Delicate parts for perfect harmony – printed quickly and delivered

• What was needed: Components for the hammer capsule of a piano
• Manufacturing process: Selective laser sintering with SLS powder
• Requirements: Precisely fitting, low-friction and wear-resistant parts
• Material: iglidur® i3
• Industry: Music industry
• Success through collaboration: cost-effective production of customised functional parts, improved moisture and weather resistance, durability

The application at a glance:
In traditional piano manufacturing, most components are made of wood. To counteract the susceptibility of wood to changes in humidity or room temperature, Phoenix Pianos developed the D3D hammer system under the cable of Richard Dain. The hammer action, which is responsible for producing the sound, consists almost exclusively of carbon fibre and plastic in the revised version. The tribologically optimised high-performance plastic iglidur® i3 was used for the moving and fixed components of the hammer capsule. The laser-sintered stop hammers enable the precise reproduction of the original components, improve the sound characteristics, increase the service life and reduce maintenance costs.

Wood as a building material is at the centre of the centuries-old tradition of piano making. The hammer action in particular, with which the strings in the piano are struck, requires a high degree of precision and therefore a high level of maintenance. The susceptibility of wood to high humidity and temperature was just one of the many reasons why the conductor of the British company Phoenix Pianos was looking for a more resistant alternative. However, the alternative materials had to fulfil the existing requirements for filigree components that fit precisely into the mechanics and operate with little friction. At the same time, the parts are exposed to a high degree of wear due to an infinite number of keystrokes.

For the hammer capsule, which consists of a movable component and a component attached to the piano, igus® was able to produce a prototype using an additive process. Instead of wood, the glide-optimised iglidur® i3 was used for the parts, a wear-resistant SLS-plastic that meets the requirements of piano construction in terms of temperature or humidity. At the same time, 3D printing enables the fast production of identical parts. Regular readjustment to avoid unwanted side tones can thus be reduced to a minimum. The ivory-like colour of iglidur® i3 rounds off the functional parts and does not suggest plastic at first glance in classic piano construction.

The mechanism with which a pianist produces sounds on the piano is basically very simple. One string per key is stretched inside the piano. Pressing a key triggers a mechanism in which a hammer attached to a handle strikes the corresponding string. In traditional piano making, hornbeam was used as the material for the fixed components of this hammer mechanism. However, wood reacts sensitively to changes in temperature and humidity and this has an effect on the sound of the piano. As a result, the piano must be regularly retuned and serviced. For the conductor of Phoenix Pianos, Richard Dain, this was a good reason to revise the hammer action. As an engineer and amateur pianist, he set himself the goal of replacing the weather-susceptible wooden parts with more durable materials without having to compromise on sound. He replaced the handle of the hammer mechanism with complex carbon fibre fabric, which is very stable and light at the same time. The uniformity and light weight enable first-class, climate-resistant performance. Dain worked with the 3D printing team at igus® GmbH for the remaining components of the hammer capsule, which consists of a fixed and a movable element.

Richard Dain's collaboration with the 3D printing team at igus® GmbH resulted in the D3D hammer system, in which each wooden part is replaced by a plastic part. The laser sintering process made it possible to produce and test a prototype for the hammer capsule in a very short time. The advantage of the process is the level of detail with which the desired shape of the components can be printed. With the plastic iglidur® i3 developed specifically for laser sintering, Dain quickly found what he was looking for. The new iglidur® components of the hammer mechanism are particularly wear-resistant and promise a durable and consistent design of the mechanism. The components of the capsule are connected with a metal pin, which has a particularly low coefficient of friction in combination with the iglidur® plastic.

The new system has also proven itself in practical tests: pianists compare the change to switching from a Ford T model to a Ferrari. After an initial period of familiarisation, they are able to produce more power with less effort and thus create a completely new bond with the instrument.

Thanks to the iglidur® i3 SLS material, it was possible to fulfil, if not exceed, the requirements for the new hammer capsule. The high wear resistance of the plastic is precisely designed for sliding applications and the components remain stable thanks to the strength of the material. In addition, the parts fit precisely and are up to 50 times more wear-resistant than other plastics, which ensures consistent mechanical movement even after many thousands of stop-dogs.

iglidur® i3 has high strength and weather resistance and, according to Dain, could even exceed the service life of the piano itself. As iglidur® plastic is enriched with solid lubricants, the components made from it run lubrication- and maintenance-free in dry operation. Added to this is the ivory-like colour of the material, which supports the overall look of the hammer action.

The production of customised components from iglidur® i3 takes only 1 to 3 days and is economical from batch size 1, as there are no tooling and reworking costs. The order is placed quickly and easily via the online 3D printing service: The 3D model of the required component can be uploaded as a STEP file via the browser window. The model, the price and the price scale depending on the material as well as the production time are displayed immediately. The manufacturability of the component in the selected process is checked immediately and potential problem areas are marked. Printed parts can be smoothed, coloured or mechanically processed if required.