FEATURE PHARMACEUTICAL & MEDICAL Reliable packaging of medicinally active ingredients
Harro Höfliger, a company that develops and builds production and packaging systems, incorporates technology from Stemmer Imaging into its machine vision processes
S
ophisticated technology for the pharmaceutical industry and the construction of machines in this sector are among the core competences of Harro Höfliger. Machine vision systems ensure reliable quality inspections at several points in a new plant for the packaging of painkillers. Mucoadhesive Buccal Film (MBF) is
the medical term for the delivery form of the strong painkiller for which the engineering company Harro Höfliger develops and builds production and packaging systems. What patients ultimately remove from
the packaging and allow to dissolve in their mouths to relieve pain must satisfy the strictest quality requirements at every stage of processing. “In our PMK 150/300 production and packaging machine the MBF active ingredient, which is applied to a carrier film, is initially wrapped up in the form of a roll and the protective film on the upper side is pulled off by an appropriate mechanism,” says Hartwig Sauer, head of the machine vision team at Harro Höfliger, explaining the first step of the machine process. “The web is subsequently printed with data for the active ingredient dosage by a flexo printer. The active ingredient is evenly distributed in the laminate so that the medicament dosage can be controlled by the size of the MBF.” In this plant the products with sizes
between 10 x 10mm and 17 x 17mm are sealed in 50 x 50mm aluminium bags between an upper and lower aluminium composite foil.
THREE IMAGE PROCESSING STATIONS The first of a total of three image processing modules in this system checks that the printing is correct on the front
34 JUNE 2018 | INSTRUMENTATION
side of all three active ingredient strips with a maximum speed of 1,050 parts per minute – or almost 18 parts per second – on each of three webs. The triggered image capture across all three strips and 150mm beyond is done by a Spyder3 line scan camera from Teledyne Dalsa with a resolution of 4k pixels and an APO-Componon lens from Schneider Kreuznach. Red LNSP line lighting from CCS provides the appropriate illumination. The images from all three image processing modules are evaluated by an industrial PC. Faulty parts are marked in the
machine’s internal shift register as “bad” and discharged into a separate ejector at the end of the machine. Subsequently, the final products are cut out of the three webs with a rotary die cutter and transferred to the lower packaging film by means of vacuum. The products should now be placed on the carrier material in three rows with correct longitudinal and transverse spacing, which is what the second image processing station checks: firstly, it checks the position of the separated products to ensure that the subsequent sealing process can proceed correctly. Secondly, this station also checks the product size and for contamination by foreign bodies. This fault is detected by the system down to a size of about 1mm². The image capture across all three
strips at this second image processing station is done once again by a combination of a Spyder3 line scan camera from Teledyne Dalsa with a resolution of 4k pixels and an APO- Componon lens from Schneider Kreuznach. Blue LNSP line lighting with coaxial attachment from CCS provides the optimum illumination of the strips here. With the aid of this blue lighting the product – and the lettering in the
Overall view of the plant
case of a later extension by printing checks – can be contrasted optimally with the background at this point. A third image processing station checks the printing of the upper packaging material web. This inspection is very similar to the first station: the items printed beforehand – the production data, shelf life, batch number and packaging material number in the form of a 2D matrix code – are checked. The third image processing station checks the printing of the upper packaging material web, reading the production data, shelf life, batch number and packing material number in the form of a 2D matrix code. The third image processing station checks the printing of the upper packaging material web, reading the production data, shelf life, batch number and packing material number in the form of a 2D matrix code.
DEMANDING EVALUATION The linear image data of all three image processing stations are transferred to a specially assembled computer in which a microEnable IV frame grabber from Silicon Software buffers the incoming line data, assembles them into complete images and then evaluates the images. “This part of the task was extremely
Below left: Printing check with up to 1,050 parts per minute. Right: The positions of the separated products are checked at the second image processing station
demanding, because the images are captured with an overlap beyond the individual products,” say the responsible application engineers Achim Hasmüller and Goran Tambolas from Harro Höfliger, explaining the particular challenges. “Each image consists of the end of the preceding product, the complete current product and the beginning of the following product. In this way we were able to ensure that errors at the interfaces between two products are also detected reliably.” Since all captures are triggered, the
positions of all faulty products in the process can be tracked precisely in order
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