Seeing the Need for Vision Systems
By Erik Swain
Fifteen to twenty years ago, machine vision systems were regarded as futuristic, and they were expensive and rare. Five years ago, they were starting to gain acceptance for pharmaceutical packaging applications, but they were still considered costly and not necessarily essential. Now, costs are much more reasonable, and it is rare to walk into a pharmaceutical packaging or labeling facility without seeing such a system.
Proof of the trend is in this year's purchasing plans study by the Packaging Machinery Manufacturers Institute (PMMI; Arlington, VA). It shows that 57% of pharmaceutical and medical personnel surveyed intend to purchase inspection or detection equipment—a category that includes vision systems—in the coming year. And 92% of those intending to buy say that they will purchase a system for a new task, as opposed to replacing an existing machine. On both counts the equipment ranks high compared to other categories.
Sud-Chemie's canister-filling lines rely on the three vision systems, ensuring 100% inpection.
The sheer breadth of applications available, and the wide range of features and complexity engineers can choose from, means that almost every pharmaceutical packager has a vision system, or a reasonable use for one. On top of that, FDA's 100% inspection mandate has encouraged the adoption of technology, and the increased emphasis on quality and efficiency from drug companies has boosted its use.
"At first most wanted it for their more difficult applications, to justify the cost of the systems," says George Blackwell, senior manager, end-user marketing, for Cognex Corp. (Natick, MA). "But now they are less expensive and the trend is to use it for simpler applications. It is also being used more to monitor in-process rather than check a package at the end of the line."
THE BREADTH OF APPLICATIONS
The scale of options goes from simple sensors to complex PC-based systems that can run an entire network, and everything in between.
"There seem to be a range of performance requirements," Blackwell says. "At the high end, there is the inspection of product inside glass bottles and ampoules, and the inspection of those containers for cracks and chips. Glass is reflective and varies in thickness, and you have to be able to distinguish the natural variations in the containers from actual defects. That requires a lot of image prepressing and sophisticated analysis. At the next level down is label inspection, from date and lot codes to making sure the correct label is on the correct package. Easier than that is checking that a cap is sealed properly, making sure carton flaps are closed, or looking inside a package to make sure things like inserts and applicators are there. The easiest are the pure presence/absence functions, making sure something is there, or in tray-loading applications, (ensuring) that the tray is empty before you put packages on it."
There are also applications in medical device packaging and secondary packaging, says Phillip Smith, president and general manager of Cincinnati Industrial Automation Ltd. (Covington, KY). "For medical devices, we see a lot of pick-and-place applications that combine vision systems with robotics," he says. "We also see vision used to verify that a kit has a complete set of parts. And in secondary packaging, we see them used to count the bottles or the packages inside of a case, or used to verify things on the outside of the box."
"As systems become more feature-laden and cost-effective, more companies will pick up on vision," he explains. "We are doing jobs that are one-fifth the cost of what they would have been a few years ago."
Another advantage of today's systems, Blackwell says, is that "the sensors are easier to use and to validate. They are often not based on a PC, which can be more difficult to validate. That means you're configuring a system as opposed to writing code for it, and validating a sensor as opposed to a program."
The drug companies aversions to human errors are spurring the use of Master of Pharma, a system being sold in Europe by Covan Vision Systems (Harelbeke, Belgium). It is an interface that connects multiple inspection systems, from labels to ampoules to bar code readers. Having the same interface for every vision system makes the operator's job easier, as does the ability to change over all the inspection systems at once by using a single product number, the company says. It also saves costs because a single computer board can serve all systems.
The system has been installed at several pharmaceutical plants in Europe, and Covan hopes to introduce it into the United States shortly. "Customers have been starting with a few modules, chiefly blisters and OCV (optical character verification), waiting to see how it is working, and then adding more inspections later," says Esther Baars, Covan's marketing and communications manager.
In addition to quality assurance, speed is a major benefit of the newer systems. "One application becoming very common is detecting that tablets are present and orientated properly in blister packages," says Saad Gilani, assistant technical manager, Keyence Corp. of America (Woodcliff Lake, NJ). "You can do approximately 30 parts per second, and can use two cameras simultaneously to go even faster."
Keeping that in mind, Micron Automation Inc. (Tampa, FL) devised a blister inspection system specifically for the pharmaceutical thermoforming industry. The company says the system incorporates high speed, high resolution, and fail-safe verification that assumes each cavity is "bad" until proven "good." Also in keeping with industry's demands, the system is validatable and integratable.
