A missing link in materials handling
How do you pick tiers or layers of cases from a full pallet load?
By David Luton -- Modern Materials Handling, 2/1/2000
There's a missing link in efficient materials handling. Indeed, it may be the biggest gap among all the tools and the methods we have to accomplish handling tasks and do so with high productivity. And, as we increasingly fulfill customer demands for smaller order sizes in the future, this gap will only grow.Specifically, what we need is an inexpensive piece of equipment or an effective process that isn't labor intensive to pick tiers or layers of cases from a full pallet load.
There are solutions to this problem in some specialized situations. But what we lack is a universal solution, particularly one that a lot of small- and medium-sized facilities can use without making a huge investment in large automated systems.
Let's assume our plant or warehouse uses a standard GMA pallet, 48 X 40 in. Our corrugated case size is slightly in excess of 1 cubic foot. The case has a stable design with a solid bottom and is not too top heavy.
Assume, further, that we have a palletizing pattern of 6 cases per layer with 8 layers high, for a total of 48 cases in a unit load.
Traditional full pallet picking takes the entire unit load. I will expand my definition of full load picking to include picks of three-quarters or more of a pallet load or greater than 6 layers.
Traditional case picking we will define as all quantities less than one-quarter of a pallet load, or 2 layers or less, or fewer than 12 cases, in our example.
For picks of full or nearly full pallets in traditional case selection systems, often the easiest way to pick them is to pull a full pallet (from a reserve storage location) and place any excess layers of cases in the pick slots.
So then the tier or layer pick problem involves selecting all order picking volumes in between one-quarter of a pallet load to three quarters of a load. Of course, these volumes can always be case picked. But that leads to an excessive amount of labor.
Examples of some solutions used today include picking cases from a lift truck equipped with a carton clamping attachment. This approach requires a case design that is clampable. And it generally works best with a limited number of stock keeping units (SKUs) in a block or bulk pile storage environment.
Or one can use a specialized lift truck fork attachment that can handle pallets and also rotate the specialized forks to do some clamping.
Finally, there is the solution that involves building one-quarter or one-half pallet sized unit loads directly off the assembly line. While this approach works well in some applications, it may just push the manual labor problem back to manufacturing. With the exception of some robotic palletizers, many automatic palletizers do not work well with differing pallet footprints.
Although many other material handling systems and much equipment have been designed to try to solve this problem, it is one that I believe still awaits a better mousetrap. The equipment supply organization that can cheaply and effectively solve this problem will likely have a very large market.
Pallet picking puzzle
How do you pick an order volume between one-quarter to three quarters of a pallet load without individually pulling each case from the unit load to reach the desired quantity?
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