Submicron precision long-stroke metal guide rail measuring and processing method

Abstract

The invention discloses a submicron precision long-stroke metal guide rail measuring and processing method, which comprises the following steps of: separating measuring errors of measuring equipment in the long side direction and the short side direction of a workpiece by using a reference mirror, and calibrating the measuring equipment by using the measuring errors in the long side direction and the short side direction of the workpiece; measuring the initial surface shape of the workpiece by using measuring equipment, generating a corresponding processing code according to the initial surface shape, and controlling a time-controlled grinding processing device to perform time-controlled grinding processing on the workpiece by using the processing code; measuring equipment is used for measuring the surface shape of the machined workpiece, if the surface shape of the machined workpiece does not meet the precision requirement, a new machining code is generated according to the surface shape of the machined workpiece, and the new machining code is used for controlling the time-controlled grinding machining device to conduct time-controlled grinding machining on the workpiece till the surface shape of the machined workpiece meets the precision requirement. According to the method, the measurement accuracy is improved by separating the measurement error of the measurement equipment, and the machining accuracy is continuously improved through the iterative machining-measurement process.

Description

Technical Field

[0001] The invention relates to mechanical processing technology, and in particular to a sub-micron precision long-stroke metal guide rail measurement and processing method. Background Art

[0002] Hydrostatic guides are widely used in the field of ultra-precision machine tools. Currently, the hydrostatic guide with the highest precision is the Nanoform X ultra-precision machine tool of Precitech, USA, with a straightness error of 0.2μm within a 200mm stroke. One of the key errors that affects the straightness error of hydrostatic guides is the manufacturing error of the guide itself. According to the error homogenization effect, in order to make the straightness error of the hydrostatic guide better than 0.1μm, the manufacturing error of the guide itself needs to be better than 1μm. Hydrostatic guides are a type of long-stroke metal guides. Due to the limitations of processing and detection methods, it is currently difficult for long-stroke metal guides to achieve a manufacturing accuracy better than 1μm. Therefore, improving the manufacturing accuracy of mechanical guides is a key factor in achieving higher-precision hydrostatic guides.

[0003] Metal guide rails are generally made of cast iron, which is difficult to process using ultra-precision turning. Currently, ultra-precision grinding is the processing method for such parts, combined with manual grinding when necessary. However, ultra-precision grinding is a processing method based on the error reflection principle, and the accuracy of the machine tool itself determines the accuracy of the grinding process. The larger the size of the workpiece, the lower the accuracy of the machine tool, and it is difficult to achieve sub-micron precision grinding. In addition, the processing accuracy is limited by various factors such as grinding wheel wear and grinding heat, which further reduces the grinding accuracy.

[0004] In terms of long-stroke metal guide rail measurement, the most common measurement method is three-coordinate measurement. The long-stroke high-precision three-coordinate XENOS CMM developed by ZEISS has a measurement stroke of 900mm×1500mm×700mm and a maximum allowable error of (0.3+L / 1000)μm. The measurement accuracy cannot meet the manufacturing requirements of sub-micron precision.

[0005] In summary, there is an urgent need for a processing method for sub-micron precision long-stroke metal guide rails. Summary of the invention

[0006] The technical problem to be solved by the present invention is: the current long-stroke metal guide rail has low processing accuracy. In view of the above problems in the prior art, a sub-micron precision long-stroke metal guide rail measurement and processing method is proposed. The long-stroke metal guide rail is processed by a time-controlled grinding processing method based on the computer deterministic shaping principle. At the same time, an optical reference mirror is used to calibrate the measurement equipment system error to improve the measurement accuracy of the metal guide rail.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A method for measuring and processing a sub-micron precision long-stroke metal guide rail comprises the following steps:

[0009] S1) using a reference mirror to separate the measurement errors of the measuring device in the long side direction and the short side direction of the workpiece, and then calibrating the measuring device using the measurement errors in the long side direction and the short side direction of the workpiece;

[0010] S2) using a measuring device to measure the initial surface shape of the workpiece, generating a corresponding processing code according to the initial surface shape, and using the processing code to control the time-controlled grinding device to perform time-controlled grinding on the workpiece;

[0011] S3) Using a measuring device to measure the surface shape of the workpiece after processing, if the surface shape of the workpiece after processing does not meet the accuracy requirements, a new processing code is generated according to the surface shape of the workpiece after processing, and the new processing code is used to control the time-controlled grinding device to perform time-controlled grinding on the workpiece until the surface shape of the workpiece after processing meets the accuracy requirements.

