Sortation System Types, Applications & Benefits
Sortation in the order fulfillment, warehousing, materials handling, and ecommerce industries has come a long way in the past years and decades. In the past, operations had few options outside of manual sorting, today’s businesses have a multitude of potential automated solutions that can boost efficiency, drive down labor costs, and fatten the bottom line.
Whether your operation is still reliant on more manual processes or you’re simply using an aging sorter and in need of an upgrade, it can be challenging to cut through the noise and select the best piece of technology for your needs.
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Below, we’ve gathered information that you can use to make a more informed decision about whether or not automated sortation is right for your operation, including the different types of sorters, their various applications, and the cost factors you should consider before pulling the trigger.
Table of Contents:
- What is Automated Sortation?
- Benefits of Automated Sortation
- Sortation System Applications
- Sorter Types
- Case Sorters
- Unit Sorters
- Case & Unit Sorters
- Alternatives to Traditional Sortation: Autonomous Mobile Robots
- Sortation System Cost Factors
- Choosing the Right Sortation System for Your Needs
- Is Automated Sortation Right for You?
1. What is the sorting process?
Sortation is the process of identifying items on a conveyor system and diverting them to a specific destination within an operation, such as different types of packing stations or parcel carrier doors.
While manual sortation relies on human workers to identify and divert items as necessary, automated sortation leverages a variety of technologies, such as barcode scanners and other sensors, to accomplish this without any associated human intervention.
Modern automated sorters vary substantially depending on the underlying technology upon which they are built. Sensors, means of conveyance, and method of diverting can all be tailored to an operation’s specific product handling and throughput needs.
2. Benefits of Automated Sortation
By automating and optimizing the low-value and easily repeated task of sortation, it is possible for an order fulfillment operation to realize substantial benefits, including:
- Less walking and double-handling of orders
- Fewer growth constraints tied to lack of labor availability
- Overall reduced labor costs
- Optimized picking strategy
- Streamlined packing operations
- Improved order accuracy
- Faster order processing
- Increased order volumes without adding proportional labor
- Fewer accidents
- Less broken or damaged product
- More efficient use of floor space
- Possibility of reclaiming unused vertical space (depending on model)
3. Sortation System Applications
When it comes to sortation, picking tends to get all of the attention, and with good reason—automated sortation can go a long way in optimizing your order fulfillment system for the modern realities your operation is facing. But that isn’t the only application it is well-suited for. Below we discuss how automated sortation can be used (including picking) in the order fulfillment environment.
Leveraging automated sortation during the receiving process can help you more efficiently process inventory as it enters your operation, granting you increased inventory visibility. Some receiving-focused applications sortation can augment include:
- Return Processing: If enough information about the return can be provided (referenced by the Carton ID barcode), cartons can be sorted to specific stations where the return can be handled most efficiently. Once the disposition of the goods has been performed, items can be automatically sorted out for destruction, return to vendor, putaway into stock, or immediately sorted to a location where the product will be used to fill an open order.
- Putaway: As mentioned above, a receiving system is a very efficient method of removing floor-loaded cases from the trailer and then sorting the cartons by SKU so they can be palletized with one touch prior to being put away in reserve storage.
- Cross Docking: For just-in-time inventory to active orders in need of consolidation. Ready to ship product such some hard goods can be routed directly to shipping, and individual units can be conveyed in a tote to an order consolidation area.
When considering a sortation solution for your receiving needs, you will need to know the following:
- The number of inbound trailers that will need to be unloaded simultaneously and
- The number of destinations that will be required to sort out the inbound work for putaway or other processing.
This information will help you determine the best equipment and system layout for your needs.
B. Picking & Packing
Order picking and packing are the most labor-intensive tasks that any order fulfillment operation will face. For operations using manual picking strategies, this means that human workers are walking the floor to pick items and put them into orders for processing, which is expensive—in terms of both time and wages.
Medium- and high-volume fulfillment operations can leverage an automated sortation system to augment or completely change their picking strategy to help your workers become more productive. If workers are no longer concerned with sorting or transporting orders, they can stay within a particular aisle or zone, waste less time traveling, and complete more picks within the same amount of time, leaving the sorter to direct the flow of goods where it needs to go for packing and shipping.
