Visual assessment of free-form surfaces in CAD/CAM

1998 ◽  
Vol 212 (3) ◽  
pp. 207-214 ◽  
Author(s):  
R J Cripps ◽  
A A Ball
Keyword(s):  
Computer Aided Design ◽  
Mathematical Theory ◽  
Visual Assessment ◽  
Free Form ◽  
Design Engineers ◽  
Surface Models ◽  
Cad Cam ◽  
Aided Design ◽  
Free Form Surfaces

This paper reviews the current graphical tools available for checking the quality of CAD/CAM (computer aided design/manufacture) surface models and highlights the difficulties of their use. A new range of geometrically based tools is proposed, especially designed for the task of enabling design engineers to visually assess the quality of free-form surfaces at a workstation screen to within an accuracy comparable with working to full-scale drawings. The tools should be easy to use without recourse to understanding the underlying mathematical theory of surface differential geometry on which the techniques are ultimately based.

Algorithmen-basierte Freiformflächenstrukturierung/Generation of NC programs for the micromilling structuring of free-form surfaces – Algorithm-based free-form surface structuring

2021 ◽  
Vol 111 (11-12) ◽  
pp. 797-802
Author(s):  
Leonhard Alexander Meijer ◽  
Torben Merhofe ◽  
Timo Platt ◽  
Dirk Biermann
Keyword(s):  
Computer Aided Design ◽  
Computational Effort ◽  
Free Form ◽  
Process Chain ◽  
Surface Structuring ◽  
Computer Aided ◽  
Cad Cam ◽  
Free Form Surface ◽  
Aided Design ◽  
Free Form Surfaces

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.

scholarly journals Influence of Sequential CAD/CAM Milling on the Fitting Accuracy of Titanium Three-Unit Fixed Dental Prostheses

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1401
Author(s):  
Doo-Bin Song ◽  
Man-So Han ◽  
Si-Chul Kim ◽  
Junyong Ahn ◽  
Yong-Woon Im ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Computer Aided Design ◽  
Dental Prostheses ◽  
Computer Aided ◽  
Cad Cam ◽  
Fixed Dental Prostheses ◽  
Gap Data ◽  
Aided Design ◽  
Fitting Accuracy

This study investigated the fitting accuracy of titanium alloy fixed dental prostheses (FDP) after sequential CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) fabrication. A three-unit FDP model connecting mandibular second premolars and molars was prepared and scanned to fabricate titanium FDPs by CAD/CAM milling. A total of six FDPs were sequentially milled in one titanium alloy disk using a new set of burs every time (n = 4). The fitting accuracy of FDPs was mesiodistally evaluated by a silicone replica technique and the measurement was triplicated at four different locations: MO (marginal opening), MG (marginal gap), AG (axial gap), and OG (occlusal gap). Data were statistically analyzed using ANOVA and Tukey’s HSD test. The fitting accuracy of PMMA (polymethyl methacrylate) FDPs milled using the worn or new bur were evaluated by the same procedure (n = 6). The mean dimensions of titanium FDP for all measuring positions, except for AG, were significantly increased from the third milling. However, no difference was noted between the first FDP and the second FDP milled with the same set of burs. Severe edge chippings were observed in all milling burs. Detrimental effects of the worn burs on the fitting accuracy were demonstrated in the CAD/CAM-milled PMMA FDP. The results recommend proper changing frequency of cutting burs to achieve the quality of fit and predictable outcomes for dental CAD/CAM prostheses.

Interval Method for Interrogation of Implicit Solid Models

2000 ◽  
Author(s):  
Jack Chang ◽  
Mark Ganter ◽  
Duane Storti
Keyword(s):  
Computer Aided Design ◽  
Boundary Representation ◽  
Free Form ◽  
Solid Models ◽  
Cad Cam ◽  
Implicit Modeling ◽  
Manufacturing Applications ◽  
Determine Surface Area ◽  
Implicit Solid ◽  
Aided Design

Abstract Computer-aided design/manufacturing (CAD/CAM) systems intended to support automated design and manufacturing applications such as shape generation and solid free-form fabrication (SFF) must provide not only methods for creating and editing models of objects to be manufactured, but also methods for interrogating the models. Interrogation refers to any process that derives information from the model. Typical interrogation tasks include determine surface area, volume or inertial properties, computing surface points and normals for rendering, and computing slice descriptions for SFF. While currently available commercial modeling systems generally employ a boundary representation (B-rep) implementation of solid modeling, research efforts have considered implicit modeling schemes as a potential source of improved robustness. Implicit implementations are available for a broad range of modeling operations, but interrogation operations have been widely considered too costly for many applications. This paper describes a method based on interval analysis for interrogating implicit solid models that aims at achieving both robustness and efficiency.

