Stretching pick-to-light

Pick-to-light and put-to-light solutions with hardwired lights are widely used because they’re effective at helping operators efficiently and accurately pick smaller items at a fast rate.

That’s the plus side of traditional, wired systems. But they do have a downside, led by a fair measure of inflexibility, in that it takes time and cost to install new systems or reconfigure existing ones. But wired pick-to-light modules and put wall solutions wouldn’t be so widely used if they weren’t effective.

“There are some opportunities where pick-to-light just really stands out,” says Chris Bratten, software sales manager at Bastian Solutions. “Being an independent integrator, what we’ve seen is that if you have a very small pick face—a lot of locations in a small area—pick-to-light is highly effective because there’s little travel involved, and the majority of the task time is on location acquisition, which is where lights really help.”

Other providers agree that light-directed solutions are efficient for dense pick faces because the illumination shows operators where to pick from or put to, as well as other information such as item quantity to pick. “Lights are a fast, visual and reliable way to pick,” says Ed Nabrotzky, director of sales and strategy for Panasonic Logiscend.

Hardwired pick-to-light systems have been around for decades. Improvements have been made with the light hardware, adds Bratten, such as light bars that span the width of module, and can have their locations reassigned to new SKUs with software. Some vendors of light-based technology also offer wearable rings that allow light systems to detect and distinguish between different operators, which enables integrated operator tracking, notes Bratten.

The downside is that traditional lights require wiring, and not just electrical, but also communications cord and networking. This need for infrastructure makes traditional pick-to-light systems harder to scale up across many areas of DC, says Seth Patin, founder and CEO of Accelogix, a provider of software-driven warehouse automation consulting services.

“If you have a small area where there is not an extensive amount of physical travel, lights can be fast and effective, but if your operation wishes to branch traditional pick-to-light across many areas of larger facility, it becomes expensive because of the wires and networking. As a result, traditional lights can have a limited scope in terms of the user company being able to justify their deployment across broader swaths of an operation,” Patin says.

However, light-directed solutions are evolving and gaining flexibility in multiple ways. Some light-based solutions have gone wireless, using small electronic tags that run on batteries. Some vendors offer vision-picking solutions that make use of augmented reality (AR) glasses to mimic the functionality of wired lights, using the AR glasses to superimpose light-based directions over physical locations.

Lights have also gone mobile, showing up on carts and on some types of autonomous mobile robots (AMRs) used to assist human pickers. Finally, various types of automated storage and retrieval systems (AS/RS) and fixed, goods-to-person fulfillment systems use lights to direct activities at operator workstations. Consider all of these incarnations as a stretching of what lights can do, while building off the speed and accuracy of lights as a means of directing work.

This light-driven pick face uses wireless e-tags, which removes wires from the setup and makes the system easily reconfigurable.

Wireless e-tags

Some vendors such as Panasonic Logiscend are making use of e-tags that communicate wirelessly with inventory software using Internet protocols and wireless gateways. The e-tags have small batteries that can last for five or six years, making them easy to install or reposition.

They light up and display information much like a hard-wired system, but are easier to set up and reconfigure, says Nabrotzky, making them more adaptable for rapidly changing SKU mixes, or in manufacturing, where the trend toward mass customization has increased the need for flexibility and speed in establishing “supermarket” pick areas for line-side replenishment.

“Where traditional pick-to-light has a problem is in its setup time and inflexibility,” Nabrotzky says. “That is where a wireless, visual system is the next step.”

Within Panasonic Logiscend’s solution for materials management, including picking, the wireless tags are placed on bin, rack or shelf locations. With a transmitter above, these “VIEW” tags communicate with Logiscend’s software to provide visual cues and instructions to operators. “One transmitter can talk to a whole bunch of tags,” says Nabrotzky. “You are able to direct your pickers using these wireless tags and their e-label displays, and update your product or part numbers dynamically.”

Users of the wireless pick-to-tag approach from Panasonic include a subsidiary of Daimler Trucks North America. The company replaced a paper-based Kanban system for parts replenishment with this solution.

One thing wireless pick-to-tag holds in common with wired pick-to-light, says Nabrotzky, is that the visual user interface is quick to learn for new operators. “You just follow the cues on the tags,” he says. “If your operation faces high turnover or hires many temporary workers to take care of peak seasons, you should consider a visual system.”

Go virtual with glasses

Another twist on traditional light-directed picking modules or put walls is using AR/smart glasses to superimpose virtual light cues over a shelf location. The lights display in the glasses, which does away with the infrastructure burden of traditional lights, says Patin, whose company implements a vision-based solution called LogistiVIEW.

With simple bar code labeling of shelf/cubby locations, supporting software from Accelogix and AR glasses from vendors such as Vuzix, Patin says fulfillment centers can rapidly deploy these AR-based vision picking solutions. Companies that have deployed the LogistiVIEW vision-picking solution include CooperVision, a medical device manufacturer.

“The AR technology allows you to create virtual lights by having the operators simply look at a shelf, which is really just a standard shelf with some bar code labels to identify locations,” Patin says. “A lot of times, the bar codes are put on small magnets, allowing them to be easily moved around to different places. For larger scale deployment of light-directed solutions, the AR and vision-based approach is dramatically less expensive, and far more flexible than traditionally installed lights.” So, for example, creating a new shelf just requires printing additional bar codes on labels. Once the data is set up and the bar codes are in place, the system can direct tasks.

