A new dimension of metrology

It is also the primary field of expertise of TESA, a global leader founded in 1941.

You will often find a TESA logo in production plants and quality control workshops. The Swiss brand is synonymous with high quality measuring instruments – from micrometers and calipers to inductive probes and the iconic height gauges. It has helped manufacturers for almost 80 years to verify lengths, widths, diameters and inter-axles, angles and curves as well as the surface quality of their parts.

TESA has never stopped innovating, launching devices that have remained unsurpassed. This is especially the case with IMICRO (a hand tool measuring the diameter of through-holes): launched in 1950, it has never been matched by the competition and is still a TESA bestseller - a clear sign of know-how in micromechanics and machining, but also of a certain trend in the sector. “It is true that part of our field is rather conservative” confirms Blaise Vuille, Technical & Business Development Director. “Some analogue products are based on processes that we designed over 50 years ago. It is quite common for our instruments – hand instruments to start with – to be used for several decades ! This is excellent for TESA’s reputation, but less so for our turnover.” Given that a micron stays a micron, who needs a new instrument to measure it? “Industrial metrology had to be rethought in order to find new business models.”

The role of metrology had to be redefined, says the expert. “20 years ago, our instruments were mostly used for checking product quality at the end of the production chain. Today, quality management is progressively integrated into every production phase and we help companies to do so.”

This new extension of services is exactly what Hexagon specialises in. The Swedish group (with a global staff of 18,000 employees) acquired TESA in 2001. “Through its applications, Hexagon is capable of simulating the entire production and control chain in order to validate, at each production phase, that the reference quality is met.”

It can contribute to the design of parts by defining the relevant quality levels (overstated quality requirements are unproductive!), in order to identify the machines best suited to perform a task to the required standard and carry out the appropriate measurements, etc. With every optimisation, the process becomes smoother and the production time shorter, with fewer errors and less material wasted.

“This is the mission of today’s metrology”, concludes Vuille,: “to offer custom solutions that enhance product quality, but also and above all, that improve the efficiency of companies.”

Global quality integration is primarily based on data collection. The time is long gone when an operator performed a measurement and jotted down the results in a notebook. “An increasing number of our instruments are designed to be connected.” explains Vuille. “Data can be automatically transferred to an acquisition centre, which ensures better traceability of measurements and so improved management of quality control workshops. It also helps to detect any irregularities and utilises statistical process control to anticipate errors and provide the means of feeding back machine adjustments via a closed-loop production system. Services, data, software, industry 4.0. This is the part of metrology offering the most opportunities for innovation.”

Integration into the Hexagon group has allowed TESA to diversify and has enabled it to contribute to innovative technologies, extending its traditional portfolio. For example, the probe heads and non-contact sensors used on the Hexagon coordinate measuring machine, multisensory and optical CMMs. These “in-house” (the TESA brand does not appear) activities have grown in importance. “Today 50% of our production is dedicated to sensors that equip measurement machines from the Hexagon group.”

However, TESA has not given up its own historic share in the market sector (still 60% of its turnover). It continues developing its instruments, but not just by making them connectable. The greatest effort is being made to simplify their use, for an obvious reason: “There are fewer and fewer metrology professionals in workshops and the responsibility for taking measurements is being taken over by production operators. Therefore, we have to make it as simple as possible to limit errors to a maximum extent.”

The last generation of MICRO-HITE, a range of vertical measurement devices launched initially in 1981 is a good example. TESA fitted it with several technologies (positioning aids, touch-screen, interface clarification) which makes it easier for the operator to handle and read the results.

A micron will always stay a micron, but in this world of infinite precision, the human factor remains intolerably uncertain.