JB/T 8771.7-1998 Inspection conditions for machining centres Part 7: Accuracy inspection of precision machined test pieces
Some standard content:
JB/T 8771.7—1998
This standard is formulated based on the draft international standard ISO/DIS10791-7 "Test conditions for machining centers Part 7: Test accuracy of precision machined test pieces". It is equivalent to the draft international standard in terms of technical content. This standard is one of the series of standards for test conditions for machining centers. The series of standards includes the following 13 parts, which can be used simultaneously or separately:
Part 1: Geometric accuracy test of horizontal and additional spindle heads (horizontal B axis) Part 2: Geometric accuracy test of vertical machining centers Part 3: Geometric accuracy test of integral universal spindle heads with horizontal main rotary axes (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 pallets Part 6: Test of feed rate, speed and interpolation accuracy (to be formulated) Part 7: Test of precision of finished test piece
Part 8: Evaluation of spherical shape 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, Beijing First Machine Tool Factory. The main drafters of this standard are: Hu Ruilin, Liang Kunhong, Chen Mingsheng. 571
JB/T 8771.7—1998
ISOForeword
ISO (International Organization for Standardization) is a federation of national standardization organizations (ISO members) around the world. The development of international standards is usually completed by ISO's technical committees. Each ISO member interested in a topic established by a technical committee has the right to express its opinions in the technical committee. International organizations, official or non-official organizations associated with ISO may also participate in this work. ISO works closely with the International Electrotechnical Commission (IEC), which is responsible for the promotion of electrical standards. Draft international standards accepted by the technical committee are sent to each member for comment and then voted on. The publication of international standards requires at least 75% of the members to vote in favor
ISO 10791-7 was prepared by ISO/TC 39
9 Technical Committee for Machine Tools.
Machinery Industry Standard of the People's Republic of China
Test conditions of machining centresPart 7 : Accuracy of finished test pieceJB/T 8771. 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 ordinary precision machining centers with linear axis travel up to 2000mm. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. The versions shown are valid at the time of publication of this standard. All standards are subject to revision, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB5342-85 Indexable face milling cutter
GB/T17421.1-1998 General rules for machine tool inspection Part 1: Geometric accuracy of machine tools under no-load or finishing conditions 3 General requirements
3.1 In this standard, all linear dimensions and corresponding tolerances are expressed in millimeters (mm); angular dimensions are expressed in degrees (°). 3.2 When using this standard, reference should be made to GB/T17421.1, especially the installation before accuracy inspection, the idling and heating of the spindle and other components, the inspection method, and the inspection of the tool accuracy.
3.3 The order of inspection items listed in this standard does not represent the actual inspection order. For the convenience of assembly and disassembly of inspection tools and inspection, inspections can be carried out in any order.
3.4 When inspecting a machine tool, it is not necessary to inspect all items in this standard according to 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. 3.5 The inspection tools specified in this standard are for example only. Other inspection tools with the same indication and at least the same accuracy may be used. The indicator shall 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 tolerance shall be converted according to the length that can be measured in accordance with the provisions of 2.3.1.1 of GB/T17421.1-1998. When the conversion result is less than 0.005mm, it shall still be calculated as 0.005mm. 4 Number of test pieces
Two types are provided in this standard, and each type has two specifications of test pieces. The types, specifications and markings of the test pieces are shown in Table 1. Table 1. Type, specification and mark of test piece
Contour machining test piece
Approved by the State Machinery Industry Bureau on July 17, 1998 Nominal specification
Test piece JB/T 8771.7—A160
Test piece JB/T 8771.7—A320
Implemented on December 1, 1998
End milling test piece
JB/T 8771. 7-1998
Table 1 (end)
Nominal specifications
Test piece JB/T8771.7—B80
Test piece JB/T8771.7---B160
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 by agreement between the manufacturer and the user. 5 Positioning of test pieces
The test piece shall be located in the middle of the X stroke and placed along the Y and Z axes at a suitable position for the positioning of the test piece and the fixture and the tool length.
