JB/T 8773-1998 Technical requirements for precision machining centers
Some standard content:
JB/T8773-1998
This standard specifies and supplements GB9061--88 "General Technical Conditions for Metal Cutting Machine Tools", ZBnJ50008.1--88 "General Technical Conditions for Mechanical Processing Parts of Metal Cutting Machine Tools", ZBmJ50008.3--88 "General Technical Conditions for Assembly of Metal Cutting Machine Tools" and other standards according to the structural characteristics and use requirements of the machining center. This standard is proposed and managed by the National Technical Committee for Metal Cutting Machine Tools Standardization. The drafting units of this standard are: Beijing Machine Tool Research Institute, Kunming Precision Machine Tool Research Institute, and Ningjiang Machine Tool Factory. The main drafters of this standard: Qian Wenming, Hong Ning, Wang Guikang, Liu Yan, Tang Qishou, 673
1 Scope
Standard of the Machinery Industry of the People's Republic of China
Technical Conditions
Precision Machining Centres
Precision machining centres
-Specifications
This standard specifies the requirements for the manufacture and acceptance of precision machining centres. This standard applies to precision vertical and horizontal machining centres with linear axis travel up to 2000mm. 2 Referenced Standards
JB/T 8773-1998
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 the parties using this standard should explore the possibility of using the latest versions of the following standards. GB9061-88 General technical requirements for metal cutting machine tools GB9239-88 Determination of allowable imbalance for balancing quality of rigid rotors GB11357-89 Pulley material, surface roughness and balance GB/T16769-1997 Method for measuring sound pressure level of noise from metal cutting machine tools JB5563-91 Inspection and evaluation of cone surface coloring method for metal cutting machine tools JB/T8772.1-1998 Inspection conditions for precision machining centers Part 1: Inspection of geometric accuracy of horizontal and attached spindle heads (horizontal Z axis)
Precision machining centers
Inspection conditions Part 2: Inspection of geometric accuracy of vertical machining centers JB/T 8772.2-1998#
JB/T 8772.4—1998#
Precision machining center
Testing conditions Part 4: Positioning accuracy and repeatability test of linear and rotary axes
JB/T 8772.5—1998
Testing conditions Part 5: Positioning accuracy and repeatability test of workpiece holding palletPrecision machining center
Precision test
JB/T 8772.7—1998#
Precision machining center
Testing conditions Part 7: Precision test of finished test piecesZB J50 003—88
Metal cutting machine tools
Determination of cleanliness
ZB J50 006-—88
Metal cutting machine tools
Compilation of random technical documents
ZBnJ50008.1-88 General technical conditions for machined parts of metal cutting machine tools ZBnJ50008.2-88 General technical conditions for welded parts of metal cutting machine tools ZBnJ50008.3--88 General technical conditions for assembly of metal cutting machine tools ISO230-2:1997 General rules for machine tool inspection Part 2: General requirements for determination of positioning accuracy and repeat positioning accuracy of coordinate axes of CNC machine tools
When accepting machine tools according to this standard, the remaining acceptance items in GB9061, ZBnJ50008.1, ZBnJ50008.3 and other standards that are not specified in this standard must be inspected at the same time. 4 Accessories and tools
4.1 The accessories and tools listed in Table 1 should be supplied randomly. Approved by the State Bureau of Machinery Industry on July 17, 1998 674
Implemented on December 1, 1998
JB/T 8773—1998
4.2 Special accessories that expand the performance of machine tools are supplied according to user requirements and agreements. Table 1
Adjustment pads
Special adjustment tools
5 Machining and assembly quality
Installing machine tools
Adjusting machine tools
5.1 The bed, column, worktable, spindle box, slide seat, and slide saddle are important castings and must be aged after rough machining. If necessary, perform aging again after semi-finishing. 5.2 Each feed motion guide pair should adopt wear-resistant cast iron, steel-inlaid guide rails, injection molded or plastic-coated guide rails, and wear-resistant measures such as induction fire. 5.3 Welded parts should comply with the provisions of ZBnJ50008.2. Important welds should be inspected by flaw detection and no cracks should be found. 5.4 Steel guide rails should be inspected by flaw detection and no cracks should be found. 5.5 The following joint surfaces should be assessed according to the requirements of "important fixed joint surfaces": a) Fixed joint surface of sliding guide rail pressure plate; b) Fixed joint surface of column and bed;
c) Fixed joint surface of front and rear bed;
d) Fixed joint surface of column and column slide; e) Fixed joint surface of spindle box and spindle box slide. 5.6 The following joint surfaces shall be assessed according to the requirements of "particularly important fixed joint surfaces": a) fixed joint surface of ball screw bracket; b) fixed joint surface of nut seat;
c) fixed joint surface of end gear plate;
d) base surface of steel guide rail
e) base surface for installing linear rail,
5.7 The following guide pairs shall be assessed according to the requirements of "sliding (rolling) guide rail": each linear motion guide pair.
