Robotics gearbox benefits from new very long fiber composite

When AndyMark, Inc. a company that invents and designs components for robotics and mobility applications, recently reviewed its catalog for components that could be improved, an aluminum gearbox kit captured its attention. Co-founder Andy Baker, a trained mechanical engineer, believed the housing could be made with a reinforced plastic, which would mean fewer parts for easier assembly, reduced weight, and increased durability.

AndyMark is a one-stop shop for specialized robotic parts as well as everything else needed by robotic builders and hobbyists around the world.  The growing company now supplies components for robotic competitions such as those sponsored by FIRST – a non-profit organization that helps students compete for scholarship funds by building their own robots. “Weight is a holy grail in these competitions,” explained Baker who is a volunteer mentor for FIRST competitions. “Everyone tries to get as much stuff on their robot as possible under the weight limit.”

Baker sought the assistance of custom compounder RTP Company for a redesign of the aluminum gearbox.  RTP Company engineers recommended using an RTP 200 Series very long fiber reinforced nylon 6/6 composite for the housing. The resulting gearbox redesign, called the CIMpleBox, has fewer parts, surer assembly, superior durability and, best of all, is half a pound (0.25 kg) lighter in weight.  It is now the standard gearbox for all FIRST robot kits and more than 2,000 teams used it in 2011 competitions without a single failure.  The CIMpleBox kit costs about the same as the old one, which is no small concern for AndyMark.  

Long fiber thermoplastics (LFT) are bulk molding materials that feature continuous fiber filaments running the full length of the pellet allowing these materials to exhibit simultaneous improvements in strength, stiffness, and impact resistance over a wide temperature range. Heralded as an exciting growth area in thermoplastics, LFT composites are widely accepted as a viable alternative to traditional reinforced thermoplastics and metals for a vast array of applications. RTP Company uses a pultrusion process to manufacture long fiber thermoplastics (LFT), which entails pulling continuous fiber rovings through a polymer melt in a specialized processing die. The resulting composite strands are cooled and chopped into pellets. Pultrusion is dramatically different than the process used to manufacture short fiber thermoplastics (SFT) where chopped fiber is melt-blended with plastic resin using conventional extrusion compoundingLunarcharge Premium