Evaluation method for evaluating defect size of additive manufacturing product measured by industrial CT (Computed Tomography)

Abstract

The invention discloses a method for evaluating the defect size of an industrial CT measurement additive manufacturing product. The method comprises the following steps: setting printing parameters for prefabricating defects, and determining the parameters, shape, material and quantity of a sample; and performing CT detection on the sample with the prefabricated defect, setting optimal parameters of sample detection, and finally obtaining a two-dimensional slice image of the sample. Determining the position of a sample defect according to a CT scanning result, cutting according to the position of the sample defect, carrying out metallographic detection on the sample, observing the defect by using a metallographic microscope, and keeping the amplification ratio consistent with a CT slice image. And finally, carrying out image processing on the two-dimensional slice image obtained by the industrial CT and the metallographic detection defect image. The defect size precision of the metal additive manufacturing product is calculated by calculating the coincidence degree of the industrial CT two-dimensional slice defect graph and the metallographic detection defect graph; and the defect size of the metal additive manufacturing product measured by the industrial CT can be effectively evaluated.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial CT detection accuracy of additive manufacturing defects, and specifically relates to an evaluation method for evaluating the size of defects of additive manufacturing products measured by industrial CT. Background Art

[0002] Additive manufacturing technology has developed rapidly in recent years and is known as "manufacturing technology with industrial revolutionary significance". It is an important development direction of advanced manufacturing technology. However, the defects caused by additive manufacturing are diverse. At this time, industrial CT, as an effective non-destructive testing method, can detect defects of a few microns and is therefore widely used in the detection of defects in additive manufacturing.

[0003] Industrial CT is a new imaging technology that is a combination of computer technology and radiology. It can provide two-dimensional and three-dimensional images of the object being tested without being restricted by the material, shape, surface condition, etc. of the object being tested. The imaging is intuitive and has high resolution. It is an important means in the field of modern industrial non-destructive testing and exploration.

[0004] At present, the three-dimensional coordinate measuring machine is mainly used to measure the external dimensions of complex structural parts, but it is powerless to measure the internal structural dimensions. In order to meet the urgent needs of the industry, industrial CT has developed from the initial field of non-destructive testing and material composition testing to the direction of dimensional measurement applications, and has successfully achieved the measurement of internal and external dimensions without destroying the workpiece structure. It is considered to be one of the most promising measurement technologies.

[0005] However, there are many limitations in the application of industrial CT measurement technology in metrology. Its dimensional measurement values ​​lack traceability, and there are great difficulties in evaluating uncertainty and determining the metrological characteristics of industrial CT systems. There are many factors affecting the measurement process.

[0006] The performance indicators of industrial CT systems can be measured by spatial resolution, density resolution and artifacts. For a given industrial CT system, the limit performance indicators of the system itself are determined, but there is currently no good evaluation method for whether the size of defects can be accurately detected during actual detection. Therefore, how to evaluate the accuracy of industrial CT in measuring the size of defects in metal additive manufacturing products is a technical problem that needs to be solved at present. To this end, the present invention proposes an evaluation method for evaluating the size of defects in additive manufacturing products measured by industrial CT. Summary of the invention

[0007] The purpose of the present invention is to provide a method for evaluating the defect size of additively manufactured products measured by industrial CT to solve the problems raised in the above background technology.

[0008] To achieve the above-mentioned object, the present invention provides the following technical solution: a method for evaluating the size of defects of additively manufactured products measured by industrial CT, the specific steps comprising: S1: determining the printing shape, material, and parameters of the sample;

[0009] S2: Industrial CT scans the sample, sets the optimal parameters for industrial CT detection of the sample, performs three measurements, and obtains a two-dimensional slice image of the sample with defects;

[0010] S3: Determine the defect position of the sample, print the sample, determine the approximate position of the defect according to the CT test result and mark the result at the corresponding scale of the sample;

[0011] S4: Process the sample, perform wire cutting according to the sample marking position, and inlay and grind the defective side;

[0012] S5: metallographic detection of sample defects to obtain image information of corresponding defects of the sample;

[0013] S6: Compare the defect images in S2 and S5 in the image processing software to obtain the image features of the industrial CT defect two-dimensional tangent image and the metallographic microscope defect image;

[0014] S7: Calculate the overlap of industrial CT detection of metal additive manufacturing product defects to calculate the accuracy of industrial CT measurement of metal additive manufacturing product defect size.

[0015] Preferably, in S1, the shape of the sample is a cylinder with a diameter of 5 mm and a height of 10 mm, and the material is aluminum alloy AlSi 10 Mg, the printing parameters select the parameters of aluminum alloy metallic prefabricated defects to generate defects.

[0016] Preferably, in S3, a plurality of long scales with equal distances are printed on the sample, and the length is 3 mm, a plurality of short scales with equal distances are printed between two adjacent long scales, the length of the short scales is 1.5 mm, and the spacing between adjacent scales is 1 mm; the width of the scale is 0.3 mm, and the scale is raised.

[0017] Preferably, in S5, a metallographic microscope is used to observe defects of the sample, and the microscope is adjusted to a suitable position to obtain image information of the defects corresponding to the sample.

[0018] Preferably, the image features of S6 include outer contours, respective contour areas, and intersection areas.

