5 Questions About MRF Sorting Systems

Incentivizing sorters. Manual sorting is the first and last line of defense in a MRF. Sorters remove objects that cause jams and downtime and remove prohibitives from final product streams. Setting targets and providing incentives to sorters can stimulate productivity, increase uptime and improve product quality. They win when you win.

Nonwrapping screens create cleaner fiber streams and are being used to target larger grades of paper, while optical sorters are now being installed to target smaller fiber using a positive sort to achieve the highest quality.

The quantity of newspaper in the stream still requires the use of traditional screening; however, the use of optical sorters to target the smaller fractions of fiber, including small OCC (old corrugated containers), is becoming increasingly popular. Positive removal of fiber from the system leaves the film in the negative fraction, which can be cleaned up using ballistic separators.

Ballistics are currently utilized for the final cleanup of the container stream to remove any remaining 2D items and small fines. The limited capacity of these machines inhibits them from completely replacing disc screening, but as the percentage of large fiber continues to drop, ballistics (in conjunction with optical sorting) will gain a stronger presence in single stream MRFs.

Robot technology never caught on in Europe after a decade of R&D, so why would it make a significant impact in the U.S.? Currently, robots are not being developed for presort, fiber QC or container separation. Their role is limited to plastic container QC. My suggestion: invest in quality optical sorting. Why do 60 ppm (picks per minute) with a robot when you can do 600 ppm with an optical sorter?