QMT Features: October 2017
Productive Metrology
In a series of articles, guest columnist Ian Wilcox, discusses metrology and resultant measurements in relation to manufacturing engineering

Yeah, we do that…… don’t we? One of the most common question I am asked is ‘what is metrology’, the accepted concise definition is ‘the science of measurement’.

If you want more detail than that, then it starts to fragment into a series of opinions and interpretations. To the typical scientist and evangelical metrologist, it would go on to promote standards and uncertainty, following the process of making sure you are planning, facilitating and checking to achieve the highest confidence in your measurement result that is feasibly possible. An alternate description given by some supply chain engineering companies would be that it is often a customer led unproductive activity, a necessary evil associated to perceived quality and supplier survival. In productive advanced manufacturing, an objective would be to utilise metrology tools to eke out every competitive advantage in an ever-competitive and fierce global marketplace. A realism is applied in that Metrology is something to embrace but find your own path through, applying the elements and levels you need into added value activities, eradicating any excess and non-added value activities wherever possible.

I will use this regular guest spot so kindly given by QMT to help guide you through the world of metrology, showing you how it connects into productive manufacturing, empowering quality and lean activities, supporting waste reduction and efficiency. But also probe deeper and indicate often overlooked wastes that the poor application of metrology creates in a typical business and of course how to mitigate and manage them. It will not be all about ‘you should do more!’ but also address ‘can I do better for less’. It will be practical, in plain English as much as is possible and adhere to a recognition of typical manufacturing business constraints.
As with a lot of knowledge it starts with a focus on the core things and the inevitable ‘hook name’ to hang that focus on. My own is a version of the three R’s. Everything flows from these three and I use them to ground and often balance my thinking wherever possible.

1. Ratio: Ultimately, costs etc aside, what a company wants is to have a valid functional part and then produce the same again and again. The laws of physics and human interaction make that impossible and so we compare them, to determine how close they are to the perfect part or design intent, alas not always the same thing. What variation would cause failures to design intent needs to be expressed as a value, so we need units of measurement that are set by international and national bodies, or even your customer. We then effectively ratio our ability to conform to them via traceable calibration and associated stated uncertainties. These ratios can also be our derived units, degrees for example often being another example of ratio, in this case the length of two sides of a right-angled triangle. Understanding your own key ratios is a business advantage.

2. Risk: To be competitive or to meet any specific business strategy you need to manage risks. From being cautious to taking chances, the determination of the associated risks and the subsequent decision making is crucial to a successful business strategy. We weigh up risk by accessing data, any analytical data will be because of measurement. It is therefore important that the risk associated to errors in any measurement process itself is considered. Within a practical confidence level this is the foundation to the wider business risk analysis process. Bad data in, bad decisions out. Managing risk effectively has a direct link to profitability and stability.

3.Resources: People, skills, equipment and processes. Do the resources exist to meet the need of your business strategy. As with the other two R’s this is not a black and white thing. For example, you fail a gauge capability study by an unacceptable margin because the equipment resolution is one decimal place short of what is needed, but its close. The next decimal place would cost you £1million in equipment, compared to the £20,000 of existing equipment costs. What’s the ratio and risk balance in sticking to what you have, customer consenting of course.

I will leave this first article with a quote, some say it is from a certain Albert Einstein others from a William Bruce Cameron either way it’s appropriate ‘Not everything that counts can be counted, and not everything that can be counted counts.’ The two lessons I draw from this quote are:
1. Think about what is important and practical, then efficiently collect and utilise its useful data.
2. We are not 100% sure who said this quote, so don’t assume the first answer is the only answer.
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