Pharmaceutical and Medical Packaging News
Magazine
PMPN Article Index
Originally Published April 1999
CASE HISTORY
Raising Container Quality
An inspection system catches defects in bottle molding.
As a supplier of plastic bottles to the pharmaceutical industry, Kerr Plastics (Lancaster, PA) realized there was an opportunity to enhance the quality of its product by changing the company's quality assurance procedures.
"Our customers were increasingly demanding higher and higher product quality. We reached a point where it was no longer possible to improve quality through standard auditing techniques," says Mark Wilson, plant manager of Kerr's Lancaster plant. The firm needed an in-line inspection system for its blow-molded pharmaceutical bottles that would monitor the bottle base, side wall, and inner neck region for contamination, inclusions, holes, thin spots, and flash.
When Kerr began working with AGR International (Butler, PA), quality assurance manager Fred Bixler gave AGR's engineers a list of the defects his team wanted to catch, reports they wanted to generate, and levels of control they wanted to give staff. "They took our criteria and tailored equipment to accomplish all of our goals."
The result was AGR's conveyor vision inspection system (CVIS). Kerr installed the CVIS downstream of its injection blow molder that produces HDPE bottles for over-the-counter and prescription pharmaceuticals. Kerr now supplements manual auditing of samples from the production line with 100% automated inspection to enhance product quality and improve process monitoring.
"The AGR technology can pick out defects that are so minute the human eye can't notice them, and we're now inspecting 100% of the bottles," says Wilson. "The CVIS is an important new tool that automatically removes defects from the production line and quickly alerts us to potential processing problems."
Kerr's CVIS uses six cameras at three separate inspection points that are integrated into one compact unit. At each of the three inspection points, a sensor indicates that a container is in place and triggers a strobe light that illuminates the container. The strobe freezes the image, and the vision system takes an electronic picture of the container. The video signal from each camera is sent to a PC-based controller that digitizes the signal, providing an image that can be processed by AGR's proprietary software. The system software compares the results of each inspection to user-defined specifications that are stored in memory. If the CVIS detects a discrepancy between the inspection image and the stored information, the system records a defect, and a downstream reject device automatically removes the nonconforming container from the production line.
"One of the most important production advantages that the CVIS brings to Kerr comes from monitoring the performance of the blow molder," Wilson says. "The system categorizes defects, offers trend analysis, and can be programmed to sound an alarm if certain conditions are met. Those data allow us to react quickly to correct production problems when the defects are still insignificant, helping us prevent out-of-tolerance bottles. As a process monitor, the CVIS actually helps us improve efficiency and reduce rework."
The reporting function of the CVIS allows Kerr to collect and document a variety of data for a range of purposes. Shift reports gather data that meet Kerr's internal quality assurance needs, and job reports provide Kerr's customers with information that supports their own auditing procedures. "We want our standards to be a notch or two above what anybody else in this industry can do," Bixler says.
AGR designed the CVIS operator interface to provide a user-friendly control panel that offers simplicity for the operator. Kerr identified the levels of control that were needed by each of three different types of users, and AGR programmed Kerr's CVIS to limit access depending on the user. "The graphical and numerical user-interface reduces the skill levels required to operate the CVIS at optimum performance, while also reducing training requirements," Wilson notes.