[0012] Furthermore, when the reference mirror is used to separate the measurement errors of the measuring device in the long side direction and the short side direction of the workpiece, it specifically includes:

[0013] The reference mirror is set on one side of the long side of the workpiece, and the measuring device is controlled to perform feeding movement at the corresponding position of the workpiece where the reference mirror is placed, so that the measurement error in the long side direction of the workpiece during the measurement process is separated in real time by the reference mirror;

[0014] The reference mirror is set on one side of the short side of the workpiece, and the measuring device is controlled to use a unidirectional grating scanning path to feed the workpiece on the side where the reference mirror is placed. The reference mirror is set at the position where the grating track wraps, and the measurement error in the short side direction of the workpiece is separated in real time by the reference mirror during the measurement process.

[0015] Furthermore, the reference mirror is arranged on one side of the long side of the workpiece, and the measuring device is controlled to perform feeding movement at the corresponding position of the workpiece where the reference mirror is placed, specifically including:

[0016] If the length of the workpiece is greater than the length of the reference mirror, two or more reference mirrors are sequentially arranged along the long side of the workpiece according to a specified step length, and then the measuring device is controlled to feed along the long side of the workpiece on the side of the workpiece where the reference mirror is placed, or the reference mirror is sequentially arranged at the next position along the long side of the workpiece according to a specified step length starting from the initial position, and each time the reference mirror is arranged at a new position, the measuring device is controlled to feed at the corresponding position along the long side of the workpiece;

[0017] When the measurement error of the long side direction of the workpiece is separated in real time by the reference mirror during the measurement process, it includes: obtaining the contour error of each section of the long side direction of the workpiece corresponding to the reference mirror, and then converting and splicing the contour error of each section of the long side direction of the workpiece to obtain the straightness error contour of the workpiece.

[0018] Furthermore, when the contour error of each section in the long side direction of the workpiece is converted and then spliced, it specifically includes:

[0019] Calculate the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece i and the position error difference ΔA i ;

[0020] According to the contour error of the latter of two adjacent sections in the long side direction of the workpiece Measurement value, slope error difference ΔB i and the position error difference ΔA i , calculate the contour error after the next transformation

[0021] The contour error of the first segment in the two adjacent segments along the long side of the workpiece The error between the measured value and the profile after the subsequent conversion Add together to get the straightness error profile of two adjacent sections along the long side of the workpiece

[0022] Furthermore, the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece is calculated i and the position error difference ΔA i Specifically include:

[0023] In the overlapping area of ​​two adjacent sections in the long side direction of the workpiece, the contour errors corresponding to the two adjacent sections in the long side direction of the workpiece are subtracted;

[0024] Using the least squares method, the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece is calculated. i and the position error difference ΔA i , the expression is as follows:

[0025]

[0026] Where k = 1, 2, ... N, N is the number of data points in the overlapping area, It is the contour error of the first segment in the overlapping area of ​​two adjacent segments along the long side of the workpiece. is the contour error of the latter of two adjacent sections in the long side direction of the workpiece in the overlapping area, x i,k It is the kth position of the workpiece in the i-th section.

[0027] Furthermore, the contour error after the latter conversion The expression is as follows:

[0028]

[0029] Among them, x i+1 It is the horizontal coordinate of the i+1th section of the workpiece.

[0030] Optionally, when measuring the initial surface shape of the workpiece using a measuring device, a Bessel point support method is used to minimize the gravity deformation of the workpiece.

[0031] Optionally, when the time-controlled grinding device is controlled by the processing code to perform time-controlled grinding on the workpiece, an edge-filling fixture is arranged around the workpiece to reduce the edge effect of the time-controlled grinding.

[0032] Optionally, after measuring the surface shape of the processed workpiece using a measuring device, the method includes: performing low-pass filtering on the measurement result according to a specified frequency band.

