Why Are Unit Sorters at the Heart of Successful eCommerce Order Fulfillment Centers?

eCommerce is expected to become the largest retail channel in the world by 2021. Its distribution requires meeting tight delivery schedules and quick turnaround times. eCommerce Order Fulfillment Centers move a wide variety of items from storage to shipping to meet customer demands at the fastest speed possible. Keeping the automated distribution machinery running efficiently requires the highest levels of sortation accuracy, with the proper speed and precision to avoid jams, recirculations, and product and equipment damage. eCommerce in the U.S. and Canada, combined, will be the largest channel in 2020, accounting for 16% of retail sales.

It is no secret that Operation Managers, VPs of Operations, Directors of Order Fulfillment, etc. are finding themselves living with excessive stress levels. The companies they work for are demanding faster and faster deliveries. Why? Because people like you and I are now used to ordering online almost anything we need. From paper clips to clothing and electronics, etc. Not only are people increasingly ordering Online, but we want it faster and faster. In other words, eCommerce order fulfillment is making the life of the DC operations people miserable. These operations people could be compared to those working at the control tower of most major airports. They make a living under constant high-pressure. The reason? If they don’t deliver accurately and on time, the shoppers will immediately complain, sometimes even to the point of venting their “frustration” on social media. This could become a nightmare to any company and would open the door to potential loss of customers...something modern retailers cannot afford to do.

The Current Situation at the DC Level

Companies dream about perfectly fulfilling all digital orders. What makes the perfect order? We could define it as the one that is accurate, leaves the DC on time, and is profitable. However, it is not an easy task to deliver eCommerce goods on time, accurately and also make a buck along the way (especially this last criteria). The DCs keep increasing in size because of eCommerce operations now demanding the storage of individual pieces to be delivered to people at their homes, instead of a truckload of boxes destined to stores, as was the case a few years ago. The modern DC or Order Fulfillment Center requires more and more people for the operation. This in turn makes the operation inaccurate, slower and expensive. It doesn’t matter how many times the operation is rearranged. The math just doesn’t add up. There is a point where if the volume of the goods grows, adding more and more people to the operation only makes the handling per unit more and more expensive. And if the DC already has some traditional material handling equipment, this equipment is not as useful as it was when performing for the previous traditional operation. Currently with eCommerce, proper automation is needed every step of the way. Otherwise, the operation eventually, and sadly, will be condemned to fail.

The Supply Chain in a Nutshell

Let’s take a quick look at the typical supply chain of a common type of retail product. Let’s say shirts. Containers leaving Eastern Asia on barges or large ships come with hundreds of thousands of shirts in many different styles, colors, sizes, etc. All of them have as a destination the different ports of entry of many countries. In this case, let’s say specifically Los Angeles. At this port, the containers are transloaded to flatbed trucks or the boxes are transloaded to a truck. Then the merchandise is taken to a cross-docking center nearby where all the boxes coming in different trucks enter at the same time through the inbound doors. They are all mixed up as they move across the many conveyor lines in a fluid operation that never stops. They are all sorted out eventually. Then the boxes leave through the different outbound doors toward the many different destinations, such as: Dallas, Memphis, Chicago, etc.

From there they go to the different distribution centers or order fulfillment centers, either owned by the brand or their retailers. They will arrive by train, airplane or roads to the DCs or omnichannel or eCommerce order fulfillment centers. At their arrival the boxes are open, merchandise is put away and orders are fulfilled as they come. A person goes and picks up the merchandise. The shirt(s) get to the shipping station and they leave through the outbound doors on a truck own by a last-mile delivery service such as USPS, UPS, FedEx, etc.

This was a very simple example. The supply chain operation can actually become very complex every step of the way. But the story does not end there. For every 10 shirts leaving the DC on eCommerce orders, at least 3 of them will return for whatever reason. That will be thousands of shirts coming back. This is another issue for the Order Fulfillment Centers that, if not addressed properly, could be a nightmare in no time.

Can the Traditional DiCe Make the Cut With eCommerce Order Fulfillment?

In our simple case I made it sound like a very easy operation at the cross-docking point and at the distribution or Order Fulfillment Center point. The truth is, both are very complex operations requiring proper study. Otherwise, the operation will take a serious hit on the finances of the company, and from many fronts. For instance, you could have too many people generating little pockets of idle time because only a few of them fit on the same isle at the same time when trying to do the picking. This slows down the operation as a result. Scaling up traditional systems will take a lot more space, and may not necessarily help to increase accuracy or speed. And then there are the returns- enough said.

