Precision Steel Amplifiers for Ultrasonic Haptic Feedback
When a steel part is designed to resonate, its dimensions stop being a manufacturing tolerance and become a tuning parameter. The ultrasonic haptic systems developed by Vibra Nova use purpose designed amplifiers that boost vibration amplitude to produce crisp tactile feedback on a flat surface, working between 50 and 120 kHz. Montanstahl produced these T-Booster profiles in carbon steel 34CrMo4 by cold working, holding the main width within 0.2 per cent of nominal, radii as small as 0.1 mm within 0.05 mm, and flatness deviation below 0.05 mm.
How an Amplifier Turns Ultrasound Into Touch
The ultrasonic haptic systems developed by Vibra Nova depend on specially designed amplifiers that raise vibration amplitude and deliver crisp, realistic tactile feedback to the user. These components work through controlled bending deformation, which is how they transfer ultrasonic energy efficiently and generate vibrations that a finger can actually perceive on the surface of a screen or a panel. Operating between 50 and 120 kHz, that deformation has to be controlled precisely, since the sensation produced is a direct consequence of how the part flexes. The accuracy of each amplifier therefore determines the quality of the tactile response, which makes dimensional stability and material consistency fundamental rather than desirable in this application. It is an unusual demand even within the machinery and equipment sector, because the specification is set by physics rather than by an assembly drawing.
Dimensions That Set the Resonance Frequency
Because of the operating frequencies involved, the project demanded extremely tight dimensional tolerances, and the reason is physical rather than procedural. Even minor dimensional variation is enough to shift the resonance frequency outside the acceptable range, at which point the amplifier stops working as designed and the tactile effect degrades or disappears. The main width of the amplifier therefore had to stay within 0.2 per cent of its nominal value to keep performance consistent from one part to the next. Small radii were equally critical, with features as tight as 0.1 mm to be held within 0.05 mm, because those transitions govern how stress distributes through the part during bending and therefore how it resonates. A radius produced slightly larger than drawn changes the local stiffness, and that change propagates through the vibration mode of the whole component.
Application Context
Each amplifier was produced in full compliance with the dimensional and tolerance specification, drawing on Montanstahl experience with high precision components. Cold working delivered the geometry, with parts cut to size within a length tolerance of 0.2 mm and flatness deviation kept under 0.05 mm, which is what makes the resonance predictable and the acoustic output stable across a production batch. The material is carbon steel 34CrMo4, a chromium molybdenum grade whose consistent response to heat treatment supports the uniform elastic behaviour a resonating part requires. That precision translates into repeatable bending performance, allowing Vibra Nova to deliver dependable ultrasonic haptic feedback in demanding applications. Components of this kind are produced as special profiles using cold rolling and drawing, with dimensional verification built into Montanstahl quality management, and questions on tolerance classes are answered in the technical Q&A.