Arguably the most important function of any warehouse is fast and accurate picking of customer orders and where we’ve been asked to deploy the most automation. Here’s my take on some of the more popular picking practices used today and the technologies used in each of those pick methods.
1. Order Picking
The most common method we encounter in manual pick processes. In support of this pick I’ve seen: pick ticket/sheets, shipping labels, RF terminals, and voice-driven terminals. The process involves giving the entire order to an individual to work this way through the warehouse. Sometimes the pick sequencing may be designated in the pick sheet but in most cases, the worker is left to his/her own discretion how to build their pick based on experience. With this process, there is typically a wide discrepancy in pick results and is heavily dependent upon the skill and experience of the warehouse worker.
2. Batch or Wave Picking
In this scenario, a batch or group of orders are released simultaneously and you may have one or more pickers picking simultaneously multiple customer orders. The trick is keeping all the orders separate. I’ve seen specially designed carts with multiple totes on them each row representing an order. Due to the potential confusion, I’ve never seen this as a paper-driven process, rather real-time technology is used to keep a running tally of what you’re picking.
3. Zone Picking
A group of orders (typically by shipping geography) are released simultaneously and broken down into the zones where the products are stored. This is used when you have products that are stored under different conditions (mezzanine, freezer, high racking, etc) and/or you have a warehouse over 50,000 sq feet. This requires a consolidation of the order and real-time tracking of the orders such individual orders are staged together and inspected all at the same time. The technology is the most variable ranging from handheld computer, truck mount units, to voice-enabled equipment.
4. Pick to Tote or Box
Travel time is often cited the biggest use of a pickers times. In this method, the tote or box travels along assembly line like via a conveyor to the picker who is waiting in at a ‘station’ containing a set number of SKUs. The technology used includes pick to light systems, voice, robot, or terminal screen output. The challenge with this process is like the rush hour; totes must travel the length of the conveyor before they reach the correct station which means workers along the line become the bottleneck as their work may be holding up other totes further upstream. Complex algorithms on the technology side have to be able to resize stations based on each day’s pick volume, support multiple induction points for case/totes to limit bottlenecks on the line, and continually monitor inventory levels in the pick faces.
5. Part to Pickers
This is a slight variation of the previous method with the product coming to the worker who ‘picks’ his product from his/her designated area. This is the warehouses of the future – the “Lights out Facility”. AS/RS (automated storage and retrieval systems) will bring cases, pallets and even piece pick to the designated picking-packing locations. This creates by the far the most predictable and reliable output as much the ‘heavy lifting’ has been automated by robots or AGV (automatic guided vehicles) and the skill and or experience level of the warehouse worker needed to operate in this environment is sharply reduced.
Your choice of automation is heavily dependent upon your budget, warehouse volume, and customer service levels. However as more companies embrace e-commerce and 24/7 operations, there will be a growing need for companies to deploy more technology to the point in the near future, human output is no longer a factor in picker productivity.
Tell us which picking method you currently use in your warehouse or which ones you have tried and loved/hated in the comments section below.
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