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September 30, 2002

10 Min Read
This molder speaks the language of medicine

It looks and smells like an OEM shop, but it’s not. This molder has put product design, FEMA, prototyping, mold design, molding, assembly, and packaging services under one roof.

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Wilden worked with Roche Diagnostics to make its new Softclix blood monitoring device more compact and easier to use. The number, complexity, and precision of the parts show the expertise required in design
and manufacturing.

Within the walls of Wilden Medical Plastics Systems in Pfreimd, Germany, you find what appears to be a modern medical and pharmaceutical systems company—an OEM. All the required disciplines are there: product concept and design, development, testing, GMP conformance, cleanroom manufacturing, assembly, packaging, and above all, market knowledge and expertise. Appearances in this case are deceiving, but only a little.

Wilden is not a medical/pharmaceutical OEM. It is the successful and growing production partner of many of the largest and best-known OEMs in the field—AstraZeneca, Boehringer Ingelheim, Roche Diagnostics, Becton Dickinson, and Novartis, to name a few. The visible investments combined with the group’s medical/pharmaceutical expertise have earned it this position, but there is something more making Wilden a formidable player in medical/pharmaceutical. (For a report on Wilden’s cleanroom operations, see “The Ideal Cleanroom: Build It and They Will Come,” March 2001 IMM, pp. 106-110.)

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In addition to making the Softclix device used by diabetics for blood monitoring, Wilden also makes the disposable lancets that pierce the skin and collect the tiny sample.

Synergizing Plastics, Medical, and More
Wilden Medical Systems is part of Wilden AG (Regensburg, Germany), which, with its 2001 turnover of 190 million euros ($186.5 million), is one of the largest plastics molders in Europe. More than 1000 employees work in 11 plants and
subsidiaries in Germany, Switzerland, the Czech Republic, Sweden, Italy, and the U.S. The medical/pharmaceutical market is not the company’s only specialty, though it is a major one. Of Wilden’s 323,000 sq ft of production space, 91,500 sq ft is in cleanrooms ranging from Class 100,000 to Class 10,000. Class 100 sterile production using laminar flow tents is also available.

Wilden’s other markets include automotive, communication and information technology, and electronics. Far from diluting Wilden’s medical/pharmaceutical effort, this broad base provides a palette of resources that are consciously synergized, most notably by means of Wilden’s Technical Center.

In addition to design, engineering, and processing expertise, the Center constantly updates a comprehensive technical database that serves all groups in the company including Medical Systems, naturally. Another estimable resource for Wilden’s Medical Systems unit is a subsidiary moldmaking and automation systems company in Wackersdorf, Germany, which serves the needs of both in-house and external customers.

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Wilden's product development program is based on many years of experience with a wide variety of medical and pharmaceutical projects. True to its role as working partner, Wilden lets clients customize the steps based on their own capabilities.

Wilden thus is able to offer the medical market its overall strength in plastics molding, virtually all of which is highly technical, integrated with its broad expertise in medical and pharmaceutical technology. It is that expertise, and in particular its all-inclusiveness, that causes Wilden Medical to resemble an OEM—and this is no coincidence. The company’s strategy is based on a knowledge of the entire medical process chain, to the patient using the device. Only then can it be a full production partner for its customers from product idea through distribution. A couple of recently introduced products illustrate how that competence is used.

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Wilden has more than 90,000 sq ft of working cleanrooms from Class 100,000 to Class 10,000. Sterile Class 100 production under laminar flow 
tents is also available.

The First Refillable Powder Inhaler
Wilden’s discussion of the Novolizer powder inhaler it makes for Viatris (formerly Sofotec) does not begin with materials, molds, processes, or even product design. It starts by pointing out that an asthma attack can be life-threatening, and the person suffering the attack can be highly stressed. Therefore, the solution must be reflexively easy to use, as well as provide the exact dose needed. The Viatris Novolizer, which was the first refillable powder inhaler on the market, is designed to do just that. It is a completely mechanical device that consists of 14 molded plastic parts and three steel springs. The cartridge for the active ingredients consists of three parts. Wilden was involved in the design and conception of the Novolizer and cartridge virtually from the start.

To avoid errors in use, the Novolizer has two signals—one visual and one audible. When the release button is pressed, the drug is dispensed, and the color in the transparent window goes from red to green. If the powder is inhaled correctly, a click is heard, and the window again shows red. If the inhalation is not correct, further dosage is blocked to prevent an overdose. An integrated counter shows both the previous and remaining doses as a control.

Wilden spent a great deal of effort in materials selection and performs extensive receiving inspections on everything, including the purchased springs. Documentation of this and every phase of production is extremely detailed. Recyclate is never used. The components of the critical dosage mechanism are molded of PBT and POM.

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The molds for the Softclix components were designed and built by Wilden's moldmaking and automation systems subsidiary in Wackersdorf, Germany, as were the automated assembly systems.

The drug powder’s tendency toward “bridging” makes it difficult to proportion precisely, so several mechanical processes are used to ensure exact dosing. A slide on the underside of the cartridge transports the exact quantity into the cyclone chamber, while a striker released by the dosing button counteracts the bridging. A lever then positions the powder for application and, together with the respiratory flow of the user, triggers the release by a valve flap.

