Wipotec GmbH (Germany) - Wipotec's Ultrafast Weigh Cells Excel in Precision when Dynamically Weighing Capsules and Tablets.

The implementation of pharmaceutical systems is one focus of Harro Höfliger Verpackungsmaschinen GmbH (Harro Höfliger Packaging Machines Ltd.), based in the Swabian town of Allmersbach. For the development of its custom-made applications the systems provider relies on Weigh Cell technology manufactured by Wipotec. These Weigh Cells play a pivotal role in the dosing of minute amounts for active ingredients in pharmaceutical products.

Usually capsules and tablets may be small, however even minimal dosage deviations of an active ingredient can turn a useful medicine into a threat for patients and their health. The elimination of this source of danger poses a challenge for Harro Höfliger.

In cooperation with the world-wide operating Wipotec GmbH based in Kaiserslautern, Harro Höfliger designs and develops standard and specialised machines to dose active ingredients with utmost precision. All parties involved benefit from this high-tech partnership - not least the end customers who buy the products. They are provided with the highest safety level possible with regard to the doses of active ingredients in the drugs they need.

Successful technical cooperation:
The successful cooperation of the two medium-sized companies was established in the mid-nineties with a traditional capsule weighing machine from the KWS series. Engineer Reiner Wurst, responsible for the fields capsules and powders at Höfliger, describes the collaboration with Wipotec as "constructive, open and based on mutual trust right from the start". The direct contact with the engineering department of the Weigh Cell specialist proved to be especially ideal. The KWS series (in German "Kapselwiegesystem", i.e. capsule weighing system) comprises of powerful technology capable of providing a 100 per cent weight check of all produced capsules. Even in the mid-nineties, the multi-track technology enabled the system to reach a throughput of up to 120,000 capsules per hour while the weight of each individual capsule was determined. The technical specialities, which to this very day characterise the KWS series, posed a demanding challenge for the experienced engineers of both companies. Reiner Wurst emphasises that the close cooperation of the brilliant minds of both companies quickly lead to some ingenious solutions.

"Our policy is that customers can always approach us, no matter what they need" Reiner Wurst explains. This flexibility was crucial to establish Harro Höfliger in the market for packaging machines. When the company was founded back in 1975 its main focus was to overhaul cartoning machines. 15 years later the pharmaceutical branch was developed as an additional focus. The aim has always been to develop processes based on the customers' requirements, listening closely to every specification. For Höfliger, having Wipotec aboard as a professional partner right from the start turned out to be ideal. Since the late eighties the Weigh Cell manufacturer has specialised in development, manufacturing and integration of ultrafast precision Weigh Cells and high-tech weighing systems for high-speed applications on an industrial scale.

According to Wurst, the cooperation with the reliable and equally flexible partners enables the company to live up to its "All you need" policy, implementing it consistently and sustainably for the customers' gain. In the case of the KWS series one objective, in addition to several other technical specialities, was to include a separate Weigh Cell to compensate for vibrations caused by ambient conditions. Further-more, after a preselected time-span the auto-tare function ensures that the weighing results always meet the highest precision requirements. The successful first cooperation laid the foundation for subsequent projects such as the Accura-C capsule weighing system. This cutting-edge successor of the KWS series, which is available as a six and twelve track system, was developed in a collaborative project of Höfliger and Wipotec. This machine can weigh up to 160,000 capsules per hour in stand-alone applications or in a loosely coupled production lines with a capsule filling machine upstream.

Within another collaborative project an employee of Harro Höfliger fills medicine into an "OmniControl". This is a system for a format-independent 100% check of capsules and tablets, which can determine the precise weight of products for a wide range of geometries and dimensions. The drugs are filled into a hopper which feeds them into the weighing system. The machine spreads the capsules or tablets evenly on a tray. A cylindrical, clockwise revolving vacuum suction wheel is equipped with numerous small nozzles to pick up the individual units. In the next step the carefully grabbed capsules are transferred to a counter-clockwise revolving pocket wheel. This wheel commits the items to a transfer slide which forwards them to a star wheel. The star wheel brings the units in contact with the Weigh Cell which determines the weight of each in-dividual capsule with utmost precision. It reveals whether the dose of the active ingredient complies with the strict targets or not. If the weight determined by the Wipotec Weigh Cell is within the permissible deviations from the target value, the load plate then feeds the capsule into the production line downstream for further processing. If the deviation exceeds a certain, predefined threshold the load plate transfers the capsule reliably into the rejection bin.

”A pleasant partnership”
The implementation of "OmniControl" technology makes Frank Naseband, product manager at Harro Höfliger, enthuse about the collaboration with Wipotec more than any other project. According to Naseband, several factors where crucial in the development of the technical solution: the expertise of both companies' engineers, their close interaction and especially the perfect teamwork. "Both sides appreciate the pleasant and constructive partner-ship", Naseband adds satisfied. This mutually beneficial collaboration looks set to continue for some time.