Specifying High-Performance Parcel Handling Conveyor Solutions
Flexibility is critical for parcel handling systems
The pressure on companies of all types to continuously ship faster and more efficiently has grown, particularly in the age of increased e-commerce, an extremely tight labor market and Covid-19 restrictions. Increased demand also affects retail distribution as companies work to develop effective delivery channels outside traditional ship-to-store.
The core mission of these operations is parcel shipping–an old art with new twists.
Parcels, packages and carton transport aren’t simple
The challenges for transporting and sorting parcels have changed, but the technologies you can deploy have also improved. The high velocity and variability of these operations are the biggest impacts. You’ll be sorting and transporting parcels to more various internal destinations than ever, and your conveyor system should be designed for that reality.
A diverse set of package sizes and configurations
Because package sizes and types can vary from single envelopes to large, heavy cartons, belts tend to be the choice for parcel applications. Belts support the entire surface of the bottom of the conveyed carton, which also reduces issues with weak, sagging or difficult bottoms with problematic features like staples or folded corners. Belt conveyor’s ability to adapt to most anything you can place on it within its size and capacity range makes it a logical choice. Belts also hold the loads steadier due to friction between the parcel and the belt, which is helpful for incline/decline and general stability.
Read more: Conveyor Belts vs. Rollers
Belts tend to be the best handling option for a wider variety of loads in general transport applications, but may not be as well suited for specific applications. Consider these factors:
- Singulation: Singulators organize bulk flows of cartons into uniformly separated and spaced lines. This organizes parcels to be fed to sorters, scanners, packaging machinery and other functions and is critical for most DCs.
- Gapping: Gapping conveyors create uniform gaps between cartons, and tend to be roller conveyor based. Gapping systems often appear upstream of other advanced functions.
- Curves: Belt curves offer many options and good functionality, but certain situations may dictate roller curves. You may see applications that mix belts and rollers in parcel conveying applications to increase functionality and accuracy. Make sure your curves orient the load correctly; consider belt curves, tapered rollers and tightly centered positioning equipment.
- Sortation: Many sortation options work best with rollers. (See sortation considerations below for details).
Roller conveyors and parcels
In general, rollers tend to offer more ways to manipulate, turn, move and transfer parcels without human interference. You can use them throughout the operation, but for many long transport operations, belts may be more suitable. Belts allow you to convey more sizes, shapes, types and weights on the same system, but rollers give you heightened functionality. Remember that tighter roller spacing is usually needed for varied load types for support and smooth product conveying.
When singulation and accuracy of product placement is important, roller conveyors can be used. Rollers should be placed close together to ensure adequate and smooth transportation of products. To ensure accurate product orientation around curves, tight-centered, tapered rollers or belt curves are your best options.
Read more: How to Convey Poly Bags & Envelopes
Sortation considerations
Whether you’re shipping direct to customers or to outlets (stores, other DCs), transport tends to be only part of the equation. You’ll need to efficiently and quickly sort parcels to destinations. You should detail your plans for acceptable speed and throughput to help you decide where and when sortation is needed.
- Manual sortation can work for certain SKUs and operations. It’s labor-intensive and relies on the accuracy and speed adequate for package volumes. It’s not uncommon to assign slow movers to manual stations in some operations.
- Automated sorting by nature is more expensive (in terms of up-front, but not long-term costs), but offers speed and accuracy that manual operations usually can’t match. It’s more complex to design and integrate, but delivers significant benefits once in place. In today’s difficult labor market, labor is hard to hire and retain, so automated sorting has become more viable for more types of companies. Automated sorters command more of your facility space, which can be an issue for some companies.
Manual vs. automated sortation: a comparison
|
Operational Factor |
Manual sortation |
Automated sortation |
Cost (up-front investment) |
Low to moderate: labor-driven systems are inherently less expensive than any type of automation. Labor systems do involve hiring and administrative costs as well as some equipment investment. |
High: automated sortation systems have up-front costs in terms of software, hardware and installation. They require WMS/WCS integrations and extensive forethought to reach their potential. |
 Costs (maintenance & power) |
Moderate: power for conveyor systems, workstations and lighting require less maintenance than sorters. Maintenance costs are comparatively low. |
Moderate: sortation systems include mechanisms that require service and maintenance. The level of maintenance isn’t onerous, but is a factor. |
Costs (labor) |
High to very high: Depending on the number and type of sortation points, labor costs for manual sortation can be extremely high. The costs include salaries, benefits, administration and more. It’s fair to say that manual sortation is less expensive to start with, but more expensive over time. | Very low: Sortation systems remove the need for people from almost all of the sortation tasks. This also contributes to better plant ergonomics. Automated sortation reduces not only labor costs, but also error rates and quality problems. It tends to lower ongoing operational costs. |
Space utilization |
Good: Manual systems mean the presence of workers, and possibly workstations at sort points. If your workers need space to roam the line, that will factor into overall space planning. |
Moderate: Sorters are naturally larger than straight-line conveyors–but do not gobble up tons of space. Remember that sorters can be placed on overhead lines where they do not take up floor space at all. |
Speed and throughput |
Slow: Your fastest workers can’t equal the speed of today’s high-speed automation. They rely on visual identification of parts and destinations, aside from hand speed and product distribution. |
Very fast: Depending on the load and situation. Some sorters are lightning-fast, while others are relatively slow-moving. The mechanical speed is only part of the evaluation, as software, scanners and identification systems often drive speed. |
Reliability |
Poor to Mediocre: Manual systems depend on the productivity and reliability of employees and managerial processes. Tight labor markets may make them less reliable since the system depends mostly on the presence of personnel to execute work. Lack of workers may reduce the ability to add shifts for seasonal spikes. |
Good: Sorters must be maintained and (like anything mechanical) can break down. They rely on good maintenance processes, spare parts inventories and the presence of qualified personnel to keep them running or respond to problems. Most sorters have excellent and documented uptime statistics. |
Remember to keep your long-term goals in mind as you make decisions about parcel sortation. There are many “right” ways to go about it. This could be your most critical decision as you move the process forward.
Merges, scan tunnels and packaging
One key factor is the ability to create the right gaps between parcels of various sizes and shapes. Any solution must consider the impact of gapping for products that vary from the size of a matchbox to the size of a big-screen television on the same conveyor line. Creating a truly high-throughput system requires thoroughly evaluating gapping and its impact on scanning and sortation.
Truck and dock cubing
When your packing department has completed their work and your cartons have been taped, how do you handle the transition from a conveyor system to truck? Optimized parcel systems transition from a conveyor system to packaging to truck trailers in a smooth, organized manner.
Some companies palletize the cartons and load them with forklifts or pallet jacks–which tends to slow loading, but has a bigger problem: pallets don’t cube the trailer’s vertical space.
For retail or point-of-sale shipments, you may be forced to distribute pallets for fast unloading at the next destination, but if you need to cube the trailer most efficiently, and want to stack cartons individually, a transitional conveyor is needed. These can be flexible or extendable conveyors, which allow you to convey parcels directly inside the trailer for loading and cubing.
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Tags: Automation
Scott Stone is Cisco-Eagle's Vice President of Marketing with more than thirty years of experience in material handling, warehousing and industrial operations. His work is published in multiple industry journals an websites on a variety of warehousing topics. He writes about automation, warehousing, safety, manufacturing and other areas of concern for industrial operations and those who operate them.