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A New Possibility for Picking

By Homayoun Taherian | N/A 2012 | 7 | 11

Picking represents about 25 percent of all labor costs in the traditional warehouse or distribution center__and it also offers a lot of opportunities to save. One possibility is to use layer picking, applicable in certain companies with the right product demand pattern combination.

Layer picking can reduce the work involved with case picking. This is achieved through automation or the use of specialized material handling equipment and warehouse layout configuration. When products are palletized, they consist of several layers per pallet with several cases on each layer. For example, a product may have 40 cases per pallet consisting of 4 layers of 10 cases each. If a customer orders 20 cases, then 2 layers would be picked.

In a traditional operation, the picker will go to a location, put the 20 cases manually onto another pallet, and then move on to the next location depending on the picking strategy and demand. With layer picking, however, the 20 cases (or two layers) can be picked using a specialized clamp that reduces the amount of manual labor needed. The clamp grabs the required number of layers from four sides and picks all the cases on the layer at once. Multiple layers can be picked in one move. These clamps are attached to sit-down forklifts with a customized mast. The cost to pick a case using layer picking is very close to the cost of picking a case through full-pallet picking (the least-expensive picking method).

The following steps outline the process for implementing layer picking:

  1. Evaluate packaging and palletization: Not every package type is suitable for layer picking. Products need to be cubed nicely on pallets with sturdy packaging that won’t get crushed by the picking clamps. Many consumer packaged goods businesses can apply this solution very effectively.
  2. Verify there is sufficient layer volume: It’s important to perform a volume analysis in order to understand how much is less-than-pallet volume that can be picked in layers versus cases. A key enabler to such analysis is having an accurate stockkeeping unit (SKU) characteristics database. It should include information on the cases, layers, pallet, case dimensions, weight, and so forth. This information is critical to understanding the layer volumes. Decision makers must look at both the percentage of units and number of picks necessary with the layer pick operation. Benchmark information on layer pick productivity can be used to understand the impact on labor. Here, it would be helpful to use the 80-20 rule to see if a few SKUs represent the majority of the layer pick volume. This information is helpful for designing the layer pick line and deciding how many layer pickers are needed.
  3. Test the products: Test some of the layer picking offerings in order to eliminate any doubts as to whether they are appropriate solutions. If product package integrity is compromised, then the answer is no.
  4. Select a vendor: Layer pick vendors do not provide the forklift, so one also must identify a material handling equipment vendor that can support this initiative and will collaborate with the layer pick vendor. The vendors must customize a solution that fits the products being handled. They typically will examine the pallet overhangs and under-hangs, package types, case weights, and pallet heights. There are two main types of layer picking tools: a swing model that moves from right to left and can pick from both sides of the line and a fixed model. Swing models provide more flexibility and speed and are more expensive.
  5. Perform a cost-benefit analysis: Know the benefits and feasibility of layer picking. The cost of the equipment should be clear. Take into consideration labor (normally one operator and one or two support workers), signage and other necessary markings, information technology support, and any revised layout of the facility. In addition, design and setup of the layer pick line are big undertakings. The line can be set up in various forms. Some companies use angle iron to guide the layer picker in a straight line. Others use 4-inch-by-4-inch parallel metal tubes that act as guides. When using guides, the forklift has no room to turn and thus can only drive back and forth in a straight line. Products can be setup on flow racks on both sides of the line to facilitate replenishment. Another part of the process is to slot the SKUs on the layer pick line based on various product characteristics such as velocity, layer weight, layer surface, and hazard properties.
  6. Perform customer impact analysis: Customer order patterns are the drivers of the layer pick volumes. Companies can affect these patterns by setting up policies to incentivize layer increment ordering or discourage ordering in non-layer increments. These initiatives can increase the volumes flowing through the layer pick operation and boost savings.
  7. Implement, train, and document operating instructions: These efforts will need to be monitored for the first few months in order to allow the team to remove all the glitches that may arise during start-up.

Layer picking is a potentially suitable cost-reduction initiative for companies that handle nicely palletized and cubed packaged goods and that have a high level of less-than-pallet picking volume. The overall process from evaluation to implementation should last between 6 to 12 months. It requires a close collaboration among several parties and considerable effort by all, but the savings generated could have a significant impact on the company’s bottom line.

Homayoun Taherian is working toward his masters of engineering at the Massachusetts Institute of Technology supply chain management program. He has 10 years experience in supply chain management and manufacturing across various industries. Taherian may be contacted at htaher@mit.edu

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