Protheses made to measure

Responding better to consumer wishes and facilitating reshoring

Fast, zero-defect and personalized manufacturing of products like prostheses, cars or shavers: the better the manufacturing industry succeeds at this, the more effectively it will be able to respond to consumers’ wishes. And the more attractive it will become for industrial players to reshore, thereby increasing domestic production capacity and boosting the economy, says UT researcher Ton van den Boogaard. ‘In manufacturing, we are seeing tolerances get smaller and smaller. It has to do with the need to make products visually more attractive to consumers, for one thing. Twenty years ago the seam between a car door and the body was at least one whole millimetre - nowadays it is mere tenths of a millimetre.’

‘Our materials are running behind our product requirements and techniques’

This far-reaching refinement creates a problem when it comes to material behaviour, says Van den Boogaard: the materials we use today were not built to meet these ever decreasing tolerances. ‘On one roll of sheet metal, the material properties that occur can differ. In the past that didn’t matter. But today’s small tolerances mean that even the most subtle differences result in unacceptable deviations and defects in the end product. The materials we use are lagging behind the latest requirements and techniques.’

On the road to flawless production

As an example, Van den Boogaard refers to Philips' shavers, one of the products researched in the MEGaFiT project (Manufacturing Error-free Goods at First Time) in which he is involved on behalf of the UT. The project’s goal: to enable error-free production of complex, metal precision components by means of adaptive process control. ‘The tolerance between a blade and the shaver head on such a device is now hundredths of a millimetre. The smallest material deviation means that the blade will not cut or the machine will get jammed. So you get a lot of end products that are defective or require additional finishing, which costs a lot of time and money. We can overcome these problems by making corrections to the production process on the basis of advanced simulation techniques. It is a way of achieving zero defect production, but only if we can apply plastic deformation corrections – bending or stretching the deviant part –at lightning speed, within the very same production process.'


Adaptive process control offers a way of overcoming this challenge. ‘First, it means that, using simulation models, we try to predict how a material deviation will work out. Sometimes these deviations occur during a part of the production process that only takes milliseconds. If we can predict it accurately and on time, we can then adjust the machine or the process – again within that very short time frame – so that the effect of the deviation is eliminated and a flawless product comes out. We develop and test the models necessary for this here at the UT. Combined with control techniques, this approach offers as lot of potential for accelerating and refining production processes. It matches with the trend towards cheaper production, higher quality, smaller and more variable product characteristics and faster delivery.’

Want to know more? Contact our Engineering Technology department.