Warehouse/DC Operations: Conveyors and sortation turn up the volume
Modularity and ease of maintenance enable the latest conveyor systems to sustain maximum uptime.
November 01, 2013
To meet the needs of the high velocity world of e-commerce, conveyors and sorters must be a smart, fast, and efficient component of a production or order fulfillment engine. Driven by the need for flexibility, speed, and maximum uptime, customers are turning to a new generation of technologies—and new ways to minimize and optimize conveyor and sortation solutions—that enable nimbleness while cutting costs.
“A successful warehouse now is about flow control and pulling levers at individual processes to keep the whole facility in balance,” says Lance Anderson, director of sales, sortation, and distribution for Beumer Corp. “Going toward this sort of ‘flow control’ requires less conveyance and more flexible conveyor technologies that can re-route things in creative ways.”
E-commerce could reasonably be credited for the dismantling of conventional thinking about conveyors. When automated materials handling systems were first introduced years ago, they were a way to move things easier and faster without back-breaking labor. “Equipment got its start handling large items,” says Tim Kraus, product management supervisor for Intelligrated. “It’s now shifting to smaller orders, smaller items, and piece handling instead of full cases. Conveyor and sortation designs have evolved to match this shift.”
But the evolution of conveyors extends beyond the multi-channel paradigm. Product tracking and visibility is becoming essential to many operations, and the pressures to do more in less space are universal. Conveyors therefore must be intelligent, more reliable, and less maintenance-intensive—all while collecting data about product movement at every opportunity. Trends in packaging such as the increased use of poly bags can also challenge conventional conveyors, even as new solutions allow for the effective handling of a wider variety of materials.
Similarly, sortation technologies have traditionally worked best with predictable packaging in large volumes. But as everyone from Amazon to Mom and Pop work to achieve speed, efficiency, and visibility, sortation solutions become more scalable, reliable, and flexible. And because downtime is not an option, new sortation systems are built with redundancy and ease of reconfiguration in mind.
“I see the industry, with e-commerce and parcel handling, going toward lots of smaller, single-line orders,” says Mitch Johnson, director of systems development for Hytrol. “It’s changing the way we think about sortation. We used to think about sorting faster and in higher quantities. Now, it’s better to be able to sort smaller things and greater numbers of orders.”
The conveyor industry is seeing an increased interest in 24-volt or motor-driven roller technologies according to Johnson, who says 24-volt systems are now Hytrol’s No. 1 product. Unlike traditional conveyor, these new modular systems don’t rely on centralized, hardwired controls to direct the system components. Instead, the intelligence driving each conveyor segment is distributed throughout the facility. Paired with intelligent software, these technologies allow smart routing, energy efficiency, and the ability to easily rearrange modules or sections of conveyors and sorters with minimal disruption.
“Each 24-volt motor has a circuit board with embedded intelligence,” says Johnson. “Each conveyor segment can look at upstream and downstream traffic, communicate with other segments, make decisions on the fly or send detailed information to management. The more we can move the brains from a distant location to a very specific location, that’s a direct increase in flexibility.”
A brainy circuit board might be located every 30 inches or 10 feet, depending on the application, and decisions are made on the conveyor rather than 500 feet away on a panel. Each segment can then adjust speed, monitor the movement of label-free product, or activate diverts. This modular approach enables easy installation and reconfiguration as well as more targeted diagnostics. Management can respond to precise areas if problems arise, and the intelligence of each motor can provide proactive information about wear rates or other potential issues.
Intelligent circuit boards at each section of the conveyor or sorter also send data back to the equipment supplier, who can remotely monitor wear indicators to reduce unplanned downtime. The ability to monitor the overall flow of a facility in real time is also a powerful tool for efficiency and uptime, according to Ken Lento, strategic business unit manager for unique products for FlexLink.
“People will say they achieved 85 percent efficiency in production and consider it a victory,” says Lento. “But they can’t explain why they lost the 15 percent because they’re not gathering the data. Now, they can start to analyze when and why a conveyor was down and how long it took to reset. They can respond and react in real time instead of looking at a report the day after.”
The management of real-time, case-level data throughout a warehouse is driving the development of mobile solutions for managers, according to Mike Khodl, vice president of solution development for Dematic. For example, a manager can use a mobile app to see if voice-enabled pickers are meeting standard rates, while another screen can illustrate sortation rates, conveyor status and overall productivity. “They can remotely see the flow of a system,” says Khodl. “Traditionally, they might focus a lot on the physical flow, but not on the data flow that goes with it. Now they are one and the same.”
Sorting it all out
When people think of sortation systems, many envision a massive 600-foot linear shipping sorter with dozens of inducts and destinations. Just as with conveyors, says Khodl, the tendency now is to work with point-solution sortation systems. “Maybe you want a divert point for a replenishment process or inside of a pick module,” Khodl says. “You now have the ability to drop a modular sorter component into a standard conveyor in an hour or two. In the past you couldn’t do that without open-heart surgery.”