5.8 Important fixed joint surfaces and particularly important fixed joint surfaces shall fit tightly. After tightening, important fixed joint surfaces shall be inspected with a 0.03mm feeler gauge and no insertion shall be made. In addition to the color coating inspection according to the IV grade accuracy of ZBnJ50008.3, particularly important fixed joint surfaces shall be inspected with a 0.03mm feeler gauge and no insertion shall be made before and after tightening (joint surfaces perpendicular or inclined to the horizontal plane shall only be inspected after tightening). In addition to the coloring inspection of the sliding guide surface according to the IV grade accuracy of ZBnJ50008.3, the sliding surface of the matching guide rail, inlay strip and pressure plate end shall be inspected with a 0.04mm feeler gauge, and the insertion depth shall not exceed the provisions of Table 2. Table 2
Machine weight
Feeler gauge insertion depth
5.9 The joints of the spliced inlay steel guide rails and bed guide rails have a gap of 0.02~0.04mm, and the misalignment of the guide surfaces of the adjacent joints shall not exceed the provisions of Table 3.
Machine weight
Misalignment of the guide surfaces of the guide rails
5.10 The ball screw pairs and CNC rotary tables of each motion coordinate axis shall be operated multiple times after assembly. The reverse clearance shall be greater than the recommended value in Table 675
4.
Reverse clearance of linear coordinates
JB/T 8773-1998
Reverse clearance of rotary coordinates
5.11 Disc springs used in broaching mechanisms and other major mechanisms shall be subjected to pressure tests according to the drawings or technical documents after assembly. 5.12 After assembly, important pressure cylinders shall be subjected to a pressure holding test of 1.5 times the system pressure for no less than 0.5h, and there shall be no leakage. 5.13 After assembly, high-speed rotating spindle assemblies shall be subjected to dynamic balancing tests, with a balancing quality grade of G6.3, and the determination of the allowable residual imbalance shall be in accordance with GB9239. The balancing of pulleys shall be in accordance with GB11357. 5.14 The contact length of important locating pins such as the spindle box, ball screw support seat and nut seat shall not be less than 70% of the working length of the taper pin, and the contact shall be evenly hooked.
5.15 After the machine tool spindle is assembled, its taper hole should be inspected by the coloring method using a gauge according to JB5563. The contact of the taper hole should be close to the maximum, and the ratio of the actual contact length to the working length should not be less than 80%. 5.16 According to ZBJ50003, the cleanliness of the machine tool after assembly shall be checked randomly, and the internal cleanliness of the spindle box and hydraulic box shall be inspected by weight. The weight of dirt per unit volume: the spindle box should not exceed 400mg/L; the hydraulic box should not exceed 150mg/L. Other parts shall be inspected by visual inspection and hand feel, and there should be no obvious dirt. 6 Machine tool idling test
6.1 Temperature rise test and main motion and feed motion inspection 6.1.1 The continuously variable speed spindle shall be tested at no less than 12 speed levels, and the stepped speed spindle shall be tested at each speed level from the lowest to the highest. At the same time, the actual deviation of each speed level (the highest and lowest speeds of the continuously variable speed) shall be sampled and checked, which shall not exceed 10% to 10% of the nominal value. The running time of each speed level shall not be less than 2 minutes, and the running time of the highest speed shall not be less than 1 hour. The spindle bearings shall reach a stable temperature, and their temperature and temperature rise shall be checked near the bearings. The temperature shall not exceed 60°C, and the temperature rise shall not exceed 30°C. The hydraulic system shall be operated continuously at the rated working pressure until the oil reaches thermal equilibrium, and then the temperature and temperature rise of the oil shall be checked. The temperature shall not exceed 58°C, and the temperature rise shall not exceed 28°C. 6.1.2. For the moving parts on the linear and rotary coordinates of the machine tool, the idling test is carried out at low, medium and high feed speeds and rapid movement respectively. At the same time, the actual deviation of each level of feed speed is sampled, which should not exceed 2% to 6% of the nominal value. When the moving parts are at high feed speed and rapid movement, the test is only carried out on 2/3 of the full stroke except for the two ends of the stroke. During the test, the moving parts should move smoothly and flexibly, without obvious creeping and vibration, and the limit should be reliable. 6.2 There should be no abnormal screaming and impact sound when the machine tool is running. At the highest speed of the main cutting movement of the machine tool (other feed movements are in a stopped state), the sound pressure level of the idling noise of the machine tool should not exceed 81dB (A). The noise of the machine tool under load operation shall be in accordance with the regulations of the manufacturer. The measurement method of machine tool noise shall be in accordance with GB/T16769. 6.3 The idling power of the main transmission system shall be assessed (spot check) according to the design regulations. 6.4 Functional test of machine tools
