Piezoelectric cutting force dynamometer reduces tool design cost

Kistler Instruments Ltdvisit website


Tucked away on a small Coventry industrial estate is Exactaform, a world leader in the design and manufacture of polycrystalline diamond (PCD) tooling for global aerospace and automotive markets. Design ingenuity combined with investment in staff and the best available machining and test equipment has built and maintained a reputation for delivering the highest quality tooling, quickly and reliably.

Piezoelectric cutting force dynamometer reduces tool design costA recent addition to the R&D capability is a cutting force dynamometer based on a Kistler Instruments piezoelectric multicomponent force link set and amplifier. The force link set is installed in a bespoke force plate assembly machined in-house from solid stainless steel to exactly meet the needs of the R&D process.

General Manager Peter Raynor says: “We chose the Kistler force link set because it allows us to analyse the performance of new designs very accurately with excellent repeatability.” A typical application is the determination of the optimum feed rate for the maxi-flute router with 12 teeth, an Exactaform exclusive, which achieves maximum performance by reducing the chip load per tooth. The maxi-flute router is designed specifically to deliver excellent surface finish and dimensional accuracy when machining difficult materials, including fibre reinforced composites (FRC), metal matrix composites (MMC) and aluminium. Using the Kistler equipped cutting force dynamometer; the design team are able to take full advantage of the 12-tooth design by optimising the feed rate for each material allowing the user to maximise productivity whilst benefiting from high surface finish and significantly increased tool life.

The outputs of the four Kistler force links are interconnected in a summing box to provide measurement of the three orthogonal forces (Fx, Fy and Fz) plus acquisition of the 6-component force and moment (Fx, Fy, Fz, Mx, My and Mz). The four sensors are mounted with ground isolation to eliminate ground loop problems. The rustproof set is protected against entry of splashing water and coolant and, when used with the special connecting cable, the set satisfies the requirements for IP67 moisture protection. With its output of around a thousand tools each week, the installation of the Kistler equipped dynamometer allows Exactaform to specify the best feed rate for each new design with total confidence whilst benefitting from a 20 per cent saving in tool design and development costs. As Peter Raynor says, “It’s a win-win solution”.

For more information about the piezoelectric multicomponent force link set and amplifier from Kistler, please visit the website at

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