A concave-convex grinding compensation method applied to a gantry guide rail grinder

Abstract

The application provides a concave-convex grinding compensation method applied to a gantry guide rail grinder, which comprises the following steps: determining the machining starting point coordinate and the machining ending point coordinate of a workpiece to be ground in the X-axis direction of the gantry guide rail grinder, and setting a target concave-convex amount; taking the machining starting point coordinate and the machining ending point coordinate as two intersection points of a parabola and the X-axis, and taking the target concave-convex amount as the longitudinal compensation amount of the vertex of the parabola, and establishing a Z-axis compensation curve; obtaining the current position coordinate of the workbench when moving along the X-axis direction through a position feedback sensor; substituting the current position coordinate into the Z-axis compensation curve to calculate the corresponding Z-axis compensation amount; generating compensation data according to the corresponding relationship between the X-axis position coordinate and the Z-axis compensation amount; starting the grinding cycle of the gantry guide rail grinder, and making the X-axis feeding and the Z-axis compensation linkage to execute, so that the grinding machining of the preset convex curve or the concave curve is completed. The concave-convex grinding compensation process can be converted into a numerical control compensation execution process, and the manual reverse pressure adjusting and regulating link is reduced.

Description

Technical Field

[0001] This invention relates to the field of CNC grinding technology, and in particular to a method for compensating for concave and convex grinding applied to gantry guideway grinding. Background Technology

[0002] Gantry grinders are typically used for grinding guideways, long reference surfaces, or flat surfaces of large parts. For workpieces that are long and heavy, the support and clamping conditions on the machine tool table are not entirely consistent with their subsequent lifting, transfer, or natural placement after removal from the machine. During machining, the workpiece is constrained by the support and clamping conditions of the worktable, and the straightness of the machined surface can meet the inspection requirements. However, when the workpiece's lifting or placement conditions change after removal from the machine, factors such as its own weight, changes in installation supports, or transportation disturbances can easily cause slight bending deformation, which can destroy the originally acceptable straightness, resulting in the final straightness or overall accuracy failing to meet the requirements in the final use state.

[0003] To address the above situation, the existing approach typically involves applying reverse pressure to the workpiece before processing, based on experience, to induce a certain degree of reverse deformation before grinding. Grinding is then performed under this condition. After processing, the reverse pressure is released, allowing the workpiece's springback or natural deformation to offset some of the subsequent deformation. While this method can mitigate the impact of deformation after machining to some extent, its operation is cumbersome, requires a long setup time, and demands a high level of experience and judgment from the operator regarding the workpiece structure, support conditions, stress locations, and deformation patterns.

[0004] Because the magnitude, location, and adjustment process of manually applied reverse pressure are difficult to quantify precisely, the compensation effect can easily vary between different operators and between different batches of workpieces, making it difficult to maintain consistent compensation during batch processing. Furthermore, this method typically requires multiple adjustments before the actual grinding, impacting processing efficiency. Therefore, a concave-convex grinding compensation method for gantry guideway grinding is proposed. Summary of the Invention

[0005] In view of this, the present invention provides a method for compensating for concave and convex grinding applied to gantry guideway grinding, so as to solve or alleviate the technical problems existing in the prior art, and at least provide a beneficial option.

[0006] The technical solution of the present invention is implemented as follows: a method for compensating for concave and convex grinding applied to a gantry guideway mill, comprising the following steps: S1, determining the coordinates of the machining start point of the workpiece to be ground in the X-axis direction of the gantry guideway mill. and processing endpoint coordinates And set the coordinates of the workpiece to be ground at the machining start point. coordinates of the processing endpoint Target bump amount between ; S2, using the aforementioned processing start point coordinates and processing endpoint coordinates The x-coordinates of the two intersection points of the parabola and the X-axis are respectively used as the x-coordinates of the machining starting point coordinates. and processing endpoint coordinates The midpoint is used as the x-coordinate of the vertex of the parabola. And using the target concavity / convexity k as the longitudinal compensation amount of the parabola vertex, a Z-axis compensation curve is established;

