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Cliff Holste

Supply Chain Digest
Material Handling Editor

Logistics News - Sorting It Out

Cliff Holste is Supply Chain Digest's Material Handling Editor. With more than 30 years experience in designing and implementing material handling and order picking systems in distribution, Holste has worked with dozens of large and smaller companies to improve distribution performance.

March 14, 2018

Sorting It Out: An In-Depth Look at Goods-to-Person Order Fulfillment Solutions - Part 2 of 2

Improving Customer Service with Flexible & Adaptable Technology


Editor’s Note: The following is a continuation of SCD’s Part 1 GTP presentation. It was originally published on 3/7/2018. To review Part 1 click here

Holste Says...

Deploying a combination of order fulfillment technologies may be the best strategy to obtaining the best overall system performance.

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Pick/Put Wall:


To lower inventory levels and hold down carrying costs, many shippers are making the decision to combine retail store and online fulfillment into one DC. However, this multi-channel strategy presents some challenges. Store orders typically consist of case and/or split-case quantities, while direct-to-consumer orders usually contain one or two individual items. When combining this mix of large and small orders in a typical batch-order picking and sorting system, efficiency is greatly reduced due to the amount of time it can take to complete the batch.


With the Pick/Put Wall alternative, cases and totes containing individual items are picked for a group of orders at one time and are transported to the put wall workstations. Each tote of picked items contains many different SKUs bound for multiple customer orders. After each item is scanned, the operator is directed via signal light to the correct put wall cubbyhole. When the order is complete, the packing operation occurs on the back side of the put wall. The number of cubbyholes and workstations depends on the shipper’s business metrics.


In a semi-automated alternative, a multishuttle carrier delivers containers, typically with one SKU in each container to the put wall. The picker removes the required amount of product from the container (light directed) and puts the indicated amount into each cubbyhole. When picking is completed, the picker dispatches the container back to the multishuttle buffer. It should be noted that in order to further increase speed and efficiency, picked items can be placed directly into shipping containers.


Automatic Guided Vehicles


In recent years a new generation of Automated Guided Vehicles (AGVs) has come to market with flexibility improvements that make them much more suitable for DC deployment (working alongside workers on the floor), including GTP case (and piece) order picking as well as basic transport functions. These advances include much more sophisticated controls, allowing flexible and dynamic movement paths, and in some cases “optical” guidance systems that enhance adaptability and safety.


The following are two relatively new AGV technologies first introduced at MODEX 2016:

  • AutoGuideĀ® introduced its TV1000 compact low profile AGV that features a highly reliable magnetic induction navigation system that’s quick to install and easy to maintain.
  • IAM Robotics introduced its fully autonomous mobile picking robot which when integrated with a WMS, recognizes SKUs with onboard RapidVisionā„¢ and navigates the DC to find, pick and fill customer orders.

AutoStore GTP Solution


GTP single-item picking delivers products to a static pick station. The picker removes the products, which are then added to a specific pallet or tote order. Swisslog’s GTP picking solutions are based on proven principles to boost efficiency, maximize storage space and make it virtually impossible to pick the wrong product and/or quantity. Ideal for e-commerce and retail warehouses and distribution centers, Swisslog’s automated GTP solutions improve throughput and minimize inventory control, resulting in a simplified, streamlined picking process.

Multishuttle GTP Solution


The automated Multishuttle GTP technology is especially design for high volume distribution environments. The following provides an overview of a typical automated multishuttle operation:


Incoming goods are transferred from the receiving dock to work stations where operators open master cartons and deposit selling units into standardized totes. Totes are then transferred to conveyors for automatic transport to induction points at a storage buffer. Each induction point has a vertical lift that transfers each tote to its vertical storage level within the storage buffer. Storage is typically random since the intent is to workload balance the aisles and levels in the system.


A storage buffer is essentially a 1-deep or a 2-deep racking system that provides storage for totes (or trays or cases). Each aisle in the system is the width of a multishuttle vehicle which is about 38". The multishuttle is like a 4-wheeled go-cart that travels back and forth on rails within the level of an aisle within the storage buffer. Thus if the storage buffer has 10 vertical levels of storage then each level can have its own multishuttle carrier so that there are 10 vehicles working concurrently within a given aisle. This provides a 10-fold higher throughput capability versus having one ASRS miniload machine working all vertical levels within an aisle - which is why multishuttle technology is a high capacity solution. In fact, more than one multishuttle carrier can work concurrently within a vertical level hence throughput capacity can be even higher if required.


When outbound orders are released, the multishuttle carriers work within their level to extract totes from their storage locations. The multishuttle carrier is equipped with a pair of extractor arms that reach into the storage location to pull the tote/tray/case out of the rack and into its belly. Once the tote is transferred onto the carrier, it is transferred at speeds of up to 787' feet per minute to a drop-off point at the end of the storage aisle where a vertical lift then takes the tote down to one of several picking work stations. Totes/trays/cases are pulled in the exact sequence that is needed to optimize the needs of the customer orders being processed.

At the picking work stations, operators perform order picking from the incoming product tote to one or multiple orders. The fastest picking productivity is to have one order being picked at a time, but this may not always be practical so there are multiple configurations that support 6 - 24 orders and even put-walls to be picked concurrently using put-to-light technology. Depending on the configuration, operators can achieve upwards of 400 - 1000 order lines per hour pick rates. Once the product tote is picked, it is pushed off and automatically transferred back into the storage buffer. The next product tote is presented to the operator within 1 second of this transaction. This process is fast, extremely accurate, and ergonomic by design.

There are companies using this technology to ship 50,000 - 100,000 order lines per day from a high density storage area. What makes this technology appealing is its ability to support very fast order turnaround times for industries where this is a critical requirement.


In addition to high capacity it is flexible in that the multishuttle carriers can work across multiple aisles and vertical levels so that they are NOT captive to an aisle/level. The risk of failure is minimized since a carrier that needs to be maintained or repaired can easily be placed onto the vertical lift and lowered to floor level such that a spare unit can immediately be put into action - no single point of failure. Lastly, no batteries required since the system is powered by bus bars and therefore, no downtime for battery charging - so the system works 7x24x365.


Multishuttle technology is being deployed in the following applications:

  • Manufacturers are storing products into the multishuttle system prior to shipping as a means to provide faster order turnaround time thus enabling extended order cutoff times for better customer service.
  • Retailers handling high volumes of split case merchandise with the goals to maximize labor productivity and accuracy; and to ensure that the heaviest totes are always sequenced to be at the bottom of the pallet.
  • Distributors seeking to maximize space utilization, efficiency and order fill rates.
  • Companies seeking a high security storage environment for products that are of high value or are highly secure (e.g. pharmaceuticals).
  • Companies that are dealing with high SKU proliferation and/or high growth rates where there is a need for system scalability since these solutions can easily be expanded in height, length or width.

Editors Note: Part 1 and Part 2 of this presentation is not intended to be a complete representation of all available Goods-to-Person technologies. The best opportunity to learn more about these technologies, along with many other order fulfillment technologies, can be found at: MODEX 2018 in Atlanta, GA April 9-12. You can check it out and register at




While GTP technology offers shippers many excellent benefits it may not be the best order fulfillment solution for every SKU - particularly fast movers. However, GTP does not have to be an either/or situation. Deploying a combination of order fulfillment technologies may be the best strategy to obtaining the best overall system performance.

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