CN103759696B - Cavity inner-cavity structure 3-D scanning detection method - Google Patents

Abstract

The invention discloses a three-dimensional scanning detection method for a cavity inner cavity structure. The detection method includes: the first step, fixing the positioning sphere on the outer wall of the cavity; the second step, establishing the same workpiece coordinate system as the product digital model on the cavity through the measurement software, and measuring each positioning sphere and recording the workpiece Coordinate value; the third step is to measure the sphere coordinate value of the positioning sphere on the sheet body through the machine coordinate system; the fourth step is to manually change the machine coordinate value of the positioning sphere on the sheet body to the workpiece coordinate value measured before the cylinder head dissection; The fifth step is to scan the internal contour of the sheet to build a 3D model, and compare it with the imported product digital model in 3D. This detection method compares the dissected sheet with the digital model of the product in 3D to observe the color deviation map of the internal contour, and can intuitively see its size deviation through the color difference zone in the picture and the color of the casting surface .

Description

Three-dimensional scanning detection method of cavity cavity structure

technical field

The invention relates to the field of three-dimensional scanning, in particular to a three-dimensional scanning detection method for a cavity inner cavity structure.

Background technique

Three-dimensional scanning is a high-tech that integrates optical, mechanical, electrical and computer technologies. It is mainly used to scan the spatial shape and structure of objects to obtain the spatial coordinates of the object's surface. Its significance lies in the ability to convert the three-dimensional information of the object into a digital signal that can be directly processed by the computer, which provides a very convenient and quick means for the digitization of the object.

As a fast three-dimensional measurement equipment, the three-dimensional scanner makes up for the existence of the three-coordinate measuring machine, which is easy to damage the probe, scratch the surface of the measured part, slow measurement speed, difficult to obtain continuous coordinate points and unable to measure fragile and fragile objects. Disadvantages of measuring deformed objects. Because of its fast measurement speed, high precision, non-contact, easy to use and other advantages, it has been used more and more.

Usually the measurement data obtained after scanning is composed of a large number of three-dimensional coordinate points, ranging from hundreds to millions of points according to the nature of the scanner, scanning parameters and the size of the object to be measured. These large number of three-dimensional data points called a "point cloud". Using a 3D scanner to scan a product, the point cloud data can be collected into a computer to create a digital model of the actual object (this process is called 3D reconstruction).

At present, the application of 3D scanning in China is to first scan the product with a 3D scanner, construct a surface through the collected point cloud data, and then use the scanned data (3D model constructed by scanning) and product digital model (3D model of product design) Carry out fitting and alignment. After the fitting is completed, perform 3D comparison to generate a color deviation map. Through the color difference zone in the picture and the color of the casting surface, you can intuitively see its size deviation, which makes it easier for us to determine the size of the part. Analyze the situation.

Notes can be created for some positions where specific size deviation is desired, so that the specific value of the deviation here can be displayed. Through the value, we can check whether the machining allowance of certain positions that need to be processed is sufficient. It is possible to check the flatness of some planes and the position of some straps through the geometric tolerance annotation. At the same time, it is also possible to make multi-point annotations for the positions with large dimensional deviations, and find the dimensional change rules according to the dimensional deviation levels of the annotations.

At present, 3D scanning is used for 3D comparative analysis, which mainly scans and analyzes the outer surface contour of the product. For the inner cavity structure, it can only be scanned after dissection, but because the dissected sheet is not consistent with the product The digital model (design three-dimensional model) has the same coordinate system, so it is difficult to compare them in 3D.

Contents of the invention

The present invention aims to overcome the defects in the above-mentioned prior art, and provides a simple and quick method that can perform 3D comparison between the dissected sheet and the product digital model to observe the color deviation map of the internal contour, and through the color difference in the figure The color of the belt and the surface of the casting can be used to visually see its size deviation. The three-dimensional scanning inspection method of the cavity structure.

