A machine tool Z-axis repeat positioning error measurement method

Abstract

The application discloses a kind of machine tool Z axis repeat positioning error measurement method, belong to machine tool Z axis repeat positioning error precision detection technical field, including the following contents: S1 using the circular arc blade edge turning tool with tool tip radius R is processed several arc grooves on the datum plane of workpiece, the Z direction theoretical feed H0 when processing several arc grooves is consistent;S2 using the optical image instrument with detection accuracy of 1 μm measures the width D of several arc grooves in S1;S3 calculates the Z direction actual feed H1 when processing several arc grooves;S4 compares the difference of Z direction actual feed H1 and Z direction theoretical feed H0, obtains Z axis repeat positioning precision, and statistics Z axis positioning error;Using the above measurement method, not only can improve the detection accuracy of machine tool Z axis repeat positioning error, and relative to the way needing to replace special measuring device, reduce detection cost, improve operation convenience, it is convenient to monitor machine tool Z axis repeat positioning error daily.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of precision detection of machine tool Z-axis repeat positioning error in ultra-precision machining, and particularly relates to a machine tool Z-axis repeat positioning error measurement method. BACKGROUND

[0002] During the reciprocating motion of the machine tool Z-axis, there is generally a certain deviation from the set theoretical movement distance, which is referred to as machine tool Z-axis repeat positioning error. The machine tool Z-axis repeat positioning error directly affects the Z-axis machining precision and plays a key role in workpiece machining quality, so it is crucial to reasonably measure the machine tool Z-axis repeat positioning error.

[0003] The prior art such as the utility model with application number 202020417441.2 and the invention patent with application number 202110486553.2 measures the machine tool Z-axis repeat positioning precision by replacing the special measuring device (such as the precision contact switch and digital differential scale in the utility model with application number 202020417441.2, and the laser light source and PSD displacement real-time detection hardware system in the invention patent with application number 202110486553.2) on the machine tool. With the extension of the use time, the machine tool Z-axis repeat positioning precision will change, so it is necessary to monitor the machine tool Z-axis repeat positioning precision at any time and adjust the production process according to the current machine tool Z-axis repeat positioning precision adaptability to ensure the production precision of the parts. However, the above measurement method has the problems of ①expensive special detection equipment, ②high measurement space requirement, ③high professional requirement of the measurement method, and ④the need to disassemble several parts of the original machine tool to replace the special measuring device, which is not suitable for daily monitoring of the machine tool Z-axis repeat positioning precision.

[0004] Therefore, it is urgent to develop a low-cost and simple machine tool Z-axis repeat positioning error measurement method for daily monitoring of the machine tool Z-axis repeat positioning precision. SUMMARY

[0005] The present application aims to overcome the defects and deficiencies in the prior art and provide a machine tool Z-axis repeat positioning error measurement method. When detecting the machine tool Z-axis repeat positioning error, the machining tool or other structure of the machine tool does not need to be replaced by a special measuring device. Compared with the measurement method in the prior art that needs to replace the special measuring device, the detection cost is reduced, the process of replacing the measuring device is saved, the measurement steps are simplified, the professional requirement is low, ordinary technical personnel can operate it, and it is convenient for daily monitoring of the machine tool Z-axis repeat positioning precision.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0007] The application provides a machine tool Z-axis repeat positioning error measurement method, and comprises the following contents.

[0008] S1 adopts a circular blade bit with a tool tip radius of R to process a plurality of arc grooves on a reference plane of a workpiece, and the Z-direction theoretical feed amount H0 during processing of the plurality of arc grooves is kept consistent;

[0009] S2 measures the width D of the plurality of arc grooves processed in S1 by using an optical image instrument with a detection accuracy of 1 μm;

[0010] S3 calculates the Z-direction actual feed amount H1 during processing of the plurality of arc grooves;

[0011]

[0012] S4 compares the difference between the Z-direction actual feed amount H1 and the Z-direction theoretical feed amount H0, obtains the Z-axis repeat positioning accuracy, and calculates the Z-axis positioning error;

[0013] Preferably, before processing the arc grooves, the circular blade bit is used to process the reference plane on the workpiece;

[0014] Preferably, a unified slotting program is used to process the plurality of arc grooves in S1;

[0015] Preferably, the Z-direction theoretical feed amount is determined according to requirements;

[0016] Preferably, after the arc grooves are processed, the workpiece is moved to a station where the optical image instrument is located, and the widths of the arc grooves are measured in sequence;

[0017] Preferably, the tool tip radius is determined according to requirements;

[0018] Preferably, at least three groups of arc grooves are processed on the reference plane;

[0019] Preferably, the Z-axis repeat positioning accuracy = H0-H1;

[0020] Preferably, the material of the arc blade bit is diamond.

