Preface

Under Papers and Reports, this section is divided into four fields:

• Economic Engineering
• Energy Economics
• Manufacturing Strategy
• Economic Strategy

You will also find published letters and articles under “Articles and Letters on the Economy”.

Article in Plastics & Rubber Weekly

S F Bush

Two years ago Foresight’s Materials Panel emphasised (PRW May 5 1995) the importance of fostering ‘continuous incremental advances rather than one or two giant leaps’. While not ruling out the latter, the North of England Polymer Processing Consortium (NEPPCO) has put particular emphasis on what may be termed the science of process development (SPD) as the best way of securing for existing processes systematic improvements in product quality, raw materials usage, energy usage, and capital efficiency.

While it has been mainly applied in the large chemical companies, SPD is particularly relevant to the on-going debate about technology transfer to small and medium-sized enterprises (SMEs), of which the polymer processing industry, including the trade moulding sector, is largely made up.

Actually the idea, implicit in the phrase ‘technology transfer’, that there are large quantities of something called ‘technology’ stored in universities and large companies waiting to be transferred to SMEs is largely wrong. Useful technology can only exist in industry. What universities may have is a store of scientific knowledge, some of which can assist in the development of industrial technology. What a number of large companies may have is a store of experience in applying systematic methodologies to operating plant. The science of process development as espoused and practised by UMIST Polymer Engineering marries these two important stores of knowledge with that which exists in the NEPPCO member companies.

To take a particular example, a trade blow moulder may have been blowing bottles successfully with a given grade of polyethylene and then one day finds he can no longer get a satisfactory parison. On the face of it nothing has changed in his process, so he naturally blames the failure on a change in the polymer. The polymer manufacturer checks the sample of the relevant batch, which he has retained (we hope), and declares that it is fully within the specification supplied previously. Meantime the moulder’s machine is idle, not producing anything. How can SPD help?

First it recognises that, with the moulder having eliminated the most obvious single cause and effect candidates, the problem is most likely caused by a combination of factors. Systems technology is a methodology especially evolved to deal with multi-factor problems such as those encountered in synthetic fibre factories with several machines operating in parallel, or those found in a series of processes such as in the manufacture of polyurethane elastomers. The methodology uses both the knowledge of polymer behaviour, which may reside in the university, and the processor’s own knowledge of the past behaviour of his machines in order to formulate a series of relationships between product outcomes and those machine variables which are under the processor’s direct control, such as screw speeds, and machine temperatures. Often these relationships will be quite primitive at first, but because they will be based on well-founded scientific mechanisms, they can be improved as more clues from the process are provided.

A recent application of the approach in NEPPCO was to multicavity insert mouldings where on occasion the injection moulding was incomplete for some inserts and process conditions. The systems model allowed experiments to be carried out within normal operating conditions in order to quantify the effects of the contributory factors: polymer, insert type, cavity position, injection temperature, and thus to formulate a remedy at acceptable cost.

Such an approach provides a ready means of increasing understanding of any currently operating polymer process and is thus a primary means of improving it and its product. But of course many trade moulders have built up a large store of in-house knowledge which enables them for particular polymer grades and types to quickly establish high quality and productions rates for each new mould they see. Increasingly however, customers demand a level of recyclate to be included, or a relatively expensive polymer, such as nylon, to be replaced by a cheaper one such as fibre reinforced polypropylene, which could perform the required duty in the given temperature range. In both these cases, there is a significant change in polymer rheology, and past processor experience may not be enough on its own to find a satisfactory operating window. The approach outlined above could be very helpful in rapidly getting to a satisfactory operating condition.

The systems model approach provides the framework for this to be done within the timescale which SMEs have to operate under.

Presentation to United Biscuits Research Centre, High Wycombe

S F Bush, Prosyma Research Ltd

Part 1

Systems Technology brings together a set of methods and concepts:

• Some are process specific;
• Others are general;
• One such is the concept of a system.

 
A system has the following elements:

• An objective realisable by manipulation of the design and operation of the system;
• A set of interconnected primary components;
• A boundary defined by constraints and conditions attached to the design and operation of the system.

Components

• Input-output relationships which are independent of the other components.
• A primary component may be a system in its own right having secondary components linked in a network.
• A component is not necessarily a mechanical item – it can be a fluid being processed for instance.

Paper, Systems Technology Group, ICI Europa

S F Bush

Summary

Systems Technology is of growing importance to industry because of the increasing emphasis on performance. The performance of a business, works or process, is rarely the sum of its parts separately determined. The need has therefore arisen to manage the complexity arising from the large number of factors which determine the whole. Meeting this need is the function of Systems Technology.

Section 1 of the paper outlines basic concepts which have been shown in real life to meet this criterion. Sections 2 and 3 illustrate their current and potential value by describing briefly some of the resulting methods developed, and applications made, over a number of years to unit operations, particularly chemical reactors, processes, polymer processing, factory control, and business planning. Examples are taken from the chemicals, fibres and plastics fields.

While not universally appropriate, a contribution common to most of the projects and fields tackled has been to perceive a common structure to two or more disparate problems and thus to decompose optimally otherwise very intractable problems. This opens up what seems to be a fruitful and systematic mode of technology transfer which is only at the beginning of its development. Examples are highlighted in sections 2 and 3.

A common need in many projects is to determine the boundary of the system considered and the appropriate level of theoretical and experimental or observational detail within it. A systematic procedure has been evolved for this, which while in many cases can be regarded as only common sense, has a clear relevance both to the conduct of a particular research project and to judging its likely cost and benefit.