AN EXTRA SET of eyes never hurts. Electronics and packaging industries have long relied on machine vision to guide, inspect, measure, and identify objects whizzing by. Now, pharmaceutical manufacturers are catching on to the benefits of having an extra set or two of electronic “eyes” watching over packaging and “back end” fill-and-finish operations.
Machine vision system deployment has been anything but a slam dunk for pharmaceutical applications. Issues such as programming, computing, integration and control interfaces prevented the first generation of machine vision technologies from providing the accuracy and reliability that pharmaceutical manufacturing demands.
However, since that time, costs for the systems have fallen dramatically, by a factor of five. At the same time, inspection speed, field vision and overall accessibility have improved ten-fold. Pharmaceutical and medical device manufacturing demand for the systems grew by 10-20% last year to $86.7 million, or 7% of the total machine vision market.
Many machine vision vendors entered pharmaceutical markets through the back door, via medical device manufacturing. Such was the case with Retina Systems, Seymour, Conn., whose technology evolved from laser position measurement in the late 1970s.
Laser systems are the “legacy technology” of machine vision, providing simple dimensional measurement, according to Retina Systems marketing director Robert Tibbing. As imaging and control functions have become more affordable through advances in computing and semiconductor technology, applications have multiplied exponentially.
Critical components of any machine vision platform are image acquisition, optics, lighting, material handling, computing, and machine control. Hundreds of vendors sell equipment that can perform some of these functions, but only a handful can fashion components into integrated systems for manufacturing.
In North America, most pharmaceutical manufacturers and their suppliers use vision systems only when big pharma customers request it, according to Luis Cruz, director of international marketing at IC-Vision (Saint-Laurent, PQ). “The drivers over here are external, not internal, whereas in Europe the opposite is true,” he observes. Cruz attributes U.S. drug-makers’ reticence to a general avoidance of new technologies and a lower commitment to operational quality compared with overseas manufacturers.
Greater Than the Sum of its Parts
Modern machine vision is more an amalgamation of interoperational components, tied in to a specific application, than an off-the-shelf device. A typical system consists of:
- Cameras, usually color CCD devices similar to those in camcorders
- Frame grabbers, which digitize analog images and interface with bus structures
- Software and fast data transfer
Imaging functions may be further broken down into image acquisition, image processing, and feature extraction.
Machine vision performs four tasks very well: guidance, inspection, gauging, and identification, suiting them for packaging. However, with the right programming, vision systems can also pick out fill errors, detect smudges on ampoules, inspect lyophilization cakes for contaminants, and accept or reject solid materials based on average particle size. Some biotech companies have even used cameras to monitor froth and turbidity during fermentations.
But process applications lie at the fringes of Zuech’s definition because of the required human intervention. Besides, traditional measurements (temperature, pH, extent of reaction) are relatively straightforward and require no new thinking. With drug-makers just getting comfortable with conventional real-time process analytics, machine vision for process monitoring is probably a long way off, at least in North America.
For example, Japanese drug makers have embraced machine vision inspection of solid dosage forms, where their peers in the U.S. have not. Vision systems excel at for inspecting pills and tablets for defects, engravings, and overall integrity. About a half-dozen companies sell inspection equipment for this type of application to Japanese markets, but Nello Zuech says vendors can barely give their equipment away to U.S. pharmaceutical manufacturers.
Seidenader Markt (Schwaben, Germany) offers a barrier-enclosed inspection system with a throughput of 2,500 tablets per minute. The company also develops machine vision systems for ampoules, prefilled syringes, and infusion bottles plus ampoule cleaning/drying machines and capsule polishers. The InspectoRx tablet/capsule inspection system from American SensoRx (Glen Rock, N.J.) accepts or rejects solid doses based on integrity, color, shape, and presence of foreign object contamination. Other solid dose inspection vendors include Driam USA (Spartanburg, S.C.), AC Compacting (North Brunswick, N.J.), and Japan’s Kanebo. A few blister-pack equipment vendors, most notably Bosch and Uhlmann, integrate inspection systems on their machinery.
Machine vision can be deployed out of the box, built into a process, or custom-installed. Off-the-shelf apps like identification code recognition perform one task very well and do not require customization. “They’re about as close to a standard application as you can get,” notes Justin Testa, senior vice president for Identification Products at Cognex (Natick, Mass.).
Although high-end implementations tend to be custom-built, with unique lighting, integration, and object presentation, vision companies have been striving to develop more general-purpose products. “One goal is to make these deployments simpler and cheaper so users can be up and running quickly,” says Testa. Another is to provide products with the capability of vision systems and the ease of use of barcode readers.