In an ideal world, the brands would like their merchandise to be continuously moving until it reaches the final user. This, of course, would save storage space and avoid large quantities of sitting stock. In the real world, however, it doesn’t work like that. Factories produce according to seasons, and people order seasonally as well. The purchases that people make and the goods produced by factories are not synchronized events. In other words, factories are manufacturing at least 6 months in advance. For example, during the summer or spring seasons the factories are already manufacturing the clothes for the next winter. People mostly will shop for winter clothes at the end of the fall and all the way through the winter. Goods on their journey from factory to user will have to stop somewhere along the way. The common points for these stops are the DCs or Order Fulfillment Centers. As explained above, for this reason, the DCs and Order Fulfillment Centers are growing larger and larger. They have to store hundreds of thousands of different SKUs, and in many cases thousands of items for each SKU. When customers order online, yes, the fun begins!

How the Magic Happens

How are these ever larger and larger Order Fulfillment Centers coping with the hundreds of thousands of products they need to move and dispatch every day? To be competitive and efficient, you will find at the heart of the most efficient DCs around the world today a very special and brilliant machine: THE UNIT SORTER. They come in different forms, shapes and sizes, but they all do one thing very well- they sort the goods at the unit level very fast and very accurately. Usually they have one or several induction points, as well as one or many exit points after going through the diverts. But, unlike a robot that must be serviced and programmed by experts, and usually enclosed in a cell (because until now they are still too dangerous to put alongside people in a DC), in many ways the unit sorter machines are the total opposite. They allow for the perfect balance between people and automation. A unit sorter system can be relatively easy to use and manage. Users quickly learn how to make the most of it, and eventually they cannot live without it. It becomes the DC operator’s best friend. It is a great resource for the operations manager or DC general manager, and an invaluable asset for the VP of distribution and order fulfillment. After adopting a unit sorter, this valuable group of people can take a vacation from time to time...finally!

What is a Unit Sorter, and How Can I Get One?

Unit sorters are systems (machine hardware plus software) with the ability to classify individual items accurately and at high-speeds. These systems can bring incredible efficiency to an operation and can dramatically and positively impact the total throughput in a DC. 

Unit sorters fit perfectly with an eCommerce operation, but don’t be fooled into thinking its use is limited to online orders. Depending on what kind of system you adopt, it could also be used for retail distribution or a combination of retail and eCommerce.

There are many kinds of sorter technologies capable of accommodating almost any retail product out there. Below, at the end of this article, I am adding a table with the common sorting technologies used at different stages in the supply chain trip of a typical eCommerce product.

Let’s explore some of the typical unit sorting technology.

One of the first factors to consider in sortation is the nature of the goods to be handled. This includes the dimensions, weight, shapes, fragility, packaging, surfaces and materials. Both the selection of the sorter and the design of the chutes and sort lanes will be influenced by the product characteristics. Throughput is another factor in the selection and design of a sortation system. Throughput requirements should account for daily volumes, hourly peaks, seasonality, operational times and forecasted business growth. It should be recognized that the sustained average operational throughput will be substantially less than the sorter’s machine capacity, as it is affected by a range of variables, such as: availability of product, workload balance, product dimensions, staffing, supervision and believe it or not, barcode quality.

Besides product and throughput, it is essential to understand the number and nature of the sort destinations. The number of destinations is typically directly related to the number of stores, orders or delivery routes to be serviced. With building and land space becoming increasingly scarce and expensive, optimizing space efficiency and layout flexibility is becoming a significant solution driver.

If we go back to our example above, what kind of unit sorter would be needed at a cross-docking operation? Remember, unlike a warehouse, which offers storage, a cross-dock is a high-performance rapid transit point that, in theory, does not provide storage. Although cross-docks have been studied with some thoroughness, what has not been seen clearly is that a cross-dock does not operate in isolation, and therefore it cannot be optimized independently from the upstream and downstream processes. To be successful, cross-dock optimization makes demands for high performance on all members of the supply chain in terms of speed, effective planning, high reliability, near error-proof processes and a high degree of transparency, visibility and information-sharing.

