You might not ever have thought of it, but Stephen Perry wants you to think of operating your car as a process with variability. “When you’re driving, you have to measure distances visually and adjust as you go by steering or applying the gas or brakes,” says Perry, senior controls engineer Tyson Foods. (Editor’s note: the views Stephen Perry shared with us for this article are his own and not necessarily those of Tyson Foods.)
Drivers must ensure the car stays within lane markers and rumble strips and avoid straying into guard rails (or worse). Full automation, in the form of self-driving cars, is not quite there yet. Partial automation—in the form of lane-departure-warning systems—can provide alerts so drivers can quickly steer back to where they should be.
In manufacturing, the production line is another process with variability—albeit a much more complex one. To stay on track, companies have used Andon lights flashing green, yellow, or red to give a visual depiction of how processes are running. Perry set out to modernize the Andon system at his company to provide a wider array of information shareable by a larger team.
He wanted to build the equivalent of a lane-departure-warning system to help team members quickly take actions that keep the production lines on target, continuously measuring actual quantity and weight against specs, with “far off-target” alerts emailed to key team members.
This is a long way off from the traditional Andon displays that have been stalwarts of the factory floor environment for decades, faithfully showing the status of machinery or process, giving visual cues when quality issues arose. Stack lights—the so-called "Christmas trees” featuring red, yellow and green bulbs—gave way a few years ago to LED lights. Andon displays have been a key element of lean manufacturing.
“Andon displays empowered operators to call for help, stop the line and cure the problem,” says John Oskin, president of Sage Clarity Solutions, which sells Andon software. “That’s one of the tenets of lean.”
But traditional Andon displays only went so far, being disconnected from other devices and limited in their communications abilities. Earlier Andon alerts were triggered manually by a worker using a pullcord or button, and rarely activated automatically by the production equipment itself. The most sophisticated of these systems included a means to stop production so the issue could be corrected.
Now, the rise of smart communication technologies has boosted the reach of Andon displays, making them a fixture of manufacturers’ Industry 4.0 initiatives. Next-generation Andon displays do everything from calculating and showing the efficiency of a production process and overall equipment effectiveness (OEE) to comparing real results with planned results and receiving service requests from stopped machines. They collect data from shop floor equipment and Industrial Internet of Things (IIoT) sensors, sending notices via email or text—accessible via mobile and web—and integrated with enterprise resource planning (ERP) systems.
Clearly on display
Andon systems give production teams an immediate and continuous view into the health of their processes. Perry began thinking of what an updated Andon might look like after it became clear that after-the-fact alerts were no way to keep shop floor processes on track.
“It’s too late to look at production performance during meetings at the end of the shift or the next morning,” says Perry. “You can’t change the past.”
Even intermittent quality checks—done every 30 minutes or every hour, for example—aren’t good enough, as the sample size is too small. To really understand performance, the calculation must include all items, he adds.
With the plethora of technology in use across manufacturing today, people can sometimes forget the shop floor is not yet fully automated. Individual machines are often automated, but, in Perry’s experience, automation of entire production lines is not as prevalent.
He viewed next-generation Andon displays as a way to unite automation and people as a team. New cars, after all, feature lane departure warnings and autonomous braking systems to keep drivers on track, why shouldn’t Andon displays show key-performance indicators and other results to help team members keep the production process on target.
The ultimate Andon display, says Perry, features results that are easy to understand and easy to see from wherever the production team members may be working, like very large font on multiple large displays, for example. “Ease of use is essential,” he says. Things that are not simple to use will not be used. It doesn’t make sense for an Andon display to show complex statistics or elaborate graphs that very few people understand.
Another lesson Perry learned is that if people have to walk anywhere to see the display, then the display will likely be ignored and ineffective.
Finally, to encourage people to look at the Andon displays often, Perry included a little bait. He asks, “When working indoors, what information is important to almost everyone?” To sweeten the deal, his Andon displays include weather so people will know what to expect when they leave their shifts.
Engine for continuous improvement
As did Perry at the food company, Oskin and his team at Sage Clarity Solutions sat down with a blank sheet of paper to imagine the possibilities of next-generation Andon just over three years ago. They quickly decided the way to go was a software-based system that could connect to a variety of devices and equipment types, enabling real-time communication.
Rather than solely focusing on quality issues that need to be corrected, Sage Clarity’s Andon software makes it possible to raise an alarm for reasons of safety, materials, and maintenance, in addition to quality. “Quality is just one part of the organization,” says Oskin. “If there’s a spill on the floor, you want to alert the safety engineer as soon as possible.”
Sage Clarity’s software can create Andon trouble tickets from a smartphone, a tablet, or any other iOS or Android device, initiated both by the human operator and the equipment itself. Manufacturers can choose to run the system on a public cloud, private cloud, or on-premises.
“It’s not just about calling for help, it’s actually addressing problems. You want to catalog the issue and set up corrective actions,” says Oskin.
Next-generation Andon systems boost communication between operators and engineers with a combined system of digital signage on the production floor, Andon lights, and email alerts. Fixing problems without delay helps reduce downtime to boost OEE and quality.
Sage Clarity’s Andon system offers role-based alarms to notify the right person at the right time based on alarm type and location. It integrates with existing Andon lights systems, as well as manufacturing execution system (MES) and ERP systems. Operators can receive alerts on their choice of smart devices with built-in reporting to track alerts over time and response time.
The necessary investment can be quite manageable. For example, you can buy a 60-inch flat-screen TV for about $1,500 and install it in an overhead central location on the plant floor for less than it would cost to buy the legacy Andon LED boards. If positioned well, everyone can see at a glance which tickets are open, how long each has been open, how the line is performing via OEE, and other measures.
Major automation vendors, including SAP, have plant maintenance modules that track production issues, but they typically focus only on maintenance—point systems, such as Maximo, have a similar focus. “They may allow a call for help within their apps, but they typically only focus on maintenance, not quality or safety or materials shortages,” says Oskin. Many of these systems only track “wrench time.”
“But the reality is, if we are generating a machine-driven Andon, we know that the total event was 30 minutes, not 10 minutes of wrench time. It’s the holistic capture of the event,” says Oskin.
The comfort of green lights on the shop floor
Consultancy Device IQ backed into the Andon software market by its involvement a few years back with a manufacturing customer. “They were building large machinery, which required a lot of hand welding,” says Scott Rulong, general manager for the company’s newly minted Shop Floor IQ organization. Each station might take 17 hours to do the job, and the managers were losing track of how much time was being spent. They were having trouble giving feedback to the operators doing the work. Dispatch was another issue, as they often needed a welding inspector to come and give a ruling on quality.
So, Rulong and his partners set out to create a software- and hardware-based systemn. “We had a virtual timer and a dispatch function. Then we made a physical Andon with LED lights that plugs into the system and follows the virtual Andon,” he says. The addition of the lights is important for everyone on the shop floor, he says. “They like the comfort of looking out over their floor and seeing a lot of green lights.”
The Andon lights plug into a USB port, and the cloud-based software runs on any Internet-connected device—including smartphones, tablets, PCs, display drivers, and Raspberry PI Linux.
With roots in the Toyota Production System, it is no surprise that use of Andon displays is widespread in the automotive space. With the expansion of communications capabilities, Andon is broadening out to multiple discrete and process industries. Wherever there is a variable process, there’s a smart Andon that can help manufacturers understand what is going on, giving them the ability to correct conditions before they grow into problems.