When there are special requirements for the positioning position of the test piece, it should be specified in the agreement between the manufacturer and the user. 6 Fixing of test pieces
The test piece should be conveniently installed on a special fixture to achieve maximum stability of the tool and fixture. The mounting surfaces of the fixture and the test piece should be flat. The parallelism of the test piece mounting surface and the clamping surface of the fixture 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 test piece with a countersunk screw to avoid interference between the tool and the screw. Other equivalent methods may also be used. The total height of the test piece depends on the fixing method selected. 7 Test piece materials, tooling and cutting parameters
The material, cutting tool and cutting parameters of the test piece shall be selected according to the agreement between the manufacturer and the user and shall be recorded. The recommended cutting parameters are shown in Chapters 9 and 10.
8 Dimensions of the test piece
If the test piece is cut several times, the outer dimensions are reduced and the hole diameter is increased. When used for acceptance inspection, it is recommended that the final contour processing test piece dimensions be consistent with those specified in this standard so as to accurately reflect the cutting accuracy of the machine tool. The test piece can be used repeatedly in cutting tests, and its specifications shall remain within ±10% of the characteristic dimensions given in this standard. When the test piece is used again, a thin layer of cutting should be carried out to clean all surfaces before a new finishing test is carried out. 9 Contouring Test Pieces
9.1 General
This test consists of a series of finishing operations on different contours to check the machine performance under different motion conditions. That is: one axis only: feed, two axis linear interpolation at different feed rates, two axis linear interpolation with one axis at a very low feed rate and circular interpolation. This 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
Two sizes of contouring test pieces are provided in this specification. 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 with a diameter of "p\ 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; e) machining an inclined surface with an angle \α" of 3\ or tana=0.05 on the square; 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), with the holes with a diameter of 26mm approaching in the positive direction of the axis and the holes with a diameter of 28mm approaching in the negative direction. These holes are located at a distance of "rr" from the center of the test piece.
JB/T 8771.7—1998
Because different profile surfaces are machined at different axial heights, the tool should be kept a few tenths of a millimeter away from the lower surface plane to avoid surface contact.
9.3 Tool
The same end mill with a diameter of 32 mm can be used to machine all the outer surfaces of the profile machining test piece. 7-7
4×Medium45
Figure 1 Large-size profile machining test piece
JB/T 8771. 7—1998
Figure 2 Small-size profile machining test piece
Nominal size
9.4 Cutting parameters
The following cutting parameters are recommended:
a) Cutting speed
JB/T 8771. 7—1998
Test piece size
For cast iron, it is about 50 m/min; for aluminum, it is about 300 m/min. b) Feed rate
is about (0.05~0.10) mm/tooth.
c) Cutting depth
The radial cutting depth of all milling processes should be 0.2 mm. 9.5 Roughing and pre-machining
The bottom of the roughing is a square base with a side length of "m". The height is determined by the installation method. In order to make the cutting depth as constant as possible, pre-machining should be carried out before fine cutting. 9.6 Inspection and tolerance
The inspection and tolerance of the test pieces finely machined according to this standard are shown in Table 3. Table 3 Geometric accuracy inspection of contour machining test pieces
Inspection items
Center hole
a) Cylindricity
b) Perpendicularity of the center axis of the hole to the base surface A
Rectangular
c) Straightness of the side surface
d) Perpendicularity of the adjacent surface to the base surface B
e) Opposite surface to the base surface B Parallelism
f) Straightness of the side surface
g) Inclination of the side surface to the base surface B
h) Roundness
i) Concentricity of the outer circle and the inner circle hole C
j) Straightness of the surface
k) Inclination of the 3° angle bevel to the B surface
n) Position of the hole relative to the inner hole C
s) Concentricity of the inner hole and the outer hole D
If conditions permit, the test piece can be placed on a coordinate measuring machine for measurement, 1
Inspection tools
a) Coordinate measuring machine
b) Coordinate measuring machine
c) Coordinate measuring machine or flat ruler and indicator||tt ||d) Coordinate measuring machine or angle square and indicator
e) Coordinate measuring machine or height gauge block and indicatorf) Coordinate measuring machine or straightedge and indicator
) Coordinate measuring machine or sine rule and indicatorh) Coordinate measuring machine or indicator or roundness measuring instrumenti) Coordinate measuring machine or indicator or roundness measuring instrumenti) Coordinate measuring machine or straightedge and indicator
k) Coordinate measuring machine or sine rule and indicatorn) Coordinate measuring machine
s) Coordinate measuring machine or roundness measuring instrument
2For straight edges (squares, rhombuses and inclined planes), in order to obtain the deviations from straightness, perpendicularity and parallelism, the probe touches the surface to be measured at least at 10 points.
