Some standard content:
Mechanical Industry Standard of the People's Republic of China
CNC Bed Milling Machine
1 Subject Content and Scope of Application
Technical Conditions
This standard specifies the requirements for the manufacture and acceptance of CNC bed milling machines. JB/T8329--96
Replaces ZBnJ5400888
This standard applies to general-purpose vertical and horizontal CNC bed milling machines of ordinary accuracy and precision grades and with a worktable width of 320~～1250mm.
2 Reference standards
GB5226
Machine tool electrical equipment
General technical conditions
GB9061
GB 10931
Metal cutting machine tools
General technical conditions
Evaluation method of position accuracy of digitally controlled machine toolsJB4139wwW.bzxz.Net
Technical conditions for safety protection of metal cutting machine tools and machine tool accessoriesZB J50 003
Determination of cleanliness of metal cutting machine tools
ZBJ50 004
Determination of sound pressure level of noise of metal cutting machine toolsZBn J50 008. 1
General technical conditions for machining parts of metal cutting machine toolsZBn J50008.3
General technical conditions for assembly of metal cutting machine toolsZB J50 016
General Technical Conditions for Hydraulic Systems of Metal Cutting Machine Tools ZB J54 010
3 General Requirements
CNC Bed Milling Machine
This standard specifies and supplements GB9061, ZBnJ50008.1, ZBnJ50008.3 and other standards. When accepting machine tools according to this standard, the remaining acceptance items in the above standards that are not specified in this standard must be inspected at the same time. 4 Accessories and Tools
The following accessories and tools should be supplied with the machine:
Milling Cutter Rod, 1 Set;
7, 24 Taper Shank Pull Stud, 1 Piece,
Special Adjustment Tool, 1 Set;
Machine Pad Iron, 1 Set;
Anchor Bolt, 1 Set.
The following special accessories can be supplied according to the agreement:
Special cutting tools;
Tool setting instrument;
Indexing rotary table;
CNC rotary table;
Peripheral equipment of control system.
Approved by the Ministry of Machinery Industry of the People's Republic of China on April 11, 1996 and implemented on October 1, 1996
5 Safety and Health
JB/T 8329-96
The machine tool should have an automatic broaching mechanism, which must be safe and reliable. 5.1
5.2 The main transmission system of the machine tool should have a braking device, which must be safe and reliable. 5.3 The sliding guide surfaces of the machine tool bed, column, workbench, etc. should have protective devices. 5.4 The speed change, reversing, stopping and locking mechanisms of the machine tool must be safe and reliable. 5.5 The moving parts on the linear motion axis should have limit and collision prevention safety devices. 5.6 Parts that are not allowed to move simultaneously shall not be linked. 5.7 The noise of the machine tool shall be tested in accordance with the provisions of ZBJ50004. The measurement shall be carried out under the condition of no-load operation. The sound pressure level of the whole machine noise shall not exceed the following provisions:
83dB(A) for ordinary precision machine tools; 80dB(A) for precision machine tools. 5.8 When accepting the machine tool according to this standard, the remaining acceptance items in JB4139 that are not specified in this standard and the acceptance items specified in GB5226 and ZBJ50016 and other standards must be inspected at the same time. 6 Processing and assembly quality
6.1 The following castings are important castings. After rough processing, they should be aged or other measures should be taken to eliminate internal stress. If necessary, they should be aged again after semi-finishing: a.
Bed;
Workbench;
Column;
Spindle box;
Saddle;
Slide seat of column or spindle box;
Slide ram.
6.2 For the easily worn parts of the machine tool's spindle, spindle sleeve, screw pair and high-speed, heavy-loaded gears, etc., wear-resistant measures suitable for their service life should be taken.
The following guide rails are important guide rails, and wear-resistant measures such as wear-resistant cast iron, steel inlay, plastic coating or high (medium) frequency induction quenching should be adopted: 6.3
Workbench and saddle guide rails;
Saddle and bed guide rails;
Column (or column slide) and bed guide rails; Ram and vertical slide guide rails;
Vertical slide and column guide rails;
Workbench and bed guide rails;
Spindle box (or spindle box slide) and column guide rails. The fixed joint surface of the sliding guide plate should be assessed according to the requirements of "important fixed joint surface". 6.4
The following joint surfaces shall be assessed according to the requirements of “particularly important fixed joint surfaces”: a.
Fixed joint surface of the screw bracket;
Fixed joint surface of the nut seat;
Fixed joint surface of the column and the bed;
Fixed joint surface of the front and rear beds;
Fixed joint surface of the column and the column slide; Fixed joint surface of the spindle box and the spindle box slide. The following guide pairs shall be assessed according to the requirements of “sliding (rolling) guides\”: 6.6
Bed guide pair;
b. Column guide pair:
c. Worktable guide pair;
Slider guide pair.
