A numerical control machine tool bed precision adjustment method
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHENGDU AIRCRAFT INDUSTRY GROUP
- Filing Date
- 2024-01-19
- Publication Date
- 2026-06-16
Smart Images
Figure CN117961648B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of CNC machine tool technology, and more specifically to a method for adjusting the accuracy of a CNC machine tool bed. Background Technology
[0002] Machine tool accuracy can fluctuate over time due to various factors such as factory temperature changes, wear and tear on machine tool components, and ground deformation. To prevent a decrease in machining accuracy, the accuracy must be measured and adjusted periodically.
[0003] For example, invention patent CN103886191A discloses a method for compensating the straightness of a machine tool bed. This method involves detecting straightness deviations in two directions of the bed and monitoring machine tool temperature data using a temperature sensor to establish a mathematical calculation model for compensation. The deviation is then compensated through the CNC machine tool control system. This patent primarily uses the CNC system for deviation compensation and requires the prior installation of a temperature sensor. It places high demands on the sensor's installation location and temperature control, making it difficult to implement in practice. Summary of the Invention
[0004] To address the problems and shortcomings of the existing technologies, this invention proposes a method for adjusting the precision of a CNC machine tool bed. The entire precision adjustment process relies on data support, eliminating dependence on experience. It can effectively process deviation data, calculate precise mechanical adjustment amounts, and the actual operation is simple and quick, effectively improving work efficiency.
[0005] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows:
[0006] A method for adjusting the accuracy of a CNC machine tool bed includes the following steps:
[0007] Step S1. Measure the interval between the feet of the CNC machine tool bed. Divide the travel of the CNC machine tool slide saddle into multiple nodes according to this interval. Each node corresponds to a foot screw on the machine tool bed. Establish the corresponding coordinate system. The coordinates of each node can be represented as (H1, H2, H3...H...). i (i = 1, 2, 3...n)), the machine tool slide saddle is controlled to move to each node according to the preset detection trajectory;
[0008] Step S2. During the movement of the machine tool slide saddle, use any one of the following instruments: level, laser interferometer, collimator, or probe, to collect the initial horizontal accuracy data corresponding to each node, which can be represented as (F1, F2, F3...F...). i );
[0009] Step S3. Using the initial horizontal accuracy data of each node, fit the optimal straight line using the least squares method. When the slope of the fitted straight line is less than or equal to the threshold, calculate the distance from each node to the optimal straight line, and combine it with the initial horizontal accuracy data to obtain the optimal adjustment amount for each node. When the slope of the fitted straight line is greater than the threshold, rotate the straight line with the midpoint of the line as the rotation center and the angle value calculated in reverse according to the slope, so that the rotated straight line is horizontal with the ground. Calculate the distance from each node to the rotated straight line, and combine it with the initial horizontal accuracy data to obtain the optimal adjustment amount for each node.
[0010] Preferably, the method of the present invention further includes: calculating the adjustment amount of the machine tool bed corresponding to one revolution of the foot adjustment screw according to the structure and pitch of the selected foot, converting the optimal adjustment amount of each node into the number of adjustment revolutions of the foot screw corresponding to each node, and finally adjusting the foot according to the calculated value.
[0011] Preferably, the method of the present invention further includes: after the foot adjustment, collecting the horizontal accuracy data of each node again according to step S2 to verify the adjustment effect, and determining whether the horizontal accuracy of the bed has been adjusted in place. If the requirements are met, the process ends; if the requirements are not met, the adjustment begins from step S3.
[0012] Further, in step S3, the optimal straight line is fitted using the least squares method, including:
[0013]
[0014]
[0015]
[0016] Among them, H i Let be the coordinates of the i-th node. F is the average value of the coordinates of each node. i Let be the initial horizontal precision data for the i-th node. Let be the average of the initial horizontal accuracy data for each node, b be the slope of the optimal line obtained by the least squares method, and a be the intercept of the optimal line obtained by the least squares method. This is the ideal horizontal accuracy data of the bed corresponding to the i-th node, estimated using the least squares method.
[0017] Furthermore, in step S3, when the slope of the fitted optimal straight line is less than or equal to a preset threshold, the optimal adjustment amount for each node is: F i This represents the initial horizontal precision data for the i-th node. This represents the vertical distance from the i-th node to the best-fit line.
