Manual medical device tray and pouch sealing can be a repetitive process for operators. Even the most dedicated employees are human and can make mistakes, whether via distraction, burnout, visual fatigue, and other issues.
At MD&M West, Kent Hevenor, VP of sealing technology at SencorpWhite, said, “People are imperfect. We use sensors and vision systems to prevent a machine from being able to cycle if it doesn't see the right product, the right pouch, in the right orientation being introduced to the machine, whether it's a pouch or a tray sealer.” Hevenor highlighted some specific examples:
Barcode/printing: A machine can be programmed to look for a given barcode printed onto a pouch associated to a given recipe. In this case, Hevenor explained that the camera or barcode scanner is looking for a specific barcode to compare to the recipe being run on the machine. If it sees a mismatch, it prevents the operator from being able to seal that pouch or tray because the recipe does not match the package.
Pouch orientation: A pouch sealing system can go a step further and look at other specific attributes printed on a pouch to make sure the pouch is right side up, and in the proper orientation inserted into the machine. “Because the operators can get distracted or confused and put something in in the incorrect orientation, these sensors correct orientation issues and package-to-recipe mismatches,” Hevenor noted.
A glare sensor can be added to a constant heat pouch sealer. “If you're sealing that film to a TyvekTM pouch, the glare sensor can discriminate between Tyvek and film. One side has a reflective property, and the other side does not. So, if the operator puts the pouch into the machine with the wrong side facing the heat, the glare sensor will give you a ‘go, no go’ signal,” he said. “If you try to cycle the machine with the wrong pouch side up, the system won't allow the machine to cycle, which will prevent the operator from making a mistake. We've seen situations where somebody puts a pouch upside down so the wrong side is facing the heat or the chevron side is inserted into the machine—the other end is still wide open—because the operator gets distracted. These vision systems, sensors, and cameras can capture these issues and prevent the machine from being able to cycle.”
Hevenor noted that it’s easier if a company is processing a printed lid, because the vision system can look for certain markings or printing with a camera from above, looking down at that package. “If it doesn't see a logo or a specific word, it knows that the lidstock is upside down, or could even be the wrong lid,” he said. “When a lid isn’t printed, a trained operator can typically tell based on feel which is the adhesive side and which is not, but even experienced operators can make mistakes, especially if they're wearing gloves and can’t feel the surface of the film.”
UV fluorescence: Certain coatings on Tyvek will fluoresce under UV light, so companies can benefit from placing UV lights above the sealing machine.
If the operator sees the pouch fluorescing, they would (ideally) identify that the adhesive side is facing up, when the adhesive side should be facing down. “So if you have a UV light looking down onto the lid, an operator would not want to see fluorescence,” Hevenor said. “If you put it upside down and you do see fluorescence, it's an indication to the operator that it may be upside down. In that case, the UV light itself does not have feedback, and we're relying on the operator to ensure that they see what they're supposed to see.”
Preventing errors from moving downstream: It’s possible to use the intelligence of the machine’s sensors to not only capture mistakes, but to communicate that conditions are correct for the machine to cycle. “It allows the machine to cycle and sends a signal downstream to the next step in the process saying, ‘You should expect one completed package to be coming off this machine.’ If your conveyor or your downstream equipment sees two packages go by when the machine only cycled once, it will stop the process to prevent errors from going further downstream,” he explained. Sensors on pouch sealers can also ensure that the right product is in the tray in the right quantity.
Tooling: Sensors on the tray sealer will identify a specific tool with either a barcode or an RFID tag, and then will compare that value to the recipe running on the machine. If the tool doesn't match the recipe, the system will automatically prevent the machine from being able to cycle.
As Hevenor explained, the technology is simply risk mitigation: “In the past, before this technology was available, we relied on people to make these decisions and be 100% aware of what they're doing. But even the best trained operators are going to make mistakes eventually, especially with a repetitive process.”
Why the technology is growing
Hevenor says that in the past, very few customers would spend the extra money to add these kinds of risk mitigation onto manual sealing equipment. But now that number is nearing 50% and growing. “One of the things that's really pushing customers nowadays is the labor shortage. You have such high turnover of personnel,” he said. “No matter how quickly you train people, they're moving on, and keeping people at a trained level and retaining experienced operators is getting harder and harder. So, people are trying to make the equipment smarter to be able to catch some of those mistakes that non-trained operators would potentially make.”