In our blog post about the optimal weight of a gaming mouse we formulated the hypothesis that the ideal weight of a gaming mouse is «zero grams». Actually engineering a zero gram mouse though is heavy going for anyone not named Tony Stark or Elon Musk. However we can get pretty close to zero by using a material some might consider overkill for a gaming mouse: carbon fiber.
In the following we will compare carbon fiber gaming mice with traditional gaming mice made out of plastic.
Gaming mice made of plastic
Plastic parts are made by a method called injection molding. This production method is over a century old. Funnily enough it was invented during a competition over finding a substitute for pool table balls that back then were made of ivory. The way injection molding works is that molten plastic is injected into a metal mould. It takes only seconds to produce a part. Hence injection molding is the best way when it comes to producing large numbers of plastic parts at low costs.
Almost every mouse you can buy today is made by injection molding of plastics. And most of the time a plastic called acrylonitrile butadiene styrene (ABS) is used. ABS is used so often due to its combination of low cost and decent mechanical properties.
When trying to make a lightweight gaming mouse ABS is not the best choice. Why? Its specific stiffness is poor. We think gaming mouse design is what is called stiffness-driven. This means that when you try to lower the weight as much as possible, stiffness is your biggest enemy. It is the limiting factor. A mouse that is lacking in stiffness will flex each time you grip it. This would be distracting, to say the least.
So in order to make a mouse out of ABS stiff enough, the wall thickness has to be quite high. Needless to say though that thick walls bring up the weight. So mice made of ABS are either not stiff enough, or too heavy.
In summary injection molded mice made of ABS are a budget solution. Using higher quality plastics than ABS, like polyether ether ketone (PEEK) for example, would be a significant improvement. However, when you want to make the lightest mouse possible not even using PEEK is enough.
Gaming mice made of carbon fiber
Ironically carbon fiber production starts by burning strings of plastics. The resulting carbon fibers are just five to nine micrometers in diameter. Thousands of these carbon fibers are then bundled into tows. And these tows in turn are woven into a cloth. And to lock these fibers into place typically they are surrounded by a matrix in the form of an epoxy resin (a special plastic). The result is a carbon fiber reinforced plastic, but most of the time it is just called carbon fiber.
The thousands and thousands of intertwined carbon fibers are what give carbon fiber their extreme stiffness.
Carbon fiber also has some other interesting characteristics like high chemical resistance, which is probably useful for fighting of sweat. Carbon fiber also has a heat expansion close to zero, meaning its material dimensions barely change when the temperature changes. And as carbon fiber is electrically conductive it shields the electronics of the mouse from electromagnetic interferences (EMI).
Finally, carbon fiber also has a high temperature resistance. The maximum service temperature of our carbon fiber mouse shell is 135 degrees celsius. Admittedly this is not very useful for gaming (although, when you think about it, gaming can get quite heated).
There are downsides, though. Everything about carbon fiber is expensive: not just the raw material, but also the production process itself. In terms of production carbon fiber is a diva: one little mistake can ruin the whole part. We make our carbon fiber mouse shells under vacuum and at a precisely controlled temperature. The tiniest leak in the vacuum bag can ruin the vacuum. As can a small variation in temperature.
When you want to push the frontiers on lightweight gaming mice though, no other material can hold a candle to carbon fiber. It is almost eerie how a carbon fiber wall with a width of less than half a millimeter can be so rigid.
When we look back at our plastic prototypes and compare them to the prototypes made of carbon fiber there is no going back. It is no coincidence that carbon fiber heavily influenced so many different kinds of sports. Be it Formula One or tennis. Next up: eSports.