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How to Convey Poly Bags & Envelopes

Ecommerce has driven new, smaller, oddly-shaped packages, which may challenge distribution centers

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poly bag package

The shift from traditional retail to ecommerce is accelerating, and with that growth there are both challenges and opportunities for order fulfillment operations. Companies that spent decades perfecting retail distribution (large, bulk orders to a network of stores) are shifting toward direct-to-consumer shipments that are orders of magnitude more difficult to manage.

Among other things, this means that ecommerce companies must focus on optimal packaging. At Modex 2018, an industry expert panel including Hytrol’s Boyce Bonham discussed these issues.

The shift to ecommerce will change the way you fill orders

Customers like near-infinite selection, which is easier to post on websites than it is to fulfill in a complex distribution operation. Customers enjoy convenience, which means DCs essentially act as shoppers, picking and packing orders that were selected off retail shelves in the past. Customers love home delivery, which means the supply chain must fill thousands of small orders rather than many fewer bulk orders shipped to retail.

All sectors of ecommerce are growing, from food to office supplies to apparel to electronics. All of these items need to be packaged for shipment, which profoundly affects order fulfillment.

The demands of dimensional shipping

For decades shipping was mostly about weights.

For less-than-truckload shipping, freight classes attempted to cope with the size of the item, but for parcel delivery, weight was the key factor. Light packages, even larger ones, were less expensive to ship than a heavy, small package. In recent years, the industry has shifted to “DIM” pricing, which is calculated using package length x width x height vs. the weight of the package. This has made it imperative for shippers to reduce package sizes.

For ecommerce retailers, it’s become critical to reduce package sizes, ship more product and less air. This has resulted in innovations that build packages based on the size of the load on the fly. Some shippers expanded the number of cartons in their systems so they could use the smallest possible parcel for the order. Others have gone to the poly bag for soft goods or other appropriate items.
Plastic chain conveyor and poly bag

Enter the poly bag

If you receive packages at home, you’re seeing fewer cartons and more bags. This has sent ripples through the order fulfillment systems of many companies.

For shippers, finding ways to reduce the size of an outgoing package may shave off millions in needless costs. The less “air” in a package, the less it costs to send to a consumers’ front door. Poly bags are increasingly used to deal with these issues. The conveyor industry predicts that 60% of products will be shipped in bags this year, and that 30% of the sensors in current distribution centers will need to detect them.

The challenge is not just how to convey these bags, but how to sort them — and how to scan them within a fulfillment system

Other items that are now being conveyed include blister packs, bottles,  padded envelopes, cylinders, tubes and others.

Adapting to new package types

The shift to these new package types doesn’t mean existing infrastructure can’t be adapted to handle them. In fact, we deal with companies who successfully ship to both retail and consumers in the same operation. Versatility is critical in the age of ecommerce, so a successful operation must be able convey, scan and sort all types of products. You should also count on the mix changing in the future. Can your current operation evolve as needed?

Conveying issues for bags and other loads

It can be difficult for a system to correctly convey a variety of package sizes and types. Many ecommerce operations ship a variety of loads, including poly bags, cartons, envelopes, blister packs, tubes and other odd shapes.

transition between conveyor belts

  • Transitions between conveyors and machinery can be difficult for bags, which don’t feature the predictable surfaces that cartons or totes. This can be overcome with planning, conveyor specification and design
  • Small item containment: Your conveyor will likely need guard rails and guides that it did not when it had to handle only totes or boxes, in order to handle the variety of loads
  • Package bottoms that aren’t uniform or rigid. This is very common with bags or blister packs. Combat this by conveying on belts or using tighter roller centers
  • Conveyed poly bags have a tendency to stick together or ride on each other in accumulation systems. This usually means you will need belted accumulation. You should also tend toward zero-pressure accumulation, as it creates more product separation at critical points. Finding points that separate these bags is critical to efficient conveying
  • Product alignment is more difficult with bags, as it may hide bar codes from scanners. This is also a function of less predictable weight distribution and size, which may make sensing leading or trailing edges more difficult. Weight distribution isn’t uniform, which can also challenge certain packaging and conveying systems. This means you may need more camera-based reading technology rather than simple scanners
  • Inclines and declines: Conveying various loads on incline and decline conveyors may present different challenges. Since poly bags tend to be lower profile than most cartons, they aren’t a major risk for tumbling, but they may present other issues transitioning onto incline conveyors. Cylinders, even in bags, tend to roll. You can designate package lifts, vertical conveyors and other solutions if you convey these types of loads

envelopes stacking on a conveyor system belt

Sortation challenges for bags and envelopes

As mentioned earlier, many of the issues you will have with irregular packages come down to sorting.

  • More destinations: Typically you’ll need to sort to more destinations in the age of ecommerce. You may have a variety of packing areas, ship areas or automated packaging machinery to which you must distribute loads
  • The need for speed: Speed is critical in ecommerce, so your system will be asked to sort faster and more accurately than ever. It’s critical to understand the rate of speed for your sorters as you build ecommerce distribution solutions
  • Irregularity is a way of life: Irregular items such as small packages, bag, jiffy packs and envelopes are more difficult for certain sortation methods and may require new approaches
  • Diverting more frequently than ever: You will often need to build more diverts, closer to each other, in a system
  • Sensitivity and vision: Sorting requires fast, accurate ways to identify the package and send it on its way. Due to the size, shape and irregularity of bags, different scanning approaches may need to be taken for correct identification
  • Single line orders are taking over: Single-line orders drive the need to ship out more packages per minute, which stresses many conventional sortation methods and creates pressure for you to ship more lines per minute to beat customer deadlines

Final thoughts

Many companies who are fulfilling to retail have already been forced to re-tool due to ecommerce demands, and that’s not slowing. The growth will continue over the next decade, as consumers and businesses move toward the convenience and economies of scale. This means that the packages you can convey today are likely to become smaller, more diverse, less regular while demands for speed and accuracy ramp up. The good news is that sensors, conveyors and reading technologies are all being built out to meet the demand.

If you need solutions as you transition towards building an efficient order fulfillment system, contact us today.

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Order Fulfillment System

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.

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