Other Voices: Optimizing WES with integrated order consolidation

Editor’s note: The following column by Kristian Toft, vice president of automation technology and IT, Beumer Group, is part of Modern’s Other Voices column, a series featuring ideas, opinions and insights from end-users, analysts, systems integrators and OEMs. Click here to learn about submitting a column for consideration.


The rise of e-commerce continues to impact the retail industry, upending buying habits, marketing methodologies, brand management, customer expectations, selection, delivery and customer service.

Drastic changes in retail have forced drastic changes in the supply chain. The increasing percentage of e-commerce orders needing to be fulfilled from distribution centers and warehouses demand new concepts for modifying existing warehouse systems to satisfy both retail store replenishment and individual delivery-to-customer requirements. Operations that have turned to warehouse execution systems (WES) should consider implementing an integrated order consolidation approach, leveraging loop sortation.

Integrated order consolidation (IOC) creates a framework for a modern, efficient and cost-effective packing system that provides long-term solutions for new market requirements and an astonishing ROI. It addresses three challenges: order cycle time, average number of items per order and order accuracy.

In the days of mostly store replenishment, the time between receiving and shipping an order was much longer and order sizes were significantly higher. Traditional pick and put-to-light systems, and high-speed, high-capacity loop sortation systems could adequately fulfill orders, with order accuracy less critical.

E-commerce growth has challenged the pure order consolidation capacity of current picking and packing systems. Increases in distribution center capacity, the daily volume of orders and smaller orders are challenges. Today’s enormous retail distribution centers are supplying a vast number of SKUs. And volume has climbed dramatically with companies needing to fulfill e-commerce orders with a much smaller average unit count.

Numerous companies have leveraged high-speed loop sortation systems to meet logistical challenges. Some have added smaller unit or shipping sorters at an existing facility to maintain a single inventory and maximize footprint productivity. Others left old operations for greenfield facilities with high-speed loop sortation to process both retail and e-commerce orders on the same system.

Today’s high-speed sorters have advanced control systems that intelligently maximize sorter utilization and adapt to the specific operational preferences. IOC takes advantage of these capabilities, providing the same reliability and sort efficiency, but with the ability to handle tens of thousands of orders quickly and efficiently.

Integration combines primary and secondary sortations without extra input, data exchange or product transfer. It also combines the handling of all order types from single-item orders to very small, medium-sized and very large orders.

Dual-pass consolidation approach
With dual-pass sortation, pick waves are sent through the sorter twice, and there are dedicated primary and secondary induction areas. As with all dual-pass systems, the sort capacity must be two times the unit capacity. Additionally, most dual-pass systems require some manual transfer of product between primary and secondary passes.

The double-capacity requirements and manual product transfer are key limitations of the dual-pass approach, likely increasing labor costs and reducing sortation productivity.

Fully integrated order consolidation
The IOC concept implements the total sort process in close vicinity of the sorter, eliminating the need for any tote transport between sort phases, or for sending orders through the sorter for a second sortation.

The objective is to achieve consolidation of all orders at the sorter, so mostly complete orders–and the occasional incomplete order–leave the area in shipping cartons or totes. This does not necessarily include final packaging or adding dunnage, but every order should be completed and ready for shipment. The integrated order consolidation concept works with both waved and waveless systems.

Primary sort process
The primary sort process is a pre-sort dividing the pack wave into multiple segments called put waves. With the integrated system, some segments of the sorter can be assigned to final order consolidation for fast-track orders, either directly at the sort destination or at dedicated put walls.

The integrated concept combines different sort methods seamlessly, driven by configuration parameters and allowing real-time changes to the sort and packing process. One important feature is that the primary sort uses information from the secondary sort to optimize the overall process.

For pre-sort purposes, sorter destinations will be simpler and fewer than for a traditional packing sorter. In most cases, there will be a mix of destinations receiving single or multiple large orders, and destinations collecting items to be post-sorted in a put wall. A well-designed put wall can be integrated to serve as the principal system for accomplishing the secondary sort.

Secondary sort at the put wall
The secondary sort takes place immediately at the destination of the sorter in a way that facilitates an efficient and ergonomically optimal packing process.

A wall of cubby holes is placed alongside the sorter, with a narrow aisle between the chute face and shelves. An operator roves back and forth, picking units from the chute and scanning barcodes. A put-to-light (PTL) display will indicate in which cubby items must be placed.

The sorter control system will attempt to discharge a unit closest to its final put-wall destination. If that destination is blocked, another chute in this segment may be used.

The most efficient design for this put wall is one that is open on both sides, with the “putter” filling the cubicles in the wall, and a “packer” pulling product and loading it into the shipping container.

Performing the secondary sort at the chutes vastly increases the possible pick wave size. The put system can be designed with different size cubbies, allowing the sorter control system to pick the appropriate destination for a given order size.

On the pack side of the wall, the PTL system lights up the cubby for completed orders one at a time. If necessary, several lights can be lit if the order is too big for one cubby. The text display at each cubby will convey special handling instructions.

Put walls perpendicular to the sorter
In this variation of the final sort, put walls are placed perpendicular to the sorter track. The benefit is that the secondary sort system is no longer limited by the track, providing for a larger pick wave.

Integrating the final sort in the sorter control system will allow put waves to overlap such that the next put wave will be assigned to a put wall when a certain amount of cubby holes have been assigned and packed out. It is possible to have the put wave assignment be influenced by the availability of the secondary sort positions such that the put wave assignment becomes continuous and fluid.