Automatic Generation of Anisotropic Patterns of Geometric Features for Industrial Design

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Diego Andrade ◽  
Ved Vyas ◽  
Kenji Shimada

While modern computer aided design (CAD) systems currently offer tools for generating simple patterns, such as uniformly spaced rectangular or radial patterns, these tools are limited in several ways: (1) They cannot be applied to free-form geometries used in industrial design, (2) patterning of these features happens within a single working plane and is not applicable to highly curved surfaces, and (3) created features lack anisotropy and spatial variations, such as changes in the size and orientation of geometric features within a given region. In this paper, we introduce a novel approach for creating anisotropic patterns of geometric features on free-form surfaces. Complex patterns are generated automatically, such that they conform to the boundary of any specified target region. Furthermore, user input of a small number of geometric features (called “seed features”) of desired size and orientation in preferred locations could be specified within the target domain. These geometric seed features are then transformed into tensors and used as boundary conditions to generate a Riemannian metric tensor field. A form of Laplace's heat equation is used to produce the field over the target domain, subject to specified boundary conditions. The field represents the anisotropic pattern of geometric features. This procedure is implemented as an add-on for a commercial CAD package to add geometric features to a target region of a three-dimensional model using two set operations: union and subtraction. This method facilitates the creation of a complex pattern of hundreds of geometric features in less than 5 min. All the features are accessible from the CAD system, and if required, they are manipulable individually by the user.

Author(s):  
Alan C Lin ◽  
Nguyen Huu Quang

A new slicing algorithm that uses multiple sets of cutting planes to automatically determine parting curves for three-dimensional parts is proposed. In this algorithm, one set of cutting planes is used to generate the slicing profiles, and two others are used to determine the intersection points with the inner and outer loops of the parting curves. The algorithm provides a highly effective solution for handling complicated models that contain free-form surfaces. The features of the algorithm are highlighted in three case studies using tessellated geometry in STL file format as the input. The resultant parting curves overcome many problems inherent in the current methods and can be used by various downstream computer-aided design systems for three-dimensional mold design.


2021 ◽  
Vol 111 (11-12) ◽  
pp. 797-802
Author(s):  
Leonhard Alexander Meijer ◽  
Torben Merhofe ◽  
Timo Platt ◽  
Dirk Biermann

In diesem Beitrag wird ein neuer Ansatz zum Erstellen von Maschinenprogrammen zur mikrofrästechnischen Oberflächenstrukturierung vorgestellt und die Anwendung der Prozesskette für ein komplexes, industrielles Verzahnungswerkzeug beschrieben. Durch die Reduzierung des Berechnungsaufwandes in der CAD/CAM (Computer-aided Design & Manufacturing)-Umgebung können die Limitierungen konventioneller Softwarelösungen umgangen und Bearbeitungsprogramme für komplexe Strukturierungsaufgaben effizient erstellt werden.   A new method for generating machine programs for micromilling surface structuring is presented, and the application of the process chain to a complex, industrial gearing die is described. By reducing the computational effort in the CAD/CAM (Computer-aided Design & Manufacturing) environment, the problems of conventional software solutions can be avoided and complex machining programs can be created.


Author(s):  
D Brujic ◽  
M Ristic

Accurate dimensional inspection and error analysis of free-form surfaces requires accurate registration of the component in hand. Registration of surfaces defined as non-uniform rational B-splines (NURBS) has been realized through an implementation of the iterative closest point method (ICP). The paper presents performance analysis of the ICP registration method using Monte Carlo simulation. A large number of simulations were performed on an example of a precision engineering component, an aero-engine turbine blade, which was judged to possess a useful combination of geometric characteristics such that the results of the analysis had generic significance. Data sets were obtained through CAD (computer aided design)-based inspection. Confidence intervals for estimated transformation parameters, maximum error between a measured point and the nominal surface (which is extremely important for inspection) mean error and several other performance criteria are presented. The influence of shape, number of measured points, measurement noise and some less obvious, but not less important, factors affecting confidence intervals are identified through statistical analysis.