[0033] Optionally, the specified band is 10mm.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] The present invention uses time-controlled grinding to continuously improve the workpiece processing accuracy according to the measurement results, so the processing accuracy is not limited by the machine tool, and the measurement errors of the measuring equipment in the long side direction and the short side direction of the workpiece are separated by the reference mirror, so the measurement accuracy of the workpiece can be guaranteed, and then the processing accuracy of the workpiece can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is the principle diagram of time-controlled grinding.

[0037] Figure 2 is a flow chart of an embodiment of the present invention.

[0038] Figure 3 Schematic diagram of the structure of the measuring device used in the embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram of the error splicing principle of the long side direction of the workpiece in an embodiment of the present invention.

[0040] Figure 5 This is the measurement result of the long side splicing of the workpiece in the embodiment of the present invention.

[0041] Figure 6 Schematic diagram of the error separation principle in the short side direction of the workpiece in an embodiment of the present invention.

[0042] Figure 7 This is the process flow chart of time-controlled grinding. DETAILED DESCRIPTION

[0043] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0044] Before introducing the specific embodiments of the present invention, related concepts are first explained.

[0045] Timed Grinding: Timed Grinding is a precision machining method that is mainly used to ensure that parts reach the required size and surface quality within a specified time. Through precise control of the grinding time, timed grinding can improve machining efficiency, reduce costs, and ensure consistency in machining quality. The basic principles of timed grinding are as follows: Figure 1 As shown, a stable removal function is formed by constant pressure and speed, and the grinding time is precisely controlled so that a certain amount of material is removed from the workpiece surface within a specified time, thereby achieving the expected size and surface quality.

[0046] Example

[0047] In order to improve the machining accuracy of long-stroke metal guide rails, this embodiment proposes a sub-micron precision long-stroke metal guide rail measurement and machining method. On the basis of the traditional grinding method, a time-controlled grinding method based on the computer deterministic shaping principle is used to process the long-stroke metal guide rails. The time-controlled grinding method uses a measurement-machining iteration method to achieve high-precision guide rail machining with a large stroke. The machining accuracy depends on the measurement accuracy and is not limited by the accuracy of the machine tool itself. At the same time, an optical reference mirror is used to measure and calibrate the system error of the measuring equipment to improve the measurement accuracy of the metal guide rail.

[0048] like Figure 2 As shown, the specific implementation steps of the method of this embodiment include:

[0049] S1) using a reference mirror to separate the measurement errors of the measuring device in the long side direction and the short side direction of the workpiece, and then calibrating the measuring device using the measurement errors in the long side direction and the short side direction of the workpiece;

[0050] S2) using a measuring device to measure the initial surface shape of the workpiece, generating a corresponding processing code according to the initial surface shape, and using the processing code to control the time-controlled grinding device to perform time-controlled grinding on the workpiece;

[0051] S3) Using a measuring device to measure the surface shape of the workpiece after processing, if the surface shape of the workpiece after processing does not meet the accuracy requirements, a new processing code is generated according to the surface shape of the workpiece after processing, and the new processing code is used to control the time-controlled grinding device to perform time-controlled grinding on the workpiece until the surface shape of the workpiece after processing meets the accuracy requirements.

[0052] Each step is described in detail below.

[0053] The measuring device used in step S1 of this embodiment is as follows Figure 3 As shown, it consists of X-axis, Y-axis, and non-contact sensors. The Y-axis measurement range is 700mm and the X-axis measurement range is 200mm. When the reference mirror is used to separate the measurement equipment, the measurement errors in the long and short sides of the workpiece include:

[0054] S11) setting the reference mirror on one side of the long side direction of the workpiece (i.e., the Y axis), controlling the measuring device to feed along the Y axis at the corresponding position of the workpiece where the reference mirror is placed, and separating the measurement error of the long side direction of the workpiece in real time during the measurement by the reference mirror. For a long-stroke metal guide rail, the measurement error of the long side direction of the workpiece is mainly the straightness error along the length direction of the guide rail;

[0055] S12) The reference mirror is set on one side of the short side of the workpiece (i.e., the X-axis), and the measuring device is controlled to feed along the X-axis at the corresponding position of the workpiece where the reference mirror is placed on the side of the workpiece. The measurement error in the short side of the workpiece during the measurement process is separated in real time by the reference mirror. For long-stroke metal guide rails, the measurement error in the short side of the workpiece includes straightness error and temperature error.