In the midst of the e-commerce boom, unit sortation systems designed to handle eaches are more common. Whatever the size of the sorter, this equipment plays a critical role in speedy, intelligent product movement. In a flow-based facility, any downtime of any step in the process will disrupt the entire fulfillment engine. Therefore, sorters are increasingly geared toward scalability, redundancy, and ease of maintenance.
Scalability is essential when working to cost-justify a sortation system that will meet peak seasonal demand while scaling back for the remainder of the year. During peak volumes, the sorter might direct totes to temporary stations with specific packaging or value-added specialties. “Off-peak, one order might go to a multipurpose station where it is packed to an outbound shipper right there,” Anderson says. “That’s one touch instead of three. That sort of flexibility is one of the ways to justify this capital equipment. Putting in a sorter that extends the life of a building is never as expensive as a new building or a third party.”
On the induction side, sorters can get bogged down when workers are paired one-to-one with inducts. The first person in line will always have an empty tray, whereas the fifth person might have to wait for an opening. Instead, five workers could continuously induct into short segments of conveyor that feed the sorter continuously, ensuring a balanced workload and optimal use of sorter locations. If fully automatic induction is not viable, this semi-automatic approach to induction is gaining popularity, according to Stephen Cwiak, vice president and general sales
manager for Interroll.
On the discharge side, sorters might feature double- or triple-level destinations that transition between batches. Between the sorter and the packer, a divider door stops product from flowing down until the order is ready. This also ensures a steady workload while taking up less space by stacking orders vertically instead of linearly. “What tends to be forgotten is how many cases per hour you can induct and how many you can close,” says Steve Schwietert, vice president of integrated systems sales for TGW Systems. “Closing is the choke point and can drop rates from 1,000 cases per hour to 500.”
To further minimize downtime, two sortation loops might be layered on top of one another, says Cwiak. This also addresses issues of SKU proliferation, as one sorter might be designed for larger, heavier items while a second handles smaller items.
Or, one could handle fulfillment while the other handles returns. If either goes down for any reason, the second sorter can take up the slack, providing redundancy and continuity of operations. Additionally, new sorter systems allow for quick repairs to individual trays or belts even as the rest of the system continues to operate.
Handling whatever may come
With the intelligence and flexibility to react to changing volumes, conveyor and sortation solutions must also adapt to changing product characteristics. Piece handling lacks the predictability of cases, and can be difficult or impossible to manage with conventional conveyor systems.
“The industry is reaching out to things previously considered non-conveyable,” says Johnson. “Cartons are a cinch, but bags of dog food or grass seed, for instance, have been a problem in the past. The more you can convey those things, the better the return on investment.”
This might include the deployment of specialized conveyor zones for certain product types, a process made easier by modular systems. Non-rigid items like poly bags or envelopes also prefer more continuous conveyance surfaces to prevent jams, Cwiak says. Belts are therefore replacing rollers in certain applications.
New sensor technology must also work with conveyors to detect irregular items. “A carton’s front and back edges are easily and consistently detected,” says Intelligrated’s Kraus. “With something shaped like a pillow, you have to detect where it starts, ends, and comes in contact with the rollers.”
Similarly, sortation technologies must allow for gravity in the case of light products sliding from tilt trays, or sensitive systems for the smooth discharge of light items from a cross-belt or sliding shoe sorter. “I have seen customers successfully adapt a sliding shoe sorter to sort poly bags, which was previously considered a recipe for disaster,” says Schwietert. “But people are starting to stretch the limit of what was thought of as a no-no.”
Maintenance is also a concern, says Johnson. “In the near future, each conveyor section might have a specific QR code label, which you could scan with a mobile app to pull up everything about the conveyor, or even order the parts right from there.”
Schwietert says 24-volt rollers tend to be easier to service, taking only five minutes to change as opposed to as much as an hour when working with a drive and reducer. He adds that in sortation systems it is now possible to add or move a divert without system downtime. “Say you have four diverts for UPS, and the next day you want to add four for FedEx. That doesn’t need to be disruptive.”
Another way to minimize disruption is to plan ahead. Traditional conveyors feature fixed guide rails, heights, and widths. New systems—that can also be retrofitted to make use of existing conveyor—use adjustable guide rails to make for quick manual transitions or even software-directed automatic transitions.
“In the past, if you wanted to switch products on a length of elevated conveyor, you would have to use a ladder, deactivate the equipment, and complete the change in a day or two,” says Lento. “Now you can go to a control panel and switch over an entire line in a matter of minutes.”
“A lot of customers ask for solutions based on what they’re doing today, just to get the line running,” Lento adds. “It’s always more expensive to make changes later than to do it during the initial project. And who today knows what their packaging will look like in two years?”
The impact of conveyors and sortation on downstream logistics
Whether to serve e-commerce or not, service levels and responsiveness are critical, and are rooted in the efficiency and nimbleness of production and fulfillment operations. Smart conveyor and sortation systems contribute to balanced product flow through a facility, but their impact doesn’t stop at the dock door. In fact, the dock is a good place to gauge the effectiveness of upstream processes, because minutes and seconds count when working to meet shipping deadlines.