[0021] The application has the following technical effects compared with the prior art:

[0022] 1. Directly measure the Z-direction actual feed amount of the arc-shaped groove, the measurement accuracy is not only limited to the detection accuracy of the measuring tool, but also limited to the inability to accurately find the maximum depth of the arc-shaped groove, that is, the measurement error of the Z-direction actual feed amount of the arc-shaped groove is large, and the measurement result is inaccurate. In order to solve this problem and improve the detection accuracy of the Z-direction actual feed amount of the arc-shaped groove, the application adopts the measurement method of indirectly calculating the Z-direction actual feed amount of the arc-shaped groove by measuring the width D of the arc-shaped groove by the optical image instrument with high precision. Because the precision of the optical image instrument is 1μm, the detection accuracy is high, and the influence value of the repeated positioning accuracy calculated by this method can be ignored, so the error of the Z-direction actual feed amount of the arc-shaped groove obtained by indirect calculation is smaller than the error of the Z-direction actual feed amount of the arc-shaped groove obtained by direct measurement, thereby improving the accuracy of the machine tool Z-axis repeated positioning error obtained.

[0023] 2. The measurement method provided by the application does not need to replace the machining tool or other structure of the machine tool with a special measuring device when detecting the machine tool Z-axis repeated positioning error, compared with the measurement method of replacing the special measuring device in the prior art, the detection cost is reduced, the process of replacing the measuring device is saved, the measurement steps are simplified, the professional requirement is low, and ordinary technical personnel can operate, thereby facilitating the daily monitoring of the machine tool Z-axis repeated positioning accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0025] Figure 1 The structural schematic diagram of machining the arc-shaped groove on the reference plane.

[0026] 1, reference plane; 2, arc-shaped groove; R, tool tip radius of the circular arc edge turning tool; D, actual width of the arc-shaped groove; H1, Z-direction actual feed amount. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0028] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0029] As shown in Figure 1 The present application provides a machine tool Z-axis repeat positioning error measurement method, comprising the following contents:

[0030] S1 adopts a circular arc blade bit tool with a tool tip radius R to process a plurality of arc grooves 2 on the reference plane 1 of the workpiece, and the Z-direction theoretical feed amount H0 during processing of the plurality of arc grooves 2 is kept consistent;

[0031] The circular arc blade bit tool needs to select a tool tip radius R in a form convenient for measurement, such as selecting an arc blade bit tool with a fixed tool tip radius R, and the specific value of the tool tip radius R of the arc blade bit tool can be selected according to requirements; during processing of the arc grooves 2, the reference plane 1 of the workpiece is uniformly taken as the initial processing position, and in order to facilitate calculation and statistics of the machine tool Z-axis repeat positioning error, the Z-direction feed amount H0 of the plurality of arc grooves 2 is kept consistent.

[0032] Before processing the arc grooves 2, a workpiece with a reference plane 1 processed by other means can be selected as the processing object of the arc grooves 2, or the above-mentioned circular arc blade bit tool can be used to process a reference plane 1 on the workpiece first, and the present application selects the mode of processing a reference plane 1 on the workpiece first by using the above-mentioned circular arc blade bit tool, which not only facilitates material selection, but also does not need to replace the tool during subsequent processing, making the operation more convenient.

[0033] There are many ways to keep the Z-direction theoretical feed amount H0 consistent, and the present application simplifies the processing steps by writing a slotting program before processing, and uniformly using this slotting program to process the plurality of arc grooves 2 in turn; in order to further reduce errors, the present application processes at least 3 groups of arc grooves 2 on the reference plane 1, and the value of the Z-direction theoretical feed amount H0 can be determined according to requirements;

[0034] S2 measures the width D of the plurality of arc grooves 2 processed in S1 by using an optical image instrument with a detection accuracy of 1 μm;

[0035] After the arc grooves 2 are processed, the workpiece is taken out from the processing device and moved to the station where the optical image instrument is located, and the width of the plurality of arc grooves 2 is measured in turn by the optical image instrument; the optical image instrument with a detection accuracy of 1 μm is selected, and the repeat positioning accuracy influence value calculated by this method can be ignored.

[0036] S3 calculates the Z-direction actual feed amount H1 during processing of the plurality of arc grooves 2;

[0037] Reference Figure 1The Z-direction actual feeding amount H1 of the arc-shaped groove 2 can be indirectly calculated according to the Pythagorean theorem, and the Z-direction actual feeding amount H1 of the arc-shaped groove 2 is calculated by the following formula: Wherein, R is the nose radius of the circular-arc blade tool, and D is the measured actual width of the arc-shaped groove 2.

