The Revolutionary Kawai Mechanism
The mechanism that revolutionized piano making…
Since its invention by Bartolomeo Cristofori di Francesco in the 18th century. The piano, both in its tail and in its closet. It has undergone several developments that have ensured more precise and refined mechanics. More complex and comprehensive sound and more robust and lasting construction. Many of the innovations of the instrument that gave it the main characteristics. That last until today were conceived and implemented in the 19th century. When the design of the instrument underwent great advancement using the technologies existing at the time.
In view of this, the raw materials used were those available. Such as wood, metal, leather and fabrics of various types, mainly felt. The later innovations of the 20th century occurred mainly with the addition of mechanisms. Such as the double escape, tonal pedal and duplex scale, among others. Which added more interpretive or sound features to the piano. However, the raw materials used have changed little in more than a century. Despite the high technology involved in obtaining more durable materials. And better performance in all fields of science and in various human activities.
Wood, for example, is susceptible to moisture and to expansion and contraction due to environmental conditions. Especially very small parts that are subject to regular movement and impact. In addition, larger parts may not be as resistant to extreme force. With the advancement of technology and the creation of more stable materials. Many high-performance products have been modified to become more resistant and perform better.
Because of this, there were several objects whose original raw material, wood. This was replaced by carbon fiber, aluminum and several other components. From tennis rackets and golf clubs to car wheels and furniture.
When critical wood components of a piano break down because of high repetitive stress, the keys simply stop working. In such cases, failure of an essential part can cause the entire mechanism to fail. But even without problems such as the breakage of a component, there are other situations. In which the state of the wood can compromise the mechanism and sound of a piano.
The place where the hammer hits the string is perhaps the most critical point of a piano’s mechanism. Accurate alignment of this component is essential. Because the slightest change in its position can drastically affect the tone and tone of the pianist. What keeps the hammer properly aligned is the hammer flange. When it remains secure and perfectly positioned, the corresponding hammer remains properly aligned.
But on a damp day, the wooden hammer flange can swell. And if this occurs, the wood under the screw expands upwards against the screw head and eventually becomes damaged. Later, when moisture decreases, the wooden flange shrinks leaving a “gap” between the flange and the bolt, which allows the flange to exit the position. To make matters worse, the space increases as the movement of the flange causes the bolt to loosen.
The hammers will hit the strings partially. Or when alignment is compromised not at all. This was resulting in severe sound loss. The hammers can also touch each other, damaging the touch or moving together. Once repaired, these problems can easily recur whenever humidity conditions return. Or when the piano is moved to another environment.
Starting from the principle that a lighter mechanism is necessarily faster. Japanese piano manufacturer Kawai researched and, from the 1980s, began incorporating some lighter materials into the mechanisms of its pianos.
A Wood Alternative
Recognizing that wood could never be truly stable, given the changes in the climate. And determined to find a solution to the imperfections of this raw material. Kawai engineers began to intensively research the properties of alternative materials, which led them to a polymer composite material called ABS Styran, which brought the perfect characteristics to the task.
It was much stronger than wood to reduce breakage, was dimensionally stable and virtually unaffected by changes in humidity, and had a successful track record in many other industries.
Challenging the conservative musical instrument industry, Kawai bet on this compound, with the proof that the material would be more stable than wood and provide better response and durability.
This belief was proven by studies conducted by Professor Abdul Sadat. Head of the Department of Industrial and Manufacturing Engineering at the California State Polytechnic University in Pomona, USA.
The study compared wooden piano pieces with their Styran ABS counterparts in terms of strength, dimensional consistency, resistance to swelling and shrinkage and longevity.
The Results Were Convincing
Styran ABS hammer flanges proved to be more than 50% stronger than wooden ones. And at the time of manufacture, Styran ABS components proved to be significantly more stable in size and shape.
In addition, after 24 hours of exposure to moisture from 90 to 100%, the wooden hammer flanges increased by more than 5% in size. While the Styran ABS parts swelled by only 0.16%, which proved that they are 30 times more resistant to swelling.
This historical research has proven that Styran ABS is superior to wood for specific uses within a piano engine. The pieces are stronger and without glued joints, so breakage is rare, which made them used on all Kawai pianos.
The Millennium III and ABS-Carbon technologyIn the Millennium III mechanism, found in most models of the brand today. The ABS is reinforced with carbon fiber, so that it becomes incredibly robust and rigid. Which allows making parts of the mechanism even lighter and more resistant.
The Mechanism Became Faster
With less mass to move (i.e. less inertia), the mechanism has become approximately 16% faster than traditional vertical pianos and 25% faster on grand pianos, which makes it more responsive to the pianist’s intentions, including faster repetition. In addition, a microscopically textured surface was created on the bayonet. Exactly at the meeting point with the hammer. The result of this subtle and important change is a significant increase in sound control during the pianissimo.
By generating more power with less general effort, the innovative design and use of ABS-Carbon in the Millennium III mechanism of the Kawai pianos provide the pianist with greater freedom of expression, flexibility and control, while at the same time updating the instrument, innovating its manufacturing and adapting it to the new performance and environmental needs.