Quality assurance of packaged products is of critical importance in the pharmaceutical industry since incorrectly packaged or damaged products may result in expensive manufacturer recalls or potentially fatal accidents. Because of this, tablets packaged in blister packaging need to be inspected carefully for defects such as the wrong color, size, whether the tablets are broken or chipped and whether there are any empty pockets in the blister packaging itself.
With the recent directives by the World Health Organization for international export of such products, inspection requirements have become more stringent. For pharmaceutical vendors, there is also ongoing pressure for volume production, and quality assurance mechanisms with sorting capabilities.
“These are demanding applications where robust, deterministic and scalable solutions are required, a problem that becomes more complex with more products being produced on the same machine, signifying a need for a flexible user interface with profile selection and editing capabilities,” says Faisal Mirza, Proprietor of Sunshine Corporation.
For one major manufacturer of pharmaceutical products. Sunshine Corporation has developed a vision system capable of inspecting 800 blister packs per minute. To accomplish this task, images of up to eight blister packaging placed on a 330mm wide conveyor are imaged by a 2MP GigE Camera running at 16 fps fitted with a 12 mm lens.
The camera is mounted inside a vertically adjustable stainless steel (SS3160) canopy that also holds a pair of model LESWLA290XD6-XQ linear array lights. The camera is mounted at a height of 640 mm from the blister guide and provides a total field of view of 330*270m.
Images from the camera are transferred to an EVS 1454 Embedded Vision System. Here, the color, size, and features of the tablets within the blister packaging are inspected as well as whether any empty pockets are present. “Since each image may capture from one to 14 blisters, different algorithms are required to process the images. These include thresholding (for white tablets on Aluminum forming) and HIS model color thresholding (for color tablets), filtering and convex hull perimeter and Feret’s diameter calculations,” says Mirza. Processed images are then analyzed by a number of bolb tools. Results of these bolb tools are then used to a actuate I/O lines on the controller that are interfaced to a number of reject plungers that are controlled by pneumatic actuators at the end of the conveyor.
By displaying the number of acceptable, failed and inspected blisters as well as availability, performance and quality parameters, the Overall Equipment Effectiveness (OEE) for the Blister Packaging Line is calculated and displayed on a 10in touch panel PC. These statistics are constantly computed in parallel (on individual cores of the i5 processor in the PC) using the results from Vision Builder for Automated Inspection (VBAI) running on the EVS 1454.
To allow for rapid product changeover on the production line , the user interface features an ALL pass/ALL fail option so that blister packs on the line can be flushed before product changeover occurs. Since multiple products may run on the same machine, the interface also allows the operator to adjust the parameters of each new product such as size, color, number of blisters and the pneumatic actuators at the out-feed allowing only blister packs with zero defects to pass to the packaging machine.
The user interface was develop using LabVIEW running on Windows Embedded Standard 7.LabVIEW’smulti-core processing capability makes it possible to add auxiliary field sensor inputs such as barcode sensors mounted at different distance from the vision station.
Already, the systems have been deployed on a number of Blister Packaging Machines including those developed by Uhlmann Packaging Systems, Romaco Pharmatechnik and The Marchesini Group.
The above information is abstracts from the Technologytrends