6.4.1 Manual functional test
The manual functional test is a test performed by manually operating various parts of the machine tool (including buttons). 6.4.1.1 The spindle shall be tested for locking, loosening and blowing the tool for no less than 5 times in a row. The action shall be flexible, reliable and accurate. 6.4.1.2 When the spindle is at medium speed, the forward and reverse start, stop (including braking) and orientation operation tests shall be performed 10 times in a row. The action shall be flexible and reliable.
6.4.1.3 For the continuously variable speed spindle, at least low, medium and high speeds shall be included. For the stepless speed spindle, the speed change operation test shall be performed at each speed. The action shall be flexible and reliable.
JB/T8773—1998
6.4.1.4 For the moving parts on each coordinate (linear coordinate and rotary coordinate), the positive and negative start and stop operation tests are carried out 10 times continuously at the medium feed speed, and the positive and negative operation tests are selected with the appropriate incremental feed. The action should be flexible, reliable and accurate. 6.4.1.5 For the feed system, 10 speed change operation tests including low, medium, high feed speed and fast speed are carried out. The action should be flexible and reliable.
6.4.1.6 For the indexing rotary table or CNC rotary table, the indexing and positioning tests are carried out 10 times continuously. The action should be flexible, reliable and accurate.
6.4.1.7 For the pallet exchange test, the action should be flexible and reliable for 5 times continuously. 6.4.1.8 For the tool magazine and manipulator, the tool change test is carried out in an optional way. The tool configuration on the tool magazine should include tools with the maximum weight, maximum length and maximum diameter specified in the design. The tool change action should be flexible, reliable and accurate. The load-bearing weight and tool change time of the manipulator should meet the design requirements.
6.4.1.9 Carry out idling test on various indicator lights, control buttons, paper tape readers and fans of the machine tool digital control. The action should be flexible and reliable.
6.4.1.10 Carry out sealing, lubrication and cooling performance test on hydraulic, pneumatic, lubrication and cooling systems. The function should be reliable, the action should be flexible and accurate, and there should be no seepage (leakage) in each system. 6.4.1.11 Test the safety, insurance, protection devices of the machine tool and the control, interlocking and protection functions of the electrical system. The function should be reliable, the action should be flexible and accurate.
6.4.1.12 Test the various auxiliary devices of the machine tool. The work should be flexible and reliable. 6.4.2 Automatic function test (can be combined with the continuous idle running test in Chapter 7) The automatic function test is a test performed by operating various parts of the machine tool using a CNC program. 6.4.2.1 When the spindle is at medium speed, the positive and reverse start, stop (including braking) and orientation operation tests are carried out continuously for 10 times. The action should be flexible and reliable.
6.4.2.2 For the spindle with continuously variable speed, at least low, medium and high speeds should be included; for the spindle with stepped speed, the speed change operation test should be carried out at each speed. The action should be flexible and reliable. 6.4.2.3 For the moving parts on each coordinate (linear coordinate and rotary coordinate), the positive and negative start, stop and incremental feed mode operation tests are carried out continuously at medium feed speed. The action should be flexible, reliable and accurate. 6.4.2.4 For the feed system, at least low, medium and high feed speeds and rapid speed change operation tests are carried out. The action should be flexible and reliable. 6.4.2.5 The indexing and positioning operation tests shall be conducted for 10 times continuously on the indexing rotary table or CNC rotary table. The action shall be flexible, and the operation shall be stable, reliable and accurate.
