Dictionary Definition

Induction: The process of identifying the product to be sorted, getting the product moving at sorter speed, and ensuring there is the appropriate gap between boxes for the specific sorter application. The sorter needs to be fed by the induction system at the rate of the intended sorter performance (e.g., 125 per minute). Usually involves a bar code scanner and a series of belts that move at different speeds to create carton gaps – a process made more challenging by today’s very high speed sorters that can operate with very small gaps between boxes.

Merge: As the name implies, a merge point is basically an area where product from one part of the total conveyor system is inserted into the main conveyor line leading to the sorter itself. Increasingly sophisticated controls and technology are being used to accomplish merge processes at ever-higher speeds today. A typical example would be a merge coming out of a given pick module. Merges come in several types, generally named according to the way the physical design looks (sawtooth merge, herringbone merge, etc.), and each is best suited to different applications.

Print and Apply: Sub-systems that apply a label in-line on the conveyor system prior to the merge point. Sortation systems generally have each carton uniquely identified, usually by a bar code (in the future, perhaps RFID). If cartons are not pre-labeled with a unique bar code identifier, then companies have two choices: pickers can apply labels to cases during the picking process, which degrades productivity, or it can deploy an in-line print and apply system. Generally, a scanner reads a generic case bar code, the WCS looks up order and other information for that SKU, a label is then printed and applied at high speed (approximately 60 per minute) with a unique serial number for that case. That label often serves as the shipping label, such as the UCC-128 label used by consumer goods companies shipping to retail.

Pallet Flow Rack: A storage type often use in full case picking modules that presents full pallets of product from which cases are picked and placed on take-away belt conveyors. Pallet flow rack can be single or double deep (or sometimes more); fresh pallets are replenished from the back; empty pallets are removed from the front.

Case Flow Rack: A storage type often used in split case pick modules that presents a single open case to order pickers. When the case is emptied, it is removed, and gravity forces the next case to the picking position. Replenishment of case flow racking is from the back.

Accumulation Conveyor: A special type of conveyor designed to stop, hold and eventually release products on a conveyor system. So-called “zero pressure” accumulation conveyors do this without creating pressure between boxes being accumulated. This type of conveyor, used before merge points and sometimes other areas of a system, is very expensive on a per-foot basis.

Slug: A group of boxes that moves as a set on the conveyor system. The most common application may be merging a slug from a pick module onto the main conveyor. The control system will determine the size of the slug, which may be all the boxes awaiting a merge, or just a portion of them, depending on conveyor conditions at the time.

Wave: A grouping of customer orders for release for order picking. Typically, pick waves are designed to last between 45 minutes and two hours. Any number of criteria may be used to group orders, such as outbound carrier(s), customer(s), priority, value-added services, and other criteria. A wave must be synchronized with sortation system activity.

Utilization: The actual throughput achieved versus the theoretical maximum. If the system is designed to sort at a rate of 100 cases per minute, and over a given period of time the average number of cases sorted is 60 per minute, the utilization of the system is 60%.