[0018] Further, in step S3, when the slope b of the straight line is greater than a preset threshold, the midpoint of the fitted straight line is used as the rotation center, and the straight line is rotated according to the slope value b, so that the rotated straight line is horizontal with the ground. Then the formula for the rotated straight line is: Calculate the vertical distance from each node to the optimal straight line, then the optimal adjustment amount of the bed feet at each node is (F1-Y, F2-Y, F3-Y...F...). i -Y), H i H1 represents the coordinates of the i-th node, H1 represents the coordinates of the first node, and F represents the coordinates of the second node. i Y represents the initial horizontal accuracy data of the i-th node, and Y represents the vertical distance from the i-th node to the optimal straight line after rotation.
[0019] Furthermore, when rotating a straight line according to its slope value, if the slope value > 0, the angle of rotation of the straight line towards the X-axis is θ = arctan(b), and if the slope value < 0, the angle of rotation of the straight line towards the X-axis is θ = 180 - arctan(b), where b represents the slope value.
[0020] Furthermore, based on the structure and pitch of the selected foot bolts, the adjustment amount of the bed caused by one rotation of the foot bolt adjusting screw can be calculated as follows:
[0021] S = kqp tan(θ);
[0022] Where k is the ratio coefficient between theoretical and actual motion, q is the number of leads, p is the lead screw pitch, θ is the slope of the inclined shim foot, and S is the vertical distance the inclined shim moves when the lead screw rotates one revolution.
[0023] Finally, the number of adjustment turns of the anchor bolts corresponding to each node is calculated by converting the optimal adjustment amount for each node:
[0024]
[0025] Among them, s i For the i-th node, the vertical distance r of the inclined shim moves when the screw rotates one revolution. i ΔF represents the number of turns of the anchor bolt corresponding to the i-th node. i This represents the optimal adjustment amount for the anchor screw corresponding to the i-th node.
[0026] The beneficial effects of this invention are:
[0027] 1. The entire precision adjustment process of this invention relies on data support, which can accurately guide maintenance personnel to make precise adjustments, freeing them from dependence on experience. It can effectively process deviation data and calculate precise mechanical adjustment amounts, thereby effectively improving work efficiency.
[0028] 2. This invention calculates the optimal adjustment amount of the bed level feet by fitting the horizontal accuracy data of the CNC machine tool bed. Each adjustment step can be supported by the best data, which has the advantages of low personnel requirements and high adjustment efficiency. This method is especially suitable for the accuracy adjustment of the bed of large or super large CNC machine tools. Attached Figure Description
[0029] The foregoing and hereinafter detailed description of the invention becomes clearer when read in conjunction with the following drawings, in which:
[0030] Figure 1 This is a flowchart of the machine tool bed precision detection and adjustment process of the present invention;
[0031] Figure 2 This is a schematic diagram of the machine tool bed structure of the present invention;
[0032] Figure 3 This is a schematic diagram of the anchor screws of the machine tool bed of the present invention;
[0033] Figure 4 This invention provides an adjustment calculation method when the slope of the fitted straight line is less than or equal to a threshold.
[0034] Figure 5 This invention provides an adjustment calculation method when the slope of the fitted straight line exceeds a threshold.
[0035] In the picture:
[0036] 1. Machine tool bed; 2. Main body; 3. Saddle; 4. Screw; 5. Bearing surface; 6. Inclined surface. Detailed Implementation
[0037] To enable those skilled in the art to better understand the technical solutions of this invention, specific embodiments will be used to further illustrate the technical solutions for achieving the objectives of this invention. It should be noted that the technical solutions claimed by this invention include, but are not limited to, the following embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort should fall within the scope of protection of this invention.
[0038] Example 1
[0039] An embodiment of the present invention proposes a method for adjusting the accuracy of a CNC machine tool bed. This method divides the travel of the CNC machine tool slide saddle into multiple nodes, with the distance between each node corresponding to the spacing between the bed feet. Each node corresponds to a foot screw on the machine tool bed. First, initial horizontal accuracy data is collected when the CNC machine tool slide saddle moves to each node. Then, based on the initial horizontal accuracy data, the optimal straight line is fitted using the least squares method. When the slope of the straight line is less than or equal to a preset threshold, the vertical distance from each node to the optimal straight line is calculated. Finally, the bed corresponding to each node is obtained by combining the initial horizontal accuracy data. Optimal adjustment amount of the machine tool bed feet: When the slope of the straight line is greater than the preset threshold, the midpoint of the optimal straight line is used as the rotation center, and the straight line is rotated according to the angle value calculated by reverse calculation of the slope, so that the rotated straight line is horizontal with the ground. The vertical distance from each node to the rotated straight line is calculated, and the optimal adjustment amount of the bed feet corresponding to each node is obtained by combining the initial horizontal accuracy data. Finally, according to the structure and inherent parameters such as the pitch of the selected feet, the adjustment amount of the bed feet by rotating the foot adjustment screw one revolution can be calculated. The number of adjustment revolutions of the foot adjustment screws at each node is calculated by converting the optimal adjustment amount of each node, and finally the horizontal accuracy of the machine tool bed is adjusted.
