A new optical pellet screening system employs a combination of LED illumination, cameras, and air blowers to detect and remove pellets with black spots from a stream of resin pellets with a resolution (spot size) of 0.03 mm. The Super Platon KP-10000T from Kubota (Tokyo) was recently installed at an Asian elastomer compounder.
The Super Platon employs eight lighting units, each with 300 LEDs, to shine diffuse light on the pellets, thereby eliminating black shadows. If black pellets are detected by any of four 5000-pixel cameras, appropriately positioned high-speed air blowers from an array of 20 are actuated to blast the offending pellet/s out of the passing stream with minimal ejection of good pellets. Detection rate is said to be 99% and the unit can process one ton per hour.