixture clamping surface shall be checked. A suitable clamping method shall be used so that the tool can penetrate and machine the full length of the center hole. It is recommended to fix the specimen with countersunk screws to avoid interference between the tool and the screws that mount the specimen. Other possible methods may be used. The total height of the specimen depends on the fixing method selected. 7 Materials, tools and cutting parameters of the specimen
The materials of the specimen, the cutting tools and the cutting parameters shall be selected in accordance with the agreement between the manufacturer and the user and shall be recorded. Recommended cutting parameters are given in Clauses 9 and 10.
8 Dimensions of test pieces
Wheel-machined test pieces, if machined several times or reused, with reduced dimensions and increased bore diameters, shall have characteristic dimensions that are kept within ±10% of those given in this standard. When the test piece is reused, a thin cut shall be made to clean all surfaces before a new finishing test. When used for acceptance purposes, it is recommended that the final profiled test piece dimensions be in accordance with those given in this standard in order to reflect the cutting accuracy of the machine tool.
9 Profiled test pieces
9.1 General
This test consists of a series of finishing operations on different wheel blades to check the machine tool performance under different motion conditions, i.e. one axis feed only, two axis linear interpolation with different feed rates, two axis linear interpolation with one axis very low feed rate, and circular interpolation. The test is usually carried out in the XY plane, but can also be carried out in other planes when a universal spindle head is available. 9.2 Dimensions
This standard provides two specifications of wheel processing specimens, their dimensions are shown in Table 2. The final shape of the test piece (as shown in Figures 1 and 2) shall be formed by the following machining: a) boring a hole located in the center of the test piece;
b) machining an outer square with a side length of (; c) machining a rhombus with a side length of g on the square (a square inclined at 60°); d) machining a circle with a diameter of q and a depth of 6mm (or 10mm) on the rhombus: 667
JB/T 8772.7—1998
e) machining an inclined surface with an angle α of 3 or tanα=0.05 on the square over the full length of its two sides; f) boring four holes with a diameter of 26mm (or 43mm on larger test pieces) and four holes with a diameter of 28mm (or 45mm on larger test pieces); the holes with a diameter of 26mm approach along the positive direction of the axis, and the holes with a diameter of 28mm approach in the negative direction. The holes are located at a distance r from the center of the test piece.
Because different contour surfaces are machined at different axial heights, the tool should be kept a few tenths of a millimeter away from the surface of the lower plane to avoid surface contact.
Table 2 Specimen dimensions
Nominal specifications!
9.3 Tools
The same end milling wheel with a diameter of 32 mm can be used to machine all the outer surfaces of the specimen. zz
Medium 220
Figure 1 Large-size wheel machining specimen
9.4 Cutting parameters
The following parameters are recommended:
JB/T 8772.7-1998
Figure 2 Small-size contour machining test piece
a) Cutting speed
JB/T 8772.7--1998
For cast iron parts, it is about 50m/min, and for aluminum parts, it is about 300m/min; b) Feed rate
It is about 0.05~~0.1mm per tooth;
c) Cutting depth
The radial cutting depth of all milling operations should be 0.2mm, and the radial depth of the milling plane [9.2b), 9.2c) and 9.2d)] is about 6mm.
9.5 Rough and pre-processing
The bottom of the rough is a square base with a side length of m and a thickness determined by the installation method. The flat-bottomed strontium hole for fixing screws should be located in the area between the rhombus side and the square base field angle, as shown in Figures 1 and 2. In order to make the depth before cutting as constant as possible, pre-machining should be carried out before the precision cutting inspection. 9.6 Inspection and tolerance
The inspection and tolerance of the test piece precision-machined according to this standard are shown in Table 3. Table 3 Geometric accuracy inspection of contour machined test pieces
Inspection items
Center hole
a) Cylindricity
b) Perpendicularity between the hole axis and datum A
Square
c) Straightness of the edge
d) Perpendicularity of the adjacent edge to datum B
e) Parallelism of the opposite edge to datum B
f) Straightness of the side
g) Side to datum B Collar slope
h) Roundness
i) Concentricity of outer circle and center hole C
i) Straightness of surface
k) Inclination of 3° angle slope to reference B
n) Position of hole relative to inner boring hole C
o) Concentricity of inner hole to outer hole D
Nominal specification of tolerance
0) 40.013
Nominal specification of toleranceWww.bzxZ.net
Inspection tool
a) Coordinate measuring machine
b) do. 007
e> 0. 007
g) 0. 007
0) ,013
If possible, place the test piece on a coordinate measuring machine for the required measurements. b) Coordinate measuring machine
c) Coordinate measuring machine or straightedge and indicator
d) Coordinate measuring machine or angle square and indicator
e) Coordinate measuring machine or height gauge or indicatorf) Coordinate measuring machine or straightedge and indicator
g Coordinate measuring machine or sine rule and indicator
h) Coordinate measuring machine or indicator or roundness measuring instrument1i) Coordinate measuring machine or indicator or roundness measuring instrumentj) Coordinate measuring machine or straightedge and indicator
k) Coordinate measuring machine or sine rule and indicatorn) Coordinate measuring machine
0) Coordinate measuring machine or roundness measuring instrument
2For straight edges (squares, rhombuses and inclined planes), in order to obtain straightness, perpendicularity and parallelism deviations, the probe touches the measured surface at at least 10 points.
