Sustained CAD/CAE Application Integration: Supporting Simplified Models

Author(s):  
Robert Kirkwood ◽  
James A. Sherwood

Abstract Computer-aided design/computer-aided manufacturing/computer-aided engineering (CAD/CAM/CAE) integration offers designers, analysts, and manufacturers the opportunity to share the data throughout the product development process. Finite element (FE) meshing applications integrated with the solid model data from CAD systems represent a major subset of CAD/CAM/CAE integration. In an earlier paper, it was demonstrated that virtual persistent identifiers (VPIs) can be used to assure or repair sustained integration with successive versions of neutral-format solid models. From that article, several follow-on issues become apparent. The geometry as per the CAE model often differs from the CAD model, so even with cross-format issues resolved, significant obstacles to sustained CAD/CAE integration remain. Along with simplification, the current article investigates additional techniques for further automating the recognition of changes between CAD models, reducing the manual interaction to just a few minutes. The article goes on to demonstrate how associativity can be sustained when using current versions of neutral formats like STEP and IGES. The overall point of the paper is to show that given a precise recognition of the differences between two solid models, a generalized means of ad-hoc integration is possible. This point is demonstrated through two case studies where simplifications of the CAD geometry are made to facilitate the meshing of the part. The integration is shown to be maintained across successive versions and to address a range of simplification processing. A summary of best practices for efficiently accommodating sustained CAD/CAE integration is also presented.

Author(s):  
G Britton ◽  
T S Beng ◽  
Y Wang

This paper describes three approaches for virtual product development of plastic injection moulds. The first is characterized by the use of three-dimensional computer aided design (CAD) for product design, two-dimensional drafting for mould design and three-dimensional computer aided design/manufacture (CAD/CAM) for mould manufacture. The second is characterized by the use of three-dimensional CAD models by all three participants, but between any two participants some form of file conversion is normally required because different CAD systems are used. The first two approaches share one common feature: the models are passed serially from the product designer to the mould designer and on to the toolmaker. They represent current practice in industry. The third approach is a proposed collaborative design process. Participants can work concurrently on the same model, sharing their knowledge and experience. The process is currently being refined and will be validated later this year with a prototype system based on Unigraphics iMAN software.


2012 ◽  
Author(s):  
Syaimak Abd. Syukur ◽  
Masine Md Tap

Sistem Rapid Prototyping (RP) ialah teknologi yang menukar sesuatu reka bentuk yang dibina dalam Computer Aided Design (CAD) ke suatu komponen model 3D. Model CAD biasanya dibina dalam sistem CAD yang kemudiannya dihantar ke sistem RP. Antaramuka yang baik antara sistem CAD dan sistem RP adalah salah satu faktor penting dalam menghasilkan prototaip yang berkualiti tinggi. Kertas kerja ini melaporkan hasil uji kaji yang dijalankan untuk mengenal pasti masalah-masalah dalam memindahkan data antara satu sistem CAD (UNIGRAPHICS) dan satu sistem RP (QUICKSLICE). Berdasarkan hasil uji kaji dan analisis yang dijalankan, satu garis panduan dicadangkan untuk perpindahan data yang lebih berkesan antara sistem CAD (UNIGRAPHICS) dan sistem RP (QUICKSLICE). Kata kunci: CAD; CAM; CAD/CAM; Rapid Prototyping Rapid Prototyping (RP) is a technology that transform a design generated in Computer Aided Design (CAD) to a 3D model parts. CAD models are usually done on a CAD system and then transported into the RP system. A good interface between the CAD and the RP system is one of the key factors of producing a good quality prototype. This paper reports on the results of an experimentation carried out to identify the problems in transferring data between a CAD system (UNIGRAPHICS) and an RP system (QUICKSLICE). Based on the experimentation’s results and analysis, a basic guideline is proposed for a safer data transfer between the CAD system (UNIGRAPHICS) and an RP system (QUICKSLICE). Key words: CAD; CAM; CAD/CAM; Rapid Prototyping


Author(s):  
A. N. Bozhko

Computer-aided design of assembly processes (Computer aided assembly planning, CAAP) of complex products is an important and urgent problem of state-of-the-art information technologies. Intensive research on CAAP has been underway since the 1980s. Meanwhile, specialized design systems were created to provide synthesis of assembly plans and product decompositions into assembly units. Such systems as ASPE, RAPID, XAP / 1, FLAPS, Archimedes, PRELEIDES, HAP, etc. can be given, as an example. These experimental developments did not get widespread use in industry, since they are based on the models of products with limited adequacy and require an expert’s active involvement in preparing initial information. The design tools for the state-of-the-art full-featured CAD/CAM systems (Siemens NX, Dassault CATIA and PTC Creo Elements / Pro), which are designed to provide CAAP, mainly take into account the geometric constraints that the design imposes on design solutions. These systems often synthesize technologically incorrect assembly sequences in which known technological heuristics are violated, for example orderliness in accuracy, consistency with the system of dimension chains, etc.An AssemBL software application package has been developed for a structured analysis of products and a synthesis of assembly plans and decompositions. The AssemBL uses a hyper-graph model of a product that correctly describes coherent and sequential assembly operations and processes. In terms of the hyper-graph model, an assembly operation is described as shrinkage of edge, an assembly plan is a sequence of shrinkages that converts a hyper-graph into the point, and a decomposition of product into assembly units is a hyper-graph partition into sub-graphs.The AssemBL solves the problem of minimizing the number of direct checks for geometric solvability when assembling complex products. This task is posed as a plus-sum two-person game of bicoloured brushing of an ordered set. In the paradigm of this model, the brushing operation is to check a certain structured fragment for solvability by collision detection methods. A rational brushing strategy minimizes the number of such checks.The package is integrated into the Siemens NX 10.0 computer-aided design system. This solution allowed us to combine specialized AssemBL tools with a developed toolkit of one of the most powerful and popular integrated CAD/CAM /CAE systems.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3819
Author(s):  
Ting-Hsun Lan ◽  
Yu-Feng Chen ◽  
Yen-Yun Wang ◽  
Mitch M. C. Chou