JB/T 8329—96
6.7 The rotary guide pair of the milling head shall be assessed in accordance with the requirements of the “displacement guide”. 6.8 The high-speed rotating spindle assembly shall be subjected to a dynamic balance test. 6.9 The plastic-laminated and coated guide rails shall fit tightly to the substrate, and the bonding shall be firm and reliable. There shall be no gaps or bubbles. The contact with the matching guide rails shall be uniform and shall comply with relevant regulations.
6.10 The inlaid steel guide rails shall be subjected to nondestructive testing after quenching and shall not have cracks. 6.11 The cleanliness of the machine tool shall be inspected in accordance with the provisions of ZBJ50003. The spindle box and other components shall be inspected by weight (spot check), and the impurities and dirt shall not exceed the provisions of Table 1.
Machine tool accuracy grade||tt ||Spindle box, feed box
Ordinary precision grade
Precision grade
Inspection parts
Lubrication system
6.12 The following important positioning pins shall be inspected by color coating method, and their contact length shall not be less than 60% of the working length: a. Positioning pins of column and bed;
b. Positioning pins of front and rear bed.
Hydraulic transmission system
6.13 The disc springs used in the broaching mechanism and other important mechanisms shall be subjected to working pressure test after assembly and shall comply with the provisions of relevant standards or design documents.
7 Machine tool idle operation test
7.1 Idle operation test of main motion mechanism Temperature and temperature rise test of operation and spindle bearings The main motion mechanism of the machine tool is tested for dry operation in sequence from the lowest to the highest speed (the stepless speed change should be no less than 10 speeds). The operation time of each level shall not be less than 2 minutes. However, the time at the highest speed shall not be less than 1 hour, so that the spindle bearings can reach a stable temperature. And measure its temperature and temperature rise near the spindle bearings, and the values shall not exceed the provisions of Table 2. When running at each speed, the operation should be smooth, and the working mechanism should be normal and reliable.
Machine tool accuracy grade
Ordinary accuracy grade
Precision grade
7.2 Dry operation test of feed motion mechanism
Use low, medium and high Feed speed and fastness: Carry out an idle operation test on the moving parts on the linear motion axis. The operation should be smooth, and the working mechanism should be normal and reliable without vibration. 7.3 Inspection of main motion and feed motion speed: Under the condition of idle operation, inspect the correctness of the spindle speed and feed speed. The actual deviation of the spindle speed of each level of stepped transmission should not exceed -2%~~+6% of the indicated value on the nameplate, and the actual deviation of the feed speed should not exceed -5%~~+3% of the indicated value on the nameplate; the actual deviation of the spindle speed and feed speed of the stepless transmission should not exceed ±10% of the indicated value on the nameplate. 7.4 Action test
7.4.1 Manual action test
JB/T 8329--96
7.4.1.1Use medium speed to conduct operation test of the main motion mechanism in positive and reverse continuous start and stop for 10 times. The action should be flexible and reliable. 7.4.1.2 At low, medium, high (stepless speed change) or various levels (stepped speed change) spindle speed, conduct speed change operation test on the main motion mechanism. The action should be flexible and reliable.
7.4.1.3Use medium feed speed to conduct operation test of positive and negative continuous start, incremental feed and stop for 10 times on the moving parts of linear and rotary coordinates. The action should be flexible, reliable and accurate. 7.4.1.4Use 10 feed speeds including low, medium and high to conduct speed change operation test on the feed motion mechanism. The action should be flexible and reliable.
7.4.1.5 Test the various indicator lights, control buttons, paper tape readers and fans of the numerical control device. They should work normally, be flexible and reliable.
7.4.1.6 Test the cooling system, hydraulic system and lubrication device of the machine tool. They should work reliably and be easy and flexible to operate and adjust. 7.4.1.7 Test the safety, protection and insurance devices of the machine tool. They should function reliably and move flexibly and accurately. 7.4.1.8 Test the broaching mechanism of the machine tool. They should move flexibly and reliably. 7.4.1.9 Test other auxiliary devices of the machine tool. They should function reliably. 7.4.2 Automatic action test (can be combined with the continuous idle operation test of the whole machine in Article 7.6). 7.4.2.1 Perform a forward and reverse continuous start and stop operation test on the main motion mechanism at medium speed. The action should be flexible and reliable. 7.4.2.2 When the main shaft speed is low, medium, high (stepless speed change) or all levels (stepped speed change), the speed change test of the main motion mechanism should be flexible and reliable.
7.4.2.3 Use medium feed speed to carry out positive and negative continuous start, incremental feed and stop operation tests on the moving parts of linear and rotary coordinates respectively. The action should be flexible and reliable. 7.4.2.4 Use feed speeds including low, medium, high and fast to carry out speed change test on the feed and fast motion mechanism. The action should be flexible and reliable.