6.4.2.6 The exchange test of the pallet shall be conducted for 5 times. The action shall be flexible and reliable. 6.4.2.7 For each tool in the total capacity of the tool magazine, including the tool with the largest weight, the automatic tool change action test shall be conducted in any optional way for no less than 2 times. The action shall be flexible and reliable. 6.4.2.8 The coordinate linkage, coordinate selection, mechanical locking, positioning, linear and circular interpolation, pitch, clearance, tool compensation, program pause, emergency stop and other instructions, tool clamping, release and other CNC functions of the machine tool shall be tested one by one. The functions shall be reliable, and the action shall be flexible and accurate. 6.4.2.9 The moving parts with clamping mechanism shall be clamped at any working position (generally 3 to 5 positions) within their entire range of motion. They shall be reliable and stable. 7 Continuous idle operation test of machine tools
Use a CNC program including the main processing functions of the machine tool to simulate the working state and perform continuous idle operation without cutting. The continuous idle operation time of the whole machine is 48 hours. Each cycle time shall not exceed 15 minutes, and the rest time between each cycle shall not exceed 1 minute. During the entire process of continuous idle operation, the machine tool should operate normally, smoothly and reliably, and no failure should occur, otherwise it must be operated again. The continuous idle operation program should include the following contents: a) The spindle includes low, medium and high speed forward and reverse operation and positioning, among which the high-speed operation time is generally not less than 10% of the time used for each cycle program;
JB/T 8773-—1998Www.bzxZ.net
b) The moving parts on each coordinate should include low, medium and high feed speeds and fast positive and negative operation. The operation should be within a range close to the full stroke, and any point can be selected for positioning. The use of the override switch is not allowed during operation. High feed speed and fast running time are generally not less than 10% of the time used for each cycle program;
c) The tools on each tool position in the tool magazine are automatically exchanged at least twice, d) Automatic indexing and positioning of the indexing rotary table or CNC rotary table; e) The linkage of each linkage coordinate:
f) Each pallet is automatically exchanged at least 5 times. 8 Machine tool load test
The machine tool should be subjected to the following tests:
a) Operation test with the maximum weight of the workpiece (spot check); b) Test of the maximum torque of the main transmission system; c) Test of the maximum cutting resistance (spot check); d) Test of the main transmission system reaching the maximum power (spot check). 8.1 Operation test with the maximum weight of the workpiece can be placed on the workbench with a weight equivalent to the maximum weight of the workpiece specified in the design, so that the load is even, and it is operated at the lowest and highest feed speeds and fast speeds respectively. When operating at the lowest feed speed, it should generally be reciprocated near the two ends and the middle of the stroke, and the moving distance at each place should be not less than 20mm. At the highest feed speed and rapid operation, the test should be conducted on 2/3 of the full stroke except the two ends of the stroke, reciprocating 1 time and 5 times respectively.
It should be stable and reliable during operation; there should be no obvious creeping phenomenon during low-speed operation. 8.2 Test of the maximum torque of the main transmission system
In the speed regulation range of the spindle constant torque, select an appropriate spindle speed and conduct the test by milling or boring. Adjust the cutting amount so that the main transmission system reaches the maximum torque specified in the design. When conducting the cutting test of the maximum torque of the main transmission system, the machine tool should work normally and smoothly, the movement should be accurate, and the transmission elements, components and speed change mechanisms should be normal and reliable.
The cutting tool used for the test is an end mill or a carbide boring tool. The test piece is a cast iron piece.
8.3 Test of the maximum cutting resistance
In the calculated speed range of the machine tool, select an appropriate spindle speed and conduct the test by milling or boring. Adjust the cutting amount so that the machine tool reaches the maximum pre-cutting resistance specified in the design. During the maximum cutting resistance test, the machine tool should work normally, all motion mechanisms should be flexible and reliable, and the overload safety device should be normal and reliable. The cutting tool used in the test is an end mill, a carbide milling cutter, or a high-speed steel drill. The test piece is a cast iron piece.
