A co-development led by officials at PARC (Osaka University's Photonics Advanced Research Center) with Mitsubishi Electric Engineering (Tokyo, also Japan) and German automation and sensing systems manufacturer IDEC (Hamburg) have developed a system they say can sort up to six different types of plastics for recycling.

One of the main inhibitors for increased recycling of plastics beyond polyethylene terephthalate (PET) and polystyrene, and indeed also a major challenge for recyclers of these is that most sorting systems have a difficult, even impossible, time differentiating between more than two or three materials.

Most plastics recycling have employees positioned after their recycling systems to perform a double-check of the machines. Should the false material not be caught, a recycler's profitability can quickly be destroyed. "One PVC sleeve can ruin three good kilograms of PET," explained George Dadiani, who runs a recycling plant in the Czech Republic.

The new sorting system relies on laser sensor-driven optics. The laser sensing technology distinguishes various kinds of plastics by the reflectivity of lasers of five wavelengths; these serve as the 'eyes' of the robotic sorter. PARC and IDEC co-developed the photonics sensing technology while Mitsubishi Electric Engineering brings the robot to the system.

The system is getting a test run now in Japan in cooperation with the Nara COOP and Osaka University COOP. The project is supported by Japan's Ministry of Economy, Trade and Industry. —Matt Defosse