A Tilt-Tray Sorter would be a good solution for our cross-docking case above. Why? Because Tilt Tray Sortation systems are used by high volume shippers and can be designed as packing or shipping sorters, or both. These systems are often employed where many gates or destinations are needed and in applications with heavy volume requirements. Packages can be manually or automatically fed onto the trays and with multiple in-feed and induction areas can achieve the highest possible sortation capacities. In-motion scales can be incorporated into the automatic inducts to add check-weight and parcel manifest capability. Another advantage is that Tilt Tray Sorters are fast, versatile, quiet, and simple to use. Tilt Tray Sorters could also be used for order assembly, outbound shipping, and return goods. They are some of the longest-lasting, most efficient and flexible means of sortation in the distribution industry. Carriages usually can tip to the right or left direction.

The Omnichannel DC

Flexibility is critical when it comes to automation. With so many changes in the marketplace (and especially as eCommerce continues to shape new trajectories for technology and infrastructure integration within the distribution center), companies must be able to adapt.

Companies and suppliers are constantly improving automation processes. The challenge is working together to drive higher throughputs, more accurately, with less of a footprint and for less cost. One key is flexible automation. For example, leveraging a unit sorter to handle both e-commerce and retail replenishment in a DC. Sharing inventory can save valuable space and financial resources.

In our example above where I mention the different stages a shirt must go through the supply chain, at the order fulfillment center level now, a handful of sorting technologies could be used. I will concentrate below on two super-trendy technologies that seem appropriate for solving the challenge.

Bomb-Bay Type Sorter

This flat sorter, as the name indicates, is a high speed automated sortation machine capable of handling lightweight items. These items would be too small and lightweight to be handled by a typical conveyor system. Such items might include: bagged garments, jewelry, pharmaceuticals, cds, mail, books, and small parcels. It opens the bay doors (trays) as they pass through the designated location.

In a bomb bay style sorter, the goods fall into either a carton ready to ship, a chute for further processing, or totes, etc. Each drop could be a store location, an eCommerce order, or a destination for items that will have an extra sortation step, such as with put walls, etc. It is a closed loop that can turn left, right, up or down as needed.

These sorters can be engineered and designed to fit tight warehouse spaces. It requires induction points where operators or automated induction systems drop the item into a passing tray. The system knows the destination because it either reads the item on the fly as it was presented for placement into the tray, or as it was carried on the trays as soon as it was dropped. This reading process allows the system to match item to destination and will instruct the machine where the bays need to be open and where the item needs to be dropped. Additionally, bomb bay sorters have unique benefits when there are space constraints in a facility. These sortation systems typically have hundreds of sort locations making these sorters rather long. However, they do make good use of space and can fit into very narrow spaces because the sort locations are positioned directly under the sorter track. These flat sorters are usually a smart solution that provides speed and accuracy, offering the flexibility of traditional cross belt and tilt tray technologies.

Pouch Sorter Systems

The pouch sorter is a very complete unit sorter. It adds storage and retrieval functionality to the sorting operation. It uses powered systems and gravity to transport, sort, and buffer items in the DC. This unique solution carries pouches handling a limitless variety of products such as flat-packed apparel items, shoes or other goods. It is an efficient buffering and sorting solution for single items. However, with software customization it could handle more than one item per pouch of the same SKU, becoming a true ASRS system. How brilliant is that? 

This solution works with either manual or automated inducting stations. It has storage areas and sorting buffers. And eventually, as needed, it delivers the goods manually or in an automated fashion to packing stations, reducing the human touch to a bare minimum, allowing for substantial savings in labor payroll. This system also shines with the pesky returns. The time-consuming sortation procedure before bringing the returned items back to the warehouse is down to zero with a pouch sorter system. They just need to be inducted again into the system. If the returned items are ordered again, they can be quickly retrieved at any time.

The pouch sorting system has a high throughput rate, good accumulation properties, and amazing three-dimensional mobility. For the eCommerce retailer, the pouch sorter is a highly efficient, accurate and affordable solution to store, sort and move items. But its flexibility does not end there. It is possible and relatively easy to expand due to its high scalability. It makes financial sense for progressive automation because it becomes attractive in small and medium-sized configurations, and it is perhaps the best choice today for very large eCommerce operations.

What Should Emerging eCommerce Companies or Well-Established Retailers with Fast Growing eCommerce Operations Do?

Given the countless directions in automation that a company could take, and the large assortment of unit sorters out there, every automation project becomes unique. Whether it is turnkey or progressive automation, there is no standard manual for how all companies should approach automation,—with one caveat. Companies and their people managing their DCs need to visualize and focus on the big picture so they don't back themselves into a corner. Automation mistakes could be expensive.

For more information about how to approach your eCommerce order fulfillment project, please contact me.