Cam­eras are on!

On the PMK web pro­cessing machines, camera sys­tems ensure that oral active ingre­dient films leave the con­veyor belt flawlessly.

Oral (ODF) and buccal films (MBF) can be effec­tive aids in the fight against severe pain. Once placed on or under the tongue, the thin ODF strips dis­solve quickly and the active ingre­dient is released. MBF adhere to the oral mucosa and release the active ingre­dient. First, a polymer matrix con­taining active ingre­dients is pro­duced in a spe­cial coating process. The PMK pro­duc­tion and pack­aging machines then con­vert the polymer matrix into strips and package the films into indi­vidual pouches. Camera sys­tems care­fully mon­itor every step.

Oral and buccal films are effec­tive aides against pain.

During web con­ver­sion, the films are cut length- and cross­wise. Typ­ical ODFs are rec­tan­gular between two and ten square cen­time­ters in size. MBFs usu­ally have rounded cor­ners for better com­fort inside the mouth. A flexo printer, for example, then imprints the active ingre­dient con­tent and the product name. This is where the first of three image pro­cessing mod­ules is used. It checks whether the imprint is cor­rect and easy to read for the patient.

“The chal­lenge is that 1,050 parts per minute pass through the machine at max­imum speed. That means almost 18 parts per second,” says Hartwig Sauer, Depart­ment Leader Vision Sys­tems at Harro Höfliger. “During this short period of time, we have to take a pic­ture of each product, eval­uate it and send the result to the machine con­trol system.” If the camera detects a faulty imprint, the prod­ucts are marked vir­tu­ally and ejected at the end of the machine.

“More than half of our machines require camera con­trols.“Hartwig Sauer, Depart­ment Leader Vision Sys­tems at Harro Höfliger

Not a mil­limeter too small

For the flaw­less prod­ucts, the next step is to pack them in 50 x 50 mil­limeter pouches, pri­marily made of child-resis­tant pack­aging mate­rial. To this end, the films are trans­ferred to the lower pack­aging mate­rial web. A camera checks whether the product has the cor­rect ­geom­etry – i.e. the exact length, width and con­tour – and is posi­tioned in the center. If the product were posi­tioned in the sealing area, the pouch would not seal and close prop­erly. In addi­tion, the films are checked for pos­sible con­t­a­m­i­na­tion by par­ti­cles, product or pack­aging mate­rial residues. 

Prior to sealing, the pack­aging mate­rial web is also printed with a batch number, expi­ra­tion date and a 2D data matrix code. A third camera sta­tion checks for cor­rect printing. “Since these films are often used in pain therapy, it is espe­cially impor­tant that all infor­ma­tion is accu­rate and leg­ible. No mis­takes can be made here,” explains Sauer.

Camera sta­tions mon­itor every step of the model PMK pro­duc­tion and pack­aging machines: 
1 Checking the imprint of active ingre­dient con­tent and product name 
2 Checking the posi­tion before pack­aging into four-side sealed pouches 
3 Checking the imprint of the upper pack­aging mate­rial web

Researching the future

Accu­racy and process mon­i­toring are also impor­tant for other forms of pack­aging. “More than 50 per­cent of our machines require camera con­trols,” says Sauer. “We used to work with external com­pa­nies, but then our cus­tomers always had two dif­ferent contacts.”

This is now in the past. For the last six years, Harro Höfliger has had its own image pro­cessing depart­ment. In the camera lab­o­ra­tory, 17 appli­ca­tion engi­neers examine which camera light color and wave­length can be used to best map spe­cific fea­tures for sub­se­quent exam­i­na­tion of the required test cri­teria with com­plex image pro­cessing soft­ware. They are also con­ducting research into future tech­nolo­gies such as thermal imaging and deep learning. “In the future this will enable our machines to detect errors better and faster to fur­ther im­prove exact pro­duc­tion of medication.”

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Photos: Helmar Lünig, Janine Kyofsky, Ishchenko