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In the design of a new device, a good manufacturer will follow quality management principles to ensure the device meets the requirements of the end-user. What does this have to do with Swedish warships? History can provide us with useful lessons on quality management systems. The Vasa was a warship built in 1626 that holds the unfortunate reputation of sinking on her maiden voyage after sailing less than a mile. From a modern perspective, the construction and launch of the Vasa suffered from one primary problem.  The lack of a quality management system during her design meant that a good design team was not assembled and new design concepts were not adequately tested and verified during construction. As a result, design changes were instituted “on the fly” after the nominal design freeze, and contradicting results from final verification tests were ignored, or never reached the right people. As a consequence, she was unable to meet the specifications required to be sea-worthy, and sank quickly when a gust of wind hit her when leaving Stockholm's harbor an incorrect weight balance resulting from overly complex superstructure. An adequate quality management system might have provided the checks and balances and gating necessary to any good design process, perhaps avoiding her sinking.

As an aside of a more polymeric nature, she was raised piece by piece from the sea floor in 1961, and currently sits in a museum in Stockholm, where she is in surprisingly good shape. She is being impregnated with polyethylene glycol as a preservative, although recent studies are suggesting that PEG application to wood in an acidic environment (the Vasa was in acidic water for centuries) will form formic acid, which could damage the wood.


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Two articles recently appeared in Qmed that discuss medical device cleanliness. The first discusses the effects of cleanliness on the application of coatings on guidewires. Guidewires are used to help steer catheters and other cardiovascular equipment through blood vessels. PTFE is often applied to improve lubricity of the guidewires. When problematic flaking of the PTFE from guidewires was observed, Surface Solutions modified their cleaning process to help adhesion. Even contamination on the atomic level can interfere with adhesion of the PTFE, resulting in the need for ultraclean processing conditions.

The second article mentions the Sulzer InterOp recall, which was previously discussed in this blog. The article discusses manufacturing decisions in medical devices, including cleaning and sterilization, and how the materials used in the device need to be considered when selecting a sterilization modality.

Manufacturers of medical devices and food products will often use packaging with a reduced oxygen level in the region of the product to minimize oxidation of the product and increase shelf-life. Inert gas, such as nitrogen or argon, may be flushed through the packaging, or vacuum may be pulled on the packaging.

Alternatively, an iron-based oxygen scavenger can be placed in the packaging. The packaging often uses a barrier film to inhibit the diffusion of oxygen through the packaging. This film is often a composite structure of multiple layers of plastics and metals.

Determination of the oxygen level in the packaging is a useful way to determine the efficacy of the
packaging process, and to monitor the packaging integrity over time. CPG has developed a technique to quantify the oxygen content in packaged components down to oxygen concentrations in the parts per million.  This technique is discussed in this application note.

Some of the staff at Cambridge Polymer Group and their spouses participated in Boston's annual Hub on Wheels, a 50 mile bike ride that winds through the Boston and its surrounding communities. The ride raises money for the Special Olympics, the Boston Parks and Recreation Fund, and Boston Bikes, an organization set up to encourage cycling in Boston.