High-volume ecommerce operations can pick individual or full cases of units for many different orders in large batches (100-200 orders per batch) and let a unit sorter divert and consolidate them into discrete orders. Once the last item arrives for an order the system will alert an operator to pack the order and send it to shipping.
Similarly in a medium volume operation, orders can be picked into totes and then a sorter can be used to consolidate multiple totes of an order from different portions of the picking area. These will arrive in the same pack station so that they can be packed into the same carton, or to route split case orders to specific types of packing tasks based on the type of shipping container required, ie. polybags, cartons, gift wrapping, etc.
When considering a sortation solution to leverage for your picking and packing needs, you should be aware of the following:
- Minimum and maximum product and shipping carton sizes and weights
- The number of packing stations required
- The different types of packing stations required (repackaging, bagging, gift-wrapping, labeling, etc.).
After orders have been picked, and packed, the next logical step is for them to be shipped. An effective sortation system used at this critical step can allow orders to skip parcel hubs—called zone skipping—by presorting groups of orders that allow for fewer days in transit and an all around shorter total order cycle time and a lower freight cost, which means more orders processed in a given timeframe and happier customers.
Orders can be sorted by LTL, small package, or carrier/service method. When selecting a sorter for your shipping needs, you should know the minimum and maximum size and weight of products to be handled, the volume of your peak hour of shipping, and the number of pallet build locations required for your operation or the number of trailers that will need to be loaded simultaneously.
4. Types of Sortation Equipment
Generally speaking, automated sortation systems fall into one of two broad categories: Case sorters, which work by sorting and transporting whole cases, totes, or orders of product from one location to another within a facility, and unit sorters, which work by sorting and transporting individual items throughout a facility. (Some sorters can handle both units and cases and we’ll let you which ones below)
5. Case Sorters
Case sorters can help you reduce the number of manual handling required to process orders and shipments, reducing total order cycle time and allowing you to put your labor resources to better use performing functions that add value to your operation.
A. Pop-up Wheel/Roller/Belt Sorter
The pop-up wheel sorter consists of wheels, rollers, or belts embedded in a belt conveyor which “pop up” to lift or transfer items at a 30- or 90-degree angle to another downstream conveyor. They are best suited to handling uniform products, such as items in a tote or carton, making them an excellent option as a packing sorter.
Throughput for pop-up wheel sorters typically falls somewhere in the range of 40-100 cartons per minute.
Pros: Pop-up wheel sorters require a relatively low investment of capital compared to other higher capacity sortation systems. The system is modular, allowing for sections to be added and removed quickly as needed, and it is reliable.
Cons: This type of sorter has a low to medium sorting rate, which can limit the maximum throughput for an operation. Operations which handle very small or light weight cartons, or unevenly-weighted cartons, might want to test their products before considering a different (more expensive) type of sortation solution.
B. Pivoting Arm Sorter
A pivoting arm sorter, also called a paddle sorter, consists of one or a series of pivoting arms, which are placed along a conveyor. When activated, the arm pivots into place, effectively diverting and sorting a case onto a secondary takeaway conveyor. Pivoting arm sorters are widely leveraged in a shipping sortation environment (especially baggage and parcel handling).
Throughput for pivoting arm sorters typically falls somewhere in the range of 50-100 cases per minute.
Pros: This variety of sorter can be relatively inexpensive compared to other solutions. For an operation that handles and processes cases of the proper size, they can be incredibly effective and reliable.
Cons: Pivoting arm sorters are generally best suited for operations handling cases. Polybags, common in ecommerce operations, can get caught under the blade of the arm and cause damage or downtime. Because product is diverted somewhat forcefully, these sorters are not well-suited for very fragile items.
C. Pusher Sorter
Pusher sorters consist of one or a series of pneumatically-actuated pushers mounted to a belt conveyor. When signaled, the pusher extends at a right angle to the conveyor, positively diverting a case or tote onto a secondary conveyor or chute for further processing. These sorters are commonly used in packing and shipping.
Throughput for pusher sorters typically falls somewhere in the range of 10-30 cartons per minute.
Pros: These relatively simple machines offer positive diverts at an economical price. Poor carton quality and unevenly weighted product is easily handled by this type of sorter.
