An Integrated DFM System for Milling

1997 ◽  
Author(s):  
Subramanian Krishnan ◽  
Edward B. Magrab
Keyword(s):  
Feature Recognition ◽  
Integrated Design ◽  
Geometric Reasoning ◽  
New Approach ◽  
Design For Manufacture ◽  
Minimum Number ◽  
Feature Based ◽  
Two Stages ◽  
Manufacturability Evaluation ◽  
General Profile

Abstract An integrated design for manufacture system for milling is developed by introducing a fundamental manufacturing entity for milling (FMEM), which represents a volume to be machined. A part is created by subtracting a user created set of FMEMs from a rectangular prismatic stock. Manufacturability evaluation is done in two stages: (1) after creating each FMEM; and (2) after placing and subtracting the volume from the stock. It is shown that the commonly used 2½ -D features used to mill a part such as slots, pockets and holes are a subset of the FMEM. Furthermore, all specific shapes of the general FMEM are represented by one compact data structure. It is demonstrated that using process specific entities greatly simplifies manufacturability evaluation, which makes it possible to base the geometric reasoning algorithms on the entity’s most general profile rather than on only a set of specific shapes. A new approach using the FMEMs is presented for generating an integrated process and fixture plan with a minimum number of setup and tool changes. The advantages of using the process specific entities approach for design and manufacturability analysis over the feature recognition approach and feature based approach are enumerated.

Performing DFM Analysis in Multiple Domains Using Interchangeable Manufacturable Entities

1997 ◽  
Author(s):  
Subramanian Krishnan ◽  
Edward B. Magrab
Keyword(s):  
Manufacturing Process ◽  
Feature Recognition ◽  
Integrated Design ◽  
Integrated System ◽  
New Approach ◽  
Small Set ◽  
Multiple Domains ◽  
Shape Characteristics ◽  
Manufacturability Evaluation ◽  
Made In

Abstract An integrated design for manufacture system that performs manufacturability analysis simultaneously in two domains using interchangeable process specific entities is presented. This new approach is illustrated by an integrated system that creates and evaluates parts for manufacture by injection molding using a C-entity, and simultaneously creates and evaluates its mold for manufacture by milling using the fundamental manufacturing entity for milling. The entity for the part manufacturing process is chosen as the complement of the entity for the mold manufacturing process. This obviates the need for converting features from one manufacturing domain to another, and also permits a single uniform data structure to capture the shape characteristics of parts made in the two manufacturing domains. Since all the shapes are represented in the same way, the manufacturability evaluation of the part and the mold is reduced to a small set of algorithms based on an evaluation of the entity’s profile. It is demonstrated that by using process specific entities one can perform manufacturability evaluation of a part without either feature extraction or designing with features. The advantages of using the process specific entities approach for design and manufacturability evaluation over the feature recognition and the design by features approach are enumerated.

Geometric Reasoning Based on Graph Grammar Parsing

1994 ◽  
Vol 116 (3) ◽  
pp. 763-769 ◽  
Author(s):  
Z. Fu ◽  
A. de Pennington
Keyword(s):  
Intelligent Design ◽  
Feature Recognition ◽  
Geometric Reasoning ◽  
Geometric Constraints ◽  
Graph Grammar ◽  
Feature Interaction ◽  
Knowledge Based ◽  
Feature Based ◽  
Feature Information ◽  
And Performance

It has been recognized that future intelligent design support environments need to reason about the geometry of products and to evaluate product functionality and performance against given constraints. A first step towards this goal is to provide a more robust information model which directly relates to design functionality or manufacturing characteristics, on which reasoning can be carried out. This has motivated research on feature-based modelling and reasoning. In this paper, an approach is presented to geometric reasoning based on graph grammar parsing. Our approach is presented to geometric reasoning based on graph grammar parsing. Our work combines methodologies from both design by features and feature recognition. A graph grammar is used to represent and manipulate features and geometric constraints. Geometric constraints are used within symbolical definitions of features constraints. Geometric constraints are used within symbolical definitions of features and also to define relative position and orientation of features. The graph grammar parsing is incorporated with knowledge-based inference to derive feature information and propagate constraints. This approach can be used for the transformation of feature information and to deal with feature interaction.

