Within the world of sorting systems we have quite some terms that aren’t always crystal clear in their definitions. Today we dive into the different capacities mentioned. System capacity, net sorting capacity, induction capacity, each has its own number. But what do they mean and more importantly: how many items per hour can you expect?
Maximum system capacity
The SD-sorter is able to reach 14.400 items per hour. This is the maximum system capacity. To reach this capacity, every tray must be filled with an item. When operators are feeding the sorter manually, it is not always easy to get all the trays filled. This requires experienced operators and items that are easy to handle. The maximum system capacity therefore will not always be the actual throughput of a system.
Net sorting capacity
The net sorting capacity is a realistic estimation of the throughput. This is determined by various factors such as the number of operators, the experience level of operators, the product mix and the feeding process. A quick benchmark: we use 90% efficiency for our calculations. This number is proven continuously by our customers. A maximum system capacity of 14.400 items per hour results in 12.960 items per hour in net sorting capacity.
In our efficiency calculation we exclude stops for wave changes, sorter stops, operator breaks and servicing. With a “clean” product mix and well trained operators it’s even possible to reach 95% efficiency.
Recirculation and efficiency
Sorters with a horizontal track often offer the recirculation of products. If an outfeed is full, the product remains in the tray and will go for another round on the sorter. This gives the operators more time to empty the outfeed. However, this recirculation affects the overall system efficiency. If one or two consecutive trays are filled with recirculating items this doesn’t affect the infeed much. But if more following trays are filled, the infeed has to be paused temporarily.
This net sorting capacity can’t be reached by one operator, no matter how experienced they are. One operator can insert between 1.200 and 2.000 items per hour. The actual number can be improved by using some smart tactics as explained in our induction capacity blog. For an SD-sorter running at max speed, you would need between 6 and 11 operators to reach the net sorter capacity of 12.960 items per hour.