Another feature pharmaceutical users have expressed interest in, Gilani says, is noninterlocked, as opposed to interlocked, systems. The difference is that the noninterlocked systems scan every row of pixels in an image, providing a better guarantee of accuracy than interlocked systems, which scan some rows and make assumptions about the others through averaging.
Different sorts of applications are being put into use all the time. For example, at a customer's request, Global Vision (St. Genevieve, Quebec) designed a system to inspect clinical-trial label databases. "These labels come in small runs and have varying information on them," says Arpad Lehockzi, product supervisor for Global Vision. "The system takes the labels as they are being printed and reads the variable information using special software. It compares what it finds to a customer's electronic file, and verifies that what is being printed matches in the right sequence with what is supposed to be printed."
West Pharmaceutical Services (Lionville, PA) is one company that has recently adopted vision technology. Previously, the stoppers produced at West's Jersey Shore, PA–plant were inspected with the human eye and with a manual device to make sure their coatings of Teflon were applied properly. The Teflon provides a barrier to prevent interaction between the stopper and the drug product, so there are serious consequences should it be missing or incomplete. But manual inspection was a time-consuming process that added to labor costs and was not 100% foolproof. It could detect missing Teflon but not shifted Teflon.
So West worked with supplier A&B Applied Machine Vision (Pittsburgh) to devise a system that could detect missing Teflon, shifts in Teflon, or any sorts of physical defects in the stopper, such as cuts or loose particulates. Another consideration was devising a gating system to space the stoppers apart properly. The first machine, installed in June, has performed so well that West is evaluating using vision for all its products, says Donald Hill, manufacturing engineering manager at the firm's Jersey Shore plant.
On top of the accuracy required, the system had to be designed to handle the stoppers carefully, so as not to generate particulates or introduce defects, Hill says. And it was programmed to generate reports on the nature of defects, which are taken to the production department to be used in correcting problems, he says.
Sud-Chemie Performance Packaging (Belen, NM) decided to use a vision system to inspect its desiccant canisters for defects.
Sud-Chemie's system has two cameras at each inspection point, a computer processor to interpret inspection data, and a monitor to display rejection results and trends. Each line has three vision systems. One inspects molded canister bottoms for defects such as holes or flash. The other does the same for molded canister caps. The third verifies that the canister has been assembled correctly and conforms in shape and size. If there is a label involved, it verifies that the label is present and positioned correctly.
"While manual inspection and random quality sampling catches the majority of defects, these methods cannot compare with a computerized vision system that inspects every canister coming off the line," says Geno Santistevan, Sud-Chemie's plant manager. "Nothing less than 100% quality inspection is acceptable. The vision system is extremely sensitive and can detect even the smallest product defect. This allows us to raise our quality standards to meet the most stringent of customer specifications."
Another successful recent application has been for the labels of GensiaSicor, a small pharmaceutical company based in Irvine, CA. The company needed to verify product code, lot code and date code of laser-printed stenciled characters with variable shapes at a speed of 500 products per minute. By working with vision supplier Performance Imaging (Oceanside, CA) and labeler supplier Sancoa International (Mt. Laurel, NJ) this was accomplished.
Steve Reyes, GensiaSicor's principal engineer, says he became a believer in vision systems while working for a larger drug company in the mid 1990s. There, he says, he was used to large, complex systems, but knew that was not what was needed at GensiaSicor. With that in mind, packaging manager Pete Montalvo recommended Performance Imaging. Upon seeing Performance Imaging's product, Reyes was "surprised at the compactness of the system," even given its two cameras and light sources, but knew it would be the right fit. "It allowed us to read and adjust to a wide variety of labels," he says. "It pulls out flaws you can't even see." The system's simplicity also allows for quick changeover, he notes.
The company has begun using the system for other applications, including detecting cracks and chips in the vials during filling operations, and verifying the print on cartons.
Given that the pace of new pharmaceutical applications for vision systems intensifies each year, it is not hard to imagine how the technology might eventually be used in ways that seem unfathomable now. In fact, blister machinery manufacturer Uhlmann Packaging Systems (Towaco, NJ) has added a vision system to its equipment that, according to a company brochure, "may appear slightly unreal."
The VisioNIR system has camera inspection to check for shape, color and geometry of tablets. But it combines that with near-infrared spectroscopy to verify the product's chemical identity. So not only will the system be able to tell if the drug looks right, it will also be able to tell if it is the right drug.
Regardless of how futuristic pharmaceutical packaging engineers want their vision systems to be, they are increasingly seeing the need for them. "I think vision is a must," Reyes says. "In pharmaceuticals, we are very critical."