By Ian Hobkirk
Managing Director of Commonwealth Supply Chain Advisors
I spent the greater part of this week at the Modex Conference in Atlanta, where I talked to a number of companies across a variety of industries about their new distribution center initiatives. Voice technology continues to top their lists, but the common question that came up over and over again was, “How should we leverage voice in other areas of the distribution center outside of picking?”
It is true that it is possible to use voice technology to execute a number of processes in the distribution center (DC) beyond simply picking orders—receiving, put-away, and shipping are some examples. The voice technology providers have been touting these additional functionalities for many years. I actually wrote a paper in 2007 that discussed how voice was beginning to be deployed for these other functions in the DC. (Read the Blog: “Voice-Directed Warehousing a Changing Role for a More Mature Technology”) However, over the last 10 years I’ve had a chance to observe and talk to many different voice users, and have found that in practice, voice works much better for picking than for any other function. The reason for this is that voice works best for processes – like picking – which are largely “system-directed.”
With a typical picking process, the WMS or voice software has already determined the workflow in advance. The system provides clear and specific instructions to workers: “Go here, pick this, put it there; now go here, pick this, put it there.” The voice user simply has to confirm that he has followed the instructions properly, which can be done by reading relatively short check digits into the voice system (usually two characters). This doesn’t take very long; it takes just as long to read two digits as it usually does to scan a barcode.
Now, contrast this “system directed” picking process with a process like receiving which is much more “operator directed.” With receiving, the workflow is not neatly prepared in advance—a truck shows up, and while the system may know the expected contents of the truck, the system does not know the sequence in which the contents will be received. The operator grabs a carton of product at random, and must “tell” the system what product he has in front of him, perhaps capture some other details about the item, and then the system will post it to inventory.
With barcode scanning, this process can be relatively fast and simple: Scan a carton, enter a quantity, move onto the next one. However, with a voice system, the operator—instead of scanning a barcode— must read a complex set of information into the voice system to identify the carton he is receiving. This is far more time consuming than reading a couple of quick check digits and it involves reading a lengthy SKU number perhaps, or worst case, trying to read a product description. With a traditional mobile device with a screen, it can be helpful to have the system display a list of the expected items on the order and have the operator select the one he is receiving. With a voice system, this is not easily done.
Similar limitations often exist with put-away and shipping. Any time the operator has to select an item and tell the system which item he is handling, that lengthy piece of information must be read into the software. This not only takes time, but it’s also prone to error. In these scenarios, my experience has been that barcode scanning is faster and more effective.
To sum it up, voice works best for functions like picking (and perhaps bin replenishment) where the system can precisely plan the workflow in advance and the operator is simply confirming that he has followed instructions properly. And while it is certainly possible to use voice in areas other than picking, the body of my experience suggests that the business case is just less compelling than it is for picking.