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Tight process control
is essential for sustainable
material usage reduction
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“Materials” in the industrial context could refer to the raw materials used to manufacture a product, materials in various stages of transformation throughout the manufacturing process or finished product. In all cases materials could be lost, and the objective of material usage reduction is to reduce the quantum of these losses. Reducing the amount of materials used in manufacturing is one of the most powerful cost-reduction strategies manufacturing organisations can take. When the life cycle impacts of materials are considered, it is also most likely the highest-leverage approach for the reduction of environmental footprint. Yet, in downturns such as what we are experiencing now, many manufacturing organisations still turn to reducing staff numbers as the primary approach to maintaining profitability, an approach which for social reasons and also in terms of unintended consequences is unsustainable.
How then does an industrial organisation best tackle material usage reduction and maintain high levels of performance in this area in the long term? The following are general guidelines based on my experiences with organisations that are able to sustainably reduce material usage:
1. Invest in Material Usage-specific Process and Equipment Knowledge
It is vital that those accountable for material usage have a deep understanding of the manufacturing processes they control, not just in terms of how to operate them to produce product, but also in terms of the drivers of material usage within these processes. Losses can arise from issues concerning individual pieces of equipment, but also from how individual processes interact with each other. These linkages need to be well understood in order to control material usage consistently.
2. Tighten up Material Accounting Systems
Managers require believable material usage data in order to make informed decisions regarding the maximisation of material yields. While the design of accounting systems is typically fairly straightforward, accurate recordkeeping is often a problem. It is important that stocktaking procedures are rigorous for raw materials, work in progress and finished product. Records of receipts and dispatches should also be accurate and apply to the period being reviewed. Wherever possible, material usage reports should be produced daily, minimising the time required to detect and act on usage problems. Finally, every instrument used for measurement should be accurate and well maintained.
3. Implement Short-interval Control Systems at Source
Plant operators and supervisory staff have accountability for material usage, and therefore require the systems to measure and manage it. The systems employed here should indicate what usage levels are at any point in time, but should capture additional process-specific information which would allow shop floor staff to gain important insights into the reasons for deviations to usage standards. Hence the yield information for a reduction furnace should be displayed side by side with the mass of process chemicals added, the furnace temperature, the precise time that the furnace was charged and when it was tapped, flue gas temperatures and any other information deemed relevant to material usage.
It is important here that where an important piece of information is not routinely measured but is relevant to material usage, that such information becomes part of routine. Hence in our example outlined here, it may be worthwhile to measure the amount of valuable metal contained in slag removed from the furnace for a few selected batches each week. Such decisions depend on the costs of additional tests relative to the potential savings to be made from access to the information.
It is also useful to automate short-interval control systems as far as possible to allow operators to focus on control of the process rather than become bogged down with administrative duties.
4. Involve the Maintenance Function
If plant maintenance is viewed as something that is required for the sake of plant uptime only, a massive opportunity is lost in terms of the contribution of good plant maintenance to material usage reduction. Functional failures can occur which do not stop a manufacturing facility from running, but which have serious consequences for material usage.
It is important that in the development of a maintenance programme for a manufacturing plant, the material usage impacts of failures are fully appreciated and factored into the risk assessment for individual failures. Preventive maintenance tasks are generally designed to be proportional in effort to the consequences of failure, and hence these types of failures will be accorded the correct amount of resources in assuring their prevention should the maintenance function be fully engaged in the reduction of material usage.
A further benefit of involving the maintenance function is that failures which result in losses of materials will receive a greater level of urgency in terms of their correction once they have been detected. In high-volume manufacturing, cost deviations multiply rapidly and speedy correction of problems is crucial.
5. Keep Track of Waste Generated
Material usage is always accompanied by liquid and/or solid and/or gaseous waste streams, and the extent and characteristics of these waste streams relate to the extent of the material losses. It is therefore important that these streams are closely monitored, since they can provide more important clues as to the reasons for excessive material usage. In the electroplating industry, for example, the volume of effluents and the concentrations of individual metal ions in these effluents point operators to the magnitude of the drag-out losses being experienced in the plating operation.
6. Integrate Quality and Cost Management
Rework always comes at a cost, even at facilities which have the capabilities to recycle defective products in order to recover raw materials. In many instances, poor quality product cannot be reworked and has to be destroyed - a worst-case scenario in terms of material losses. A powerful cost reduction strategy is therefore to focus resolutely on quality, not just in terms of final product, but for every individual process step employed.
Question what you do continuously, and understand the measures taken in the name of material usage reduction which may be negative for product quality and vice versa. There is an optimum point at which you should be operating which maximises quality while minimising material usage.
7. Assess Raw Material Performance
The raw materials used in manufacturing are typically purchased according to defined specifications, but variations within these specifications can sometimes have an impact on how the materials behave from a yield perspective. In some industries not even comprehensive specifications can adequately account for the characteristics of materials and how they will behave when processed. Materials can also exhibit changes in characteristics during storage. It is therefore not sufficient to simply procure to a specification – one has to closely monitor the performance of each batch of material used to assess whether there are any negative material usage impacts arising from its use. This is particularly important when there has been a change in supplier or changes in the processes employed by existing suppliers. Action can then be taken to resolve the problem at source.
The above are some of the more easily-identifiable operating practices which I have observed to have a positive impact on material usage. Each one requires significant effort to implement. When we assess the impact that material usage has on the financial and environmental performance of a manufacturing unit however, I am sure you will agree that the potential rewards are worth the effort.
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