33 research outputs found
Automated feature recognition system for supporting engineering activities downstream of conceptual design.
Transfer of information between CAD models and downstream manufacturing process planning software typically involves redundant user interaction. Many existing tools are process-centric and unsuited for selection of a "best process" in the context of existing concurrent engineering design tools. A computer based Feature-Recognition (FR) process is developed to extract critical manufacturing features from engineering product CAD models. FR technology is used for automating the extraction of data from CAD product models and uses wire-frame geometry extracted from an IGES neutral file format. Existing hint-based feature recognition techniques have been extended to encompass a broader range of manufacturing domains than typical in the literature, by utilizing a combination of algorithms, each successful at a limited range of features. Use of wire-frame models simplifies product geometry and has the potential to support rapid manufacturing shape evaluation at the conceptual design stage. Native CAD files are converted to IGES neutral files to provide geometry data marshalling to remove variations in user modelling practice, and to provide a consistent starting point for FR operations. Wire-frame models are investigated to reduce computer resources compared to surface and solid models, and provide a means to recover intellectual property in terms of manufacturing design intent from legacy and contemporary product models. Geometric ambiguity in regard to what is ?solid? and what is not has plagued wire-frame FR development in the past. A new application of crossing number theory (CNT) has been developed to solve the wire-frame ambiguity problem for a range of test parts. The CNT approach works satisfactorily for products where all faces of the product can be recovered and is tested using a variety of mechanical engineering parts.
Platform independent tools like Extensible Mark-up Language are used to capture data from the FR application and provide a means to separate FR and decision support applications. Separate applications are composed of reusable software modules that may be combined as required. Combining rule-based and case-based reasoning provides decision support to the manufacturing application as a means of rejecting unsuitable processes on functional and economic grounds while retaining verifiable decision pathways to satisfy industry regulators
Reverse engineering : an evaluation of contact technology and application in manufacturing systems
There are many instances where one-of-a-kind parts, such as prototypes or custom-built parts, need to be reproduced. When a Computer Aided Design (CAD) of an existing part is not available, reverse engineering is involved in recreation of such part. Currently, geometric measurements from the surface of a prototype are extracted manually and sent to a CAD system. It is typically time consuming, tedious, and potentially a source of error. This study outlines a methodology, for the development of a CAD model, rapid prototype, and subsequently manufacturing of the part. The method developed uses a contact technique to extract 2-D or 3-D data from the surface of parts using a coordinate measurement machine. Procedures for processing the data into a polygon mesh representation and orthographic projections are detailed. CAD solid modelling to Computer Aided Manufacturing (CAM), which is an important step in manufacturing industries are described by CNC code generations and use of ethernet to send the machine code file to the CNC machine tool on the shopfloor
Advancement in robot programming with specific reference to graphical methods
This research study is concerned with the derivation of advanced robot
programming methods. The methods include the use of proprietary
simulation modelling and design software tools for the off-line
programming of industrial robots. The study has involved the generation
of integration software to facilitate the co-operative operation of these
software tools.
The three major researcli'themes7of "ease of usage", calibration and the
integration of product design data have been followed to advance robot
programming. The "ease of usage" is concerned with enhancements in the
man-machine interface for robo t simulation systems in terms of computer
assisted solid modelling and computer assisted task generation.
Robot simulation models represent an idealised situation, and any off-line
robot programs generated from'them may contain'discrepancies which could
seriously effect thq programs' performance; Calibration techniques have
therefore been investigated as 'a method of overcoming discrepancies
between the simulation model and the real world.
At the present time, most computer aided design systems operate as
isolated islands of computer technology, whereas their product databases
should be used to support decision making processes and ultimately
facilitate the generation of machine programs. Thus the integration of
product design data has been studied as an important step towards truly
computer integrated manufacturing.
The functionality of the three areas of study have been generalised and
form the basis for recommended enhancements to future robot programming
systems
Methodologies for CIM systems integration in small batch manufacturing
This thesis is concerned with identifying the problems and constraints faced by
small batch manufacturing companies during the implementation of Computer
Integrated Manufacturing (CIM). The main aim of this work is to recommend
generic solutions to these problems with particular regard to those constraints
arising because of the need for ClM systems integration involving both new and
existing systems and procedures. The work has involved the application of
modern computer technologies, including suitable hardware and software tools, in
an industrial environment.
