In this case study, Loson and Ensinger cooperated to improve the performance of a robotic arm used in a Delta robot for food packaging lines. Such fast and accurate machines are used in factories for picking and packaging thanks to their speed that makes it possible, in some cases, to perform up to 300 picks per minute.
Carbon fiber composite parts (in this case carbon woven fabric in an epoxy matrix) are designed and produced to reduce weight and inertia, preserving high mechanical properties typical of high quality metal alloys. Although lightness is one of the main targets, heavy metal inserts (steel, aluminum or, in few cases, titanium) are normally necessary to connect carbon fiber composite parts to other mechanical components, so the benefit of the carbon fiber is partially reduced.
Fig. 1 shows a robotic arm for a machine in the food packaging industry: of a total weight of about 300 g, more than 80 g (27%) are accounted for by aluminum inserts, so the effort to reduce the weight of the part (to reduce inertia) is partly compromised. Also, in harsh environments, where aggressive acids/bases are used for cleaning (e.g. food packaging lines), this configuration is subject to a high risk of salt corrosion or galvanic coupling corrosion.