[0040] It should be noted that the machine tool bed precision adjustment of this invention mainly refers to the horizontal precision adjustment of the bed.
[0041] This embodiment discloses a method for adjusting the accuracy of a CNC machine tool bed, as detailed in the appendix of the instruction manual. Figure 1 The method mainly includes the following steps:
[0042] Step S1. Measure the interval between the feet of the CNC machine tool bed, divide the CNC machine tool slide saddle travel into multiple nodes according to this interval, and then control the machine tool slide saddle to move to each node according to the preset detection trajectory.
[0043] In this invention, the spacing between the bed feet can be determined by consulting foundation drawings or by directly measuring the foot spacing. This spacing is used to divide the saddle travel distance into i nodes, each node corresponding to a foot screw on the machine tool bed. A coordinate system is established, with the X-axis parallel to the ground. The coordinates of each node can then be denoted as (H1, H2, H3…H…). i ), where i = 1, 2, 3...n; the machine tool stops for 4 seconds when the saddle reaches each node, to observe and record the initial level accuracy of the machine tool at each node.
[0044] Step S2. When the machine tool saddle moves to each node, the initial horizontal accuracy of each node is collected. The initial horizontal accuracy of each node can be expressed as (F1, F2, F3...F...). i ).
[0045] In this invention, any instrument or device such as a level, laser interferometer, collimator, and probe can be used to collect the horizontal accuracy data of each node. The horizontal accuracy data of each node is denoted as (F1, F2, F3...F...). i ).
[0046] In this invention, the coordinates of each node (H1, H2, H3...H...) i This can be understood as the X-axis (ground) coordinate, while the horizontal precision data of each node (F1, F2, F3...F...) i This can be understood as the Y-axis coordinate relative to the X-axis (ground).
[0047] Step S3. Using the obtained coordinates of each node and the corresponding initial horizontal accuracy data, fit the optimal straight line using the least squares method. When the slope of the fitted straight line is less than or equal to the set threshold, calculate the vertical distance from each node to the optimal straight line, and combine it with the initial horizontal accuracy of the node to obtain the optimal adjustment amount of the corresponding footing. When the slope of the straight line is greater than the threshold, rotate the straight line with the midpoint of the straight line as the rotation center and the angle value calculated in reverse according to the slope, so that the rotated straight line is horizontal with the ground. Calculate the vertical distance from each node to the rotated straight line, and combine it with the initial horizontal accuracy of the node to obtain the optimal adjustment amount of the corresponding footing at this time.
[0048] In this invention, the calculation expression for the optimal straight line obtained by least squares fitting is as follows:
[0049]
[0050] Furthermore, in the above optimal straight line calculation expression, b and a are calculated using the following formula:
[0051]
[0052]
[0053] Among them, H i Let be the coordinates of the i-th node. F is the average value of the coordinates of each node. i This represents the initial horizontal accuracy data of the bed corresponding to the i-th node. Let be the average of the initial horizontal accuracy data of the bed at each node, b be the slope of the optimal straight line obtained by the least squares method, and a be the intercept of the optimal straight line obtained by the least squares method. This is the ideal horizontal accuracy data of the bed corresponding to the i-th node, estimated using the least squares method.
[0054] Furthermore, when the slope b of the fitted optimal straight line is less than or equal to a preset threshold, the vertical distance from each node to the optimal straight line is calculated. Then, the optimal adjustment amount for the bed anchor screws corresponding to each node at this time is... Among them, when When, it indicates that the leveling screw needs to be adjusted downwards; when At this time, the leveling screws need to be adjusted upwards.
[0055] It should be noted that, when calculating the vertical distance, this invention uses the current coordinates H of the node. i Substituting the above-mentioned fitted formula into the optimal straight line formula Then, you can obtain the vertical distance.
[0056] Furthermore, when the slope b of the fitted optimal line is greater than a preset threshold, the line is rotated around its midpoint by the slope b, making the rotated line horizontal to the ground. The rotated line then becomes:
[0057]
[0058] Then calculate the vertical distance from each node to the rotated line. The optimal adjustment amount of the bed anchor screws corresponding to each node at this time is (F1-Y, F2-Y, F3-Y...F...). i -Y). Similarly, when F i When -Y>0, the leveling screw is adjusted downwards; when F i When -Y < 0, adjust the foot adjustment screw upwards.
