Medical devices can have complex shapes, including grooves, textures, and knurls that are difficult to clean.
Photo Credit: All photos courtesy of MicroCare
As medical devices become more compact, minimally invasive, and more efficient, manufacturing techniques are evolving to keep pace with these highly complex designs.
Building new miniature devices, however, can be a challenge. Medical devices must be cleaned, dried and finished to the highest standards to ensure they are ready for the next step in the manufacturing process. Any remaining particles or residue can cause inconsistent results, impacting not only device performance, but also the validation process.
Manufacturers must be certain that production procedures, including finishing processes, have the controls necessary to produce products that meet quality and regulatory specifications.
Why is cleaning so important?
Medical devices can be complex assemblies that encompass intricate shapes and delicate materials, which makes cleaning during production particularly difficult. Despite these challenges, the requirement for a perfect finish is essential. Complete removal of production debris such as machining, stamping or cooling oils, dust, metal filings, marking inks, fingerprints and other soiling must be carried out before assembly, packaging, sterilization or coating.
The cleaning process must be tailored to remove contamination and meet the stringent regulations and validation controls typically required for medical devices, especially those produced or assembled in a clean room environment. This, however, has become more difficult as medical devices become smaller, incorporate tighter spaces, and have deep blind holes or complex openings that are particularly difficult to clean and dry.
There is also hardware compatibility to consider. Medical devices are made from a variety of materials, including metals, ceramics, polycarbonate, and acrylic, so the cleaning method should not damage delicate surfaces or components.
To meet cleanroom standards and strict cleanroom validation criteria, the cleaning process chosen must also be consistent, easy to use and compatible with established procedures. Vapor degreasing cleaning is a well-designed process that is simple, predictable, and repeatable, making it easier to qualify for medical device manufacturing.
Steam degreasers do not introduce outside contamination into a clean room.
Steam degreasing – the advantages
Vapor degreasing is a closed loop system containing two chambers, the boiling sump and the rinsing sump. The boiling sump contains a specially formulated low boiling, non-flammable cleaning fluid. The parts are immersed and cleaned inside the heated fluid. Once cleaned, they are mechanically transferred to the rinse sump for the final rinse and dried into a purer, uncontaminated fluid, or within the fluid vapors themselves. As a result, parts come out clean, dry, blemish-free and immediately ready for the next step in the process, be it assembly, finishing, sterilization or final packaging.
A vapor degreaser is easy to incorporate into a cleanroom because it does not introduce outside contamination into the cleanroom. It also has a small footprint, especially compared to large volume aqueous cleaning machines, so it doesn’t take up a lot of expensive cleanroom space.
When used inside a steam degreaser, modern cleaning fluids are specially designed to effectively clean and dry delicate parts of medical devices without damaging them. They exhibit unique low boiling temperatures, low surface tensions and low viscosities. These factors combine to completely dissolve contaminants and remove them easily. The fluid penetrates and cleans very tight spaces easily and, above all, evaporates completely without leaving any residue. Most vapor degreasing fluids are also heavy and dense. They are up to 40% heavier than water, which helps them lift and float solid particles from parts.
It is also possible to combine the vapor degreasing cleaning process with a second stage surface treatment for the application of medical grade lubrication or a special film. This means that the cleaning and coating process can be completed quickly to streamline the overall finishing process.
Eliminate the microbial load
It is important to use cleaning processes that do not pose a risk of bioburden. Trace amounts of water or water-based cleaners can allow bacteria to grow and create related bioburden issues, compromising the ability to properly sterilize medical devices. Using modern solvent-based vapor degreaser cleaners eliminates this risk as it does not contain water, ensuring a pyrogen-free cleaning environment.
Another advantage of a vapor degreaser is its consistency. Once established and tested, the cleaning fluid inside the Vapor Degreaser remains chemically stable for thousands of uses. Modern vapor degreasers require very little maintenance and most new cleaning fluids used indoors will not require daily monitoring or acid acceptance testing. This ensures that part cleaning meets all required process validation specifications.
Since steam degreasers come in different sizes, they meet different needs. Whether it’s a small batch job requiring only a tabletop version or a mass-produced part requiring a machine with thousands of gallons of cleaning fluid, cleaning results always remain consistent. Parts are cleaned using the same repeatable process. This means that equipment additions or upgrades are rarely necessary when new products are introduced to the vapor degreaser, even if they are a different size or made from a different material.
Because the vapor degreasing process is consistent, it operates within established constraints that can be easily audited and documented for validation purposes. A complete cleaning record of the batch can be kept to demonstrate that all steps defined by the procedures and instructions have been undertaken and that the result has been as expected.
The daily operation of a steam degreaser is simple and can often be automated. This simplifies worker training and ensures that trained personnel can always be available to properly perform parts cleaning procedures.
Parts used in medical devices not only require long-term functionality, but they must also withstand stringent regulations put in place by governing bodies. For example, the Food and Drug Administration (FDA), which reviews toxicity and sterility, and the International Organization for Standardization (ISO), which identifies quality management processes.
Compliance with durability requirements is also important. Cleaning fluids must comply with increasing environmental laws governing the use and disposal of cleaning fluids. A growing number of regulatory bodies around the world are strengthening legislation and enforcing laws to reduce any negative impact on workers or the planet.
Most modern vapor degreasing fluids have zero ozone depletion potential (ODP) and low global warming potential (GWP), reducing air quality concerns. They are also not a Hazardous Air Pollutant (HAP) and do not require a permit for the National Hazardous Air Pollutant Emission Standards (NESHAP).
Cross the finish line
The very nature of medical devices is changing as they become smaller and more complex. Yet they must maintain their long-term performance and functionality at all times. Cleaning is an important step in ensuring parts are finished to the highest standard and meet stringent regulatory, quality and reliability requirements.
The use of modern cleaning fluids and vapor degreasing equipment not only enables effective and consistent cleaning, but also helps to ensure compliance with environmental regulations as well as process validation.
When considering vapor degreasing and modern cleaning fluids, look for a cleaning fluid supplier who can provide expert advice to simplify the selection process. This includes personalized advice, access to lab testing and a selection of compliant cleaning fluid options that include both ready-to-use and custom formulations. This will ensure you get the right cleaning fluids and methods for your specific needs.
About the Author
Photo credit: MicroCare
Elizabeth Norwood is a senior chemist at MicroCare LLC. Visit microcare.com.
Landscape photo credit: MicroCare
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