Morphological Offset Computing for Contour Pocketing

2006 ◽  
Vol 129 (2) ◽  
pp. 400-406 ◽  
Author(s):  
R. Molina-Carmona ◽  
A. Jimeno ◽  
R. Rizo-Aldeguer
Keyword(s):  
Computer Aided Design ◽  
Tool Path ◽  
Free Form ◽  
Computer Aided Manufacturing ◽  
Theoretical Formulation ◽  
Topological System ◽  
Computer Aided ◽  
Cad Cam ◽  
Tool Shape ◽  
Aided Design

Background. Tool path generation problem is one of the most complexes in computer aided manufacturing. Although some efficient algorithms have been developed to solve it, their technological dependency makes them efficient in only a limited number of cases. Method of Approach. Our aim is to propose a model that will set apart the geometrical issues involved in the manufacturing process from the purely technology-dependent physical issues by means of a topological system. This system applies methods and concepts used in mathematical morphology paradigms. Thus, we will obtain a geometrical abstraction which will not only provide solutions to typically complex problems but also the possibility of applying these solutions to any machining environment regardless of the technology. Presented in the paper is a method for offsetting any kind of curve. Specifically, we use parametric cubic curves, which is one of the most general and popular models in computer aided design (CAD)/computer aided manufacturing (CAM) applications. Results. The resulting method avoids any constraint in object or tool shape and obtains valid and optimal trajectories, with a low temporal cost of O(n∙m), which is corroborated by the experiments. It also avoids some precision errors that are present in the most popular commercial CAD/CAM libraries. Conclusions. The use of morphology as the base of the formulation avoids self-intersections and discontinuities and allows the system to machine free-form shapes using any tool without constraints. Most numerical and geometrical problems are also avoided. Obtaining a practical algorithm from the theoretical formulation is straightforward. The resulting procedure is simple and efficient.

Sketch-based shape exploration using multiscale free-form surface editing

2012 ◽  
Vol 26 (3) ◽  
pp. 337-350
Author(s):  
Günay Orbay ◽  
Mehmet Ersın Yümer ◽  
Levent Burak Kara
Keyword(s):  
Computer Aided Design ◽  
Free Form ◽  
Levels Of Detail ◽  
Solid Models ◽  
Free Form Surface ◽  
Conceptual Flexibility ◽  
Aided Design ◽  
Free Form Surfaces ◽  
Surface Editing ◽  
Different Levels

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.

Automatic Side-Cores Construction in Injection Plastic Mold Design for Free-Form NURBS Surface Models

2013 ◽  
Vol 275-277 ◽  
pp. 2635-2639 ◽  
Author(s):  
Nguyen Huu Quang ◽  
Alan C. Lin
Keyword(s):  
Computer Aided Design ◽  
Complex Geometry ◽  
Automatic Generation ◽  
Free Form ◽  
Mold Design ◽  
Manufacturing Cost ◽  
Synthetic Approach ◽  
Nurbs Surface ◽  
Surface Models ◽  
Aided Design

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.

Force-Enabled Sculpting of CAD Models

2000 ◽  
Author(s):  
Pietro Buttolo ◽  
Paul Stewart ◽  
Yifan Chen
Keyword(s):  
Computer Aided Design ◽  
Free Form ◽  
Design Models ◽  
Trade Off ◽  
Cartesian Space ◽  
Computer Aided ◽  
Cad Models ◽  
Geometrical Information ◽  
Aided Design ◽  
Free Form Surfaces

Abstract Transferring geometrical information between Computer-Aided Design models and physical prototypes is a time-intensive task and as such is one of the critical bottlenecks in the automotive design process. Sculpting of free-form surfaces in force enabled CAD applications could bridge the gap between digital models and certain physical prototypes. In this paper a novel force-enabled surface manipulation method called stick-to-surface/stick-to-pen is presented. During sculpting, the haptic device is constrained to follow the virtual surface, and simultaneously the surface is controlled to follow the device. The trade-off between which follows which is managed by partitioning the Cartesian space into a browsing subspace and a manipulation subspace.