The computer-aided design/computer-aided manufacturing (CAD/CAM) fabrication technique has become one of the hottest topics in the dental field. This technology can be applied to fixed partial dentures, removable dentures, and implant prostheses. This study aimed to evaluate the feasibility of NaCaPO4-blended zirconia as a new CAD/CAM material. Eleven different proportional samples of zirconia and NaCaPO4 (xZyN) were prepared and characterized by X-ray diffractometry (XRD) and Vickers microhardness, and the milling property of these new samples was tested via a digital optical microscope. After calcination at 950 °C for 4 h, XRD results showed that the intensity of tetragonal ZrO2 gradually decreased with an increase in the content of NaCaPO4. Furthermore, with the increase in NaCaPO4 content, the sintering became more obvious, which improved the densification of the sintered body and reduced its porosity. Specimens went through milling by a computer numerical control (CNC) machine, and the marginal integrity revealed that being sintered at 1350 °C was better than being sintered at 950 °C. Moreover, 7Z3N showed better marginal fit than that of 6Z4N among thirty-six samples when sintered at 1350 °C (p < 0.05). The milling test results revealed that 7Z3N could be a new CAD/CAM material for dental restoration use in the future.


2021 ◽  
Vol 11 (4) ◽  
pp. 145
Author(s):  
Nenad Bojcetic ◽  
Filip Valjak ◽  
Dragan Zezelj ◽  
Tomislav Martinec

The article describes an attempt to address the automatized evaluation of student three-dimensional (3D) computer-aided design (CAD) models. The driving idea was conceptualized under the restraints of the COVID pandemic, driven by the problem of evaluating a large number of student 3D CAD models. The described computer solution can be implemented using any CAD computer application that supports customization. Test cases showed that the proposed solution was valid and could be used to evaluate many students’ 3D CAD models. The computer solution can also be used to help students to better understand how to create a 3D CAD model, thereby complying with the requirements of particular teachers.


Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1986
Author(s):  
Andreas Koenig ◽  
Julius Schmidtke ◽  
Leonie Schmohl ◽  
Sibylle Schneider-Feyrer ◽  
Martin Rosentritt ◽  
...  

The performance of dental resin-based composites (RBCs) heavily depends on the characteristic properties of the individual filler fraction. As specific information regarding the properties of the filler fraction is often missing, the current study aims to characterize the filler fractions of several contemporary computer-aided design/computer-aided manufacturing (CAD/CAM) RBCs from a material science point of view. The filler fractions of seven commercially available CAD/CAM RBCs featuring different translucency variants were analysed using Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS), Micro-X-ray Computed Tomography (µXCT), Thermogravimetric Analysis (TG) and X-ray Diffractometry (XRD). All CAD/CAM RBCs investigated included midifill hybrid type filler fractions, and the size of the individual particles was clearly larger than the individual specifications of the manufacturer. The fillers in Shofu Block HC featured a sphericity of ≈0.8, while it was <0.7 in all other RBCs. All RBCs featured only X-ray amorphous phases. However, in Lava Ultimate, zircon crystals with low crystallinity were detected. In some CAD/CAM RBCs, inhomogeneities (X-ray opaque fillers or pores) with a size <80 µm were identified, but the effects were minor in relation to the total volume (<0.01 vol.%). The characteristic parameters of the filler fraction in RBCs are essential for the interpretation of the individual material’s mechanical and optical properties.


Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1401
Author(s):  
Doo-Bin Song ◽  
Man-So Han ◽  
Si-Chul Kim ◽  
Junyong Ahn ◽  
Yong-Woon Im ◽  
...  

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.


1999 ◽  
Vol 121 (4) ◽  
pp. 502-506 ◽  
Author(s):  
Q. J. Ge ◽  
M. Sirchia

This paper brings together the notion of analytically defined two-parameter motion in Theoretical Kinematics and the notion of freeform surfaces in Computer Aided Geometric Design (CAGD) to develop methods for computer aided design of two-parameter freeform motions. In particular, a rational Be´zier representation for two-parameter freeform motions is developed. It has been shown that the trajectory surface of such a motion is a tensor-product rational Be´zier surface and that such a kinematically generated surface has a geometric as well as a kinematic control structure. The results have not only theoretical interest in CAGD and kinematics but also applications in CAD/CAM and Robotics.


Biology ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1170
Author(s):  
Giulio Marchesi ◽  
Alvise Camurri Piloni ◽  
Vanessa Nicolin ◽  
Gianluca Turco ◽  
Roberto Di Lenarda

Restorative materials are experiencing an extensive upgrade thanks to the use of chairside Computer-aided design/computer-assisted manufacturing (CAD/CAM) restorations. Therefore, due to the variety offered in the market, choosing the best material could be puzzling for the practitioner. The clinical outcome of the restoration is influenced mainly by the material and its handling than by the fabrication process (i.e., CAD/CAM). Information on the restorative materials performances can be difficult to gather and compare. The aim of this article is to provide an overview of chairside CAD/CAM materials, their classification, and clinically relevant aspects that enable the reader to select the most appropriate material for predictable success.


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