8.4 Test of the main transmission system reaching maximum power Within the speed regulation range of the spindle constant power, select an appropriate spindle speed and use the milling method to conduct the test. Adjust the cutting amount so that the machine tool reaches the rated power of the main motor or the maximum power specified in the design. During the cutting test of the main transmission system reaching maximum power, the machine tool should work normally without obvious vibration, and record the metal removal rate, cm'/min.
The cutting tool used in the test is a carbide end mill. The test piece is a steel piece or a cast iron piece.
9 Small setting unit test
9.1 Linear coordinate minimum setting unit test
9.1.1 Test method
JB/T 8773—1998
First, quickly move the moving parts on the linear coordinates to a certain distance in the positive (or negative) direction. After stopping, give several instructions of the minimum setting unit in the same direction, and then stop. Use this position as the reference position, give one instruction each time, and give a total of 20 instructions of the minimum setting unit, move in the same direction, and measure the stop position of each instruction. From the above-mentioned final position, continue to give several instructions of the minimum setting unit in the same direction. After stopping, give several instructions of the minimum setting unit in the negative (or positive) direction, and return to the above-mentioned final measurement position. The stop positions of these instructions of the minimum setting unit in the positive and negative directions are not measured. Then, starting from the above-mentioned final position, give one instruction each time, and give a total of 20 instructions of the minimum setting unit, continue to move in the negative (or positive) direction, and measure the stop position of each instruction, see Figure 1. Each linear coordinate must be tested at least at the middle and two ends of the stroke. Calculate the error according to the provisions of 9.1.2, and take the maximum error value at the three positions as the error of this item. For machine tools equipped with pitch error and clearance compensation devices, the test should be carried out with these devices in use. Actual moving distance
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Stop position of several minimum setting unit instructions
No measurement
Measurement range
9.1.2 Error calculation method
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Minimum setting unit
9.1.2.1 Minimum setting unit error S. Calculate according to formula (1): S. =IL,-mlm
Where: L1 Actual displacement of the minimum setting unit instruction, mm; Note: If the direction of the actual displacement is opposite to the given direction, the displacement should be negative. m
Theoretical displacement of 1 minimum setting unit instruction, mm. 9.1.2.2 The relative error S of the minimum setting unit is calculated according to formula (2): 20m
Wherein: L
9.1.3 Tolerance
X 100%
-The sum of the actual displacements of 20 minimum setting unit instructions, mm. Note: 1) Pay attention to the actual moving direction.
(2)
It shall be specified by the manufacturer according to the specific conditions of the machine tool. 9.1.4 Inspection tools
JB/T 8773—1998
Laser interferometer or reading microscope and metal wire scale. 9.2 Test of minimum setting unit of rotary coordinates
9.2.1 Test method
First, quickly rotate the moving parts on the rotary coordinates in the positive (or negative) direction for a certain angle, and after stopping, give several instructions of minimum setting units in the same direction, and then stop again. Use this position as the reference position, give one instruction at a time, and give a total of 20 instructions of minimum setting units, and "rotate in the same direction", and measure the stop position of each instruction. From the above-mentioned final position, continue to give several instructions of minimum setting units in the same direction, and after stopping, give several instructions of minimum setting units in the negative (or positive) direction, and return to the above-mentioned final measurement position. The stop positions of these several instructions of minimum setting units in the positive and negative directions are not measured. Then, starting from the above-mentioned final position, give one instruction at a time, and give a total of 20 instructions of minimum setting units, and continue to rotate in the negative (or positive) direction. (or positive) rotation, measure the stop position of each instruction, see Figure 2. The stop position of several minimum setting unit instructions
is not measured
Measurement range
2588080588898
Actual rotation angle
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Minimum setting unit
Each rotation coordinate needs to be tested at any 3 positions in the rotation range. Calculate the error according to the provisions of 9.2.2, and take the maximum error value at the 3 positions as the error of this item. Machine tools equipped with pitch error and clearance compensation devices should be tested with these devices. 9.2.2 Error calculation method
9.2.2.1 Minimum setting unit error w. Calculate according to formula (3): wa =1 0,—mo Imax
Where: 6,-
Actual angular displacement of 1 minimum setting unit instruction, (\); Note: If the direction of the actual angular displacement is opposite to the given direction, the angular displacement should be negative. mo
Theoretical angular displacement of 1 minimum setting unit instruction, (\). 9.2.2.2 The relative error w of the minimum setting unit is calculated according to formula (4): Note: 1) Pay attention to the actual direction of rotation. 680
Where:
9.2.3 Tolerance
JB/T 8773—1998
-The sum of the actual angular displacements of 20 minimum setting unit instructions, (\). According to the specific conditions of the machine tool, it shall be specified by the manufacturer. 9.2.4 Inspection tools
Autocollimator and polyhedron.
