CN104596465B - For detecting feature exemplar and the method for three axle diamond lathe axial system errors - Google Patents

Abstract

The invention discloses a characteristic sample and a method for detecting the shaft system error of a three-axis diamond lathe. The feature sample is composed of a base and a feature body. The feature body is arranged on the top end surface of the base and coaxially with it. The overall shape of the feature body is a cylinder, and the middle position of the height direction of the cylinder is A ring-shaped concave surface is provided. The detection method is as follows: 1. Use a three-axis diamond lathe with a T-shaped layout to process the characteristic sample; 2. After the processing is completed, use a cylindricity meter to measure the outer cylindrical surface of the characteristic sample, and use a cylindricity meter to measure the end face of the characteristic sample. And the annular concave surface; 3. According to the detection result of step 2, infer the axis system error of the three-axis diamond lathe. The sample designed by the invention has the characteristics of simple structure, convenient processing, and can effectively reflect the error of the shaft system, etc., and provides a new method for error detection and machine tool acceptance of the three-axis diamond lathe.

Description

Characteristic sample and method for detecting shaft error of three-axis diamond lathe

technical field

The invention belongs to the field of ultra-precision diamond lathes, and relates to a characteristic sample and a method for detecting shafting errors of a three-axis diamond lathe.

Background technique

At present, there are no national standards and related patent documents for the error detection and acceptance of diamond lathes. Lathes have certain limitations.

At this stage, most of the error detection methods between the axes of the three-axis diamond lathe rely on high-precision instruments and equipment such as square rulers, high-precision micrometers, laser autocollimators, and laser interferometers. These equipment are not only expensive and cumbersome to operate, but also There are extremely strict requirements on the detection environment, and the measurement results are closely related to the technical level of the operator.

CN100468038C discloses an "S"-shaped test piece for comprehensively testing the accuracy of a CNC milling machine and a testing method thereof. The linkage performance and processing capability of a five-axis milling machine can be judged through the processing quality of the S-shaped sample. Most of the existing detection methods based on characteristic samples are for five-axis milling machines, and there are no related patents for diamond lathes at present.

Contents of the invention

The purpose of the present invention is to provide a characteristic sample and method for detecting the error of the shaft system of a three-axis diamond lathe, and reversely characterize the error between the shaft systems of a three-axis diamond lathe by processing a feature sample and detecting the geometric accuracy of the sample . The designed sample has the characteristics of simple structure, convenient processing, and can effectively reflect the shaft error, etc., which provides a new method for error detection and machine tool acceptance of three-axis diamond lathe.

The purpose of the present invention is achieved through the following technical solutions:

A characteristic sample for detecting the shafting error of a three-axis diamond lathe, including two parts: a base and a characteristic body. The characteristic body is arranged on the top end surface of the base and coaxially with it. The overall shape of the characteristic body is a cylinder body, the middle position in the height direction of the cylinder is provided with an annular concave curved surface.

A method for detecting shaft error of a three-axis diamond lathe based on characteristic samples, the specific implementation steps are as follows:

1. Use a three-axis diamond lathe with a T-shaped layout to process feature samples. When machining the outer cylindrical surface of a cylinder, only the Z axis needs to be fed in a straight line, and the other two axes remain stationary; when machining the top end plane of the cylinder, only The X axis needs to be fed in a straight line, and the other two axes remain stationary; when machining a circular concave surface, the X and Z axes perform circular interpolation motion at the same time;

2. After the processing is completed, use a cylindricity meter to measure the characteristic sample, mainly including the taper of the outer cylindrical surface, the flatness of the end surface and the roundness of the annular concave surface;

3. According to the detection results of step 2, infer the shafting error of the three-axis diamond lathe.

In the present invention, the base may be a cylinder of revolution, with a thickness of 10mm and excessive chamfering. The diameter of the base is about 30mm larger than the diameter of the cylinder.

In the present invention, the total length of the characteristic body depends on the maximum processing range of the Z axis. When the characteristic length is too short, it cannot fully reflect the error of the axis system, and the processing range within 70% is the usual range. Therefore, the total length of the feature body should be between 60-70% of the maximum processing range of the Z-axis.

In the present invention, the radius dimension of the top surface of the cylinder depends on the maximum processing range of the X-axis. If the diameter of the end face is too small, it cannot fully reflect the error of the shaft system, and the processing range within 70% is the usual range. The end face is a rotationally symmetrical structure, so the radius of the end face should be within 30-35% of the maximum processing range of the X-axis.

In the present invention, the annular concave surface is a concave spherical surface of R50D20, the radius of the ball is 50 mm, the diameter D of the cylinder is 20 mm, and the position of the spherical surface is distributed at the center of the cylinder in the length direction.