3 For roundness (or cylindricity) inspection, if the measurement is non-continuous, at least 15 points (cylindricity in each measuring plane) shall be inspected: 577
9.7 Information to be recorded
JB/T 8771. 7-1998
When inspecting according to 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 size of the tool;
c) Cutting speed;
d) Feed rate;
e) Depth of cut;
f) Choice between 3° and tan-10.05 for the bevel. 10 End milling test piece
10.1 Overview
The purpose of this test is to inspect the flatness of the surface milled by end milling, with the overlap of the two passes being approximately 20% of the milling cutter diameter. Normally the test is performed by longitudinal movement along the X-axis and transverse movement along the Y-axis, but it may be performed by other methods as agreed between the manufacturer and the user.
10.2 Specimen dimensions and cutting parameters
The selection of the two specimen dimensions and the relevant tools shall be in accordance with the manufacturer's specifications or with the user's agreement. In Table 4, the face width of the specimen is 1.6 times the tool diameter, and the cutting face width is completed with two passes of 80% of the tool diameter. In order to make the cutting width in the two passes approximately the same, the tool should extend 20% of the tool diameter from the specimen surface in the first pass, and the tool should extend about 1 mm from the other side in the second pass (see Figure 3). The specimen length should be 1.25 to 1.6 times the width. Table 4 Cutting parameters
Test piece surface width W
Test piece surface length L
100~130
200~250
Cutting width
Figure 3 End milling test mode
Tool diameter
20%Tool diameter
1st pass
2nd pass
Number of tool teeth
The material of the test piece is not specified. When cast iron is used, the cutting parameters in Table 4 can be referred to. When the feed speed is 300mm/min, the feed per tooth is approximately 0.12mm, and the cutting depth should not exceed 0.5mm. If possible, the axis perpendicular to the machined surface (usually axis B) should be locked during cutting.
10.3 Use an indexable sleeve face milling cutter (see GB5342). The tool installation should meet the following tolerances: a) radial runout ≤ 0.02mm;
b) end runout ≤ 0.03mm.
4 Roughing and pre-machining
JB/T 8771.7—1998
The roughing base should have sufficient rigidity and be suitable for clamping to the workbench or the pallet and fixture. In order to make the cutting depth as constant as possible, pre-machining should be carried out before fine cutting.
10.5 Flatness tolerance of fine-machined surface
The flatness tolerance of the machined surface of small-sized test pieces should not exceed 0.02mm; the flatness tolerance of large-sized test pieces should not exceed 0.03mm. The straightness test perpendicular to the milling direction reflects the influence of the overlap of the two passes, and the straightness test parallel to the milling direction reflects the influence of the tool coming out and entering the tool.
10.6 Recorded information
In accordance with the requirements of this standard, the following information should be recorded in the inspection report as completely as possible: 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.6 Inspection and tolerance
The inspection and tolerance of the test pieces finished 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 center axis of the hole and the base surface A
Square
c) Straightness of the side surface
d) Perpendicularity between the adjacent surface and the base surface B
e) Opposite surface to the base surface B Parallelism
f) Straightness of the side surface
g) Inclination of the side surface to the base surface B
h) Roundness
i) Concentricity of the outer circle and the inner circle hole C
j) Straightness of the surface
k) Inclination of the 3° angle bevel to the B surface
n) Position of the hole relative to the inner hole C
s) Concentricity of the inner hole and the outer hole D
If conditions permit, the test piece can be placed on a coordinate measuring machine for measurement, 1
Inspection tools
a) Coordinate measuring machine
b) Coordinate measuring machine
c) Coordinate measuring machine or flat ruler and indicator||tt ||d) Coordinate measuring machine or angle square and indicator
e) Coordinate measuring machine or height gauge block and indicatorf) Coordinate measuring machine or straightedge and indicator
) Coordinate measuring machine or sine rule and indicatorh) Coordinate measuring machine or indicator or roundness measuring instrumenti) Coordinate measuring machine or indicator or roundness measuring instrumenti) Coordinate measuring machine or straightedge and indicator
k) Coordinate measuring machine or sine rule and indicatorn) Coordinate measuring machine
s) Coordinate measuring machine or roundness measuring instrument
2For straight edges (squares, rhombuses and inclined planes), in order to obtain the deviations from straightness, perpendicularity and parallelism, the probe touches the surface to be measured at least at 10 points.