[0056] In step S11 of this embodiment, the reference mirror uses an optical reference mirror with a length of 500mm and an accuracy of 0.1μm. When the length of the workpiece is less than the length of the reference mirror, the reference mirror can be used directly to separate the measurement error in the long side direction of the workpiece. In this case, how to use the reference mirror to separate the measurement error belongs to the conventional method. However, in this embodiment, the workpiece is a long-stroke metal guide rail, and its length direction is generally greater than 500mm. Therefore, in this embodiment, it is considered to use splicing to separate the error in the long side direction of the workpiece.

[0057] Correspondingly, in step S11, when the reference mirror is set on one side of the long side of the workpiece, it specifically includes:

[0058] If the length of the workpiece is greater than the length of the reference mirror, two or more reference mirrors are sequentially arranged along the long side of the workpiece according to the specified step length, so that during the process of controlling the measuring device to perform feeding motion along the Y axis, each reference mirror measures the measurement error of the corresponding section of the workpiece respectively;

[0059] Or, if Figure 4 As shown, a reference mirror is set from an initial position to the next position in sequence along the long side of the workpiece according to a specified step length. After the reference mirror is placed at the new position, the measuring device is controlled to feed along the Y-axis at the corresponding position, thereby obtaining the measurement error of each section of the workpiece through a reference mirror.

[0060] Therefore, when the measurement error in the long side direction of the workpiece is separated in real time by the reference mirror during the measurement process, specifically, the straightness error of the i-th section of the workpiece in the long side direction of the workpiece corresponding to the i-th reference mirror or the i-th placement position of the reference mirror is separated, so that the contour error of each section in the long side direction of the workpiece can be obtained, and then the contour error of each section in the long side direction of the workpiece is converted and spliced ​​to obtain the straightness error contour of the workpiece.

[0061] In this embodiment, when the contour error of each section in the long side direction of the workpiece is converted and then spliced, it specifically includes:

[0062] First, calculate the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece i and the position error difference ΔA i ;

[0063] For the i-th section of the workpiece, the measurement result of the profile error of the i-th section by the reference mirror when separating the measurement error is: The straightness error measurement result is z i As shown in formula (1) and formula (2):

[0064]

[0065]

[0066] Where B i , A i is the slope error and position error of the i-th segment contour error, x i is the horizontal coordinate of the i-th workpiece.

[0067] Due to the existence of slope error and position error, the contours of the overlapping areas of the i-th and i+1-th sections of the guide rail are not equal, as shown in formula (3):

[0068]

[0069] However, the guide straightness error profiles are equal in the overlapped area:

[0070] z = z (4)

[0071] i,k i+1,k

[0072] Where k = 1, 2, ... N, N is the number of data points in the overlapping area.

[0073] Therefore, the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece is calculated i and the position error difference ΔA i When , in the overlapping area of ​​two adjacent segments in the long side direction of the workpiece, the contour errors corresponding to the two adjacent segments in the long side direction of the workpiece are subtracted, that is, equation (1) and (2) are subtracted, and the following can be obtained:

[0074]

[0075] Where ΔB i =B i -B i+1 , ΔA i =A i -A i+1 .

[0076] B and A can be calculated using the least squares method, as shown in formula (6):

[0077]

[0078] in, It is the contour error of the first segment i in the overlapping area of ​​two adjacent segments along the long side of the workpiece. is the contour error of the latter i+1 segment in the overlapping area of ​​the two adjacent segments along the long side of the workpiece, x i,k It is the kth position of the workpiece in the i-th section.

[0079] Then, according to the contour error of the latter of the two adjacent sections in the long side direction of the workpiece Measurement value, slope error difference ΔB i and the position error difference ΔA i , calculate the contour error after the next transformation The expression is as follows:

[0080]

[0081] Among them, x i+1 It is the horizontal coordinate of the i+1th section workpiece.

[0082] Finally, the converted i+1th rail profile z is used i+1 t , and the measured value z of the rail profile of the i-th section i m The straightness error profile of the guide rail after splicing can be obtained, and the expression is as follows:

[0083]

[0084] Based on the above formula, when the workpiece length is greater than the reference mirror length, the straightness error of the long-stroke guide rail can be spliced ​​and the measuring equipment can be calibrated. The results are as follows: Figure 5 shown.