The present invention has the following advantages:

1. The detection process of the shafting relationship of the diamond lathe is simplified, and the detection results are more effective than the conventional detection method. The detection results of the conventional detection are all static detection results, which cannot accurately reflect the spatial relationship of the shafting under the real working conditions of the diamond lathe. Machine tool processing will be affected by factors such as the actual working environment and workpiece process parameters, and the feature samples directly processed by the machine tool can completely and accurately reflect the real operating state and shafting relationship of the machine tool.

2. The present invention introduces the reverse detection method based on characteristic samples to the field of ultra-precision diamond lathes, simplifies the detection method and detection process, and provides an effective new idea for the detection of ultra-precision diamond lathes.

3. The shaft relationship detection of diamond lathes can be detected without high-precision and expensive professional testing equipment, and professional testing personnel are not required to operate. After editing the processing program, automatic processing can be realized.

Description of drawings

Fig. 1 is the process flow diagram of detection method of the present invention;

Figure 2 is a three-axis diamond lathe with a typical T-shaped layout;

Fig. 3 is a three-dimensional view of a feature sample;

Fig. 4 is the front view of characteristic sample;

Fig. 5 is a schematic diagram of the parallelism error between the main axis and the Z axis;

Fig. 6 is a schematic diagram of the perpendicularity error between the main axis and the X axis.

detailed description

The technical solution of the present invention will be further described below in conjunction with the accompanying drawings, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered by the present invention. within the scope of protection.

Specific Embodiment 1: This embodiment provides a method for detecting the axis error of a three-axis diamond lathe based on a characteristic sample. Through theoretical derivation and analysis, it can be known that the spatial relationship between the three axes affects the surface shape error of the processed workpiece. Influence relationship, and then according to the above relationship, design a characteristic sample that can accurately reflect the spatial relationship of the machine tool shaft system, use precision equipment such as cylindricity to test the processed characteristic sample, and use various measurement data to reversely characterize the diamond. Spatial relationship between lathe shafts.

As shown in Figure 1, the specific implementation steps are as follows:

1. Use a diamond lathe to process feature samples. A three-axis diamond lathe with a T-shaped layout is shown in Figure 1. The X and Z linear axes are arranged vertically in a T-shape. The main shaft (with C-axis function) is placed on the X-axis, and the tool post is placed on the Z-axis. As shown in Figure 3-4, the characteristic sample is composed of two parts, the base 1 and the characteristic main body 2. The characteristic main body 2 is arranged on the top end surface of the base 1 and is coaxial with it. The overall shape of the characteristic main body 2 is a cylinder. body 4, the middle position in the height direction of the cylinder body 4 is provided with an annular concave curved surface 3. The size range of the designed feature samples is consistent with the most commonly used working range of diamond lathes.

2. During the machining process, when machining the outer cylindrical surface of the cylinder, only the Z axis needs to be fed in a straight line, and the other two axes remain stationary; when machining the end surface of the cylinder, only the X axis is required to be fed in a straight line, and the other two axes remain stationary; When machining the circular concave surface, the X and Z axes perform circular interpolation motion at the same time.

3. After the processing is completed, use a cylindricity meter to measure the characteristic sample, mainly including the taper of the outer cylindrical surface, the flatness of the end surface and the roundness of the annular concave surface.

4. Through the test results of the outer cylindrical surface, we can know the parallel relationship between the Z axis and the main axis; the test results of the flatness of the end surface can know the perpendicularity relationship between the X axis and the main axis. The verticality relationship between the outer cylindrical surface and the end surface can determine the verticality between the X and Z axes. The surface shape accuracy of the annular concave surface can infer the interpolation ability between the X and Z axes.

Specific embodiment two: This embodiment provides a method for detecting the axis error of a three-axis diamond lathe based on a characteristic sample, and the specific implementation steps are as follows:

1. Use a diamond lathe to process feature samples.

2. When processing the outer cylindrical surface of the cylinder, only the Z axis needs to be fed in a straight line, and the other two axes remain stationary; When the surface is concave, the X and Z axes perform circular interpolation motion at the same time.

3. Measure the change in diameter of the cylinder 4 with a cylindricity meter. Separately divide the upper and lower parts of the cylinder 4 into 5 segments uniformly according to the size in the length direction for measurement and recording, measure the roundness at the corresponding segments, and record the results. Finally, the cylindricity of the outer cylindrical surface can be fitted by 10 measured data, and the parallel relationship between the Z axis and the diameter of the spindle axis can be known through the result of cylindricity, and the degree of non-parallelism can be deduced from the diameter change value and the length of the feature body get.