In order to achieve the above object, according to the present invention, a three-dimensional scanning detection method for cavity inner cavity structure is provided, and the specific steps include:

The first step is to fix the positioning sphere on the outer wall of the cavity, and ensure that there are at least three positioning spheres on each slice of the cavity after dissection;

The second step is to establish the same workpiece coordinate system as the product digital model on the cavity through the measurement software, and measure each positioning sphere and record the coordinate values of the workpiece;

In the third step, the cavity is dissected into slices by wire cutting, and the spherical coordinate value of the positioning sphere on the slice is measured through the machine coordinate system;

The fourth step is to manually change the machine coordinate value of the positioning sphere on the sheet body to the workpiece coordinate value measured before the cylinder head dissection, and use the best fitting function on the 3D comparison software to create the workpiece coordinate value through the workpiece coordinate value of the positioning sphere Tie;

The fifth step is to import the newly created workpiece coordinate system of the sheet on the scanning software, and then scan the internal contour of the sheet to construct a 3D model, and perform 3D comparison with the imported product digital model.

In the above technical solution, the cavity is a cylinder head.

In the above technical solution, three positioning spheres are fixed on each piece of the multi-piece anatomical cavity.

In the above technical solution, the positioning sphere is welded and fixed on the outer wall of the cavity.

In the above technical solution, the measurement software of the second step adopts PC-DMIS2010.

In the above technical solution, the 3D comparison software in the fourth step adopts GeomagicQualify2012.

In the above technical solution, the scanning software in the fifth step is ScanWorksV5.5.

Compared with the prior art, the present invention has the following beneficial effects: the three-dimensional scanning detection method of the inner cavity structure is simple and fast, and the color deviation of the inner contour can be observed by comparing the dissected sheet with the product digital model in 3D The size deviation can be seen intuitively through the color difference zone in the picture and the color of the casting surface.

Description of drawings

Fig. 1 is the schematic diagram of the welding positioning sphere of the three-dimensional scanning detection method of cavity inner cavity structure of the present invention;

Fig. 2 is the schematic diagram of measuring the coordinate value of the sphere through the machine coordinate system of the three-dimensional scanning detection method of the cavity inner cavity structure of the present invention;

Fig. 3 is a flow chart of the three-dimensional scanning detection method for cavity inner cavity structure of the present invention.

detailed description

A specific embodiment of the present invention will be described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific embodiment. It should be understood that the "upper", "lower", "left", "right", "front" and "reverse" mentioned in the following embodiments of the present invention are all based on the directions shown in the figures, These words used to limit the direction are only for convenience of description, and do not mean to limit the specific technical solution of the present invention.

The three-dimensional scanning detection method of the cavity inner cavity structure of the present invention is simple and fast. By comparing the dissected sheet with the product digital model in 3D, the color deviation map of the internal contour can be observed, and the color difference zone in the figure and the surface of the casting can be observed. The color can visually see its size deviation.

The following detailed description illustrates the present disclosure by way of example and not limitation, and it should be understood that various aspects of the present disclosure can be implemented alone or in combination with other aspects. This specification clearly enables one skilled in the art to make and use what we believe to be new and non-obvious improvements, describes several embodiments, workarounds, variations, alternatives, and applications of systems, including The best mode of the inventive principle described in the specification. The use of "a", "an", "the" and "said" when describing elements or features and/or embodiments is intended to mean having one or more of the elements or features. The terms "comprising", "comprising" and "having" are intended to be inclusive and mean that there are additional elements or features other than those specifically described.

The three-dimensional scanning detection method of the inner cavity structure of the cavity proposes a new method of establishing working coordinates to complete the three-dimensional scanning comparison of the inner cavity structure of the product. The following is an example of a cylinder head, as shown in Figure 3. Steps include:

The first step is to weld positioning spheres on the outer wall of the cylinder head, and ensure that there are at least three positioning spheres on each piece of the cylinder head after multi-piece dissection;

For example, weld sphere 1, sphere 2, and sphere 3 on the planned positions around the cylinder head (as shown in Figure 1). There should be three spheres, marked with the numbers 1, 2, 3.

The second step is to establish the same workpiece coordinate system 4 as the product digital model (three-dimensional product design model) on the cylinder head through the measurement software, and measure the sphere 1, sphere 2, and sphere 3 and record the workpiece coordinate values of the spheres; Among them, the measurement software adopts PC-DMIS2010.

For example: Sphere 1, Sphere 2, and Sphere 3 have measured and recorded workpiece coordinate values: Sphere 1 (X: 20.115, Y: -97.454, Z: 62.312), Sphere 2 (X: 128.256, Y: 63.668, Z: 87.845), sphere 3 (X: 128.253, Y: 238.698, Z: 70.688).