[0007] The Z-axis compensation curve is as follows:

[0008]

[0009] In the formula, This represents the current position coordinates of the worktable along the X-axis. Current position coordinates The corresponding Z-axis compensation amount; S3. Obtain the current position coordinates of the worktable as it moves along the X-axis by using a position feedback sensor to detect the X-axis position of the gantry guideway grinding worktable. ; S4. Set the current position coordinates Substitute the Z-axis compensation curve to calculate the current position coordinates. Corresponding Z-axis compensation amount ; S5. Based on the X-axis position coordinates and Z-axis compensation amount The corresponding relationship is used to generate compensation data, and the compensation data is written into the Z-axis compensation table of the CNC system so that the compensation data takes effect at the corresponding X-axis position. S6. Start the grinding cycle of the gantry guide rail mill, so that the gantry guide rail mill performs Z-axis linkage compensation according to the Z-axis compensation table during the X-axis feed process, and completes the grinding process of the preset convex curve or concave curve.

[0010] Further, in step S1, the target unevenness amount Positive and negative values ​​are used to distinguish between them. Positive values ​​represent the target concavity / concavity of the upward convex curve, while negative values ​​represent the target concavity / concavity of the downward concave curve.

[0011] Further, in step S2, the Z-axis compensation curve is expanded as follows: in, .

[0012] Furthermore, in step S3, the position feedback sensor is one of a magnetic grating ruler, a laser displacement sensor, a pull rope sensor, or a gear and rack encoder.

[0013] Furthermore, the position feedback sensor is a magnetic scale, which is mounted on the worktable of the gantry guide mill and moves with the worktable to detect the current position coordinates of the worktable in the X-axis direction. .

[0014] Further, in step S4, the Z-axis compensation amount The PLC determines the position based on the current coordinates. The Z-axis compensation curve is calculated.

[0015] Further, in step S4, the Z-axis compensation amount The calculation unit of the CNC system calculates the current position coordinates. The Z-axis compensation curve is calculated.

[0016] Further, in step S5, the compensation data includes multiple X-axis position coordinates and Z-axis compensation amounts corresponding to each X-axis position coordinate, wherein the multiple X-axis position coordinates are located at the machining start point coordinates. coordinates of the processing endpoint between.

[0017] Furthermore, the CNC system performs interpolation processing between the Z-axis compensation amounts corresponding to adjacent X-axis position coordinates, so that the Z-axis compensation amount changes continuously with the X-axis feed.

[0018] Furthermore, in step S6, the X-axis of the gantry guide mill is fed according to the set machining path, and the Z-axis is adjusted to grind the position according to the compensation data in the Z-axis compensation table, so that the workpiece is ground to form a concave-convex grinding surface corresponding to the Z-axis compensation curve.

[0019] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: I. This invention establishes a parabolic Z-axis compensation curve based on the machining start point coordinates, machining end point coordinates, and target concavity / convexity amount, so that the concavity / convexity grinding compensation amount can be determined in a parametric manner, which facilitates CNC compensation during gantry guideway grinding.

[0020] II. This invention obtains the current position coordinates of the X-axis of the worktable through a position feedback sensor, and calculates the corresponding Z-axis compensation amount based on the current position coordinates, so that the Z-axis compensation can be adjusted accordingly with the change of the X-axis feed position, thereby realizing the grinding of concave and convex curves.

[0021] Third, this invention writes the correspondence between the X-axis position coordinates and the Z-axis compensation amount into the Z-axis compensation table of the CNC system, so that the compensation data can take effect in the grinding cycle, reducing the manual reverse pressure pre-deformation adjustment step, which is conducive to improving the consistency of the compensation method during batch processing.