A Hybrid Approach to Intelligent Geometric Design Using Features-Based Design and Feature Recognition

1993 ◽  
Author(s):  
Rajit Gadh
Keyword(s):  
Computer Aided Design ◽  
Feature Recognition ◽  
Hybrid Approach ◽  
Systems Design ◽  
Design Feature ◽  
New Approach ◽  
Geometric Entity ◽  
Current Article ◽  
Aided Design ◽  
Manufacturability Evaluation

Abstract The current article presents a new approach to computer aided design based on an abstract geometric entity called a C-loop (Convex/Concave-loop). The approach currently being developed overcomes design limitations in current systems. Design-by-features systems are fast, but not flexible. Design-by-surfaces systems are flexible but cumbersome to use. The current research integrates a design-by-features approach with a design-by-surfaces approach followed by feature recognition. It allows the designer to create a design using design features and to modify these features as needed. The C-loop is the design feature that allows such flexibility. Subsequent to the design step, features pertinent to manufacturing are recognized from the model to perform Design-for-Manufacturability evaluation of the part.

scholarly journals Facial Feature Extraction Using a 4D Stereo Camera System

2011 ◽  
pp. 21-25
Author(s):  
Soumya Kanti Datta ◽  
Dr. Philip Morrow ◽  
Prof. Bryan Scotney
Keyword(s):  
Feature Extraction ◽  
Feature Recognition ◽  
Facial Feature ◽  
Camera System ◽  
New Approach ◽  
Stereo Camera ◽  
Second Stage ◽  
Facial Feature Extraction ◽  
Two Stages ◽  
Biological Shape

Facial feature recognition has received much attention among the researchers in computer vision. This paper presents a new approach for facial feature extraction. The work can be broadly classified into two stages, face acquisition and feature extraction. Face acquisition is done by a 4D stereo camera system from Dimensional Imaging and the data is available in ‘obj’ files generated by the camera system. The second stage illustrates extraction of important facial features. The algorithm developed for this purpose is inspired from the natural biological shape and structure of human face. The accuracy of identifying the facial points has been shown using simulation results. The algorithm is able to identify the tip of the nose, the point where nose meets the forehead, and near corners of both the eyes from the faces acquired by the camera system.

Geometric Reasoning Based on Graph Grammar Parsing

1991 ◽  
Author(s):  
Zhuo Fu ◽  
Alan de Pennington
Keyword(s):  
Intelligent Design ◽  
Feature Recognition ◽  
Geometric Reasoning ◽  
Geometric Constraints ◽  
Graph Grammar ◽  
Feature Interaction ◽  
Knowledge Based ◽  
Feature Based ◽  
Feature Information ◽  
And Performance

Abstract It has been recognized that future intelligent design support environments need to be able to reason about the geometry of products and to evaluate product functionality and performance against given constraints. A first step towards this goal is to provide a more robust information model which directly relates to design functionality or manufacturing characteristics, on which reasoning can be carried out. This has motivated research on feature-based modelling and reasoning. In this paper, an approach is presented to geometric reasoning based on graph grammar parsing. Our work combines methodologies from both design by features and feature recognition. A graph grammar is used to represent and manipulate features and geometric constraints. Geometric constraints are used within symbolic definitions of features and also to define relative position and orientation of features. The graph grammar parsing is incorporated with knowledge-based techniques to derive feature information and propagate constraints. This approach can be used to the transformation of feature information and to deal with feature interaction.

Perceiving at a distance: enaction, exteriority and possibility – a tribute to John Stewart

2021 ◽  
pp. 105971232110310
Author(s):  
Charles Lenay
Keyword(s):  
Experimental Study ◽  
Perceptual Experience ◽  
Spatial Perception ◽  
Distant Object ◽  
New Approach ◽  
Second Stage ◽  
The Moment ◽  
Two Stages

The aim of this article is to offer a new approach of perception regarding the position of a distant object. It is also a tribute to John Stewart who accompanied the first stages of this research. Having already examined the difficulties surrounding questions of the perception of exteriority within the framework of enactive approaches, we will proceed in two stages. The first stage will consist of an attempt to explain distal perception in terms of individual sensorimotor invariants. This poses the problem but fails to solve it. The second stage will propose a new pathway to account for spatial perception; a pathway that does not deny the initial intuitions of the autopoietic enactive approaches, but one which radically changes the conception of cognition by considering, from the perceptual stage, the need to take into account interindividual interactions. The protocol of an original experimental study will characterize this new approach considering the perceptual experience of objects at a distance, in exteriority, in a space of possibilities without parting from the domain of interaction. To do this, we have to work at the limits of the perceptual crossing, that is, at the moment when the perceptual reciprocity between different subjects begins to disappear.

