Simultaneous Computer-Aided Design of Rotational Plastic Parts

Author(s):  
Colin Chong ◽  
Kiyoshi Sogabe ◽  
Kosuke Ishii

Abstract This paper addresses the problem of balancing rotational plastic parts during the early stages of design. The study develops an interactive methodology that uses a solid modeling CAD system and considers injection molding concerns simultaneously with static and dynamic balance. The Transfer Matrix Method evaluates the dynamic characteristics by predicting the approximate critical speed of the part. Design Compatibility Analysis (DCA) checks for injection molding guidelines. Using these evaluation modules interactively, designers can develop a functional and manufacturable part quickly.

Author(s):  
Xun Xu

One of the key activities in any product design process is to develop a geometric model of the product from the conceptual ideas, which can then be augmented with further engineering information pertaining to the application area. For example, the geometric model of a design may be developed to include material and manufacturing information that can later be used in computer-aided process planning and manufacturing (CAPP/CAM) activities. A geometric model is also a must for any engineering analysis, such as finite elopement analysis (FEA). In mathematic terms, geometric modelling is concerned with defining geometric objects using computational geometry, which is often, represented through computer software or rather a geometric modelling kernel. Geometry may be defined with the help of a wire-frame model, surface model, or solid model. Geometric modelling has now become an integral part of any computer-aided design (CAD) system. In this chapter, various geometric modelling approaches, such as wire-frame, surface, and solid modelling will be discussed. Basic computational geometric methods for defining simple entities such as curves, surfaces, and solids are given. Concepts of parametric, variational, history-based, and history-free CAD systems are explained. These topics are discussed in this opening chapter because (a) CAD was the very first computer-aided technologies developed and (b) its related techniques and methods have been pervasive in the other related subjects like computer-aided manufacturing. This chapter only discusses CAD systems from the application point of view; CAD data formats and data exchange issues are covered in the second chapter.


1987 ◽  
Vol 31 (2) ◽  
pp. 214-217
Author(s):  
Douglas H. Harris ◽  
Steven M. Casey

A methodology for measuring the organizational effectiveness of computer-aided design (CAD) was developed and applied. A total of 295 of the 500 most frequent users of CAD in a major aerospace company provided data for the study. User-CAD effectiveness was found to be influenced by 43 major factors and 145 specific system and organizational issues. The 43 factors were classified into the following categories: system functions, system hardware, working environment, system reliability and consistency, user access, user support and training, and system administration. Indexes of User-CAD Effectiveness (UE) and System Availability and Reliability (AR) were combined into an Index of CAD Organizational Effectiveness (OE). Through the application of these methods and indexes, CAD system and organizational deficiencies can be diagnosed, potential high-payoff improvements can be identified, and the impact of developmental efforts can be assessed.


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):  
Chi-Cheng Chu ◽  
Rajit Gadh

In this paper, a series of interface tests on interaction approach for the generation of geometric shape designs via multi-sensory user interface of a Virtual Reality (VR) based System is presented. The goal of these interface tests is to identify an effective user interface for VR based Computer-Aided Design (CAD) system. The intuitiveness of the VR based interaction approach arises from the use of natural hand movements/gestures, and voice commands that emulate the way in which human beings discuss geometric shapes in reality. The focus of this paper is on determining a set of effective interaction approaches by using the combinations of auditory, tactile, and visual sensory modalities to accomplish typical CAD tasks. In order to evaluate the proposed interaction approach, a prototypical VR-CAD system is implemented. A series of interface tests were performed on the prototypical systems to determine the relative efficiency of a set of potential interaction approach with respect to specific fundamental design tasks. The interface test and its results are presented in this paper.


Author(s):  
E.V. Belov ◽  
E.A. Brusin

In this paper we propose the design of the receiving path of an advanced satellite modem. The receiver comprises only the components produced by Russian domestic companies. The parameters of the receiver are discussed in the paper. 3D model of the receiver board obtained using the Altium Designer integrated computer-aided design (CAD) system is also presented.


Author(s):  
G C Vosniakos ◽  
T Giannakakis

This work discusses issues concerning the implementation of scanning of unknown engineering objects containing just simple (i.e. no freeform) surfaces with touch probes on three-axis computer numerical control (CNC) measuring machines in order to reconstruct their shape in a computer aided design (CAD) system. Several ideas are put forward e.g. scanning along vertical slicing planes adaptive point sampling distances in-process ‘proactive’ segmentation of points into curve sections and probe radius compensation in two directions as well as limited remedy of edge scanning ambiguities. Most of the suggested algorithms are implemented as parametric numerical control (NC) programs on an OKUMA machining centre.


2014 ◽  
Vol 6 (3) ◽  
pp. 185 ◽  
Author(s):  
Yong-Joon Seo ◽  
Taek-Ka Kwon ◽  
Jung-Suk Han ◽  
Jai-Bong Lee ◽  
Sung-Hun Kim ◽  
...  

2002 ◽  
Vol 2 (3) ◽  
pp. 216-223 ◽  
Author(s):  
Chi-Cheng Chu ◽  
Jianzhong Mo ◽  
Rajit Gadh

In this paper, a series of interface tests on interaction approach for the generation of geometric shape designs via multi-sensory user interface of a Virtual Reality (VR) based System is presented. The goal of these interface tests is to identify an effective user interface for VR based Computer-Aided Design (CAD) system. The intuitiveness of the VR based interaction approach arises from the use of natural hand movements/gestures, and voice commands that emulate the way in which human beings discuss geometric shapes in reality. In order to evaluate the proposed interaction approach, a prototypical VR-CAD system is implemented. A series of interface tests were performed on the prototypical systems to determine the relative efficiency of a set of potential interaction approach with respect to specific fundamental design tasks. The interface test and its results are presented in this paper.


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