This series of four posts is designed to discuss some of the challenges faced by mid-sized postal organizations and parcel carriers wanting to take advantage of the growth in parcel volumes. In the initial post, we advocated that it is critical to develop a clear operations strategy focused on parcel distribution, rather than “piggy-backing” parcels on the letter mail processing network. In the second post, we talked about important characteristics of a parcel network, including its resilience. In this post, we cover some of the emerging processing automation technologies that must fuel any parcel network transformation.
Space is at a premium for companies with legacy sorting plants, sometimes near city centers. Handling a wide range of parcel shapes,weights and sizes in various states of consolidation (single piece, bundles, pallets) is increasingly important. Adaptable and flexible automation systems use emerging mechanical capabilities as well as more intelligent controls. New controls use the physical characteristics of a package to eject it into its bin at the right time and at the right acceleration, improving sort accuracy and shrinking chute sizes. Other controls are designed to vary total sorter throughput based on induction rates in order to reduce energy consumption, wear and maintenance.
Vertically-oriented sorters are designed to fit in places where space is tight. 0º induction lines are used to feed items on the upper part of the sorter, granting very high throughputs while 30º induction line can be installed both on the upper and lower part of the sorter. Multiple types of chutes accommodate various product types. Information capture devices provide information during the loading process, directing the items to the proper chute.
Contactless sorting increases the mechanical efficiency of sorting systems while reducing energy consumption, and wear and tear. The footprint of contactless sorting systems is generally smaller than other systems and its speed can be modulated based on actual demand. These sorters typically use linear synchronous motors, inductive power transfer and direct-drive motor rollers by embedding them into cells, thus eliminating transmission-belt mechanisms. The activation of cells via Wifi eliminates the need for dedicated equipment at each cell. These sorters are more easily expanded and system installation is considerably simplified.
While increasing conveyance speed will increase throughput, the difficulty, and therefore the importance, of maintaining accuracy increases as the speed of conveyance increases. In order to discharge articles to their intended location, the items must be delivered to their designated discharge location within acceptable tolerance ranges. As speed of conveyance increases the timing of the discharge becomes very critical, as does the acceptable tolerance ranges decreases.
The dynamic discharge compensation technique makes real time adjustments to the timing of the discharge based on the determined actual position of the item on the crossbelt. By detecting the relative location of the item positioned off-center on the crossbelt cell, the technique determines a release point for discharging to the assigned chute. This release point is determined so as to compensate for the relative location of the item on the crossbelt cell. A discharge is initiated once the release point is reached.
Traditional tilt tray or cross-belt sorters are actuated by electromechanical motors or traditional rotating motors. The use of linear asynchronous or synchronous induction motors provides more accurate automation and higher accelerations, reducing unloading time and improving trajectory precision. Operating speeds can be increased and the spacing of outlets can thus be reduced. These motors eliminate actuator wear, a critical issue in conventional tilt mechanisms, and reduce noise and power consumption.
High loading capacity induction can be achieved by using 30-degree lines with acceleration/speed adjustment tied to the sorter throughput. Item orientation can be used to increase system stability and production capacity. Accelerations are generally limited to 4 m/sec, ensuring high object stability, improving loading precision, and handling a wide range of objects.