Author(s):  
J. R. R. Mayer ◽  
Y. A. Mir ◽  
F Trochu ◽  
A Vafaeesefat ◽  
M Balazinski

Obtaining CAD (computer aided design) descriptions of actual parts having complex surfaces is a key part of the process of reverse engineering. This paper is concerned with the estimation of actual surfaces using coordinate measuring machines fitted with a spherically tipped touch probe. In particular, it addresses in detail the problem of probe radius compensation. A general mathematical model, using kriging, is proposed which first generates the initial probe centre surface and then estimates the compensated or part surface. The compensation is achieved using normal vectors to the initial probe centre surface at each measured point to compensate for the probe radius. The method is validated experimentally on known and free-form surfaces.


2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Diego F. Andrade ◽  
Kenji Shimada

This paper presents a new computational method for the automatic generation of geometric feature patterns for industrial design. Such patterns include speaker holes, showerhead holes, and bumpy textures on a grip, and they play a key role in making a designed object aesthetically pleasing and functional. While modern CAD packages support the automated creation of basic patterns, rectangular grids, and radial grids, they are not applicable to more general cases required in industrial design, including arbitrarily shaped target geometry and graded feature sizes. The proposed computational method takes as input a target region along with sizing metrics and generates feature patterns automatically in three steps: (1) packing circles tightly in the target region, (2) scaling features according to the specified sizing metrics, and (3) adding features on the base geometry. The proposed method is installed as a plugin module to a commercial CAD package, and a pattern of hundreds of features can be added to a 3D CAD model in less than 5 min. This allows the industrial designer to explore more design alternatives by avoiding the tedious and time-consuming manual generation of patterns.


Author(s):  
Günay Orbay ◽  
Mehmet Ersın Yümer ◽  
Levent Burak Kara

AbstractThe hierarchical construction of solid models with current computer-aided design systems provide little support in creating and editing free-form surfaces commonly encountered in industrial design. In this work, we propose a new design exploration method that enables sketch-based editing of free-form surface geometries where specific modifications can be applied at different levels of detail. This multilevel detail approach allows the designer to work from existing models and make alterations at coarse and fine representations of the geometry, thereby providing increased conceptual flexibility during modeling. At the heart of our approach lies a multiscale representation of the geometry obtained through a spectral analysis on the discrete free-form surface. This representation is accompanied by a sketch-based surface editing algorithm that enables edits to be made at different levels. The seamless transfer of modifications across different levels of detail facilitates a fluid exploration of the geometry by eliminating the need for a manual specification of the shape hierarchy. We demonstrate our method with several design examples.


2013 ◽  
Vol 275-277 ◽  
pp. 2635-2639 ◽  
Author(s):  
Nguyen Huu Quang ◽  
Alan C. Lin

In computer-aided design for moldings, automatic generation of side-cores is a crucial design task that has an influence on the entire mold structure and manufacturing cost. This paper proposes a synthetic approach for creating the side-cores of free-form NURBS surface models. Based on the geometric properties of entities, surfaces of undercut features which are molded for side-cores are identified. After determining the withdrawal directions for each group of undercut’s surface features, the number of side-cores is optimized. The heads and the bodies of side-cores are finally obtained through the combination of the Boolean operation and 3D oriented extrusion. The algorithm is efficiently for both protruded and indented portions of undercut features. A complex industrial part is used to demonstrate the performance and robustness of the proposed algorithm. Since the approach is generic in nature, it is easy to be applied to any complex geometry in 3D mold design.


Author(s):  
S Ding ◽  
D C H Yang ◽  
Z Han

Boundary-conformed machining is a new method to mill free-form surfaces with tool paths that reflect the natural shapes of the surfaces. It is suitable for the machining of turbine blades taking into account the direction of tool marks left on the vanes. To facilitate this type of machining, this paper introduces an application of the ‘boundary-conformed algorithm’ to generate continuous boundary-conformed flow line tool paths for the milling of blade surfaces. With this approach, the initial segment of the flow line tool paths is along the top edges of the blade while the final segment follows the intersection curves between the blade and the hub surface. The intermediate segments cover the surface by changing smoothly from the initial tool path to the final tool path. The two opposite sides of the blade, which are two trimmed surfaces, are machined together continuously from top to bottom with these continuous boundary-conformed tool paths. This method has been successfully integrated into an industrial computer-aided design and manufacture system (Pro/Engineer) by using Pro/Toolkit. A detailed algorithm and implementation processes have been introduced.


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