[0022] The above overview is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features of the invention will become readily apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0026] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0027] like Figure 1 As shown, this embodiment of the invention provides a method for convex-concave grinding compensation applied to a gantry mill. This method is used when a gantry mill grinds large parts. It establishes a Z-axis compensation curve based on the preset convex-concave compensation requirements of the workpiece, and utilizes the compensation function of the gantry mill's CNC system to coordinate the X-axis feed process with the Z-axis compensation process, thereby completing the grinding of the preset convex or concave curve.

[0028] In this embodiment, the gantry mill includes a worktable, an X-axis feed mechanism, a Z-axis feed mechanism, a grinding mechanism, a CNC system, and a position feedback sensor. The worktable is used to support the workpiece to be ground. The X-axis feed mechanism is used to move the worktable or grinding mechanism relative to the length of the workpiece. The Z-axis feed mechanism is used to adjust the vertical position of the grinding mechanism relative to the workpiece. The CNC system is used to receive position feedback data, call or execute compensation data, and control the Z-axis to perform compensation movement according to the compensation data.

[0029] For gantry mills using hydraulically driven worktables, since the X-axis coordinates corresponding to the machining position are needed during the worktable's movement, a position feedback sensor is installed on the worktable to detect its X-axis position. This position feedback sensor can be one of a magnetic scale, a laser displacement sensor, a draw rope sensor, or a rack and pinion encoder.

[0030] In this embodiment, a magnetic scale is preferably used. The magnetic scale is installed on the worktable of the gantry guide mill and detects the current position coordinates of the worktable in the X-axis direction as the worktable moves. The detected position coordinates are then fed back to the PLC or CNC system.

[0031] Before performing concave-convex grinding compensation, the machining range of the workpiece to be ground along the X-axis of the gantry guideway must first be determined. This machining range is defined by the coordinates of the machining start point. and processing endpoint coordinates Limited, processing start point coordinates and processing endpoint coordinates These are used as the x-coordinates of the two intersection points of the preset parabolic compensation curve and the X-axis. In actual settings, the coordinates of the machining start point... and processing endpoint coordinates The grinding length of the workpiece to be ground is determined based on the machine tool coordinate position and the start and end positions in the machining program.

[0032] Determine the coordinates of the processing start point and processing endpoint coordinates Then, input the target concavity / convexity amount in the CNC system parameter setting interface. Target unevenness Indicates the coordinates of the workpiece to be ground at the machining start point. coordinates of the processing endpoint The maximum longitudinal compensation required between these points, i.e., the longitudinal compensation at the vertex of the parabola. This target convexity / concavity... Used to control the amount of protrusion or concavity in the final convex-concave grinding curve.

[0033] In this embodiment, the target unevenness amount Positive and negative values ​​are used for differentiation. When the target's convexity / concavity... When the value is positive, the Z-axis compensation curve corresponds to an upward convex curve. At this time, as the worktable moves from the machining start point coordinate to the machining end point coordinate, the Z-axis compensation amount gradually changes from 0 at the start point to the target concavity / convexity amount at the apex, and then gradually changes back to 0 at the end point, thus forming an upward convex curve in the grinding trajectory; when the target concavity / convexity amount... A negative value indicates that the curve to be processed is a concave curve. The operator can input the corresponding target concavity / convexity amount into the CNC system based on the workpiece's deformation trend after machining, processing requirements, and preset compensation direction. .

[0034] Obtain the coordinates of the processing starting point Coordinates of the processing endpoint and target bump amount Then, a Z-axis compensation curve based on a parabola is established. Since the deformation curve of the large part under natural gravity can be approximated as a parabola, this embodiment uses a parabolic equation to describe the convexity / concave compensation curve to be processed.

[0035] Calculate the x-coordinate of the vertex of the parabola :

[0036] in, Coordinates of the starting point of processing and processing endpoint coordinates The x-coordinate of the midpoint. That is, in this embodiment, the midpoint of the processing area is used as the position of the vertex of the parabola along the X-axis, and the target concavity / convexity is used as the coordinate. This serves as the Z-axis compensation amount corresponding to that vertex.