7.4.2.5 Test the CNC functions such as machine tool coordinate linkage, positioning, linear interpolation, circular interpolation, etc. one by one. Their functions should be reliable. The action should be flexible and accurate.
7.4.2.6 For machine tools with numerically controlled rotary tables and indexing rotary tables, online operation tests and 10 indexing and positioning tests shall be conducted. The operation shall be stable and the movements shall be flexible, reliable and accurate. 7.5 Idle power test
The percentage of the idle power of the main transmission system of the machine tool (excluding the no-load power of the main motor itself) to the rated power of the main motor shall not exceed the provisions of Table 3.
Rated power of the main motor
7.6 Continuous idle test of the whole machine
Main motion speed change form
Mechanical speed change
Motor speed regulation
Mechanical speed change
Motor speed regulation
Idle power of the main transmission system/rated power of the main motor%
7.6.1 The continuous idle test shall be conducted after the tests (or inspections) specified in Articles 7.1 to 7.4 and before the accuracy inspection. 7.6.2 The continuous idle running test program shall be controlled by digital control belt or other instructions. The program shall meet the following conditions:. The spindle shall be operated in positive and reverse directions including low, medium and high speeds and speed changes, and the high speed operation time shall not be less than 10% of a cycle time;
b. The moving parts on the linear motion axis shall be tested for positive and negative movement including low, medium, high feed speeds and rapid speeds, and the moving speed shall be changed; when moving at feed speed, its stroke shall be close to the full stroke, and any point can be selected for positioning; when moving at rapid speed, its stroke shall not be less than 1/3 of the full stroke; the time of high feed speed and rapid movement shall not be less than 10% of a cycle time; c. The linkage of each linkage coordinate;
d. Various other CNC functions of the machine tool; e. Online operation of special accessories;
f. The interval time between two cycles shall not exceed 1min. Note: A cycle, that is, the whole process of idling under the above conditions. 7.6.3 The continuous idling test time of the whole machine is 16h, and at least two cycles of idling should be carried out. The operation should be stable and reliable, and no failure should occur.
8 Machine tool load test
8.1 This series of machine tools should be subjected to the following load tests: Operation test with the maximum weight of the workpiece (spot check); a.
b. Test of the maximum torque of the main transmission system; C. Test of the main transmission system reaching maximum power (spot check). 8.2 Operation test with the maximum weight of the workpiece 8.2.1 Use a heavy object equivalent to the maximum weight of the workpiece specified in the design as the workpiece, place it on the workbench, and make its load uniform. 8.2.2 Run the workbench at the lowest, highest feed speeds and fast speed respectively. When running at the lowest feed speed, it is generally carried out at the two ends and the middle of the stroke, and the moving distance of the workbench at each location should not be less than 20mm. When using the highest feed speed and fast operation, it should be carried out on the full stroke of the workbench, reciprocating once and five times respectively. The operation should be smooth and reliable. When running at a low feed speed, the workbench should not have obvious creeping phenomenon.
8.3 Test of the maximum torque of the main transmission system
8.3.1 Within the adjustment range of the constant torque of the main transmission system, select an appropriate spindle speed, use the milling method to test, and adjust the cutting amount so that the main transmission system reaches the maximum torque specified in the design. 8.3.2 The test piece material is HT200 or 45 steel: the cutting tool is an insert end milling cutter. 8.3.3 During the test, the transmission components and speed change mechanism of the machine tool transmission system should work reliably and run smoothly. 8.4 Test of the main transmission system reaching maximum power8.4.1 Within the speed adjustment range of the constant power of the main transmission system, select an appropriate spindle speed, use the milling method to test, and adjust the cutting amount so that the power of the main transmission system reaches the rated power of the main motor. 8.4.2 The test material is 45 steel; the cutting tool is an insert end mill. 8.4.3 During the test, the machine tool should have no obvious chatter, all parts should work normally, the electrical system should be reliable, and the metal removal rate should be recorded. 9 Minimum setting unit test of linear motion axis 9.1 Test method
First, the moving part on the linear motion axis is quickly moved to a certain distance in the positive (or negative) direction and then stopped. Then, several minimum setting unit instructions are given in the same direction to make the moving part stop at a certain position, and this position is used as the reference position. Then, one minimum setting unit instruction is given in the same direction at a time, totaling 20 minimum setting unit instructions, so that the moving part moves and stops continuously, and its stop position under each instruction is measured. From the above-mentioned final measurement position, continue to give several minimum setting unit instructions in the same direction to make the moving part move and stop, and then give several minimum setting unit instructions in the negative (or positive) direction to make the moving part return to the above-mentioned final measurement position. The stop position of the moving part under these positive and negative minimum setting unit instructions is not measured. Then, give one instruction in the negative (or positive) direction at a time, and give a total of 20 minimum setting units, continue to move the moving part continuously, stop, return to the reference position approximately, and measure its stop position under each instruction, see Figure 1. Note: It must be noted that sometimes the actual moving direction is not consistent with the instruction direction. Each linear motion axis must be tested at least in the middle of the stroke and at three positions near the two ends. Calculate the error in accordance with the provisions of Article 9.2, and calculate the maximum error value at the three positions. The stop position of several minimum setting unit instructions is not measured
