U. La Commare

Business process-oriented design of Enterprise Resource Planning (ERP) systems for small and medium enterprises

In the last few years, many organizations have used business process modelling as an effective tool for managing organizational changes. However, process modelling has rarely been exploited for supporting the entire business process management life cycle. This includes the design of business processes as well as their implementation and control. The adoption and implementation of Enterprise Resource Planning (ERP) systems is a crucial issue if referred to small and medium-sized enterprises. The main problem is that the cost of implementation of ERP, intended as the process of customization of the ERP system towards the actual enterprise business processes, overtakes the cost of ERP acquisition. Thus, there is a need to use the same workflow systems for both modelling the enterprise business processes and designing the ERP. The paper presents the results of a collaborative project between academia and industry aimed at developing a business process management integrated approach to the design, implementation and control of an ERP information system.

An evolutionary approach to multi-objective scheduling of mixed model assembly lines

In this paper a multi-objective genetic algorithm for the scheduling of a mixed model assembly line is proposed, pursuing the line stop time minimisation together with the component usage smoothing. Specific features of the developed GA are step by step random selection of diversified crossover and mutation operators, population control for the substitution of duplicate chromosomes, and in-process updating of GA control parameters. Three different formulation of the fitness function were been tested with some distinct line configurations.

Optimum tool replacement policies with penalty cost for unforeseen tool failure

Abstract Models for tool replacement strategies in manufacturing systems introducing a penalty cost if the tool fails during the cut are proposed. These models are developed for general stochastic tool life distribution and applied to the case of a log-normal distribution.

Cutting Conditions and Work Material State Identification through Acoustic Emission Methods

Summary This paper examines the problem of in-process monitoring of metal cutting operations carried out on aluminum alloys for aeronautical applications. Turning tests were conducted on annealed and heat treated aluminum alloy bars, using carbide tools. For both work material conditions, different combinations of cutting parameters were used. During cutting tests, acoustic emission (AE) and cutting force sensor data were detected and processed. The comparison between AE responses from the annealed and heat treated aluminum alloys allowed, with the help of force sensor data, to verify the applicability of AE and sensor fusion techniques for in-process and real time identification of work material state.

Off-line Programming and simulation for automatic robot control software generation

In this paper an off-line programming approach for welding robots is presented. The approach is based on the integration of a software tool for robot simulation and an user-friendly interface for automatic generation of the control program. The user can graphically arrange the components in a robotic work-cell and simulate the movements and operations of robotic arms before converting motions and operating sequences in controller-specific tasks. This methodology guarantees high level of flexibility of the robotic system when high variety of work-pieces needs to be welded. The approach has been implemented and tested in a real welding work-cell.

UML design and AWL programming for reconfigurable control software development of a robotic manipulator

The goal of the presented research is to face the topic of reconfigurable control software development in a concrete fashion, i.e., by presenting a control software system development approach which has been used for a specific, although easy to be generalized, robotized manufacturing cell component. In particular, a methodology for the control software development of a planar robot (2-degrees of freedom) is presented, from the conceptual design to the actual implementation. The methodology suggests UML and object-oriented modeling and programming techniques for the design phase, while AWL programming language run by a PLC for the implementation phase. The analysis has been conducted considering the internal and external requirements of the manufacturing system which comprises the robot, mostly driven by the contemporary industrial need of reconfigurable control systems, critical key to succeed in the new era of mass customization

Lower and upper bounds of manufacturing cost in FMS

Abstract The use of traditional techniques of product costing, cost control and performance evaluation in advanced manufacturing environment supplies poor results to operations management. In this paper, after a brief review of the major drawbacks of traditional machining economics, a new framework for product costing will be presented. The basis of the proposed approach lies on an analysis of the production process aimed at single out proper cost drivers for the use of the various employed manufacturing resources. As a consequence, the quota of the manufacturing cost of uncertain allocation is drastically reduced. A lower and an upper bound value of the unit production cost are also defined with reference to the given manufacturing system. The range between the above bounds is used for accounting the costs of uncertain allocation.

Relevance of Tool Life Testing for Tool Replacement Strategies

Several analytical and simulation models have been proposed in order to select the optimal tool replacement strategies both in single and multi-tool machining operations. All of these models, however, assume as known the probability density function that describes the stochastic behaviour of tool life. The costly efforts required in order to achieve an accurate estimate of the p.d.f. limits the use in the shop practice of the above models.

Integrating Manufacturing Equipments Using a Shop Floor Control System

A generic manufacturing system must interact with an environment characterized by a strong competition and by continuous technological changes. For this reason there is the necessity to make the system easily and economically modifiable in its hardware and software configuration. One of the main problems in making a manufacturing system re-configurable concerns its control system which has to be accordingly scalable and object oriented. This paper presents a methodology for making a manufacturing control system actually reconfigurable and adaptable to hardware changes in the manufacturing systems components. In particular, a PC-based shop-floor control system has been realized. Such system allows easy integration of new robotic systems in a generic manufacturing system

Possibilistic Programming and Gas for Aggregate Production Planning under Vague Information

In production planning activities, aggregate planning is surely the phase where the lack of information is more relevant. The reasons for that can be summarised in: a) the planning product is an aggregate one, very often not corresponding to actual products; b) the delay from the actual production is relevant so that information regarding actual production resources availability and performances are vague; c) the planning activity is often based on forecasts. On the other hand, all the subsequent production planning activities are based on the result of aggregate planning. In the paper a research going on at the Workgroup for Soft Computing Application in Manufacturing is presented. A Decision Support System (DSS) for assisting the decision maker in Aggregate Production Planning decisions in a vague environment has been developed using possibilistic formulation. First results are presented and discussed.