[0037] Then, establish the following intersection-type Z-axis compensation curve:

[0038] In the formula, This represents the current position coordinates of the worktable along the X-axis. Current position coordinates The corresponding Z-axis compensation amount, This is the coefficient of the quadratic term. Because... and These are the two intersection points of the parabola and the X-axis, therefore, when x=x1 or x=x2, the Z-axis compensation amount is... =0; when At that time, Z-axis compensation amount Achieve the set target bump amount .

[0039] Substituting the vertex coordinates into the intersection formula above, we can obtain the coefficient of the quadratic term. :

[0040] Therefore, at the coordinates of the processing starting point Coordinates of the processing endpoint and target bump amount Once determined, the complete Z-axis compensation curve can be established. This curve describes the Z-axis compensation amount corresponding to different positions on the X-axis.

[0041] In an alternative expression, the Z-axis compensation curve can also be expanded into a general form:

[0042] in: , .

[0043] The intersection form and the general form described above represent the same Z-axis compensation curve. In actual calculations, one of these forms can be selected based on the data processing method of the PLC or CNC system.

[0044] To avoid errors in parameter input affecting the generation of compensation data, the input parameters should be validated before establishing the Z-axis compensation curve. For example, confirm the coordinates of the machining start point. coordinates of the processing endpoint Different, confirm the target unevenness. The positive and negative directions should be consistent with the desired upward or downward convex curve, and the x-coordinate of the parabola's vertex should be confirmed. Located at the coordinates of the processing start point and processing endpoint coordinates between.

[0045] The above confirmation is used to ensure that the parabolic compensation curve can be generated according to the set processing range.

[0046] During the grinding process, the magnetic scale moves with the worktable to detect the current position coordinates of the worktable in the X-axis direction in real time. The detected current position coordinates The feedback is sent to the PLC or CNC system. The PLC or CNC system then uses the current position coordinates... Use the Z-axis compensation curve mentioned above to calculate the Z-axis compensation amount corresponding to the current position. .

[0047] In one implementation, the compensation calculation is performed by the PLC. A magnetic scale measures the current position coordinates of the worktable. The data is fed back to the PLC, which then sends the current position coordinates. Substitute into the formula The Z-axis compensation amount corresponding to the current position is calculated. Then calculate the Z-axis compensation amount. Send to the CNC system.

[0048] In another implementation, the compensation calculation is performed by the computational unit of the CNC system. The magnetic scale sets the current position coordinates of the worktable. The system's processing unit feeds back the input machining start point coordinates. Coordinates of the processing endpoint Target convexity and current position coordinates Calculate Z-axis compensation amount .

[0049] Obtain Z-axis compensation amount Then, compensation data is generated based on the correspondence between the X-axis position coordinates and the Z-axis compensation amount; the compensation data includes multiple X-axis position coordinates and the Z-axis compensation amount corresponding to each X-axis position coordinate. The multiple X-axis position coordinates are located at the machining start point coordinates. coordinates of the processing endpoint Between these values, the Z-axis compensation value is used to characterize different positions within the machining range.

[0050] After generating the compensation data, the compensation data is written into the Z-axis compensation table of the CNC system, and the Z-axis compensation table is made effective in the corresponding machining program. After the compensation table is effective, the CNC system can call the corresponding Z-axis compensation amount when the X-axis moves to the corresponding position, so that the Z-axis performs compensated movement according to the compensation data in the compensation table.

[0051] For the machining interval between adjacent X-axis position coordinates in the compensation table, the CNC system can perform interpolation processing on the Z-axis compensation amount between adjacent compensation points according to its own interpolation function, so that the Z-axis compensation amount changes continuously with the X-axis feed. Thus, during the X-axis feed process, the Z-axis can perform linkage compensation according to the preset parabolic compensation curve.