[0059] It should be noted that, referring to the expression for the straight line after rotation mentioned above, the midpoint of the optimal straight line refers to the midpoint of the line segment obtained by intercepting the corresponding end nodes at both ends of the machine tool bed on the optimal straight line.
[0060] It should also be noted that when rotating a straight line by the slope value b, if b>0, the angle of rotation of the straight line towards the X-axis is θ=arctan(b), and if b<0, the angle of rotation of the straight line towards the X-axis is θ=180-arctan(b).
[0061] Step S4. Based on the structure and pitch of the selected foot, the adjustment amount of the machine tool bed corresponding to one rotation of the foot adjustment screw can be calculated. The number of adjustment turns of the foot screw at each node is calculated by converting the optimal adjustment amount of each node. Finally, the foot is adjusted according to the calculated values.
[0062] In this invention, based on the inherent parameters such as the structure and pitch of the selected foot bolts, the adjustment amount of the bed caused by one revolution of the foot bolt adjusting screw can be calculated as follows:
[0063] S = kqptan(θ);
[0064] Where k is the ratio coefficient between theoretical and actual motion, q is the number of leadscrews, p is the leadcrew pitch, tan(θ) is the slope of the inclined pad, and S is the vertical distance the inclined pad moves when the leadcrew rotates one revolution.
[0065] Furthermore, based on the optimal adjustment amount for each node and the adjustment amount S of the bed caused by one rotation of the leveling screw, the number of adjustments required for each leveling screw is calculated:
[0066]
[0067] Among them, s i For the i-th node, the vertical distance r of the inclined shim moves when the screw rotates one revolution. i ΔF represents the number of turns of the anchor bolt corresponding to the i-th node. i This represents the optimal adjustment amount for the anchor screw corresponding to the i-th node.
[0068] Therefore, when the slope b of the fitted straight line is less than or equal to the preset threshold, the optimal adjustment amount of the anchor screw corresponding to each node is: When the slope b of the fitted straight line is greater than the preset threshold, the optimal adjustment amount of the anchor screw corresponding to each node is (F1-Y, F2-Y, F3-Y...F...). i -Y).
[0069] Step S5. After adjusting the feet, collect the horizontal accuracy data of each node again according to step S2 to verify the adjustment effect and determine whether the horizontal accuracy of the bed has been adjusted to the correct level. If the requirements are met, the process ends; if the requirements are not met, start readjusting from step S3 and repeat steps S3 to S5 until the accuracy requirements are met.
[0070] It should be noted that before adjusting the anchor bolts, markings should be made on the four quadrants of the anchor bolts to determine whether the actual adjustment amount matches the planned adjustment amount.
[0071] Example 2
[0072] This embodiment is based on Embodiment 1, and refers to the appendix to the instruction manual. Figure 2 In step S1, the machine tool is controlled to move to each node according to the preset detection trajectory. Taking the X-axis as an example, the CNC machine tool slide saddle movement trajectory is programmed as follows:
[0073] G500
[0074] G01 F3000 XH1
[0075] G4F4
[0076] G01 F3000 XH2
[0077] G4F4
[0078] …
[0079] G01 F3000 XH n
[0080] M30
[0081] That is, when the slide saddle 3 moves to the first node H1, the machine tool stops moving for 4 seconds. At this time, the initial horizontal accuracy data of the machine tool bed corresponding to the first node is detected by the corresponding detection instrument and is F1. And so on, moving the slide saddle 3 to the nth node H n When the machine tool stops moving for 4 seconds, the nth node H is detected. n The corresponding initial horizontal accuracy data for the machine tool bed is F. n .
[0082] Example 3
[0083] This embodiment is based on embodiment 1, such as... Figure 4 and Figure 5 The method for calculating the optimal adjustment amount of the bed frame feet after fitting the best straight line using the least squares method in step S3 is based on the different slopes of the straight line. The two methods for calculating the adjustment amount have been described in the above embodiment 1, so they will not be repeated here.
[0084] Example 4
[0085] This embodiment is based on Embodiment 1, and refers to the appendix to the instruction manual. Figure 3 The diagram shows a common inclined iron foot structure in step S4. The main body 2 is cast into one piece with the foundation and is fixed in place. The bearing surface 5 is in contact with the machine tool bed 1. The bearing surface 5 is provided with a screw and a nut 4 is fitted on the screw. The nut 4 abuts against the groove surface along the inclined surface. By adjusting the nut 4, the bearing surface 5 slides along the inclined surface 6, thereby adjusting the accuracy level of the machine tool bed.
[0086] The above description is merely a preferred embodiment of the present invention and is not intended to hinder the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.