As shown in Figure 5, when there is no parallelism error between the main axis and the Z axis, the cylindricity of the outer cylindrical surface is the theoretical profile. When there is a parallelism error between the two axes (clockwise as shown in the figure), the fitted outer cylindrical surface is tapered and gradually becomes smaller from the bottom to the top. Conversely, if the fitted outer cylindrical surface is a tapered shape that gradually increases from the bottom to the top, the parallelism error between the two axes is counterclockwise. The magnitude of the non-parallelism is determined by the ratio of the difference between the largest and smallest diameters to the length of the feature body.

Assuming that the difference between the largest and smallest diameters is D, the length of the feature body is L, and the parallelism error is a, then: a=arctan(D/2*L).

4. Measure the flatness of the top end surface of the cylinder 4 with a cylindricity meter. When the cylindricity meter measures the flatness of the end face, the center line of rotation of the feature sample should be determined based on the outer cylinder. When measuring, it should be ensured that the running track of the cylindricity meter probe passes through the center of revolution of the end face or is as close as possible to the center of revolution so that the data is more realistic. Finally, the perpendicularity relationship between the X-axis and the diameter of the spindle axis can be known through the flatness results of the end face, and the perpendicularity error can be derived from the flatness of the end face.

As shown in Figure 6, when there is no perpendicularity error between the main axis and the X axis, the flatness of the end face is the theoretical profile. When there is a squareness error between the two axes (clockwise as shown in the figure), there is an error in the flatness of the end face, and the center is lower than the edge. Conversely, if the flatness is that the center is higher than the edge, the squareness error between the two axes is counterclockwise. The squareness error can be derived from the flatness of the end face.

Assuming that the difference between the highest point and the lowest point of the plane is L, the radius of the end face is R, and the verticality error is b, then: b=arcsin(L/R).

5. The verticality relationship between X and Z axes can be obtained from the verticality between the outer cylindrical surface and the end surface. The perpendicularity error between the outer cylindrical surface and the end surface is the perpendicularity error between the X and Z axes.

6. Use a cylindricity meter to detect the roundness error of the annular concave surface. To complete the machining of the circular concave surface, the X and Z axes need to be linked in the form of circular interpolation at the same time, and the feed speed of the two axes is not equal, which is determined by the size and structure of the spherical surface. Therefore, the roundness error of the annular concave surface can reflect the two-axis linkage performance, and the smaller the roundness error, the better the linkage performance.

When testing, first determine the centerline of rotation of the feature sample based on the outer cylinder, and then need to drive the cylindricity meter probe to perform cylindricity testing on any generatrix of the outer cylindrical surface along the axis direction, and export the measurement data through manual processing The roundness error of the annular concave surface is obtained by the method.

During data processing, the straight line segment data corresponding to the upper and lower parts of the cylinder 4 are subjected to slope removal and leveling processing, and the leveled straight line is used as a reference. The circular arc data corresponding to the annular concave surface 3 is fitted by the least squares circle method, and compared with the ideal circular arc, the roundness error can be obtained.

Claims (4)

1. A method for detecting the shafting error of a three-axis diamond lathe using a characteristic sample. The characteristic sample is composed of a base and a feature body. The feature body is arranged on the top end surface of the base and coaxially with it. The feature The overall shape of the main body is a cylinder, and the middle position of the height direction of the cylinder is provided with an annular concave surface; It is characterized in that the method steps are as follows: 1. Use a three-axis diamond lathe with a T-shaped layout to process feature samples. When machining the outer cylindrical surface of a cylinder, only the Z axis needs to be fed in a straight line, and the other two axes remain stationary; when machining the top end plane of the cylinder, only The X axis needs to be fed in a straight line, and the other two axes remain stationary; when machining a circular concave surface, the X and Z axes perform circular interpolation motion at the same time; 2. After the processing is completed, use a cylindricity meter to measure the characteristic sample; 3. According to the detection results of step 2, infer the shafting error of the three-axis diamond lathe. 2. The method for detecting the axis error of a three-axis diamond lathe using a characteristic sample according to claim 1, wherein the total length of the characteristic body should be between 60-70% of the maximum processing range of the Z axis. 3. The method for detecting the shafting error of a three-axis diamond lathe using a characteristic sample according to claim 1, wherein the radius dimension of the top end surface of the cylinder should be between 30-35% of the maximum processing range of the X-axis. 4. the method for utilizing characteristic samples to detect the axis error of a three-axis diamond lathe according to claim 1 is characterized in that the specific inference method of the axis error is as follows: by the detection result of the outer cylindrical surface, it can be known that the Z axis and The parallelism relationship between the main shafts; the verticality relationship between the X axis and the main shaft can be known through the test results of the flatness of the end surface; the verticality between the X and Z axes can be judged by the verticality relationship between the outer cylindrical surface and the end surface degree; the interpolation capability between the X and Z axes can be inferred from the surface shape accuracy of the annular concave surface.