NEWS
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A quality engineer performs validation testing utilizing a CMM for automated part inspection. Photo courtesy The Tech Group. |
To prepare for and keep up with such demand, redundant manufacturing processes were in order, including those for the delivery device’s injection-molded components. The Tech Group (Scottsdale, AZ) and Bespak (Milton Keynes, UK) worked hand in hand to ensure that all the components each firm made were interchangeable, reports Mike Treadaway, general manager, drug delivery device division, The Tech Group, a West Pharmaceuticals company.
The Tech Group has been working with Nektar Therapeutics, Pfizer’s collaborator on Exubera, for more than seven years. The contract manufacturer developed the injection molds for both its own operations as well as those for Bespak. “This was done to make sure that we both had identical equipment,” says Treadaway.
Those molds feature intricate designs. “The dimensional tolerances were challenging,” Treadaway explains.
For instance, a two-shot process was used to make the product’s airtight chamber. The top portion of the chamber features a gasket created with two-shot injection molding that seals the chamber. “We used the two-shot process to make this chamber a one-part device, making it more reliable,” says Treadaway. “Traditionally, there would be a base piece and a separate gasket added.” In addition to making it more reliable, the two-shot process eliminated an assembly step.
During mold development, mold-flow analysis was performed on every part to ensure a robust design. To ensure shot-to-shot consistency, six-sigma techniques were used during mold design and process development.
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An operator visually inspects a device component prior to assembly. Photo courtesy The Tech Group. |
Redundancy didn’t stop with the molds. The Tech Group and Bespak each installed identical injection molding machines from Netstal Machinery Inc. (Näfels, Switzerland) for use in Class 100,000 cleanrooms. The two companies, usually competitors, worked closely to ensure that they used the machines identically. “A lot of engineering went into making sure that we had robust, repeatable processes,” says Treadaway. That engineering included adding transducers for measuring cavity pressure inside the molds to monitor process output.
Bespak took the lead in developing the necessary automation. “Automated assembly was required for small components to ensure a precise fit,” Treadaway explains. Vision systems were employed for 100% inspection during many of the automated steps.
Bespak also developed the supply chain for the materials. “A number of polymers were used, including custom-compounded materials with additives,” explains Treadaway.
Treadaway is proud of the engineering that went into the device. “When you develop a combination product, there is a lot of due diligence required,” he says. “The device has to be very robust to function in the field, and it has to be very easy to use.”