Claims
1. A method for adjusting the accuracy of a CNC machine tool bed, characterized in that, Includes the following steps: Step S1. Measure the interval between the feet of the CNC machine tool bed, divide the CNC machine tool slide saddle travel into multiple nodes according to this interval, and control the machine tool slide saddle to move to each node according to the preset detection trajectory; Step S2. Collect the initial horizontal accuracy data for each node; Step S3. Using the initial horizontal accuracy data of each node, fit the best straight line according to the least squares method, calculate the distance from each node to the best straight line, and combine the initial horizontal accuracy data obtained by measurement to obtain the optimal adjustment amount of the anchor screws of each node. In step S3, when the slope of the best fitted line is less than or equal to the threshold, the distance from each node to the best line is calculated, and the optimal adjustment amount of each node is obtained by combining the initial horizontal accuracy data; when the slope of the best fitted line is greater than the threshold, the line is rotated with the midpoint of the line as the rotation center and the angle value calculated in reverse according to the slope is used to make the rotated line horizontal with the ground, the distance from each node to the rotated line is calculated, and the optimal adjustment amount of each node is obtained by combining the initial horizontal accuracy data. The optimal straight line is fitted using the least squares method, and the calculation expression is as follows: ； ； ； in, For the first The coordinates of each node, The average value of the coordinates of each node. For the first The initial horizontal precision of each node. This represents the average initial horizontal precision of each node. The slope of the optimal straight line obtained by the least squares method. The intercept of the optimal line obtained by the least squares method. To estimate the first by least squares method The ideal horizontal accuracy corresponding to each node; When the slope of the fitted best line is less than or equal to the preset threshold, the optimal adjustment amount for each node is ( - , - , - ... - ),in ; In step S3, when the slope b of the best-fit line is greater than a preset threshold, the line is rotated around its midpoint by the slope b, making the rotated line horizontal to the ground. The formula for the rotated line is then: Calculate the distance from each node to the optimal straight line, then the optimal adjustment amount of the bed feet at each node is ( -Y、 -Y、 -Y…… -Y), where, , Indicates the first The coordinates of each node, This represents the coordinates of the first node. Indicates the first The initial horizontal precision data for the nth node, Y represents the nth node. The distance from each node to the optimal straight line after rotation.
2. The method for adjusting the accuracy of a CNC machine tool bed according to claim 1, characterized in that, The method further includes: calculating the adjustment amount of the machine tool bed corresponding to one rotation of the foot adjustment screw based on the structure and pitch of the selected foot, converting the optimal adjustment amount of each node into the number of adjustment turns of the foot screw corresponding to each node, and finally adjusting the foot according to the calculated values.
3. The method for adjusting the accuracy of a CNC machine tool bed according to claim 1, characterized in that, The method further includes: after the foot adjustment, collecting the horizontal accuracy data of each node again according to step S2 to verify the adjustment effect, and determining whether the horizontal accuracy of the bed has been adjusted in place. If the requirements are met, the process ends; if the requirements are not met, the adjustment begins from step S3.
4. The method for adjusting the accuracy of a CNC machine tool bed according to claim 1, characterized in that: When rotating a straight line according to its slope value, if the slope value > 0, the angle of rotation of the straight line towards the X-axis is θ = arctan(b). If the slope value < 0, the angle of rotation of the straight line towards the X-axis is θ = 180 - arctan(b), where b represents the slope value.
5. The method for adjusting the accuracy of a CNC machine tool bed according to claim 2, characterized in that, Based on the structure and pitch of the selected foot, the adjustment amount of the bed by one rotation of the foot adjusting screw can be calculated as S=kqp tan(θ); where k is the ratio coefficient of theoretical motion to actual motion, q is the number of leadscrews, p is the lead screw pitch, θ is the slope of the wedge foot, and S is the vertical movement distance of the wedge foot by one rotation of the lead screw.
6. The method for adjusting the accuracy of a CNC machine tool bed according to claim 5, characterized in that, The number of adjustment turns of the anchor bolts at each node is calculated by converting the optimal adjustment amount at each node. , For the first For each node, the lead screw rotates one revolution, and the inclined shim moves a certain distance vertically. Indicates the first The number of turns to adjust the anchor bolts corresponding to each node. Indicates the first The optimal adjustment amount for each node.
7. The method for adjusting the accuracy of a CNC machine tool bed according to claim 1, characterized in that, The initial horizontal accuracy data of each node is collected using any one of the following instruments or devices: level, laser interferometer, collimator, or probe.
8. The method for adjusting the accuracy of a CNC machine tool bed according to claim 1, characterized in that, The midpoint of the optimal straight line is the midpoint of the line segment obtained by intercepting the corresponding end nodes at both ends of the machine tool bed on the optimal straight line.