10 Origin return test
10.1 Linear coordinate origin return test
10.1.1 Test method
The moving parts on each true line coordinate are tested to return to the origin P. five times quickly from any point on the stroke in the same moving direction. The deviation X (i=1, 2,, 5) between the actual position P and the theoretical position P. of the origin is measured each time, see Figure 3. P
Each linear coordinate is tested at least at any three positions in the middle of the stroke and near the two ends, and the error is calculated according to the provisions of 10.1.2, and the maximum error value at the three positions is taken as the error of this item. This test is only carried out on machine tools equipped with the function of automatic return to the origin. Machine tools equipped with pitch error and clearance compensation devices should be tested with these devices in use. 10.1.2 Error calculation method
The maximum value of four times the standard deviation in the origin return test in each linear coordinate is the origin return error. Calculate according to formula (5): R. 4S.
Where: R. -Origin return error, mm
S. Standard deviation during origin return, mm. Note: S. Calculate according to the relevant formula of ISO230-2. 10.1.3 Tolerance
It shall be specified by the manufacturer according to the specific conditions of the machine tool. 10.1.4 Inspection tools
Laser interferometer or reading microscope and metal wire scale. 10.2 Rotational coordinate origin return test
10.2.1 Test method
The moving parts on each rotational coordinate are tested to return to the origin Poe five times quickly from any point on the stroke in the same direction of rotation. The deviation Q (i-1, 2,, 5) between the actual position P and the theoretical position Poe of the origin is measured each time, see Figure 4. Poe
Each rotational coordinate needs to be tested at least at any three positions within the rotation range. The error is calculated according to the provisions of 10.2.2, and the maximum error value at the three positions is taken as the error of this item. This test is only carried out on machine tools with automatic return to the origin function. Machine tools with pitch error and clearance compensation devices should be tested with these devices in use. 10.2.2 Error calculation method
The maximum value of 4 times the standard deviation during the origin return test in each rotation coordinate is the origin return error. Calculate according to formula (6): Ron = 4Soo
Where: Roo—origin return error, (\); Soe—standard deviation during origin return, (\). Note: See is calculated according to the relevant formula of ISO230-2. 10.2.3 Tolerance
is specified by the manufacturer according to the specific conditions of the machine tool. 10.2.4 Inspection tools
Autocollimator and polyhedron.
11 Machine tool accuracy inspection
·(6)
11.1 The inspection of machine tool geometric accuracy shall be in accordance with JB/T8772.1 and JB/T8772.2; the inspection of linear and rotary axis positioning accuracy shall be in accordance with JB/T8772.4; the inspection of pallet positioning accuracy shall be in accordance with JB/T8772.5; the inspection of test piece accuracy shall be in accordance with JB/T8772.7. 11.2 The inspection of G10 and G14 items in JB/T8772.1 and JB/T8772.2 shall be carried out when the machine tool spindle reaches the medium speed stable temperature.
11.3 When inspecting the working accuracy of the machine tool, the surface roughness of the milling plane and boring hole of the test piece: the maximum allowable value of the surface roughness Ra of the milling plane is 3.2μm; the maximum allowable value of the surface roughness Ra of the boring hole is 1.6um. 12 Random Technical Documents
12.1 The preparation of random technical documents of machine tools shall comply with the provisions of ZBJ50006. Two copies of the instruction manual shall be provided with the machine tool. 12.2 The machine tool qualification certificate shall be accompanied by the relevant data of the positioning accuracy inspection of the machine tool, and relevant charts shall also be attached when the user requires.2 The machine tool qualification certificate should be accompanied by relevant data on the machine tool positioning accuracy inspection, and relevant charts should also be attached when the user requires.
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