Since the research has been undertaken with particular emphasis on the industrial
implementor's viewpoint, it is supported by the results of a two phased
implementation of computer based control systems within the machine shop of a
manufacturing company. This involved the specific implementation of a
Distributed Numerical Control system on a single machine in a group technology
cell of machines followed by the evolution of this system into Cell and Machine
Management Systems to provide a comprehensive decision support and
information distribution facility for the foremen and uperators within the cell. The
work also required the integration of these systems with existing Factory level
manufacturing control and CADCAM functions. Alternative approaches have
been investigated which may have been applicable under differing conditions and
the implications that this specific work has for CIM systems integration in small
batch manufacturing companies evaluated with regard not only to the users within
an industrial company but also the systems suppliers external to the company.
The work has resulted in certain generic contributions to knowledge by
complementing ClM systems integration research with regard to problems
encountered; cost implications; the use of appropriate methodologies including
the role of emerging international standard methods, tools and technologies and
also the importance of 'human integration' when implementing CIM systems in a
real industrial situation
Technology 2002: The Third National Technology Transfer Conference and Exposition, volume 2
Proceedings from symposia of the Technology 2002 Conference and Exposition, December 1-3, 1992, Baltimore, MD. Volume 2 features 60 papers presented during 30 concurrent sessions
Application of definitive scripts to computer aided conceptual design
The creative phases of design are based upon the human ability to conceptualise or abstract ideas from physical observations of the real world. That ability comes from experience, based on experiment: discerning patterns of behaviour in particular sets of observations. In this work it is shown that the process of identification, experiment and abstraction may be modelled accurately on a computer by definitive, or agent-oriented, programming, so forming a powerful aid to conceptual design. A new computer modelling language, called EdenLisp, has been developed by the author around Definitive Notations and interfaced to a commercial Computer Aided Design package. It provides a tool whereby computer models of systems can be originated that have state and on which state change can be made, not only by the designer but also by other autonomous agents of change Experiments with the language are described that show that scripts of definitions can have characteristics that permit the design to proceed as if there were an engineering prototype of the physical system being designed. The explicit representation of state at the lowest levels permits experimentation, observation of properties and addition of further observations. The interactive construction of EdenLisp is analogous to the conceptual design process It is used to illustrate and test design meta-theories for modelling conceptual design. It is shown to have potential for concurrent or multi-agent design, and is also an excellent vehicle for design education
Technology 2002: the Third National Technology Transfer Conference and Exposition, Volume 1
The proceedings from the conference are presented. The topics covered include the following: computer technology, advanced manufacturing, materials science, biotechnology, and electronics
Knowledge-based automatic tolerance analysis system
Tolerance measure is an important part of engineering, however, to date the system of
applying this important technology has been left to the assessment of the engineer using
appropriate guidelines. This work offers a major departure from the trial and error or random
number generation techniques that have been used previously by using a knowledge-based
system to ensure the intelligent optimisation within the manufacturing system. A system to
optimise manufacturing tolerance allocation to a part known as Knowledge-based Automatic
Tolerance Analysis (KATA) has been developed. KATA is a knowledge-based system shell
built within AutoCAD. It has the ability for geometry creation in CAD and the capability to
optimise the tolerance heuristically as an expert system. Besides the worst-case tolerancing
equation to optimise the tolerance allocation, KATA's algorithm is supported by actual
production information such as machine capability, types of cutting tools, materials, process
capabilities etc. KATA's prototype is currently able to analyse a cylindrical shape workpiece
and a simple prismatic part. Analyses of tolerance include dimensional tolerance and
geometrical tolerance. KATA is also able to do angular cuts such as tapers and chamfers. The
investigation has also led to the significant development of the single tolerance reference
technique. This method departs from the common practice of multiple tolerance referencing
technique to optimise tolerance allocation. Utilisation of this new technique has eradicated
the error of tolerance stackup. The retests have been undertaken, two of which are cylindrical
parts meant to test dimensional tolerance and an angular cut. The third is a simple prismatic
part to experiment with the geometrical tolerance analysis.
The ability to optimise tolerance allocation is based on real production data and not imaginary
or random number generation and has improved the accuracy of the expected result after
manufacturing. Any failure caused by machining parameters is cautioned at an early stage
before an actual production run has commenced. Thus, the manufacturer is assured that the
product manufactured will be within the required tolerance limits. Being the central database
for all production capability information enables KATA to opt for several approaches and
techniques of processing. Hence, giving the user flexibility of selecting the process plan best
suited for any required situation
Technology 2004, Vol. 2
Proceedings from symposia of the Technology 2004 Conference, November 8-10, 1994, Washington, DC. Volume 2 features papers on computers and software, virtual reality simulation, environmental technology, video and imaging, medical technology and life sciences, robotics and artificial intelligence, and electronics