[0085] In step S12 of this embodiment, the reference mirror uses a 100 mm optical reference mirror with an accuracy of 0.1 μm. Since the workpiece material is cast iron, it is easy to produce thermal expansion. In order to reduce the error in the short side direction of the workpiece, the measuring device changes the traditional bidirectional grating scanning path to a unidirectional grating scanning path, and sets the reference mirror at the position where the grating track wraps, such as Figure 6 As shown in the figure, a 100mm optical reference mirror is placed on the right side of the workpiece, and the control measuring device changes the traditional bidirectional grating scanning path to a unidirectional grating scanning path, and only feeds on the right side of the workpiece. The measurement data of the optical reference mirror is used to separate the measurement error in the short side direction of the workpiece (i.e., the X-axis direction) in real time. Since the reference mirror is an ideal plane, the error in the short side direction of the workpiece can be obtained through the data separation of the reference mirror, including the straightness error E ZX (x) and temperature error E TZX (x), as shown in formula (9).

[0086] E(x)=(E ZX (x) +E TZX (x)) (9)

[0087] It should be noted that in order to ensure that the reference mirror and the workpiece have the same thermal expansion, the same cast iron material as the workpiece is used under the reference mirror to ensure that the thermal expansion of the auxiliary mirror and the workpiece is consistent.

[0088] like Figure 7 As shown, steps S2 and S3 of this embodiment process the long-stroke metal guide rail by measuring-processing iteration, wherein step S2 specifically includes the following steps:

[0089] S21) measuring the initial surface shape of the workpiece by using the measuring device after separating the measurement error in step S1, and in order to avoid installation deformation of the workpiece during measurement, using a Bessel point support method to minimize the gravity deformation of the workpiece, specifically supporting the workpiece at an optimal support position based on the Bessel principle;

[0090] S22) after obtaining the initial surface shape of the workpiece, a processing code corresponding to the initial surface shape is generated based on the principle of time-controlled grinding processing, specifically, a removal function is calculated according to the initial surface shape, thereby obtaining a processing residence time, that is, the residence time of the tool at the processing position, the longer the residence time, the higher the material removal amount, and then a processing code is generated to perform the first processing according to the residence time and the required processing trajectory;

[0091] S23) Using the processing code to control the time-controlled grinding device to perform time-controlled grinding on the workpiece, based on the deterministic shaping principle, high-precision processing is achieved through a stable removal function. In this embodiment, in order to avoid the processing edge effect, a filler fixture is added around the workpiece during processing.

[0092] After the processing is completed, step S3 is performed, such as Figure 7 As shown, the workpiece surface shape after processing is measured to determine whether the processing accuracy is less than 1 μm. If the accuracy requirement is not met, the removal function is calculated again according to the workpiece surface shape after processing, so as to obtain the processing residence time and generate the corresponding processing code; if the requirement is met, the process ends. In this embodiment, due to the periodic texture on the workpiece surface, the workpiece surface shape measurement result is low-pass filtered, and the filter frequency band is set to 10 mm.

[0093] It can be seen from the above process that the time-controlled grinding processing principle belongs to the deterministic shaping processing principle. The workpiece processing accuracy is continuously improved according to the measurement results. Therefore, the processing accuracy is not limited by the machine tool. This embodiment separates the main system errors of the measuring equipment through the optical reference mirror, so it can ensure the surface measurement accuracy of the long-stroke metal guide rail, and thus can greatly improve the processing accuracy of the long-stroke metal guide rail.

[0094] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for measuring and processing a sub-micron precision long-stroke metal guide rail, characterized in that: The following steps are involved: S1) using a reference mirror to separate the measurement errors of the measuring device in the long side direction and the short side direction of the workpiece, and then calibrating the measuring device using the measurement errors in the long side direction and the short side direction of the workpiece; S2) using a measuring device to measure the initial surface shape of the workpiece, generating a corresponding processing code according to the initial surface shape, and using the processing code to control the time-controlled grinding device to perform time-controlled grinding on the workpiece; S3) Using a measuring device to measure the surface shape of the workpiece after processing, if the surface shape of the workpiece after processing does not meet the accuracy requirements, a new processing code is generated according to the surface shape of the workpiece after processing, and the new processing code is used to control the time-controlled grinding device to perform time-controlled grinding on the workpiece until the surface shape of the workpiece after processing meets the accuracy requirements.

2. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 1 is characterized in that: When using a reference mirror to separate the measurement equipment for the measurement errors in the long side and short side directions of the workpiece, specifically including: The reference mirror is set on one side of the long side of the workpiece, and the measuring device is controlled to perform feeding movement at the corresponding position of the workpiece where the reference mirror is placed, so that the measurement error in the long side direction of the workpiece during the measurement process is separated in real time by the reference mirror; The reference mirror is set on one side of the short side of the workpiece, and the measuring device is controlled to use a unidirectional grating scanning path to feed the workpiece on the side where the reference mirror is placed. The reference mirror is set at the position where the grating track wraps, and the measurement error in the short side direction of the workpiece is separated in real time by the reference mirror during the measurement process.

3. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 2 is characterized in that: The reference mirror is set on one side of the long side of the workpiece, and the measuring device is controlled to perform feeding movement at the corresponding position of the workpiece where the reference mirror is placed, specifically including: If the length of the workpiece is greater than the length of the reference mirror, two or more reference mirrors are sequentially arranged along the long side of the workpiece according to a specified step length, and then the measuring device is controlled to feed along the long side of the workpiece on the side of the workpiece where the reference mirror is placed, or the reference mirror is sequentially arranged at the next position along the long side of the workpiece according to a specified step length starting from the initial position, and each time the reference mirror is arranged at a new position, the measuring device is controlled to feed at the corresponding position along the long side of the workpiece; When the measurement error of the long side direction of the workpiece is separated in real time by the reference mirror during the measurement process, it includes: obtaining the contour error of each section of the long side direction of the workpiece corresponding to the reference mirror, and then converting and splicing the contour error of each section of the long side direction of the workpiece to obtain the straightness error contour of the workpiece.

4. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 3 is characterized in that: When the contour error of each section of the long side of the workpiece is converted and spliced, it specifically includes: Calculate the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece i and the position error difference ΔA i ; According to the contour error of the latter of two adjacent sections in the long side direction of the workpiece Measurement value, slope error difference ΔB i and the position error difference ΔA i , calculate the contour error after the next transformation The contour error of the first segment in the two adjacent segments along the long side of the workpiece The error between the measured value and the contour after the subsequent conversion Add together to get the straightness error profile of two adjacent sections along the long side of the workpiece 5. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 4, characterized in that: Calculate the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece i and the position error difference ΔA i Specifically include: In the overlapping area of ​​two adjacent sections in the long side direction of the workpiece, the contour errors corresponding to the two adjacent sections in the long side direction of the workpiece are subtracted; Using the least squares method, the slope error difference ΔB of the contour error of two adjacent sections in the long side direction of the workpiece is calculated. i and the position error difference ΔA i , the expression is as follows: Where k = 1, 2, ... N, N is the number of data points in the overlapping area, It is the contour error of the first segment in the overlapping area of ​​two adjacent segments along the long side of the workpiece. is the contour error of the latter of two adjacent sections in the long side direction of the workpiece in the overlapping area, x i,k It is the kth position of the workpiece in the i-th section.

6. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 4, characterized in that: Contour error after the last conversion The expression is as follows: Among them, x i+1 It is the horizontal coordinate of the i+1th section of the workpiece.

7. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 1, characterized in that: When using a measuring device to measure the initial surface shape of a workpiece, the Bessel point support method is used to minimize the gravity deformation of the workpiece.

8. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 1, characterized in that: When the time-controlled grinding device is controlled by the processing code to perform time-controlled grinding on a workpiece, an edge-filling fixture is arranged around the workpiece to reduce the edge effect of the time-controlled grinding.

9. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 1, characterized in that: After measuring the surface shape of the processed workpiece using a measuring device, the following steps are performed: low-pass filtering is performed on the measurement result according to a specified frequency band.

10. The sub-micron precision long-stroke metal guide rail measurement and processing method according to claim 9, characterized in that: The specified band is 10mm.

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