The 14 molded parts of the Novolizer are made in a Class 100,000 cleanroom and are assembled manually, along with the three purchased springs. Every inhaler is 100 percent performance tested. The cartridge components—lid, body, and proportioning slide—are molded in ABS and assembled in a Class 10,000 cleanroom.

Wilden has an in-house pharmaceutical laboratory and is licensed to produce powder mixtures and to do filling and packaging. Although in this case the client performs those operations, the lab is another investment that lets Wilden differentiate itself from other injection molders.

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Simulation software, including Moldflow, was used to detect critical issues in advance for the Softclix lancing device and to optimize the
multicavity mold design.

Take Something Good, Make it Better
Wilden’s objective with Softclix, a lancing device for blood glucose monitoring by diabetics from Roche Diagnostics, was to transport the excellent performance characteristics of a previous system into a design that was smaller and easier to operate. As Wilden points out, monitoring blood glucose several times a day is tiresome for diabetics. New analysis methods have minimized the amount of blood needed, but until needle-free measuring becomes reality, it is still necessary to lance a fingertip or ear lobe. The right system can at least make this necessity virtually painless.

A particular requirement for this project was to bring it to market as soon as possible. Wilden made extensive use of Moldflow and other simulation software to save time. Once the concept was defined, 3-D CAD was used to develop the necessary components. Prototypes, another Wilden in-house service, followed quickly and subsequently became the basis for the production molds. Wilden now produces two versions of the Softclix, one for home use and the other for medical professionals; it also makes the disposable lancets used in each test.

Perhaps the most critical role in making the lancing device uncomplicated and as painless as possible is played by the actuating sleeve that creates a gentle skin penetration. Wilden’s designers say this sleeve transmits the torque of a tension spring in an axial movement—the lancing movement.

The entire energy of the spring acts on an integral clip that is the release element for the lancing process. Pressing the release button is what triggers the lancing movement, but while the device is under tension, the spring’s energy has to be absorbed by the clip of the actuating sleeve. To ensure the precise functioning of the actuating sleeve, it was necessary to build a prototype mold and thoroughly test the parts. Only after thorough modification was it possible to release that part to production.

These are but a few examples of the many Wilden medical products being made or under development. Customer focus breeds success, and Wilden has gone beyond mere focus to become a part of the medical industry; in fact, its highly experienced engineering and product development group is full of medical specialists. When Burkhard Stolz, Wilden’s head of engineering, says, “We speak the language of our customers,” he is referring not to German or English but to medical-ese. In Wilden’s case, there is no foreign accent.

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The overall 60-station assembly system built by Wilden and used by Dade Behring in Marburg, Germany to assemble critical blood platelet measuring cells used by doctors to determine bleed time.

Medical automation to go
One of Wilden’s main assets in the medical market is its moldmaking and automation subsidiary located in Wackersdorf, Germany. However, its products are not always used in Wilden’s medical production plants in Pfreimd, Germany and Zug, Switzerland. A good example is the extensive automation system that Wilden created for Dade Behring of Deerfield, IL—60 stations covering 55 sq m (600 sq ft). Currently operating in Dade Behring’s Marburg, Germany plant, this fully automatic system produces blood platelet cells used in the often-critical process of measuring bleed time.

These special measuring cells enable doctors to simulate a blood vessel injury and determine the bleed time critical to beginning the correct treatment. The cells are very small, and their design dictates stringent assembly requirements under cleanroom conditions. In the Wilden-built system, the three components of each 5g measuring cell are assembled and furnished with various reagents.

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Visual inspection systems are used at virtually every stage of this assembly, such as this one checking that the specified one microliter of reagent has been added to the cell.

Central to the cell is a fiber membrane into which a 150-µm-diameter hole is punched, and the diameter verified by a camera equipped with a microscope lens. The membrane is transferred with vacuum assistance to the floor of the cup and ultrasonically welded in place. Weld quality is camera checked before a microdosing pump applies 1 µl of reagent onto the fiber. The dosing is then camera checked, and the parts go to a drying line.

When the fluid has penetrated the fiber membrane, it turns gray, which is controlled by a color sensor. If no change took place, the cell is sorted out as a reject. At the next station, a second fluid is applied, and the 1 µl volume is verified again. Following a reaction period, the cell blank is dried for about 30 minutes at a precise temperature and air velocity. Reagents are kept cooled to 4C in tanks containing a magnetic stirrer that prevents sedimentation of the molecule chain in the suspension.

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Since the hole punched in this fiber web must measure precisely 150 micrometers, it is verified by a camera fitted with a microscope lens.

A conveyor takes the cups to an assembly station where a capillary is ultrasonically welded in place. A camera system checks for correct positioning of the capillary needles. A gripper then inserts each cup with its capillary into a molded plastic housing and presses it into a holding device. The housings are sealed by a bottom sheet previously verified leakproof, and the assemblies are again sensor-checked. The housing is sealed by aluminum foil, batch numbered, and taken from the system. Stored data documents every phase of the assembly, and batch numbers permit tracing an individual cell at any time.

Contact information
Wilden AG, Regensburg, Germany
Karin Strasser; +49 (941) 7058 140
www.wilden.com
[email protected]

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