Integration of CAD, CAPP and Process Modeling Using XML Technologies

Author(s):  
Pravin Khurana ◽  
Dusan N. Sormaz ◽  
Raghunath Khetan

Integration of CAD (Computer Aided Design), CAPP (Computer Aided Process Planning) and Process Modeling activities plays a vital role in enabling concurrent product and process design. Typically each of these functions is performed in its own dedicated software environment. The integration will require interfacing several disconnected processes and software components built in different languages, and platforms. This paper presents an integration methodology, validated using a case study, in which a steering housing was analyzed and its process planning and design tasks were integrated using several software tools. The first integration task was to generate a feature based CAD model (in Unigraphics) and map these design features to a set of manufacturing features. Feature based design was performed using the Horizontal Modeling™ approach developed at Delphi. Features developed using this approach were then mapped to manufacturing features using APPS, a software tool developed at Delphi Dynamics and Propulsion Innovation Center. This task involved interrogation of the geometric CAD model to generate geometric and tolerance information and represent them in a format suitable for feature-based process planning. The second task of integration is generation of feasible “production-intent” process plans. This task is performed using APPS and IMPlanner process planner, a knowledge based software tool developed at Ohio University. The third and final task of integration is automated generation of in-process CAD models. This task involved the integration of Delphi process design techniques to generate CAD models (in Unigraphics) to represent the component at each stage of the manufacturing process. Evaluation of these steps through the case study has identified the strengths and weaknesses of the proposed integration methodology, which is reported in this paper.

Author(s):  
Soonjo Kwon ◽  
Byung Chul Kim ◽  
Duhwan Mun ◽  
Soonhung Han

The required level of detail (LOD) of a three-dimensional computer-aided design (3D CAD) model differs according to its purpose. It is therefore important that users are able to simplify a highly complex 3D CAD model and create a low-complexity one. The simplification of a 3D CAD model requires the application of a simplification operation and evaluation metrics for the geometric elements of the 3D CAD model. The evaluation metrics are used to select those elements that should be removed. The simplification operation removes selected elements in order to simplify the 3D CAD model. In this paper, we propose the graph-based simplification of feature-based 3D CAD models using a method that preserves connectivity. First, new evaluation metrics that consider the discrimination priority among several simplification criteria are proposed. Second, a graph-based refined simplification operation that prevents the separation of a feature-based 3D CAD model into multiple volumes is proposed. Finally, we verify the proposed method by implementing a prototype system and performing simplification experiments using feature-based 3D CAD models.


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.


2014 ◽  
Vol 598 ◽  
pp. 591-594 ◽  
Author(s):  
Li Yan Zhang

ISO 14649, known as STEP-NC, is new model of data transfer between CAD/CAM systems and CNC machines. In this paper, the modeling based on machining feature is proposed. The machining feature comes from the manufacturing process considering the restriction of machining technology and machining resource. Then the framework for computer aided process planning is presented, where the algorithms of operation planning is studied. The practical example has been provided and results indicate that machining feature based model can integrate with CAPP and STEP-NC seamlessly.


Author(s):  
Jean-Pierre Kruth ◽  
Geert Van Zeir ◽  
Jan Detand

Abstract This paper describes the ideas and developments that lead to a new Computer Aided Process Planning (CAPP) approach : a blackboard-style, interactive CAPP system, in which the human process planner is assisted by expert modules, each capable of performing a process planning task. At all times, the human operator has full control over all planning activities. An important reasoning mechanism, that is inevitably linked with the interactive CAPP kernel, is opportunistic process planning. The implementation of this mechanism in an automatic feature based CAPP system will also be elaborated in this paper.


2009 ◽  
Vol 131 (12) ◽  
Author(s):  
Min Li ◽  
Y. F. Zhang ◽  
J. Y. H. Fuh ◽  
Z. M. Qiu

In product design, a large proportion of three-dimensional (3D) computer-aided design (CAD) models can be reused to facilitate future product development due to their similarities in function and shape. This paper presents a novel method that incorporates modeling knowledge into CAD model similarity assessment to improve the effectiveness of reuse-oriented retrieval. First, knowledge extraction is performed on archived feature-based CAD models to construct feature dependency directed acyclic graph (FDAG). Second, based on the FDAG subgraph decomposition, two useful component partitioning approaches are developed to extract simplified essential shapes and meaningful subparts from CAD models. Third, the extracted shapes and their FDAG subgraphs are indexed. Finally, the indexed shapes that are similar to user-sketched queries are retrieved to reuse, and FDAG information of the retrieved shapes is provided as redesign suggestions. Experimental results suggest that the incorporation of modeling knowledge greatly facilitates CAD model retrieval and reuse. Algorithm evaluations also show the presented method outperforms other 3D retrieval methods.


Author(s):  
Yogesh H. Kulkarni ◽  
Anil Sahasrabudhe ◽  
Mukund Kale

Computer-aided design (CAD) models of thin-walled solids such as sheet metal or plastic parts are often reduced dimensionally to their corresponding midsurfaces for quicker and fairly accurate results of computer-aided engineering (CAE) analysis. Computation of the midsurface is still a time-consuming and mostly, a manual task due to lack of robust and automated techniques. Most of the existing techniques work on the final shape (typically in the form of boundary representation, B-rep). Complex B-reps make it hard to detect subshapes for which the midsurface patches are computed and joined, forcing usage of hard-coded heuristic rules, developed on a case-by-case basis. Midsurface failures manifest in the form of gaps, overlaps, nonmimicking input model, etc., which can take hours or even days to correct. The research presented here proposes to address these problems by leveraging feature-information available in the modern CAD models, and by effectively using techniques like simplification, abstraction, and decomposition. In the proposed approach, first, the irrelevant features are identified and removed from the input FbCAD model to compute its simplified gross shape. Remaining features then undergo abstraction to transform into their corresponding generic Loft-equivalents, each having a profile and a guide curve. The model is then decomposed into cellular bodies and a graph is populated, with cellular bodies at the nodes and fully overlapping-surface-interfaces at the edges. The nodes are classified into midsurface-patch generating nodes (called “solid cells” or sCells) and interaction-resolving nodes (“interface cells” or iCells). In a sCell, a midsurface patch is generated either by offset or by sweeping the midcurve of the owner-Loft-feature's profile along with its guide curve. Midsurface patches are then connected in the iCells in a generic manner, thus resulting in a well-connected midsurface with minimum failures. Output midsurface is then validated topologically for correctness. At the end of this paper, real-life parts are used to demonstrate the efficacy of the proposed approach.


Author(s):  
Thiago Weber Martins ◽  
Lars Niemczik ◽  
Reiner Anderl

This paper introduces a concept to integrate measurements data into feature-based 3D CAD models. The concept focuses on its application in the measurement of bifurcated sheet metal profiles. For that, an interface to read and import this data into the CAD system is developed. Since the measurement data is stored as a point cloud, further data processing (reverse engineering) is necessary to recreate the work piece shape in the CAD system. If the measured work piece model and the CAD model of the design piece are available, an automated comparison of the defined dimension takes place. The result is a notification in the CAD model indicating which dimension deviates from the target values. Use-cases are elaborated for integrating the concept in the product development process. To implement this concept, an experimental setup is built up consisting of a measurement system and 3D CAD system. The COPRA ProfileScan Desktop is used to measure the profile. Siemens NX 11 is the chosen CAD system. Based on this setup, the concept is validated on a manufactured profile.


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