How voice picking stacks up against paper, RF scanning and Pick-to-Light

    Posted by Tailar Kennedy on May 22, 2020 9:30:00 AM


    Over the years, this post has been one of our most popular and helpful pieces, so we’ve decided to update it to keep the information as relevant as possible.

    Warehouse order picking describes the process of selecting and pulling an item from inventory to fulfill a customer’s order. The labor, materials, and technology involved in picking make up an average of 55 percent of operational costs within a given distribution center (DC).[1] Therefore, it’s essential for supply chain managers to optimize their picking processes in order to avoid unnecessary costs.

    When it comes to determining the most effective picking solutions, there are four main options that are typically considered: paper, radiofrequency (RF) scanning, pick-to-light, and voice. Each of these solutions has their own unique benefits and drawbacks, especially when it comes to warehouse productivity, order accuracy, and overall flexibility.

    In this article, we take a look at the ideal applications of each warehouse picking option — and how they compare to one another in key areas. As you evaluate your choices, it’s important to consider future projects and updates in order to make the right choice for your operation.

    Paper Picking

    Paper-based order picking, or label processing, is the process of completing warehouse procedures with the use of paper orders. Paper picking is typically coupled with after-the-fact data entry using desktop terminals. Associates perform warehouse tasks off of pick lists, put-away labels, printed VAS instructions, and other paper documents. Upstream processes (such as how the information is sorted on the documents), and downstream processes (such as scan and verify on a desktop terminal), directly impact paper picking’s performance and functionality.

    Paper/label processing may be a good fit for smaller operations with relatively straightforward transaction requirements. Even operations that rely on RF scanning for the bulk of transactions usually employ paper/label processing for some functions. It can be purely a manual proposition or part of an automatic flow, such as a label case pick-to-belt, where the pick is confirmed by an in-line conveyor scan.

    Yet, while paper picking is a great starting point for many smaller operations, it tends to be a barrier to large scale growth and improvement. Paper does not offer real-time visibility into inventory, employees, or systems. Instead, the entire process is held up until data entry begins, and that process is prone to errors.

    Additionally, burdening workers with paper handling slows down the processes that are key to the functioning of your DC. Having to pick up and put down clipboards removes the workers attention from the task, and can lead to unwanted errors or mispicks.

    Radio Frequency(RF) Scanning

    RF scanning terminals have long been considered a prerequisite for larger, more complex operations. However, RF scanning can be found in all different types and sizes of operations, primarily due to direct support by most Warehouse Management Systems (WMS). Even operations running non-RF enabled legacy fulfillment systems can turn to automated data collection software for this functionality.

    RF scanning offers some distinct advantages over paper/label processing. It can provide positive verification that a warehouse associate is at the right location or has picked the correct SKU through a barcode scan or key entry. Work can be pushed out to associates based on location and task priority instead of handed out from a manually managed queue. Transaction data is captured in real time as associates perform tasks. Furthermore, RF scanning makes some functions like multi-order cart selection possible or more practical than paper/label processing.

    While they are popular with many companies, RF and barcode scanners do have some drawbacks. Training on RF scanners can be extensive, with some operations requiring up to three weeks before workers are self-sufficient. Once fully trained, these workers can still be distracted with something in their hands, and are unable to complete warehouse processes without picking up and putting down the scanner.

    Additionally, maintenance costs for the devices can be high, as many workers drop or mishandle the scanners during use. This can lead to expensive screen or keyboard replacements, as well as the need for extra equipment to compensate for the damaged units.

    Pick-to-Light (PTL)

    Pick-to-Light remains a popular selection technology due to its ease-of-use and ability to support high pick rates. It is typically used in a zone-based, pick and pass flow where an associate scans a tote or carton barcode label. The PTL software activates light displays for every location that shows the required quantity needed for the tote or carton. The associate walks the zone, selecting SKUs and confirming picks by pressing display buttons. Displays can also be provided to show SKU, order, or other relevant information.

    As its name implies, PTL technology is about the order selection process. Unlike the other technologies discussed in this article, it is not employed to drive other warehousing functions such as receiving, put-away, and cycle counting. This means any investment in the technology cannot be leveraged beyond the confines of the PTL module and order selection process.

    Pick-to-light also presents some challenges that go beyond pick rates and raw productivity numbers. It is an inherently more costly and complex technology that typically requires a significantly higher start-up investment and a relatively rigid product flow. Totes and cartons are generally routed between fixed pick zones via a conveyor system. Managing workflow can be an ongoing issue, because of daily workload fluctuations between zones that result in bottlenecks in some and under-utilization in others. Furthermore, changing the configuration of a pick-to-light module can require additional changes to the light displays, communications backbone, and pick-to-light software as well as physical storage media and WMS changes.

    Voice Picking

    Voice technology offers much more flexibility and visibility into operations than the other three solutions. It enables associates to redeploy resources to match daily changes in overall workload on the warehouse floor. Further, reconfiguring pick modules supported by voice is a simple proposition that generally only requires labeling in addition to storage media and WMS changes.

    Because voice technology is relatively quick to learn, it can drastically for new or temporary employees. In some cases, training can be cut down to thirty minutes without sacrificing worker safety and productivity.

    Voice technology allows workers to complete tasks reduce training time, with workers able to keep their attention on the project at hand. The voice picking process can cut the information exchange down to just a few simple steps, which leads to a direct increase in picking speeds. It also eliminates a variety of human errors, boosting order accuracy by up to 85 percent.[2]

    Plus, when it comes to worker safety, voice picking stands significantly above other warehousing solutions. With their eyes and hands free, workers are less easily distracted and prone to injury. Further, as voice technology can be used to guide autonomous mobile robots, it can help with heavy lifting and reduce worker fatigue. Using voice-enabled headsets, workers are able to direct AMRs while lowering their risks of falls, exhaustion, and collisions.

    Final Comparisons

    Paper vs. Voice:

    • Productivity - Voice is 15-25+% faster
    • Accuracy - Voice has 10-20 less errors per 1,000
    • Training - Voice reduces time by 50%
    • Paper Issues:
      • Lack of real-time associate visibility and accountability
      • Lack of real-time inventory, people and system updates
      • Difficult to batch-pick
      • Data entry errors
      • Labor and materials cost to handle paper
      • Not hands or eyes free

    RF Scanning vs. Voice:

    • Productivity - Voice is 10-15+% faster
    • Accuracy - Voice has 2-4 less errors per 1,000
    • Training - Voice reduces time by 50-65%
    • RF Scanning Issues:
      • Average 2-3 weeks of training for associate to be self-sufficient
      • Operator is distracted: data entry, read, scan
      • Safety issues (head-down)
      • Not ergonomic
      • Not hands or eyes free
      • Battery issues
      • Risk of equipment damage

    Pick-to-Light vs. Voice:

    • Productivity - Same as voice
    • Accuracy - Voice has 2-4 less errors per 1,000
    • Training - Similar training effort as voice
    • PTL Issues:
      • Inflexible
      • Expensive to add additional SKUs
      • Can't efficiently manage two order selectors in one zone
      • Difficult to batch-pick
      • Sized based on SKUs vs. number of people on floor
      • Thousands of points of failure

    Although each of these warehouse picking solutions has its merits, voice often outperforms the other options. And many businesses are realizing voice’s benefits. As such, the voice-directed solutions market is expected to gain a total incremental opportunity of $1,703.3 million during the period from 2018 to 2026.[3] With better productivity, accuracy, training time, and flexibility, voice can improve your warehouse while delivering an ROI in 9-12 months.

    Topics: Voice