NO. 5: A rotary encoder was produced in a single step in a highly automated demonstration by Arburg of Lossberg, Germany. The automated production used three-component injection molding, assembly, and in-mold magnetization of an inserted sensor. An Allrounder 370 S press (70 tons) was equipped with three injection units for the demonstration.
The injection mold was designed and built by Oechsler, who developed the concept with the Chair of Plastics Technology of the University of Erlangen.
In the first station, magnetic discs were molded with a ferrite-containing nylon. The discs were positioned and magnetized inside the mold. A robot moved the discs on the ejector side on to the second station, while at the same time inserting a sensor component into the second station on the opposing nozzle side. The sensor component was encapsulated with a carrier plate of 30% glass polybutylene terephthalate. The carrier plate also acts as a moving mounting for the magnetic disc.
The third station molded the protective cap for the magnetic disc from methyl methacrylate/ABS. Finally, the robot removed the cap and carrier plate before assembling them, to form the finished rotary encoder.
The three injection units, the robots, and the mold functions are integrated on one control system. Cycle time is 30 seconds.