[0038] The Z-direction actual feeding amount of the arc-shaped groove 2 is directly measured by a measuring tool, and the measurement accuracy is not only limited by the measurement accuracy of the measuring tool, but also cannot accurately find the lowest point of the arc-shaped groove 2, so the measurement error of the Z-direction actual feeding amount of the arc-shaped groove 2 directly measured by the measuring tool is relatively large; in order to overcome this defect and improve the accuracy of the Z-direction actual feeding amount of the arc-shaped groove 2, the width D of the arc-shaped groove 2 is first measured by a high-precision optical image instrument, and then the Z-direction actual feeding amount of the arc-shaped groove 2 is indirectly calculated, because the accuracy of the optical image instrument is 1 μm, the detection accuracy is high, and the influence value of the repeated positioning accuracy calculated in this way can be ignored, so the error of the Z-direction actual feeding amount of the arc-shaped groove 2 obtained by indirect calculation is smaller than the error of the Z-direction actual feeding amount of the arc-shaped groove 2 obtained by direct measurement, and the accuracy of the Z-direction actual feeding amount of the arc-shaped groove 2 is improved.

[0039] S4 compares the difference between the Z-direction actual feeding amount H1 and the Z-direction theoretical feeding amount H0, and obtains the Z-axis repeated positioning accuracy and the Z-axis positioning error; wherein the Z-axis repeated positioning accuracy = H0-H1.

[0040] Example 1:

[0041] Step 1: a diamond tool with a nose radius of R500 μm is selected, and a plane on the workpiece surface is processed as a reference plane 1;

[0042] Step 2: a groove cutting program is written, the Z-direction theoretical feeding amount H0 is controlled to be 1 um, then the Z-axis is retracted, and the first arc-shaped groove is cut;

[0043] Step 3: according to the direction indicated by the arrow in Figure 1 Step 3: according to the direction indicated by the arrow in

[0044] Step 4: continue to cut the third arc-shaped groove according to the above steps;

[0045] Step 5: stop processing, take down the workpiece, and place it on the detection station of the optical image instrument for detection, and measure the width of each groove;

[0046] Step 6: the actual cutting depth of the Z-axis, i.e. the Z-direction actual feeding amount H1, is obtained according to the formula;

[0047] Step 7: Compared with the theoretical cutting depth of the machine tool, the repeat positioning accuracy of the machine tool is calculated, the Z round positioning error is counted, and the statistical data are shown in Table 1. According to the data in the table, it can be concluded that the repeat positioning error of the Z axis of the machine tool is ±0.06 μm.

[0048] Table 1:

[0049]

[0050] It should be noted that, for those skilled in the art, it is obvious that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting, the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present application, and any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. A method of measuring a machine tool Z-axis repeatability error, characterized by: The application relates to a method for measuring the Z-axis positioning accuracy of a lathe tool. The method comprises the following steps: S1: a circular-arc blade tool with a tool tip radius R is used to process a plurality of arc-shaped grooves on a reference plane of a workpiece, the shape of the arc-shaped grooves corresponds to the shape of the tool tip outer circle of the circular-arc blade tool, and the Z-direction theoretical feed amount H0 of the arc-shaped grooves is kept consistent; S2: an optical image instrument with a detection accuracy of 1 mu m is used to measure the width D of the arc-shaped grooves processed in S1; S3: the Z-direction actual feed amount H1 of the arc-shaped grooves is calculated; S4: the difference between the Z-direction actual feed amount H1 and the Z-direction theoretical feed amount H0 is compared to obtain the Z-axis positioning accuracy, and the Z-axis positioning error is counted; 2. The method of claim 1, wherein: Before the arc-shaped grooves are processed, the circular-arc blade tool is used to process the reference plane on the workpiece.

3. The method of claim 1, wherein: The arc-shaped grooves are processed by using a unified slotting program in S1.

4. The method of claim 1, wherein: The Z-direction theoretical feed amount is determined according to requirements.

5. The method of claim 1, wherein: After the arc-shaped grooves are processed, the workpiece is moved to a work station where the optical image instrument is located, and the width of the arc-shaped grooves is measured in sequence.

6. The method of claim 1, wherein: The tool tip radius R is determined according to requirements.

7. The method of claim 1, wherein: At least three groups of arc-shaped grooves are processed on the reference plane.

8. The method of claim 1, wherein: The Z-axis positioning accuracy = H0-H1. The material of the circular-arc blade tool is diamond.

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