[0052] When the target bump amount When the value is negative, the Z-axis compensation curve corresponds to a concave curve. At this time, as the worktable moves from the machining start point coordinate... To the coordinates of the processing endpoint As the object moves, the Z-axis compensation gradually changes from 0 at the starting point to the negative target convexity at the apex. Then it gradually changes to the endpoint 0, thus forming a concave curve in the grinding trajectory.

[0053] The uneven grinding compensation method in this embodiment can be executed according to the following process: The first step is to identify the machining area of ​​the workpiece to be ground and determine the coordinates of the machining start point. and processing endpoint coordinates .

[0054] The second step is to input the target concavity / convexity amount into the CNC system. The positive or negative value is selected according to the required processing shape, where a positive value corresponds to an upward convex curve and a negative value corresponds to a downward concave curve.

[0055] The third step is to determine the coordinates of the processing start point. Coordinates of the processing endpoint and target bump amount Calculate the x-coordinate of the vertex of the parabola And determine the coefficient of the quadratic term. .

[0056] The fourth step is to establish the Z-axis compensation curve. The curve is used to generate the correspondence between the X-axis position coordinates and the Z-axis compensation amount.

[0057] The fifth step is to use a magnetic ruler mounted on the worktable to detect the current position coordinates of the worktable as it moves along the X-axis. It then feeds back the current position coordinates to the PLC or CNC system.

[0058] Step 6: The PLC or CNC system will transmit the current position coordinates. Substitute the Z-axis compensation curve into the equation and calculate the Z-axis compensation amount corresponding to the current position. ; Step 7: Generate compensation data based on multiple X-axis position coordinates and their corresponding Z-axis compensation values, write the compensation data into the Z-axis compensation table of the CNC system, and make the compensation data effective.

[0059] Step 8: Start the grinding cycle of the gantry guideway grinder. The X-axis feeds according to the machining path, and the Z-axis performs linkage compensation based on the compensation data in the Z-axis compensation table to complete the grinding process of the preset convex curve or concave curve.

[0060] Through the above implementation method, the concavity / convexity compensation requirement of the workpiece to be ground is transformed into the coordinates of the machining start point. Coordinates of the processing endpoint and target bump amount The determined parabolic compensation curve; the current position of the X-axis of the worktable is detected by the position feedback sensor, and the Z-axis compensation amount corresponding to the current position is calculated by the PLC or CNC system and written into the CNC system Z-axis compensation table; during grinding, the X-axis feed and Z-axis compensation are executed in conjunction to achieve the preset concave-convex curve grinding.

[0061] In this embodiment, using a magnetic scale as a position feedback sensor is only a preferred method. If the current X-axis position coordinates of the worktable can be detected and fed back to the PLC or CNC system, a laser displacement sensor, a drawstring sensor, or a rack and pinion encoder can also be used. The selection of different position feedback sensors does not affect the implementation method of this invention, which calculates the Z-axis compensation amount through X-axis position feedback and writes it into the Z-axis compensation table.

[0062] In this embodiment, after the Z-axis compensation data is written into the compensation table of the CNC system and takes effect, the gantry guideway grinder can complete the grinding of the concave and convex curves by performing cyclic processing. This method transforms the manual reverse pressure to form pre-deformation processing method into a CNC system compensation processing method, which can reduce the manual pre-pressure adjustment steps and make the compensation processing process under the same concave and convex amount setting have good repeatability.