Cons: Pusher sorters are not as gentle or as fast as other sortation options, such as sliding shoe and pop-up wheel sorters, limiting the volume of products or orders that they are suited to handle. High growth rate operations may want to consider a different sorter if their projected growth will exceed this sorter’s range.
6. Unit Sorters
Unit sorters will empower your operation to realize tremendous gains in efficiency throughout the fulfillment process. Many, though not all of these technologies, are sometimes referred to as “loop sorters” because of their orientation and the fact that they commonly form a circular loop.
A. Tilt-Tray & Crossbelt Sorters
Tilt tray and Crossbelt sorters are each their own unique type of sorter, but due to certain similarities that they share, they are often discussed side-by-side. They typically share the same type of undercarriage and drive mechanisms.
A tilt-tray sorter consists of trays mounted to a series of carts linked together into a train of trays, which carry product and run in a continuous-loop.
There are one or more induction areas where product is introduced to the trays and sort destinations (typically chutes) where discrete orders are consolidated. As necessary, these trays “tilt” to transfer the product they are carrying to the appropriate chute. Items can be either inducted manually or automatically onto the trays via induction stations at one or multiple locations throughout the loop.
A crossbelt sorter sorts items by diverting products into a chute. The key difference is the mechanism by which it achieves this. While a tilt-tray consists of a tray, a crossbelt consists of a miniature belt conveyor that runs perpendicular to the floor of the loop. When the belt is activated, it transfers/pushes the product off of the loop conveyor into a chute or take away conveyor.
Both systems are often leveraged in high volume batch order fulfillment sortation and shipping sortation. They are especially popular in the ecommerce apparel industry.
Throughput for both tilt-tray and crossbelt sorters typically falls somewhere in the range of 100-200+ cartons per minute.
Pros: Tilt-tray and crossbelt sorters offer the highest sorting rates when compared to other sortation systems. They are also capable of handling a diverse range of product types, making them ideal for operations which handle many types of product. Low noise levels make for a safer and more comfortable working environment for personnel.
Cons: The biggest drawback to these sorters is cost. They typically have the highest price when compared to other sortation systems. They also do not necessarily handle fragile product well.
B. Push Tray Sorter
A push tray sorter consists of trays mounted to carts, which carry products and run on a continuous-loop conveyor. The key difference is that while tilt-tray sorters tilt and rely on a gravity chute in order to divert product, a push tray sorter leverages a push bar to divert product.
Throughput for push tray sorters typically falls somewhere in the range of 30-60 cartons per minute.
Pros: Because it doesn’t send product down a gravity chute, a push tray sorter typically offers a gentler form of sortation compared to the tilt-tray, making it better suited for operations handling more fragile goods. They can also be more cost effective compared to tilt-trays or crossbelts.
Cons: Though gentle, the push tray comes with a slower rate of sortation, which can be too slow for operations which require higher throughput.
C. Bombay Sorters
A bombay sorter, also known as a flat sorter, consists of trays that act literally as trap doors (the technology takes its name from the bomb bay found in military aircraft) which open to drop product. The product can either be dropped into a gravity chute for further manual sortation, or directly into a shipping carton or tote . These sorters are primarily used in the apparel, jewelry, and pharmaceutical industries.
Throughput for bombay sorters typically falls somewhere in the range of 100-230 trays per minute.
Pros: Bombay sorters offer high-speed unit sortation at a more cost-effective price point compared to tilt-tray and crossbelt sorters. They are also more efficient if product can be sorted directly into a shipping carton, greatly reducing packing time and labor costs.
Cons: These sorters are best-suited to handling small products, and are not typically capable of handling a wide range of product sizes and types. They generally do not handle cases very well and do not run as fast as tilt-tray and crossbelt sorters.
D. Pouch/Pocket Sorter
A pouch/pocket sorter consists of a series of pouches/bags which hang from an overhead trolley (one bag per trolley). They are often used in picking operations, where items are picked into the pouches in batches (one unit per pouch). Some pouch sorters can store product in carousel type loops where products can be automatically pulled for orders. This functionality makes them a great choice for returns processing. As SKUs are returned they can be put in the storage loops until a large enough volume of one SKU has been accumulated, then pulled out automatically to be boxed up for put away in storage.
