As your operation grows, the type of order selection vehicles that will work best for you may change. Growth often means increasing numbers of SKUs, and larger on-hand quantities. It is not uncommon for shelving storage requirements to grow to cases on pallet rack shelving, and then to full pallet loads of a single SKU. In a business where items are constantly added and changing, you may find that SKUs will proliferate. All of these factors can combine to create extra travel that can place a growing burden on your order picking staff. Fortunately, there are some powered vehicle options that can help.
For operations that have a steady flow and backlog of orders, it is easy to sort orders into common groupings, and then pick a group of orders together. Orders that are picked together on a single picking run are often referred to as a “batch,” and picking a batch of orders almost always cuts down on the total traveling distance needed to fill the orders. Manually pushed carts are the lowest cost vehicles used for order batching, but you can also batch orders and combine them with a powered vehicle. When “Batching” you can pick to order, or you can pick by item, and sort things out on the back end. Tuggers can help with either batch picking strategy.
A tugger is a vehicle that can tow carts behind it, with each cart carrying several orders. Since the tugger is a powered vehicle, carts with heavy items or large numbers of items can be towed with ease. As a result, the operator can pick larger batches than he could if they were using a manual push cart.
A tugger may have a chain of carts behind it, with each shelf containing requirements for a particular order. Alternately, it is possible to pick all the materials for the batch en-masse without placing to order, and then pick from the shelves of the carts once they are delivered to the pack station.
To make these applications concrete, here are a couple examples:
Farm Supply: Pick units first, then create orders Consider a farm supply picking operation where customers order just a few items and units per order. Items are big and bulky, such as a bag of fertilizer, or a 5-gallon pail. A tugger can be used with a chain of carts to pick the individual items for a batch of several orders to shelves on the cart. The picker would use a pick list that summarizes the pick location and total quantity of units needed to satisfy all orders. Items from a stock location would be picked to a single shelf and placed together, even when they are required for multiple orders. When the cart is delivered to a pack station, the packer can select those items from the tugger carts that belong to a particular customer order.
Battery Distribution: Pick to order on the cart Consider a specialty battery distribution center that is picking car batteries, a heavy commodity. Here we have many one or two item orders. If we use a cart with “cubbies,” each cubby can hold a single order, the tugger can move around the warehouse while the order selecting associate picks and places batteries to order cubbies. As each battery is picked from the stock location, it is then placed to a specific cubby designated for a single customer order. When the carts are dropped off the packer just pulls the battery and paperwork out of a single cubby to ship the order.
Sam Flanders is president of Durham, NH-based consultancy Warehouse Management Consultants.