The realization of the data exchanges between the reverse engineering system and CAD / CAM system is by Graphics Interchange standards, of which the initial graphics exchanges specification IGES is one of the important ways that data exchanges in systems. At first, the paper introduces the structures of the five parts that composes the IGES file. Secondly, it also introduces the meaning of the parameters that the rational B-spline surface in IGES and gives the method to identify and extract IGES surface data in the reverse engineering system. At last, it uses the OpenGL graphics system to show the surface data. Then, the exchanges of the surface data between the systems can realize easily by the method.
Porous metals are applied in many more fields than other porous materials. Pores in porous metal parts manufactured by selective laser melting (SLM) should not be regarded as defects but favorable characters because they are the main composition of porous metal parts. Therefore, fully densification is not the only target in forming metal parts via SLM. The formation mechanism of pores in SLM is studied mathematically in this article, and mathematical model is built to describe the formation mechanism. It is concluded that the shape of pores and the porosity of parts are the function of SLM processing parameters and the diameter of powder particles. Pores can be controlled and estimated by adjusting processing parameters and the nature of forming materials. Porous metal parts produced by SLM can be applied in many more fields owing that SLM technology is flexible to change the shape of these part and the nature of materials.
With the development of the computer vision and information on optics, three-dimensional grating surface measuring apparatus has been increasingly widely used, which is mainly used in industrial inspection, quality control, reverse engineering, virtual reality, cultural reproduction and other areas. It has high precision, fast, non-contact advantages. And the image acquisition system is one of the core and first part of three-dimensional grating surface measuring apparatus, which determines measuring accuracy in the three-dimensional shape. This paper mainly introduces image acquisition system's hardware configuration and software development methods in the apparatus, and finally gives the experimental results.
In reverse engineering, in order to get the entire point data of the object surface, which must be merged from point data cloud obtained from different angles. And in order to acquire exactly merge effect, a method to stick reference points on object surface to acquire base point. Thus, the precision of center extraction of reference point affect the merge result. Firstly a new method to center extraction of reference point is presented based on the characteristics to the images in reverse engineering in this paper. And the new method is that the region recognition algorithm combining to least squares algorithm. Secondly, in order to improve the computational efficiency, the modified sequential algorithm is applied to optimize the region recognition. Lastly, the availability and accuracy to the new method are proved by the experiment.
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