Tiny dyno

Louise Smyth

Kistler has launched MicroDyn, its smallest series-produced cutting force meter. This now provides manufacturing companies and research institutions with a solution for highly precise measurements of cutting forces in the development of micro tools.

The machining of very small workpieces puts high demands on the tools used. In order to examine cutting forces in micro machining applications for example, in watchmaking, highly compact and sensitive measuring instruments are needed. With the new MicroDyn 9109AA dynamometer, Kistler is creating new opportunities for its customers in the fields of ultra-fine machining, micro-precision machining and ultra-precision machining – especially in the development of tools for the machining of brittle-hard materials and the optimisation of machining processes.

Measuring only 30x30mm, the MicroDyn is the smallest dynamometer in the world. Thanks to the high natural frequency of 15kHZ in all three axes, an increase of about a factor of 2.5 compared to its predecessor, highly dynamic forces up to 500N can be measured very accurately and the resulting torques of up to 50Nm calculated. This makes it possible to detect forces with tool speeds of up to 120,000RPM on individual blades of the tool. The piezoelectric measuring crystal rings ensure high sensitivity and a very low threshold. They are also installed in such a way that temperature influences are largely compensated.

It is crucial to know how new tools behave. With typical questions being what cutting forces occur? How does the tool behave in different situations (process stability)? How can the tool be designed so that force peaks are avoided (service life) and the machining process still takes place quickly and efficiently? Only accurate measurements during the development ensure the achievement of process reliability and prevention of rejects. For example, when milling a case, a watchmaker needs to ensure that the process runs smoothly and is stable, even in constantly changing engagement conditions, and that the tool is not overstressed.

The new device is equipped with a variety of mounting options. It can be both mounted vertically and horizontally to the machine tool machine tool table and the workpiece can be clamped accordingly; this benefits measurement accuracy. For quick and error-free data recording and analysis, the combination of MicroDyn with multi-channel charge amplifiers, in particular the high-end solution 5080A; is recommended. Kistler offers corresponding complete packages including the Dynoware software for an easy and error-free configuration in which the rules for the force and torque calculation are already stored. In principle, however, the MicroDyn can also be used with other analysis systems.