Electric skateboards are an effortless way to get around and offer their fans a thrill that is quite different from conventional skateboarding. They are also extremely challenging to design.
The electric components — the battery and motors that drive the wheels — need to be housed in very confined spaces to keep the board light, compact, and easy for the rider to handle. Tepex dynalite continuous-fiber-reinforced thermoplastic composites from Lanxess open up new opportunities in this regard, as evidenced by the Okmos SL-01 electric skateboards from EMI SAS, a family business based in France.
Conventional skateboards usually consist of a relatively flat wooden board where the rider stands, also known as the deck. Under the deck on electric versions is a plastic box containing equipment including the battery. The EMI design, however, has a trough-shaped deck. With the exception of the motors, which are mounted on the back of the skateboard, this houses all the electric and electronic functions, including the battery. The trough is enclosed by a cover manufactured with a wall thickness of just 3 mm.
Image courtesy of Lanxess
|The skateboard's electronic componentry is housed in a trough-shaped deck enabled by a composite material.|
The trough-shaped composite part is manufactured in a single hybrid molding process step. First, a robot inserts the metal base plate used to attach the axles into an injection molding tool. It then places a heated and plasticized Tepex section in the tool. In one operation, the section is then formed and the entire structure overmolded with a short-glass-fiber-reinforced plastic compound. “The process is efficient and integrated, meaning that not only can the base plate be fixed in place, but fastening elements, wire ducting, and the battery holder can also be mounted in the same operation. Thus, unlike many conventional electric skateboards, the latter does not have to be screwed in separately,” explains Jules Staedelin, Manager for Research and Development at EMI.
The composite section is made from polyamide-6-based Tepex dynalite 102-RG600(6), which is reinforced with six layers of continuous-glass-fiber rovings. The deck cover is also made from this material. Lanxess polyamide 6 Durethan BKV30H2.0EF is used for overmolding. This compound, which contains 30% short glass fibers by weight, is optimized precisely for this purpose. Its melt flows very easily, which means that even long flow paths can be implemented without any filling issues.
“Tepex is extremely resilient thanks to its high torsional and bending strength, and it’s very lightweight in the bargain. The deck weighs just 2.5 kilograms,” says Jean-Marie Olivé, Technical Manager, Application Development, at the High Performance Materials (HPM) business unit at Lanxess. Despite the thin walls, the electric and electronic components in the deck are safely protected against impact as well as moisture.