3 For roundness (or cylindricity) inspection, when the measurement is non-continuous, at least 15 points (cylindricity in each measuring plane) shall be checked. 670
9.7 Information recorded
JB/T 8772,7—1998
For inspections carried out in accordance with the requirements of this standard, the following information shall be recorded in the inspection report as completely as possible: a) Material and marking of the test piece;
b) Material and dimensions of the tool;
c) Cutting speed;
d) Feed rate
e) Depth of cut
f) Choice of chamfer 3° or tan-10.05. 10 End milling test piece
10.1 Overview
The purpose of the test is to check the flatness of the end face when it is finished milled in two passes, with the two passes covering approximately 20% of the tool diameter. Usually the test is completed by longitudinal movement along the X-axis and transverse movement along the Y-axis, but it can also be completed by other methods according to the agreement between the manufacturer and the user.
10.2 Specimen size and cutting parameters
The two specimen sizes and the selection of related tools are specified by the manufacturer or according to the agreement between the manufacturer and the user. In Table 4, the face width of the specimen is 1.6 times the tool diameter. In order to make the cutting width of the two passes approximately the same, the tool extends about 20% of the tool diameter from the specimen face during the first pass; during the second pass, the tool should extend about 1mm on the other side (see Figure 3). The specimen length should be 1.25 to 1.6 times the face width.
Cutting parameters
Face width W
10.3 Tool
Face length L
100130
200~250
Indexable face milling cutter (see GB5342).
The tool should meet the following tolerances when installed:
a) Radial runout: ≤0.012mm;
b) Face runout: ≤0.018mm.
Cutting width
Figure 3 End milling tool path
Tool diameter
Burning limit solution!
Number of teeth
10.4 Cutting parameters
JB/T 8772.7--1998
This standard does not specify the material of the test piece, but when using cast iron parts, the cutting parameters in Table 4 can be used. When the feed speed is 300mm/min, the feed per tooth is about 0.12mm, and the cutting depth should not exceed 0.5mm. If possible, the axis perpendicular to the surface to be processed (usually the Z axis) should be locked during cutting. 10.5 Roughing and pre-machining
Roughing shall have a sufficiently rigid base and be suitable for clamping to a workpiece holding table or pallet or fixture. Pre-machining shall be performed to make the cutting depth as constant as possible.
10.6 Flatness tolerance of finished surface
Small size test piece: ≤0.013 mm;
Large size test piece: ≤0.020 mm.
The straightness perpendicular to the milling direction reflects the overlap of the two passes, while the straightness check parallel to the milling direction reflects the influence of the tool entering and exiting the tool.
10.7 Recorded information
The following information shall be recorded in the inspection report as completely as possible for the inspection carried out in accordance with the requirements of this standard: a) material and dimensions of the test piece;
b) material and dimensions of the tool;
c) cutting speed;
d) feed rate,
e) depth of cut.013
If possible, place the test piece on a CMM and make the required measurements. b) CMM
c) CMM or straightedge and indicator
d) CMM or angle square and indicator
e) CMM or height gauge or indicatorf) CMM or straightedge and indicator
g CMM or sine gauge and indicator
h) CMM or indicator or roundness measuring machine1i) CMM or indicator or roundness measuring machinej) CMM or straightedge and indicator
k) CMM or sine gauge and indicatorn) CMM
0) CMM or roundness measuring machine
2For straight edges (squares, rhombuses and inclined planes), the probe touches the surface to be measured at least at 10 points in order to obtain deviations from straightness, perpendicularity and parallelism.
3 For roundness (or cylindricity) inspection, when the measurement is non-continuous, at least 15 points (cylindricity in each measuring plane) shall be checked. 670
9.7 Information recorded
JB/T 8772,7—1998
For inspections carried out in accordance with the requirements of this standard, the following information shall be recorded in the inspection report as completely as possible: a) Material and marking of the test piece;
b) Material and dimensions of the tool;
c) Cutting speed;
d) Feed rate
e) Depth of cut
f) Choice of chamfer 3° or tan-10.05. 10 End milling test piece
10.1 Overview
The purpose of the test is to check the flatness of the end face when it is finished by two passes, with the two passes covering approximately 20% of the tool diameter. Usually the test is completed by longitudinal movement along the X-axis and transverse movement along the Y-axis, but it can also be completed by other methods according to the agreement between the manufacturer and the user.
10.2 Specimen size and cutting parameters
The two specimen sizes and the selection of related tools are specified by the manufacturer or according to the agreement between the manufacturer and the user. In Table 4, the face width of the specimen is 1.6 times the tool diameter. In order to make the cutting width of the two passes approximately the same, the tool extends about 20% of the tool diameter from the specimen face during the first pass; during the second pass, the tool should extend about 1mm on the other side (see Figure 3). The specimen length should be 1.25 to 1.6 times the face width.