[0019] Preferably, in S7, the area of ​​the intersection of the industrial CT defect two-dimensional slice image and the metallographic microscope defect image and the combined area are used to calculate the corresponding overlap, and the calculation formula is:

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: the method designed by the present invention for evaluating the accuracy of defect size of metal additive manufacturing products measured by industrial CT performs image processing on the two-dimensional slice image obtained by industrial CT and the image of the defect detected by metallographic examination; the degree of overlap between the two-dimensional slice defect image of industrial CT and the defect image detected by metallographic examination is calculated to calculate the accuracy of defect size of metal additive manufacturing products, which can effectively evaluate the defect size of metal additive manufacturing products measured by industrial CT. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the method flow of the present invention;

[0022] Figure 2 This is a schematic diagram of sample printing in this embodiment. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1 to Figure 2 , which is the first embodiment of the present invention, and this embodiment provides a technical solution: a method for evaluating the defect size of additively manufactured products measured by industrial CT, and the specific steps include: S1: determining the sample printing shape, material, and parameters;

[0025] In this embodiment, preferably, in S1, the shape of the sample is a cylinder with a diameter of 5 mm and a height of 10 mm, and the material is aluminum alloy AlSi 10 Mg, the printing parameters select the parameters of aluminum alloy metallic prefabricated defects to generate defects.

[0026] S2: Industrial CT scans the sample, sets the optimal parameters for industrial CT detection of the sample, performs three measurements, and obtains a two-dimensional slice image of the sample with defects;

[0027] S3: Determine the defect position of the sample, print the sample, determine the approximate position of the defect according to the CT test result and mark the result at the corresponding scale of the sample;

[0028] In this embodiment, preferably, in S3, a plurality of long scales with equal distances are printed on the sample, and the length is 3 mm, a plurality of short scales with equal distances are printed between two adjacent long scales, the length of the short scales is 1.5 mm, and the spacing between adjacent scales is 1 mm; the width of the scale is 0.3 mm, and the scale is raised; Figure 2 shown.

[0029] S4: Process the sample, perform wire cutting according to the sample marking position, and inlay and grind the defective side;

[0030] S5: metallographic detection of sample defects to obtain image information of corresponding defects of the sample;

[0031] In this embodiment, preferably, in S5, a metallographic microscope is used to observe the defects of the sample, and the microscope is adjusted to a suitable position to obtain image information of the defects corresponding to the sample.

[0032] S6: Compare the defect images in S2 and S5 in the image processing software to obtain the image features of the industrial CT defect two-dimensional tangent image and the metallographic microscope defect image;

[0033] In this embodiment, preferably, the image features of S6 include outer contours, respective contour areas, and intersection areas.

[0034] S7: Calculate the overlap of industrial CT detection of metal additive manufacturing product defects to calculate the accuracy of industrial CT measurement of metal additive manufacturing product defect size.

[0035] In this embodiment, preferably, in S7, the area of ​​the intersection of the industrial CT defect two-dimensional slice image and the metallographic microscope defect image and the combined area are used to calculate the corresponding overlap, and the calculation formula is:

[0036]

[0037] Although embodiments of the present invention have been shown and described (see the above detailed description for details), it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for evaluating the size of defects in additively manufactured products measured by industrial CT, characterized in that: The specific steps include: S1: determining the sample printing shape, material, and parameters; S2: Industrial CT scans the sample, sets the optimal parameters for industrial CT detection of the sample, performs three measurements, and obtains a two-dimensional slice image of the sample with defects; S3: Determine the defect position of the sample, print the sample, determine the approximate position of the defect according to the CT test result and mark the result at the corresponding scale of the sample; S4: Process the sample, perform wire cutting according to the sample marking position, and inlay and grind the defective side; S5: metallographic detection of sample defects to obtain image information of corresponding defects of the sample; S6: Compare the defect images in S2 and S5 in the image processing software to obtain the image features of the industrial CT defect two-dimensional tangent image and the metallographic microscope defect image; S7: Calculate the overlap of industrial CT detection of metal additive manufacturing product defects to calculate the accuracy of industrial CT measurement of metal additive manufacturing product defect size.

2. The method for evaluating the size of defects in additively manufactured products measured by industrial CT according to claim 1, characterized in that: In S1, the shape of the sample is a cylinder with a diameter of 5 mm and a height of 10 mm, and the material is aluminum alloy AlSi 10 Mg, the printing parameters select the parameters of aluminum alloy metallic prefabricated defects to generate defects.

3. The method for evaluating the size of defects in additively manufactured products measured by industrial CT according to claim 1, characterized in that: In S3, a plurality of long scales with equal distances are printed on the sample, and the length is 3 mm, a plurality of short scales with equal distances are printed between two adjacent long scales, the length of the short scales is 1.5 mm, and the spacing between adjacent scales is 1 mm; the width of the scale is 0.3 mm, and the scale is raised.

4. The method for evaluating the size of defects in additively manufactured products measured by industrial CT according to claim 1, characterized in that: In S5, a metallographic microscope is used to observe the defects of the sample and is adjusted to a suitable position to obtain image information of the defects corresponding to the sample.

5. The method for evaluating the size of defects in additively manufactured products measured by industrial CT according to claim 1, characterized in that: The image features of S6 include outer contours, respective contour areas, and intersection areas.

6. The method for evaluating the size of defects in additively manufactured products measured by industrial CT according to claim 1, characterized in that: In S7, the corresponding overlap degree is calculated using the area of ​​the intersection of the industrial CT defect two-dimensional slice image and the metallographic microscope defect image and the combined area, and the calculation formula is:

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