The manufacturing model is an information model that describes the manufacturing capability of a particular enterprise. To achieve general applicability, the model consists of the entities that are relevant and important for any type of manufacturing firm, namely: manufacturing resources (e.g. machines, tools, operators, etc.), manufacturing processes (e.g. machining processes, assembly, etc.) and manufacturing strategies (e.g. how these resources are organized and used). The manufacturing model is a four-level model based on a de facto standard (i.e. factory, shop, cell, station) that represents the functionality of the manufacturing facility of any firm. The manufacturing model concept presented in this paper represents the manufacturing capability of a high-performance flexible manufacturing facility.

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Providing a consistent source of manufacturing information to both users and applications is key to the successful CAE support of concurrent engineering This paper describes an information model that aims to fulfill this role This information model, which has been named the "Manufactunng Model," is intended to enable the manufacturing capability of a particular facility to be reliably represented The model consists of three types of information, namely manufacturing resources, processes and strategies The Manufacturing Model has four levels based on a de-facto standard (i e , Factory, Shop, Cell, Station) This information model has been modelled in EXPRESS and developed using the Booch Object Oriented Methodology In order to validate this approach the characteristics and capabilities of a number of complex contemporary turning centres and related manufacturing processes have been modelled at the Station Level An experimental software implementation of the Station level has been developed using DEC Object/DB and C ++ The Manufacturing Model is one key element of a prototype research system called the Model Oriented Simultaneous Engineering System (MOSES) which aims to support concurrent engineering more effectively than conventional CAE systems

The phenomenon of ‘stick-slip’ oscillations of the feed drives of machine tools is an important problem in the design of certain types of machine tools. The factors contributing to this particular type of instability are studied both experimentally and analytically with the aid of a simple model based on dynamic measurements. The experimental work is restricted to a scraped cast iron-cup ground cast iron slideway interface. The principal experimental variables are lubricant viscosity and the natural frequency of the drive. The dynamic observations provide evidence and data that enable the use of a simple model rather than the more usual application of an involved analysis. The consideration of analytical and experimental results allows further understanding of the mechanism of feed drive instability to be developed.

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