Cutting parameters
Face width W
10.3 Tool
Face length L
100130
200~250
Indexable face milling cutter (see GB5342).
The tool should meet the following tolerances when installed:
a) Radial runout: ≤0.012mm;
b) Face runout: ≤0.018mm.
Cutting width
Figure 3 End milling tool path
Tool diameter
Burning limit solution!
Number of teeth
10.4 Cutting parameters
JB/T 8772.7--1998
This standard does not specify the material of the test piece, but when using cast iron parts, the cutting parameters in Table 4 can be used. When the feed speed is 300mm/min, the feed per tooth is about 0.12mm, and the cutting depth should not exceed 0.5mm. If possible, the axis perpendicular to the surface to be processed (usually the Z axis) should be locked during cutting. 10.5 Roughing and pre-machining
Roughing shall have a sufficiently rigid base and be suitable for clamping to a workpiece holding table or pallet or fixture. Pre-machining shall be performed to make the cutting depth as constant as possible.
10.6 Flatness tolerance of finished surface
Small size test piece: ≤0.013 mm;
Large size test piece: ≤0.020 mm.
The straightness perpendicular to the milling direction reflects the overlap of the two passes, while the straightness check parallel to the milling direction reflects the influence of the tool entering and exiting the tool.
10.7 Recorded information
The following information shall be recorded in the inspection report as completely as possible for the inspection carried out in accordance with the requirements of this standard: a) material and dimensions of the test piece;
b) material and dimensions of the tool;
c) cutting speed;
d) feed rate,
e) depth of cut.013
If possible, place the test piece on a CMM and make the required measurements. b) CMM
c) CMM or straightedge and indicator
d) CMM or angle square and indicator
e) CMM or height gauge or indicatorf) CMM or straightedge and indicator
g CMM or sine gauge and indicator
h) CMM or indicator or roundness measuring machine1i) CMM or indicator or roundness measuring machinej) CMM or straightedge and indicator
k) CMM or sine gauge and indicatorn) CMM
0) CMM or roundness measuring machine
2For straight edges (squares, rhombuses and inclined planes), the probe touches the surface to be measured at least at 10 points in order to obtain deviations from straightness, perpendicularity and parallelism.
3 For roundness (or cylindricity) inspection, when the measurement is non-continuous, at least 15 points (cylindricity in each measuring plane) shall be checked. 670
9.7 Information recorded
JB/T 8772,7—1998
For inspections carried out in accordance with the requirements of this standard, the following information shall be recorded in the inspection report as completely as possible: a) Material and marking of the test piece;
b) Material and dimensions of the tool;
c) Cutting speed;
d) Feed rate
e) Depth of cut
f) Choice of chamfer 3° or tan-10.05. 10 End milling test piece
10.1 Overview
The purpose of the test is to check the flatness of the end face when it is finished milled in two passes, with the two passes covering approximately 20% of the tool diameter. Usually the test is completed by longitudinal movement along the X-axis and transverse movement along the Y-axis, but it can also be completed by other methods according to the agreement between the manufacturer and the user.
10.2 Specimen size and cutting parameters
The two specimen sizes and the selection of related tools are specified by the manufacturer or according to the agreement between the manufacturer and the user. In Table 4, the face width of the specimen is 1.6 times the tool diameter. In order to make the cutting width of the two passes approximately the same, the tool extends about 20% of the tool diameter from the specimen face during the first pass; during the second pass, the tool should extend about 1mm on the other side (see Figure 3). The specimen length should be 1.25 to 1.6 times the face width.
Cutting parameters
Face width W
10.3 Tool
Face length L
100130
200~250
Indexable face milling cutter (see GB5342).
The tool should meet the following tolerances when installed:
a) Radial runout: ≤0.012mm;
b) Face runout: ≤0.018mm.
Cutting width
Figure 3 End milling tool path
Tool diameter
Burning limit solution!
Number of teeth
10.4 Cutting parameters
JB/T 8772.7--1998
This standard does not specify the material of the test piece, but when using cast iron parts, the cutting parameters in Table 4 can be used. When the feed speed is 300mm/min, the feed per tooth is about 0.12mm, and the cutting depth should not exceed 0.5mm. If possible, the axis perpendicular to the surface to be processed (usually the Z axis) should be locked during cutting. 10.5 Roughing and pre-machining
Roughing shall have a sufficiently rigid base and be suitable for clamping to a workpiece holding table or pallet or fixture. Pre-machining shall be performed to make the cutting depth as constant as possible.
10.6 Flatness tolerance of finished surface
Small size test piece: ≤0.013 mm;
Large size test piece: ≤0.020 mm.
The straightness perpendicular to the milling direction reflects the overlap of the two passes, while the straightness check parallel to the milling direction reflects the influence of the tool entering and exiting the tool.
10.7 Recorded information
The following information shall be recorded in the inspection report as completely as possible for the inspection carried out in accordance with the requirements of this standard: a) material and dimensions of the test piece;
b) material and dimensions of the tool;
c) cutting speed;
d) feed rate,
e) depth of cut.
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