Real-Time Machinability Analysis of Free Form Surfaces on the GPU

2009 ◽  
Vol 9 (2) ◽  
Author(s):  
Mikola Lysenko ◽  
Roshan D’Souza ◽  
Keyvan Rahmani
Keyword(s):  
Real Time ◽  
Computer Aided Design ◽  
Graphics Processing Units ◽  
Three Dimensional ◽  
Free Form ◽  
Complex Objects ◽  
Cad System ◽  
Solid Models ◽  
Aided Design ◽  
Free Form Surfaces

In this paper a new hardware accelerated method is presented to evaluate the machinability of free-form surfaces. This method works on tessellated models that are commonly used by computer aided design (CAD) systems to render three-dimensional shaded images of solid models. Modern graphics processing units (GPUs) can be programed in hardware to accelerate specialized rendering techniques. In this research, we have developed new algorithms that utilize the programmability of GPUs to evaluate the machinability of free-form surfaces. The method runs in real-time on fairly inexpensive hardware (<$600), and performs well regardless of the surface type. The complexity of the method is dictated by the size of the projected view of the model. The proposed method can be used as a plug-in in a CAD system to evaluate the manufacturability of a part at early design stages. The efficiency and the speed of the proposed method are demonstrated on some complex objects.

scholarly journals Compendium of current ceramic materials used for the CAD/CAM dentistry.

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Kristýna Hynková ◽  
Iva Voborná ◽  
Bernard Linke ◽  
Liran Levin
Keyword(s):  
Computer Aided Design ◽  
New Technologies ◽  
Ceramic Materials ◽  
Clinical Situation ◽  
Computer Aided ◽  
Cad Cam ◽  
Ceramic Blocks ◽  
Materials Used ◽  
Aided Design

Abstract Nowadays, patients require the highest quality of treatment, but generally prefer to spend as little time as possible in the dental chair. Therefore, there is significant benefit for using new technologies such as CAD/CAM (computer aided design/computer aided manufacturing), which provides both quality and speed. There is an increase in ceramic materials and ceramic blocks/discs available, with varying properties. This has resulted in some confusion and difficulty in making an informed decision about which material is best for a specific clinical situation. The objective of this review is to provide an overview and comparison of basic mechanical properties of currently used CAD/CAM ceramic materials based on a review of the currently available literature.

scholarly journals Standard vs computer-aided design/computer-aided manufacturing customized self-ligating systems using indirect bonding with both:

2020 ◽  
Vol 91 (1) ◽  
pp. 74-80
Author(s):  
Nastasia Jackers ◽  
Nathalie Maes ◽  
France Lambert ◽  
Adelin Albert ◽  
Carole Charavet
Keyword(s):  
Computer Aided Design ◽  
Comparative Trial ◽  
Fine Tuning ◽  
Computer Aided Manufacturing ◽  
Indirect Bonding ◽  
Patient Reported ◽  
Computer Aided ◽  
Cad Cam ◽  
Aided Design

ABSTRACT Objective To compare treatment duration and quality between standard vs computer-aided design/computer-aided manufacturing (CAD/CAM) customized self-ligating systems using indirect bonding with both. Materials and Methods This comparative trial included 24 patients: 12 treated with a CAD/CAM custom indirect bonding self-ligating system (CAD/CAM) and 12 others treated with an indirect bonding self-ligating standard system (I-STD). For each group, overall orthodontic treatment (OT) time was calculated and included the time needed to place each arch as well as the duration of the alignment and fine-tuning phases. The quality of the final result was analyzed using the American Board of Orthodontics Cast-Radiograph Evaluation. Patient-reported outcome measures (PROMs) were also evaluated. Results Patient characteristics were similar between the 2 groups except for age, which was slightly lower in the I-SDT group. Overall OT time was increased by 26% in the I-STD group compared with the CAD/CAM group (497 ± 40 days vs 393 ± 55 days, P = 0.0002) due to a shorter fine-tuning phase in the latter group (P&lt;0.01). No difference was found between the groups for alignment phase. Quality of the final result was similar (I-STD, 25.7 ± 6.1; CAD/CAM, 21.6 ± 6.3) among the groups. Finally, no difference was found in the PROMs variables. Conclusions Despite a 26% longer OT time when compared with the CAD/CAM customized bracket system, the indirect bonding self-ligating bracket system demonstrated the same quality of treatment. PROMs demonstrated a high level of acceptance and satisfaction for both techniques.

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