Mike Khodl, vice president of solution development for Dematic, says even the smallest ripples in product flow can become big problems by the time orders reach the dock. “A simple jam on a merge somewhere can cause a batch to not meet its shipping cutoff time,” Khodl says. “With smart conveyors, all those real-time interaction points are now available to help an operator control his destiny before he’s in a situation he can’t recover from.”
Traditionally, managers would look at equipment for operational data, then at the warehouse management system for inventory information. “We’re working to bring harmony to all of that info to control the warehouse in a different way, and conveyors play an important role,” Khodl says. Conveyors can even begin to impact labor management when paired with increasing levels of visibility into individual worker performance. “If picking is an hour ahead of shipping, that’s a sign of inconsistent flow through the warehouse. When conveyor and pick rate data is overlaid, it allows the movement of labor from one module to another,” says Khodl, “or conveyor speed can increase for one hour to move product out of picking, then slow back down with no manual intervention required.”
From a maintenance perspective, Khodl says every conveyor and sorter product should offer a 15-minute average time-to-repair window, including the induction belt, sorter motor, or photo eye. “To change out a belt in the past could take two hours to four hours. Quick-access modularity means four screws and a lever, and you can pop in a new belt in 15 minutes.”
The multi-channel challenge involves using creative conveyance and sortation techniques to allow a common inventory to serve multiple outbound processes.
“If you’re trying to blend five lines of flow into a single sorter, you have to be sure the sequence of events at a specific dock door are managed properly. It’s not just about bulk movement of cases onto the sorter,” says Khodl. “You need to be smart and fast, not just fast.”
Smaller, modular sorters come into play in a multi-channel methodology, enabling some product to be routed direct to the trailer and some through packout or value-add to a cart for UPS, Fedex, DHL, or all three. “What’s changing is we are being forced to be more dynamic in our shipping process depending on the type of outbound flow,” Khodl says. “Say suddenly you want to do quality control checks for a new e-commerce approach. You can drop in a small module to pull one in 10 cases to QC. Use a tablet to perform the check, and no hardwired terminal is needed.”
Once product reaches the trailer, the right picking approach, software and sortation solutions can ensure the product is properly sequenced for quick loading of the trailer and optimal utilization of the space. “In transitioning to a well-balanced facility, you can take three trailers a week off the road for each store the DC serves,” Khodl says. “That obviously has a huge impact on transportation costs.”
Track and trace capabilities are also critical to effective shipping. Sorters and conveyors that monitor product movement become an important piece of that verification.
New twin DCs feature two unique sortation systems
When Germany-based Adidas Group purchased British-based rival Reebok in January of 2006, the company decided to examine its combined U.S. distribution network. When consolidating DCs, the company installed a range of customized sortation systems to handle 18,000 units per hour.
The new campus in Spartanburg, S.C., would become the largest Adidas Group distribution site in the world at more than 2 million square feet. Two DCs, set on a 258-acre site, receive and ship hundreds of thousands of units of footwear and apparel each day. DC1 handles apparel and provides value-added services (VAS), such as hangers and price tags, while DC2 handles footwear and hard goods.
According to facility manager Bob Henriques, planning for the DCs began with three overall goals: improving service levels, reducing operating costs and preparing for future growth, particularly in e-commerce. “Our direct-to-consumer business is growing significantly,” says Henriques. “The ability to fulfill these types of orders was an integral part of our planning process.”
The company selected a system integrator and an equipment supplier to develop specialized conveyor and sortation systems. Two custom materials handling concepts were engineered. For poly bags and irregular garments, a “waterfall” induction in DC1 replaces manual sorter induction with a gaylord dumping system. Belt conveyors then lift garments into induction stations nearly 20 feet overhead. A “domino” system for DC2 uses conveyors to singluate shoe boxes into the cross-belt sorter. Boxes are manually inducted in groups of as many as eight at a time, oriented vertically on edge, like a domino. The boxes are then toppled one at a time onto the incline conveyor to the sorter.
In DC2, full cases of shoes are distributed to workstations in a round-robin pattern. The company completes emergency waves (e-waves) two or more times per day, once in the morning for those orders that were placed after 3 p.m. the previous day, and once around 4 p.m. to fulfill the guarantee of same-day shipping response.
Another key difference between DC1 and DC2 is how and where individual cartons are packed. The unit sorters can sort both apparel and footwear, up to 18,000 units per hour, and are very similar in each DC. In DC1, totes are packed off the unit sorter and sent to the mezzanine level for packing and VAS. Because footwear in DC2 requires significantly less VAS, cartons are sorted directly from the chute to a final shipping carton.
After a carton is complete in both DC1 and DC2, it is then transported through the print-and-apply area, where boxes receive up to three labels. Cartons move onto the central packing merge and are routed to shipping via a sliding shoe sorter. In both shipping departments, Adidas has the ability to load parcel, less-than-truck (LTL) or full truckload (TL) trailers. Each DC’s shipping area also processes consumer and associated returns.
The adidas team was able to bring both DCs online on-time and on-budget. “We are happy to report that we’re meeting our productivity numbers,” says Henriques. “Our savings are on track as calculated and we improved our service levels.”
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