Midsurface Abstraction From 3D Solid Models for Engineering Analysis

1996 ◽  
Author(s):  
Mohsen Rezayat
Keyword(s):  
Feature Recognition ◽  
Analysis Model ◽  
Thin Sections ◽  
New Approach ◽  
Solid Models ◽  
Product And Process ◽  
Plastic Parts ◽  
3D Solid ◽  
User Friendly ◽  
Analysis Models

Abstract An integral part of implementing parallel product and process designs is simulation through numerical analysis. This simulation-driven design requires discretization of the 3D part in an appropriate manner. If the part is thin or has thin sections (e.g., plastic parts), then an analysis model with reduced dimensionality may be more accurate and economical than a standard 3D model. In addition, substantial simplification of some details in the design geometry may be beneficial and desirable in the analysis model. Unfortunately, the majority of CAD systems do not provide the means for abstraction of appropriate analysis models. In this paper we present a new approach, based on midsurface abstraction, which holds significant promise in simplifying simulation-driven design. The method is user-friendly because very little interaction is required to guide the software in its automatic creation of the desired analysis model. It is also robust because it handles typical parts with complex and interacting features. Application of the method for feature recognition and abstraction is also briefly discussed.

A Manufacturability Evaluation and Improvement System

1991 ◽  
Author(s):  
Nicholas J. Yannoulakis ◽  
Sanjay B. Joshi ◽  
Richard A. Wysk
Keyword(s):  
Life Cycle ◽  
Concurrent Engineering ◽  
Knowledge Bases ◽  
Machining Parameters ◽  
Life Cycle Design ◽  
Machined Parts ◽  
Feature Based ◽  
Feature Based Design ◽  
Manufacturability Evaluation ◽  
Quantitative Indicators

Abstract The increasing application of CAE has lead to the evolution of Concurrent Engineering — a philosophy that prescribes simultaneous consideration of the life-cycle design issues of a product. The Concurrent Engineering (CE) systems that have been developed so far have relied on knowledge bases and qualitative evaluations of a part’s manufacturability for feedback to the design engineer. This paper describes a method for developing quantitative indicators of manufacturability. Feature-based design and estimation of machining parameters are used for ascertaining a part’s manufacturing requirements. These requirements are then combined into indices which lead the designer to features that must be redesigned for improved manufacturability. This method is illustrated on a system for rotational machined parts: the Manufacturability Evaluation and Improvement System (MEIS).

Feature-Based Machining Precedence Reasoning and Sequence Planning

1998 ◽  
Author(s):  
Yong Se Kim ◽  
Eric Wang ◽  
Choong Soo Lee ◽  
Hyung Min Rho
Keyword(s):  
Feature Recognition ◽  
Search Space ◽  
Machining Process ◽  
Planning System ◽  
Process Information ◽  
Computer Aided Process Planning ◽  
Sequence Planning ◽  
Precedence Relations ◽  
Feature Based ◽  
Form Features

Abstract This paper presents a feature-based method to support machining sequence planning. Precedence relations among machining operations are systematically generated based on geometric information, tolerance specifications, and machining expertise. The feature recognition method using Alternating Sum of Volumes With Partitioning (ASVP) Decomposition is applied to obtain a Form Feature Decomposition (FFD) of a part model. Form features are classified into a taxonomy of atomic machining features, to which machining process information has been associated. Geometry-based precedence relations between features are systematically generated using the face dependency information obtained by ASVP Decomposition and the features’ associated machining process information. Multiple sets of precedence relations are generated as alternative precedence trees, based on the feature types and machining process considerations. These precedence trees are further enhanced with precedence relations from tolerance specifications and machining expertise. Machining sequence planning is performed for each of these precedence trees, applying a matrix-based method to reduce the search space while minimizing the number of tool changes. The precedence trees may then be evaluated based on machining cost and other criteria. The precedence reasoning module and operation sequence planning module are currently being implemented within a comprehensive Computer-Aided Process Planning system.

scholarly journals Recombination hotspots as a point process

2005 ◽  
Vol 360 (1460) ◽  
pp. 1597-1603 ◽  
Author(s):  
Maria De Iorio ◽  
Eric de Silva ◽  
Michael P.H Stumpf
Keyword(s):  
Point Process ◽  
Dna Sequences ◽  
Recombination Rate ◽  
Population Genetic ◽  
Process Model ◽  
Chromosomal Dna ◽  
New Approach ◽  
Recombination Hotspots ◽  
Minimum Number ◽  
Fully Bayesian

The variation of the recombination rate along chromosomal DNA is one of the important determinants of the patterns of linkage disequilibrium. A number of inferential methods have been developed which estimate the recombination rate and its variation from population genetic data. The majority of these methods are based on modelling the genealogical process underlying a sample of DNA sequences and thus explicitly include a model of the demographic process. Here we propose a different inferential procedure based on a previously introduced framework where recombination is modelled as a point process along a DNA sequence. The approach infers regions containing putative hotspots based on the inferred minimum number of recombination events; it thus depends only indirectly on the underlying population demography. A Poisson point process model with local rates is then used to infer patterns of recombination rate estimation in a fully Bayesian framework. We illustrate this new approach by applying it to several population genetic datasets, including a region with an experimentally confirmed recombination hotspot.

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