When Schering-Plough expanded its packaging capacity for Claritin allergy medication it had three key criteria for putting codes on the cartons:
• Lot and expiration date codes had to be clear and crisp.
• They had to allow inspection by a machine vision system.
• The equipment to do that had to be installed with a minimum of complication and run with a minimum of maintenance.
What answered those criteria was an HP thermal inkjet printer system delivered through Nutec Systems Inc. It offered the best solution when compared to several options considered in engineering two new lines.
The two new lines are in a Kenilworth NJ facility and each produces blister packs. Blister cards come off a thermoform/fill/ seal unit. They feed into a Marchesini cartoner where SBS paperboard blanks are erected loaded folded shut and glued at speeds of up to 320 cartons per minute.
The coding and inspection system had to fit within the cartoner. Alternatives considered were laser coding matte printing and embossing.
Al Martino Schering-Plough project engineer explains some of the thoughts that went into the decision:
“One trend has been toward laser coders-they’re high-tech and sexier. But there’s the issue of the laser head insider the cartoner. Lasers are large. They create dust and odors as they burn off the cartonboard” Martino explains. “You have to have a dust extraction system and a hood.”
Alternatives such as matte printing and embossing were dismissed because they could not deliver the print quality needed for the subsequent machine-vision system.
As Schering-Plough’s engineers probed deeper into the requirements the use of the HP thermal inkjet system began to emerge as the solution. A key difference in this system—compared to other inkjet systems—is the HP configuration with the ink in a cartridge that is also the print head.
Chinna Chinnakaruppan manager of project engineering believes that the cartridge approach is cleaner than other inkjet printers where ink supply configurations sometime lead to drips. “There are spots on the floor with other systems” he says.
The HP system prints a two-line code on each carton. The first line is a production code and the second an expiration date. Nutec specifies the ink formulation tailored to the SBS board’s porosity. The coding and inspection system on the packaging line has several features that simplify operations and make it compliant with Food and Drug Administration 21CFR Part 11 regulations.
One step that adds simplicity is the procedure of installing new print heads/ink cartridges each time a line is changed over to a new lot. The cartridges hold 42 milliliters of ink. That is more than enough for the top-end 300 carton quantities run on the lines. While there would be ink left over for the subsequent runs changing cartridges when changing to a new lot precludes the need for changes in the middle of later runs.
“It is less expensive to change out the print heads with each new lot rather than stop the line and change heads in the middle of a run” explains Martino.
Linking print heads vision system
The linkage between the print head its controller and the vision system was a key issue in engineering the line.
The print head is driven by the Wolke m600 controller. The unit is a non-PC solid-state controller that helps simplify the line’s operation. Nutec Systems Inc. is the exclusive U.S. distributor for the Wolke system.
Immediately following the coder is an optical character vision system. Its camera scans the imprint made by the HP thermal inkjet printers.
In a move to add accuracy the code to be printed for each run is actually set up in the vision system’s controller and then linked to the Wolke m600 controller for the print heads. The information is verified by keying in the information into the Wolke controller. If the two data sets match then the system accepts it as a valid setup.
The system was integrated at the Marchesini facility in Europe and the machine builder’s familiarity with the Wolke and HP technology helped smooth the process. “It really was a team effort with Marchesini Nutec Wolke and the vision system supplier” says Martino. “The HP system has simplified the process. It takes up less space is pretty much zero maintenance and its print quality opened up the world of machine vision.”
Implementing the printing technology is part of Schering-Plough’s quality improvement strategy. Raymond Jahn Director of Maintenance & Engineering says “Schering has been working diligently the past few years to be a pharmaceutical industry leader in quality and compliance. It’s been a collaborative effort with the Packaging Qualification and Quality departments.”
Jahn continues “Several years ago Kent Brown Director Packaging Operations laid out a strategic plan for packaging. It included the latest in on-line verification and facilities. My group led by Chinna Chinnakaruppan translated Kent's plan into a four-year roadmap. A large part of the success relied on finding the right technology and companies to deliver quality levels we are aspiring to.”