This thesis presents a study of process planning instabilities and inefficiencies within a plastic component manufacturing company. The company was increasingly pressurised by high customer expectations and competition from the global market. A series of tools were used to highlight some of the prominent issues within the organisation. To improve on production efficiencies several lean manufacturing tools such as Value Stream Maps, Production Flow Analysis and Systems Thinking were applied. This thesis proposes a methodology for processing product lines within a supplier in the off-highway and niche vehicle industry and focuses upon categorising product lines depending upon their ranking of volume and value. The methodology presents a logical procedure for categorising parts into five "broad categories" analogous to the classical ABC stock control theory. On completion of the categorisation process, product lines are processed by a set of practical rules within the context of an "expert system". These rules have been devised by using multi-criteria ABC analysis and further applied to process the product lines throughout the manufacturing system. These rules are based on product line activity and they are defined in order to maintain minimum inventory levels as well as ensure the stable implementation of the factory production plan (smoothed over the production period), to also achieve a low throughput time and increase delivery performance, all with the goal of 100% on-time delivery to the customer. The analysis of sales data and high volume-to-value product lines has shown that there are five classes of product lines (A1, A2, A3, B1 and B2) which vary in their requirements for planning and operations as outlined in this paper. Evidence is presented which shows that an empirical relationship results a new "merit" parameter that can be determined by fitting a response surface to volume and value quantities and this relationship holds for a wide range of organisations. Indeed the technique can indicate which product lines are behaving in the market as expected and which are asynchronous with the market demand. The methodology was further simulated using Arena (R) software. The simulation study compared the models (before and after methodology implementation) and the results were analysed to assess the impact of the methodology on the production system.
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