3 For roundness (or cylindricity) inspection, if the measurement is non-continuous, at least 15 points (cylindricity in each measuring plane) shall be inspected: 577
9.7 Information to be recorded
JB/T 8771. 7-1998
When inspecting according to 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 size of the tool;
c) Cutting speed;
d) Feed rate;
e) Depth of cut;
f) Choice between 3° and tan-10.05 for the bevel. 10 End milling test piece
10.1 Overview
The purpose of this test is to inspect the flatness of the surface milled by end milling, with the overlap of the two passes being approximately 20% of the milling cutter diameter. Normally the test is performed by longitudinal movement along the X-axis and transverse movement along the Y-axis, but it may be performed by other methods as agreed between the manufacturer and the user.
10.2 Specimen dimensions and cutting parameters
The selection of the two specimen dimensions and the relevant tools shall be in accordance with the manufacturer's specifications or with the user's agreement. In Table 4, the face width of the specimen is 1.6 times the tool diameter, and the cutting face width is completed with two passes of 80% of the tool diameter. In order to make the cutting width in the two passes approximately the same, the tool should extend 20% of the tool diameter from the specimen surface in the first pass, and the tool should extend about 1 mm from the other side in the second pass (see Figure 3). The specimen length should be 1.25 to 1.6 times the width. Table 4 Cutting parameters
Test piece surface width W
Test piece surface length L
100~130
200~250
Cutting width
Figure 3 End milling test mode
Tool diameter
20%Tool diameter
1st pass
2nd pass
Number of tool teeth
The material of the test piece is not specified. When cast iron is used, the cutting parameters in Table 4 can be referred to. When the feed speed is 300mm/min, the feed per tooth is approximately 0.12mm, and the cutting depth should not exceed 0.5mm. If possible, the axis perpendicular to the machined surface (usually axis B) should be locked during cutting.
10.3 Tool
Use an indexable sleeve face milling cutter (see GB5342). The tool installation should meet the following tolerances: a) radial runout ≤ 0.02mm;
b) end runout ≤ 0.03mm.
4 Roughing and pre-machining
JB/T 8771.7—1998
The roughing base should have sufficient rigidity and be suitable for clamping to the workbench or the pallet and fixture. In order to make the cutting depth as constant as possible, pre-machining should be carried out before finishing.
10.5 Flatness tolerance of finished surface
The flatness tolerance of the machined surface of small-sized test pieces should not exceed 0.02mm; the flatness tolerance of large-sized test pieces should not exceed 0.03mm. The straightness test perpendicular to the milling direction reflects the influence of the overlap of two passes, and the straightness test parallel to the milling direction reflects the influence of the tool coming out and entering the tool.
10.6 Recorded information
In accordance with the requirements of this standard, the following information should be recorded in the inspection report as completely as possible: 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.6 Inspection and tolerance
The inspection and tolerance of the test pieces finished 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 center axis of the hole and the base surface A
Square
c) Straightness of the side surface
d) Perpendicularity between the adjacent surface and the base surface B
e) Opposite surface to the base surface B Parallelism
f) Straightness of the side surface
g) Inclination of the side surface to the base surface B
h) Roundness
i) Concentricity of the outer circle and the inner circle hole C
j) Straightness of the surface
k) Inclination of the 3° angle bevel to the B surface
n) Position of the hole relative to the inner hole C
s) Concentricity of the inner hole and the outer hole D
If conditions permit, the test piece can be placed on a coordinate measuring machine for measurement, 1
Inspection tools
a) Coordinate measuring machine
b) Coordinate measuring machine
c) Coordinate measuring machine or flat ruler and indicator||tt ||d) Coordinate measuring machine or angle square and indicator
e) Coordinate measuring machine or height gauge block and indicatorf) Coordinate measuring machine or straightedge and indicator
) Coordinate measuring machine or sine rule and indicatorh) Coordinate measuring machine or indicator or roundness measuring instrumenti) Coordinate measuring machine or indicator or roundness measuring instrumenti) Coordinate measuring machine or straightedge and indicator
k) Coordinate measuring machine or sine rule and indicatorn) Coordinate measuring machine
s) Coordinate measuring machine or roundness measuring instrument
2For straight edges (squares, rhombuses and inclined planes), in order to obtain the deviations from straightness, perpendicularity and parallelism, the probe touches the surface to be measured at least at 10 points.