These sorters are often leveraged in the apparel and general ecommerce merchandise industries. Most have a weight limit of 10 pounds or less, though certain models can handle goods up to 20 pounds. They can handle hanging and flat apparel, small hardgoods, and shoe boxes.
Throughput for pouch/pocket sorters typically falls somewhere in the range of 100-120 pouches per minute.
Pros: In the right operation, pouch/pocket sorters can be a highly effective means of sortation for a range of applications. They can also handle a wide range of product sizes and types; typically anything that can fit into the pouch can be effectively sorted. They can also sequence product packing so that heavy product is presented first to go on the bottom of the carton and lighter product last to go on the top. Products can be sequenced in style, color, size to expedite put away in a retail store.
Cons: While pouch/pocket sorters can handle hard goods effectively, they are not well-suited to handling fragile items or excessively large or heavy items.
E. Garment-on-Hanger (GOH) Sorter
A garment-on-hanger (GOH) sorter is in many ways similar to a pouch/pocket sorter, except instead of pouches, the overhead trolley conveys garments. They are primarily used to process and ship garments and apparel faster, and with greater accuracy, than manual or other forms of automated sortation.
Induction to a GOH sorter is achieved manually or automatically by adding a mechanical device that synchronizes a screw conveyor with the hooks, which delivers the hangers to the hooks as they pass through the induction area. The induction process can also be integrated with an automatic trolley stripper. The garment-on-hanger sortation system has a variable speed controller, allowing the operations to optimize the travel speed of the garments, as well as the induction rate.
Pros: For an operation primarily concerned with garment sortation, the GOH sorter can be a highly effective means of sortating, buffering and sequencing. This can lead to reduced manual labor costs, decreased processing time, increased order accuracy, and overall fewer errors. Additionally, the mechanics of the system allow for the delivery of store-ready products without creasing.
Cons: GOH sorters are truly limited to garment sortation. So organizations having multiple types of products will likely need a consolidation system further upstream prior to shipping.
7. Case & Unit Sorters
In addition to the technologies outlined above, which fall squarely into either the case sorter or unit sorter category, there are others which can be utilized as either a case sorter or a unit sorter depending upon the needs of your operation.
A. Sliding Shoe Sorter
A sliding shoe sorter is a long straight conveyor. It has two chains on the outside that carry perpendicular aluminum slats. On top of the slats ride “shoes”. The shoes are plastic blocks. Cartons ride on top of the slats and the shoes are aligned to one side of the slats (opposite side to the divert lanes). Underneath the slats are switches, one at every divert location. Once the product reaches the point at which it must be diverted off of the sorter, the switch is activated, pushing the product off the sorter to the correct divert lane.
Sliding shoe sorters are traditionally used to handle cases, but with the growth of ecommerce, manufacturers of these systems have increasingly modified them to handle things like polybags as well. They are often used in packing and shipping applications.
Throughput for sliding shoe sorters typically falls somewhere in the range of 100-300 cartons per minute.
Pros: Sliding shoe sorters can handle a wide range of product types and sizes, despite originally being used primarily for cases. They are also incredibly flexible in the applications they can be utilized in. Because of the diagonal motion generated by the shoes as they slide to divert product, these sorters are gentle, especially compared to other solutions.
Cons: This type of sorter is expensive compared to narrow belt sorters, but less expensive than loop sorters. Although diverts can be added at initial installation for future diverts, it is impractical to add diverts later.
B. Narrow Belt Sorter
A narrow belt sorter relies on a set of narrow strip belts to carry the product. Narrow belt sorters come in two varieties: One with a 90-degree divert (NBS-90) and one with a 30-degree divert (NBS-30). On the NBS-90, a series of high friction rollers mounted between the carrying belts raise above the carrying belts to engage the product and divert it off of the sorter at a right angle. The NBS-90 is especially suited to allow for sortation of product directly into a shipping gaylord/container without any manual intervention..
On the NBS-30, fixed-angle wheels rise up between the carrying strip belts and divert product off the sorter at a 30-degree angle. Throughput for an NBS-30 typically falls somewhere in the range of 30-100 cartons per minute, while throughput for the NBS-90 falls somewhere in the range of 10-50 cartons per minute.
Pros: The narrow belt sorter is an incredibly flexible and economical sortation solution. The sorter is quiet, and uses minimal energy.