The third step is to dissect the cylinder head into pieces 6 by wire cutting (as shown in Figure 2), and then measure the coordinate values of sphere 1, sphere 2 and sphere 3 on the piece 6 through the machine coordinate system 5;

At this time, the measured sphere coordinates are machine coordinates. For example, the machine coordinates of each sphere in the third step are: sphere 1 (X: 698.951, Y: 223.805, Z: 60.471), sphere 2 (X: 831.174, Y: 379.882, Z: 72.553), sphere 3 (X: 850.582, Y: 548.814, Z: 48.648).

The fourth step is to manually change the machine coordinates of the spheres on sheet 6 to the workpiece coordinates measured before dissection of the cylinder head. Each sphere must correspond one by one. After changing the coordinates, use the coordinates of the three spheres to use The best fitting function on the three-dimensional comparison software creates a coordinate system; among them, the three-dimensional comparison software uses GeomagicQualify2012.

Using the coordinate values of these three spheres to create a coordinate system using the best fit function on the software utilizes the inverse principle. In this way, the workpiece coordinate system 4 built on the sheet body 6 is the same as the workpiece coordinate system before the cylinder head was dissected, and then the coordinate system is derived.

The fifth step is to import the piece workpiece coordinate system 4 on the scanning software, and then scan the internal contour of the piece, and then import the product digital model (3D model of product design) for 3D comparison; among them, the scanning software adopts ScanWorksV5 .5.

Because the product digital model (three-dimensional model of product design) is an overall three-dimensional picture, the product digital model (three-dimensional model of product design) should also be cut in the same way as the real thing, so that the color deviation map of the internal contour can be observed through comparison. The color difference zone in the casting and the color of the surface of the casting can be seen intuitively to see its size deviation.

In summary, the three-dimensional scanning detection method of the cavity structure is simple and fast. By comparing the dissected sheet with the product digital model in 3D, the color deviation map of the internal contour can be observed, and the color difference zone in the picture and the casting The color of the surface visually shows its size deviation.

The above disclosures are only a few specific embodiments of the present invention, however, the present invention is not limited thereto, and any changes conceivable by those skilled in the art shall fall within the protection scope of the present invention.

Claims (7)

1. a cavity inner-cavity structure 3-D scanning detection method, it is characterized in that, concrete steps comprise:

The first step, at chamber outer wall stationary positioned spheroid, and ensure multi-disc dissect rear chamber each lamellar body on have three positioning ball at least;

Second step, sets up the workpiece coordinate system same with product digital-to-analogue by Survey Software on cavity, and measures each positioning ball and record workpiece coordinate value;

3rd step, dissects into lamellar body with Linear cut by cavity, and measures the spheroidal coordinate value of the positioning ball on lamellar body by coordinate system of machine, and the spheroidal coordinate value at this moment measured is machine coordinates value;

4th step, manually changes to the machine coordinates value of positioning ball on lamellar body the workpiece coordinate value of the pre-test of cylinder cap dissection, and utilizes the best-fit function on three-dimensional alignment software to create workpiece coordinate system by the workpiece coordinate value of positioning ball;

5th step, scanning software imports the workpiece coordinate system that lamellar body newly creates, and then carries out scanning to the in-profile of lamellar body and builds three-dimensional model, and carry out 3D comparison with the product digital-to-analogue imported.

2. cavity inner-cavity structure 3-D scanning detection method according to claim 1, is characterized in that: described cavity is cylinder cap.

3. cavity inner-cavity structure 3-D scanning detection method according to claim 2, is characterized in that: each lamellar body of described multi-disc dissection rear chamber is fixed with three positioning ball.

4. cavity inner-cavity structure 3-D scanning detection method according to any one of claim 1 to 3, is characterized in that: described positioning ball is weldingly fixed on chamber outer wall.

5. cavity inner-cavity structure 3-D scanning detection method according to claim 1, is characterized in that: the Survey Software of described second step adopts PC-DMIS2010.

6. cavity inner-cavity structure 3-D scanning detection method according to claim 1, is characterized in that: the three-dimensional alignment software of described 4th step adopts GeomagicQualify2012.

7. cavity inner-cavity structure 3-D scanning detection method according to claim 1, is characterized in that: the scanning software of described 5th step adopts ScanWorksV5.5.