3 For roundness (or cylindricity) inspection, if the measurement is non-continuous, at least 15 points (cylindricity in each measuring plane) shall be inspected: 577
9.7 Information to be recorded
JB/T 8771. 7-1998
When inspecting according to 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 size of the tool;
c) Cutting speed;
d) Feed rate;
e) Depth of cut;
f) Choice between 3° and tan-10.05 for the bevel. 10 End milling test piece
10.1 Overview
The purpose of this test is to inspect the flatness of the surface milled by end milling, with the overlap of the two passes being approximately 20% of the milling cutter diameter. Normally the test is performed by longitudinal movement along the X-axis and transverse movement along the Y-axis, but it may be performed by other methods as agreed between the manufacturer and the user.
10.2 Specimen dimensions and cutting parameters
The selection of the two specimen dimensions and the relevant tools shall be in accordance with the manufacturer's specifications or with the user's agreement. In Table 4, the face width of the specimen is 1.6 times the tool diameter, and the cutting face width is completed with two passes of 80% of the tool diameter. In order to make the cutting width in the two passes approximately the same, the tool should extend 20% of the tool diameter from the specimen surface in the first pass, and the tool should extend about 1 mm from the other side in the second pass (see Figure 3). The specimen length should be 1.25 to 1.6 times the width. Table 4 Cutting parameters
Test piece surface width W
Test piece surface length L
100~130
200~250
Cutting width
Figure 3 End milling test mode bzxz.net
Tool diameter
20%Tool diameter
1st pass
2nd pass
Number of tool teeth
The material of the test piece is not specified. When cast iron is used, the cutting parameters in Table 4 can be referred to. When the feed speed is 300mm/min, the feed per tooth is approximately 0.12mm, and the cutting depth should not exceed 0.5mm. If possible, the axis perpendicular to the machined surface (usually axis B) should be locked during cutting.
10.3 Use an indexable sleeve face milling cutter (see GB5342). The tool installation should meet the following tolerances: a) radial runout ≤ 0.02mm;
b) end runout ≤ 0.03mm.
4 Roughing and pre-machining
JB/T 8771.7—1998
The roughing base should have sufficient rigidity and be suitable for clamping to the workbench or the pallet and fixture. In order to make the cutting depth as constant as possible, pre-machining should be carried out before fine cutting.
10.5 Flatness tolerance of fine-machined surface
The flatness tolerance of the machined surface of small-sized test pieces should not exceed 0.02mm; the flatness tolerance of large-sized test pieces should not exceed 0.03mm. The straightness test perpendicular to the milling direction reflects the influence of the overlap of the two passes, and the straightness test parallel to the milling direction reflects the influence of the tool coming out and entering the tool.
10.6 Recorded information
In accordance with the requirements of this standard, the following information should be recorded in the inspection report as completely as possible: 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.03mm.
4 Roughing and pre-machining
JB/T 8771.7—1998
The roughing base should have sufficient rigidity and be suitable for clamping to the workbench or the pallet and fixture. In order to make the cutting depth as constant as possible, pre-machining should be carried out before finishing.
10.5 Flatness tolerance of finished surface
The flatness tolerance of the machined surface of small-sized test pieces should not exceed 0.02mm; the flatness tolerance of large-sized test pieces should not exceed 0.03mm. The straightness test perpendicular to the milling direction reflects the influence of the overlap of the two passes, and the straightness test parallel to the milling direction reflects the influence of the tool coming out and entering the tool.
10.6 Recorded information
In accordance with the requirements of this standard, the following information should be recorded in the inspection report as completely as possible: 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.03mm.
4 Roughing and pre-machining
JB/T 8771.7—1998
The roughing base should have sufficient rigidity and be suitable for clamping to the workbench or the pallet and fixture. In order to make the cutting depth as constant as possible, pre-machining should be carried out before finishing.
10.5 Flatness tolerance of finished surface
The flatness tolerance of the machined surface of small-sized test pieces should not exceed 0.02mm; the flatness tolerance of large-sized test pieces should not exceed 0.03mm. The straightness test perpendicular to the milling direction reflects the influence of the overlap of the two passes, and the straightness test parallel to the milling direction reflects the influence of the tool coming out and entering the tool.
10.6 Recorded information
In accordance with the requirements of this standard, the following information should be recorded in the inspection report as completely as possible: 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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