Virtual measurement range
9.2 Error calculation method
9.2.1 Minimum setting unit error S.
JB/T 8329--96
Actual moving distance
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District Han Administrative District Administrative District
Minimum setting unit error, the maximum absolute value of the difference between the actual displacement of a minimum setting unit instruction and the theoretical value in each position test on each linear motion axis, as shown in formula (1). S. =IL, -m I max
Where. S.—
Minimum setting unit error, mm;
L;—Actual displacement value of a minimum setting unit instruction i=1 or 2, 320), mm; m
Theoretical value of a minimum setting unit instruction, mm. Note: If the direction of the actual displacement is opposite to the direction of the instruction, the displacement should be a negative value. 9.2.2 Minimum setting unit relative error Sb
(1)
The minimum setting unit relative error is calculated as the absolute value of the difference between the maximum value of the sum of the actual displacement values of 20 consecutive minimum setting unit instructions and the theoretical value of the 20 minimum setting unit instructions in each position test on each linear motion axis as a percentage of the theoretical value of the 20 minimum setting unit instructions, as shown in formula (2). -20m
Where S.—minimum setting unit relative error; 20m
The sum of the actual displacement values of 20 consecutive minimum setting unit instructions (i=1 or 2, 3.20), mm. (2)
9.3 The tolerance
shall be specified by the manufacturer's enterprise standard. It is recommended that S. should not be greater than five minimum setting units; for ordinary precision machine tools, S should not be greater than 25%, and for precision machine tools, S should not be greater than 20%. 9.4 Test tools
Laser interferometer or reading microscope and metal wire ruler. 288
Origin return test of linear motion axis
10.1 Test method
JB/T8329-96
Make the moving parts on each linear motion axis return to a certain set origin P from the same direction five times quickly. Measure the difference between the actual return position P of the moving parts each time and the theoretical position of the origin, that is, the origin return deviation X. (i=1, 2, ... 5), see Figure 2.
Each linear motion axis must be tested at least at the middle of the stroke and at three positions near both ends. Calculate the error according to the provisions of Article 10.2, and calculate the maximum error value at the three positions. X2
10.2 Error calculation method
Origin return error, calculated as six times the maximum standard deviation of the origin return deviation calculated in at least three position tests on each linear motion axis, as shown in formula (3). R. 6Somax
Where: R. —Origin return error, mm;
..+...( 3 )
S. Standard deviation of origin return deviation, mm. /2(xx.), origin return deviation Xx = P -P,, the average deviation of origin return deviation refers to GB10931, S.
10.3 Tolerance
It shall be specified by the enterprise standard of the manufacturer (it is recommended that R. shall not be greater than 1/2 of the repeat positioning accuracy). 10.4 Test tool
Laser interferometer or reading microscope and metal wire scale. 11 Machine tool accuracy inspection
11.1 Accuracy inspection shall be carried out in accordance with ZBJ54010. 289
JB/T 8329--96
11.2The following items in ZBJ54010 should be tested when the machine tool spindle runs at medium speed and reaches a stable temperature: G6 Radial runout of the spindle taper axis;
G7 Parallelism of the spindle rotation axis to the worktable surface; b.
G8 Verticality of the spindle rotation axis to the worktable surface: c.
d. G9 Parallelism of the spindle rotation axis to the lateral movement of the worktable (or column, or ram). 11.3 Items G14, G15 and G16 in ZBJ54010 can only be tested after the machine tool load test and before the working accuracy test. 11.4 The cutting specifications during the working accuracy test shall be in accordance with the provisions of the design documents. The Ra value of the surface roughness of the test piece after fine milling should not be greater than 3.2um for ordinary precision milling machines and should not be greater than 1.6μm for precision milling machines. 11.5 Use the hand feel method or indicator to check the unevenness of the moving parts on the linear motion axis at a low feed rate. There should be no obvious creeping phenomenon.
12 Random technical documents
12.1 Two copies of the machine tool instruction manual should be provided randomly. 12.2 The machine tool qualification certificate should be accompanied by a chart showing the qualified inspection of the relevant position accuracy items. Additional notes:
This standard is proposed by the National Technical Committee for Standardization of Metal Cutting Machine Tools. This standard is under the jurisdiction of the Beijing Milling Machine Research Institute. This standard was drafted by the Qinghai First Machine Tool Factory. 290
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