Cons: Although Narrow Belt sorters are flexible, they are not best used with all types of products and all rates. Very small cartons (6” or less) or those that are unevenly weighted at high speeds are not the best handled. It is also not typically used above 100 cartons per minute.
Alternatives to Traditional Conveyor Sortation: Autonomous Mobile Robots (AMRs)
While the technologies listed above are primarily what comes to mind for most people who are considering automated sortation for their operations, they are not the only options that exist. Autonomous mobile robots (AMRs) are another solution for high speed sortation with the most flexibility and scalability.
Depending on the specifics of your operation, it may be possible to leverage anywhere from a handful to a full fleet of AMRs to supplement or replace your existing sortation operation. It requires a minimum amount of low cost conveyor and can be installed in almost any location in your operation.
Advantages of Autonomous Mobile Robots
Whether or not leveraging AMRs for sortation makes sense for your operation will depend on the specifics of your business. That being said, for the right business the technology can bring benefits like:
- A reduced investment in floorspace
- Increased flexibility and ease when it comes to reconfiguring the system
- Increased redundancy and reduced risk of operation-wide shutdown
The TiltSort-Bot Sortation Putwall AMR is just one of many potential solutions. This system is available with a tilt tray or crossbelt models that runs on a triple level table or dual level mezzanine configuration. It provides not only agile and high density, but a cost effective alternative to conveyor solutions.
The Hi-Tilt-Bot AMR provides either tilt tray or crossbelt models that provide a quick and expandable sortation system utilizing sort to bins or gaylords. Because the system requires induction stations and standard warehouse flooring. The system can be expanded, reduced or moved quickly and easily. The Hi-Tilt-Bot can be used for either items or parcels or a combination of both.
If you are interested in considering an AMR-based sortation solution for your operation, an AMR Proof-of-Concept program like the one that Conveyco offers can be an excellent way of testing the waters before fully committing.
Sortation System Cost Factors
One of the most common questions that we hear from businesses considering automated sortation for their operation is this: How much is this going to cost?
Unfortunately, there is no single number that rings true across the board; the final cost of implementing a sortation solution can and typically does vary substantially from operation to operation.
That being said, there are a number of factors which will impact the cost of your sortation system. Understanding these factors and how they may impact your budget can make it much easier to choose the right sortation solution for your budget and your own unique business challenges. These cost factors include:
- The length and size of the system: The longer and larger your sortation system is, the more it will cost to put in place. This is due to both the cost of materials, as well as the labor costs associated with implementing such a system.
- The type of sorter: Different sorter types operate in different ways, typically by leveraging different mechanisms or components. Generally speaking, the more complex the core components of your system are, the more expensive the system will be.
- The number of diverts or destinations: Related to both points above, the more diverts or destination your system requires, the more expensive it will be, due to both material costs as well as engineering costs.
- Required throughput: Systems with higher handling rates require additional conveyor to buffer product and specialty induction systems in order to optimize the gap between cartons as they enter the sorter and optimize capacity.
Choosing the Right Sortation System for Your Needs
As demonstrated above, you’ve got many different options when it comes to selecting an automated sortation system for your operation. If you are unsure of the specific type of sorter or technology that makes most sense for you, it can help to ask yourself questions like:
- What challenges or operational goals are leading you to consider automated sortation to begin with?
- Are there any other technologies that might be better suited to helping you reach these goals?
- What is the specific application (receiving, picking, packing, shipping, etc.) will the system be supporting within your application?
- How might the characteristics of the product you handle (size, weight, dimensions, rigidity, fragility, etc.) impact sorter selection?
- What is your required throughput?
- Do you anticipate substantial operational growth in either the short- or long-term which will need to be accounted for?
- How many destinations or diverts are required?
- Do you have any space considerations (such as a small footprint) within which the new system will need to fit?
If after answering these questions yourself you are still unsure of which sortation system is best suited to addressing your needs, a systems integrator can help you analyze your existing performance and determine the best path forward for your business.
Is automated sortation right for your operation?
Ultimately, the answer to this question will depend on a number of factors unique to your business and the industry that you operate within. Your operational goals, your current and expected future level of growth, your business cycle, and the level of capital available for investment will all play a role in determining whether or not automated sortation makes sense for you. Speaking with a trusted systems integrator can help you answer this and other questions around automated sortation.