[0063] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for compensating for uneven grinding in a gantry guideway grinder, characterized in that: The method comprises the following steps: S1, determining the machining starting point coordinate and the machining ending point coordinate of the workpiece to be ground in the X-axis direction of the gantry guide rail grinder, and setting the target concave-convex amount between the machining starting point coordinate and the machining ending point coordinate of the workpiece to be ground . . . . . S2, using the aforementioned processing start point coordinates and processing endpoint coordinates The x-coordinates of the two intersection points of the parabola and the X-axis are respectively used as the x-coordinates of the machining starting point coordinates. and processing endpoint coordinates The midpoint is used as the x-coordinate of the vertex of the parabola, and the target concavity / convexity k is used as the longitudinal compensation amount of the vertex of the parabola to establish the Z-axis compensation curve. The Z-axis compensation curve is as follows: In the formula, This represents the current position coordinates of the worktable along the X-axis. Current position coordinates The corresponding Z-axis compensation amount; The coefficient of the quadratic term; S3. Obtain the current position coordinates of the worktable as it moves along the X-axis by using a position feedback sensor to detect the X-axis position of the gantry guide rail grinding worktable. S4. Substitute the current position coordinates into the Z-axis compensation curve to calculate the current position coordinates. Corresponding Z-axis compensation amount ; S5. Based on the X-axis position coordinates and Z-axis compensation amount The corresponding relationship is used to generate compensation data, and the compensation data is written into the Z-axis compensation table of the CNC system so that the compensation data takes effect at the corresponding X-axis position. S6. Start the grinding cycle of the gantry guide rail mill, so that the gantry guide rail mill performs Z-axis linkage compensation according to the Z-axis compensation table during the X-axis feed process, and completes the grinding process of the preset convex curve or concave curve.

2. The method for compensating for uneven grinding applied to gantry guideway grinding according to claim 1, characterized in that, In step S1, the target unevenness amount Positive and negative values ​​are used to distinguish between them. Positive values ​​represent the target concavity / concavity of the upward convex curve, while negative values ​​represent the target concavity / concavity of the downward concave curve.

3. The method for compensating for uneven grinding applied to a gantry guideway mill according to claim 1, characterized in that, In step S2, the Z-axis compensation curve is expanded as follows: ;in, , 4. The method for compensating for uneven grinding applied to gantry guideway grinding according to claim 1, characterized in that, In step S3, the position feedback sensor is one of a magnetic grating ruler, a laser displacement sensor, a pull rope sensor, or a gear and rack encoder.

5. The method for compensating for uneven grinding applied to a gantry guideway mill according to claim 4, characterized in that, The position feedback sensor is a magnetic scale, which is mounted on the worktable of the gantry mill and moves with the worktable to detect the current position coordinates of the worktable in the X-axis direction. .

6. The method for compensating for uneven grinding applied to a gantry guideway mill according to claim 1, characterized in that, In step S4, the Z-axis compensation amount The PLC determines the position based on the current coordinates. The Z-axis compensation curve is calculated.

7. The method for compensating for uneven grinding applied to gantry guideway grinding according to claim 1, characterized in that, In step S4, the Z-axis compensation amount The calculation unit of the CNC system calculates the current position coordinates. The Z-axis compensation curve is calculated.

8. The method for compensating for uneven grinding applied to gantry guideway grinding according to claim 1, characterized in that, In step S5, the compensation data includes multiple X-axis position coordinates and Z-axis compensation amounts corresponding to each X-axis position coordinate, wherein the multiple X-axis position coordinates are located at the machining start point coordinates. coordinates of the processing endpoint between.

9. The method for compensating for uneven grinding applied to a gantry guideway mill according to claim 8, characterized in that, The CNC system performs interpolation between the Z-axis compensation amounts corresponding to adjacent X-axis position coordinates, so that the Z-axis compensation amount changes continuously with the X-axis feed.

10. The method for compensating for uneven grinding applied to a gantry guideway mill according to claim 1, characterized in that, In step S6, the X-axis of the gantry guide mill is fed according to the set machining path, and the Z-axis is adjusted to grind position according to the compensation data in the Z-axis compensation table, so that the workpiece is ground to form a concave-convex grinding surface corresponding to the Z-axis compensation curve.

Images