Smart glasses can pair up with wireless, wearable scanners, and offer the ability to provide voice-based instructions, or other visual instructions besides light cues. “You’re not just getting a virtual put wall or virtual pick-to-light capability; you also have the ability to include the best of RF scanning, and the ability to provide additional text, images or work instructions using the glasses,” says Patin.

Empowering goods-to-person

Lights are also leveraged in goods-to-person automation, including automated storage and retrieval system (AS/RS) solutions with ergonomic work centers where human operators carry out tasks with the help of the lights.

Visual light cues are an ideal way to show operators where to pick goods from, especially with solutions such as vertical lift modules (VLMs) that use fairly large trays holding many items, says Douglas Card, director of systems and integrator sales at Kardex Remstar.

“We use lights because it’s all about productivity and accuracy for the operators,” says Card. “Especially when you get into solutions like VLMs, there may literally be hundreds of pick locations on a single tray, so you don’t want to have the operator hunt and peck to locate the right items. With lights, we illuminate the position and show them exactly what to pick and where to pick it from.”

AR glasses are enabling “virtual” pick- and put-to-light functionality.

Depending on the type of AS/RS, different lights are used. Some use light bars that can convey other information such as quantity, while others with large trays may have laser pointers to illuminate the correct locations with a light beam from above. Over the years, these lights have improved their ability to convey more information and to define SKU locations using software, says Card.

With Kardex Remstar’s solutions, adds Card, a more recent innovation is lights that support color-based picking. Color-based picking combines several orders into one batch that can be simultaneously processed using a team-picking approach.

“You can have multiple operators working in the same zone at the same time, and it’s all based on color,” says Card. “For example, you could have a red picker and a green picker, and when the operators start to pick from the machine, they press a button that tells the system, ‘I’m the green picker,’ or ‘I’m the red picker,’ and then they turn to the batch station where order totes are lit up in either in red or green to direct the work.”

Color-picking with lights allows an operation to be more flexible and scalable with automation, says Card. “We can configure these systems so that when the operation is not that busy, the system can run with a single operator, and as they get progressively busier, we can introduce a second, a third or a fourth operator into the process, and they can all be picking simultaneously, under the direction of this color technology.”

Kardex Remstar also deploys two other color-based workflows, says Card. One is based on assigning different colors to different AS/RS machines, and using totes with corresponding colors. Another scenario is cart-based color picking, in which carts are assigned a color, and operators travel down an aisle and the machines that have picks for that color cart will light up with the corresponding color.

The innovation with color-based picking is not so much the lights themselves, but in the software logic that batches and governs the workflows by color, so more operators can be using the same AS/RS capacity and processing more orders.

“It gives you scalability,” says Card. “In this world of e-commerce, you can have significant fluctuation in terms of the throughput level you need to get out of your system. With this color picking technology, if 80% of the time you don’t need that maximum rate, you could run it with fewer operators and fewer batches to keep your labor costs down, but when you do have bigger spikes, you can scale up to handle those peak periods.”

Taking lights mobile

One of the most widely deployed types of AMRs are collaborative AMRs that assist human pickers in order fulfillment. Cloud-based software is typically used to send robots to workers to optimize the associates’ pick paths, reducing walking time and increasing value-added picking or replenishment time.

Once at a location to perform picks or put items into a location to replenish the forward pick area, collaborative picking AMRs typically use light technology to direct associates.

Fergal Glynn, vice president of marketing with 6 River Systems, says its mobile robots, called “Chucks,” use lights on the sides as a primary user interface, complemented by additional instructions such as product images that can be shown on Chuck’s flat panel display.

“Pick-to-light is proven technology,” says Glynn. “The default is to think about lights as being on static shelving, so we’ve taken that idea and built lights into the design of our robots because the technology is easy to learn for new associates, and when you are directed by lights at a location, it makes the tasks faster and highly accurate.”

An increasingly common incarnation of lights is on collaborative mobile robots. Between lights on the shelf structure and flat panels to convey additional information, associates have clear visual guidance on pick or put tasks.

The Chucks have LEDs built into their sides to illuminate the cubbies or locations on each Chuck at the appropriate moment, Glynn explains. “When doing replenishment, the lights are showing the person which container to pick an item from to place it at the location on the shelf, or if they are picking from the shelf, it’s lighting up the area on the Chuck that is the correct location to put that product,” Glynn says. “It helps with both the accuracy of the task that’s being performed and the speed it is performed.”

The Chucks also use a flat panel to convey additional information, such as product images. However, when picking smaller items at operations that don’t have images of the items in a pick zone, the lights on the Chucks are the primary user interface. “The lights make it obvious to the associate where to put the item they just picked from the shelf,” says Glynn.

6 River Systems also offers a light-enabled “mobile sort” solution that includes smart kiosks, mobile put-to-light walls with validation sensors that work with the company’s Cloud-based software, and its Chuck robots. The mobile sort walls and kiosks can be moved, allowing them to be rolled into place to enable batch picking and sorting during peak periods, or rolled out of the way or even moved to another warehouse when not needed.

Lights are turning up in more automation, and in all these solutions, the value is ultimately software driven. The light hardware may present the visuals, but it’s the capabilities within the inventory, warehouse execution or fulfillment software a vendor offers that releases the work, and triggers the lights to do their thing.

That makes examination of the software a key part of a light-directed solution decision. As Bratten observes, “it is the software that is driving the tasks, triggering the lights and messages, and how the system responds to tasks complete.”