Papers by Keyword: IGES

Abstract: Sheet Metal Forming is a widely used process in industry. However, it is also an expensive onedue to the diversity and complexity of methodologies used to obtain the adequate tools combination.In fact, even though there is already finite element based software to compute the final shape of aformed sheet from a given tool, there is no efficient procedure to predict the inverse problem: the toolgeometry from the formed component final shape.The final aim of this work is to improve the current trial-and-error process for the inverse problem.To achieve this objective, an integrated approach for tools geometry manipulation is presented, basedon the parametric NURBS description of the tools surface. This is applied to perform a sensitivityanalysis in order to evaluate the effect of numerical noise and small disturbances on the tools designvariables in the final formed sheet. Furthermore, the robustness of the proposed approach is evaluatedusing two parts with distinct complexity.

Abstract: In order to input graphics of NC machining parts efficiently, now take the turning IGES rotary parts graphic input for example, it introduced the manual input and methods of obtaining the feature information of the parts generated from UG5.0 IGES file. The feature information contains geometry information (such as line, arc, spline curve, etc) and process information (such as size tolerance, form tolerance, technical conditions and the title bar, etc). In VC++6.0, it set up three modules, that’s the IGES file information input, data processing and data output. Feature extraction and input were realized by using intersection algorithm of graphic elements. Through data processing module, the read pixel information could be transformed into the feature information of the parts, generating the system data structure. OpenGL technologies were used to realize the IGES graphics display, finally offering supports for NC turning visualization of virtual machining.

Abstract: For realizing the three-dimensional display of machine parts, in UG5.0 graphic drawing environment, it provides an interactive experimental method to carry out the display of IGES graphics, taken as the data-exchanged interface. Based on depth analysis of IGES, with VC++6.0, the information of all figures could be obtained. Through data processing, three-dimensional data of rotary entity could be generated, which is based on 3D data of lathe turning IGES rotary entity. Afterwards, OpenGL graphic processing technologies (with light, material, textures, et al.) were applied on the three-dimensional display of graphics input from files or program modules. Finally the parts designer could get a full view of machine parts, going on with some proper modifications.

Abstract: As the EMUs (Electrical Multiple Unit) light frame structure, combined of many complex surfaces, building its geometric model directly is a big challenge. Reverse Engineering Technology is adopted to make the light frame redesign. Considering the characteristics of the frame surface with big curvature changed, irregular contours of structural features and IGES based model, authors proposed the model reconstruction method, by using independent geometric module in Pro/E. Firstly, establish base planes from IGES file, then duplicate light frame surface from IGES file to generate a set of intersection curves with the base planes and surface duplicated above as mixed guide curves. After that, curvature analysis technique is presented for intersection curves precision check. And finally, the 3D model is reconstructed by boundary blend technology. The original data imported can be removed from this model in order to support parts redesign as well as their manufacturability analysis. Research outcomes above offer an efficient innovation solution for surface reconstruction with curvature changed dramatically and IGES based model as well.

Abstract: With the help of IGES standard file which was the exchange specification of initial graphics, different CAD system could change the data of product by neutral file’s format conversing. The automatic generation of 3D-Model curve surface in the MCNP input file was realized by using VC++ language.This method has solved the problem of the complication of MCNP geometric modeling process and the 3D-Model input problem in the MCNP. The input of MCNP was transferred the application problem of CAD/CAM software. The data and figure of varies software could be shared and converted. The work of design could be simple, the process of design could be speeded up and the cycle of design was shorted. Work efficiency and practicability were improved. If precision was controlled in 3D-Model, the result could be expected by contrast.

Abstract: IGES (Initial Graphics Exchange Standard) is a general graphics data exchange standard, which has been widely used for data exchange between different CAD/CAM systems. But the inherent defect of IGES makes it difficult to use in the field of automatic programming. This article focuses on the automatic programming of holes processing. Entities were labeled with different entity number, on which the hole entity could be distinguished and extracted based. The intersection lines of hole and NURBS surface could be calculated by NURBS surface intersection algorithm. The redundancy of intersecting lines is a key problem. This article gives an intuitive treatment.

Abstract: To improve machining efficiency and accuracy for surface, a method of machining Non-Uniform Rational B-spline (NURBS) surface based on IGES was put forward. The algorithms for surface information processing machining path planning and real time locus interpolation involved in this method have been worked out from the research results. A prototype of the CNC milling system with “PC+PMAC motion controller” is designed by toolpath planning, coordinate transformation and acceleration-deceleration control, which using VC ++ and openGL in Windows NT + RTX system platform. The simulation experiment was conducted to test the effectiveness and accuracy of the proposed method.

Abstract: 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.