D.K. Harrison

Information systems development within supply chain management

In order to improve effectiveness of supply chain management and compete in todays dynamic global markets, it is not sufficient to have effective integrated processes within a business; synchronized operations of all partners in the supply chain is required. In the past, this has been achieved by one company owning or having control over all businesses in the chain. Now, it is more likely that this integration is carried out by using interorganisational information systems. This paper analyses the development and role of interorganisational information systems within supply chain management. The Internet has improved interorganisational information systems capability and therefore is being adopted as a routine platform for information systems development. An evaluation of its use is carried out.

Web-based design and manufacturing support systems: Implementation perspectives

With the great progress of web technology in the past few years, many approaches have been proposed to implementing web-based systems for design and manufacturing. However, the implementation of the approaches and associated systems is not an easy task because design and manufacturing are normally sophisticated engineering operations. In this paper the authors present an engineering approach for implementing web-based design and manufacturing support systems. The implementation issues are critically discussed with an exemplar-a web-based bearing design support system developed by the authors. These issues include design information integration, remote execution of the systems, use of Java programming, client - server architecture, open computing and user interface design, and the human - computer interaction aspects.

Implementation of agile manufacturing—an AI and Internet based approach

Abstract This paper presents a new approach to implementing agile design and manufacturing concepts. The approach is based on the integration of artificial intelligence (AI) and Internet technologies with the conventional design and manufacturing techniques. An architecture based on AI and Internet programming is proposed for remotely and quickly accessing bearing design and manufacturing expertise at low cost and thus implementing design and manufacturing agility. The expertise includes the intelligent selection of journal bearings and their mounting techniques as developed so far. The expertise can be accessed globally through the Internet interface with the selection of a bearing type and configuration for a specific rolling bearing application, the bearing mounting details and the bearing lubrication and sealing devices design. The paper concludes with a discussion on the potential benefits, and the future applications of AI and Internet based agile manufacturing technology in industry.

An opportunity for system dynamics in manufacturing system modelling

The computer simulation of manufacturing systems is commonly carried out using discrete event simulation (DES). Indeed, there appears to be a lack of applications of continuous simulation methods, particularly system dynamics (SD), despite evidence that this technique is suitable for industrial modelling. This paper investigates whether this is due to a decline in the general popularity of SD, or whether modelling of manufacturing systems represents a missed opportunity for SD. On this basis, the paper first gives a review of the concept of SD and fully describes the modelling technique. Following on, a survey of the published applications of SD in the 1990s is made by developing and using a structured classification approach. From this review, observations are made about the application of the SD method and opportunities for future research are suggested.

Analysis of a ferroresonant circuit using bifurcation theory and continuation techniques

In this contribution, the analysis of the dynamics of a ferroresonant circuit are presented using continuation techniques and bifurcation theory. Despite its great simplicity, this circuit can assume a diverse range of steady-state regimes including fundamental and subharmonic ferroresonance, quasiperiodic oscillations, and chaos. The system dynamics are explored through the continuation of periodic solutions of the associated circuit equations. A detailed picture is drawn of various transitions between the individual periodic steady-state regimes of the circuit. Bifurcation points are computed, revealing a clearly defined succession of periodic steady-state regimes, including the Feigenbaum route to chaos through a cascade of period doublings. The analysis presented is performed using the freely available software package XPPAUT. The contribution of this paper is to provide a detailed description of how to define the circuit equations in XPPAUT and how to conduct the interactive bifurcation analysis. The proposed approach is shown to be both computationally efficient and robust, as it eliminates the need for numerically critical and long lasting transient simulations.

Modelling and Experimental Investigation of Laser Assisted Jet Electrochemical Machining

Abstract Laser Assisted Jet Electrochemical Machining is a hybrid process which combines a relatively low power laser (375mW) with an electrolyte jet to facilitate metal removal. The main purpose of the laser is to enhance the localisation effect of electrochemical dissolution from the workpiece, thus giving better precision and machining efficiency. The laser thermally activates the material surface where it impinges thereby increasing the electrochemical current density in that localised zone. A theoretical model is used to explain the effects of localisation of electrochemical dissolution process. Experimental analysis using aluminium alloy and stainless steel has proved that laser assistance can yield up to 54% higher volumetric rate and up to 38% better accuracy than using electrolytic jet alone.

A consideration of modelling techniques that can be used to evaluate manufacturing strategies

Practising engineers frequently seek to understand what the effects of various manufacturing strategies will be on the performance of their production facilities. In this situation a computer model can help to provide insight and form predictions about future manufacturing system performance. Various types of modelling methods exist and each provide models that have distinct characteristics. This paper presents a review of popular modelling techniques and, based on the results of a structured experimental study, summarises their capabilities to support the evaluation of manufacturing strategies.

Rolling element bearing fault diagnosis using Laplace-wavelet envelope power spectrum

The bearing characteristic frequencies (BCF) contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations. They are difficult to find in their frequency spectra when using the common technique of fast fourier transforms (FFT). Therefore, Envelope Detection (ED) has always been used with FFT to identify faults occurring at the BCF. However, the computation of the ED is suffering to strictly define the resonance frequency band. In this paper, an alternative approach based on the Laplace-wavelet enveloped power spectrum is proposed. The Laplace-Wavelet shape parameters are optimized based on Kurtosis maximization criteria. The results for simulated as well as real bearing vibration signal show the effectiveness of the proposed method to extract the bearing fault characteristic frequencies from the resonant frequency band.

The Development of a Simulation Model and the Determination of the Die Control Data for the Free-Bending Technique

Abstract A novel bending technique known as free-bending, which is particularly suitable for the bending of profile and tube cross-sections, is investigated. Advantageous characteristics, such as fast bending speed and an almost free definable bending geometry with transitionless bend-in-bends and spline bends, make free-bending highly applicable in the manufacture of car components. This paper gives an introduction to this new technique and presents the development of a finite element analysis (FEA) model for the simulation of this bending technology. Furthermore, a theoretical model for the determination of the bend dies control data is introduced. For the verification of the FEA model the simulation results are compared with the results from bending tests that have been carried out.

Computer-aided design and manufacturing of scroll compressors

Abstract Scroll type compressors have been becoming increasingly popular in refrigeration and air conditioning products due to their high efficiency, low noise, fewer components, low vibration, light weight and small size compared with other types of compressors. To design and manufacture scroll compressors, however, is not easy as their key parts have complex shapes with involute curves. A high degree of accuracy during assembly is required which brings difficulty into the manufacturing cycle. This paper presents the integrated approach of computer-aided design (CAD) and computer-aided manufacturing (CAM) for the design and manufacture of refrigeration scroll compressors. The approach is based on concurrent engineering and is implemented in Pro/ENGINEER software and Visual C++ programming. The work presented is focused on the integration of constructive solid geometry (CSG) solid modelling and CAM to effect the design of scroll compressors in particular. The involute scroll curve is created from equations. Designers can transfer the model to a manufacturing engineer for process planning, etc. The manufacturing engineer can also advise the designer if some revisions are needed and the model can even be evaluated through the Internet. Many experts can check the models and processes of design and manufacturing. Thus, solid modelling and machine tool path simulation can bridge the gap between design and manufacturing which is essential for concurrent engineering. With this approach a correct and precise solid model can be achieved, which leads to an optimal design in terms of quality, delivery time and cost. This work is essential for the manufacturing of the scroll components and their inspection on co-ordinate measuring machines (CMMs) during manufacture. This CAD/CAM system has a potential application to other complex mechanical components, as the approach is a generic one.