Cleaners and carrier fluids

by Elizabeth Norwood

8 June 2023

14:00

Elizabeth Norwood, senior chemist at MicroCare, examines reliable ways of preventing contamination ahead of cleanroom manufacturing of medical devices.

Maintaining high standards of product quality is essential when manufacturing medtech devices inside a cleanroom. Device parts must be free from any contamination which may impact long-term functionality and reliability. Particulate, dust, oils or inorganic contamination must be removed to meet strict testing and validation requirements. Modern, non-flammable solvents used for cleaning and coating operations are an excellent way to help produce medtech device parts quickly and efficiently while adhering to cleanroom standards and requirements.

Complete cleaning

Vapour degreasing using low-boiling cleaning fluids is a consistent, repeatable, and easy-to-validate cleaning process. The cleaning fluids combine high densities, low surface tensions and low viscosities to completely dissolve contaminants and remove particulate from small intricate parts with complex geometries.

How vapour degreasing works

Vapour degreasing is a closed-loop system that has two chambers: the boil sump and the rinse sump. The boil sump heats the cleaning fluid to generate a vapour cloud. The soiled parts are lowered through the vapour cloud and immersed in the fluid. Once cleaned, the parts are mechanically transferred to the rinse sump for a rinse in pure, uncontaminated fluid. The parts come out clean, dry, spot-free and immediately ready for assembly operations, coating/marking, or packaging. Vapour degreaser cleaning also offers several benefits for medtech manufacturers.

Manage bioburden risk

Controlling bioburden is extremely important when producing medical devices inside the cleanroom. This can be challenging within the cleaning process, particularly if using aqueous cleaning, because water is a primary growth medium for bacteria. Even small amounts of moisture in hard-to-reach areas can encourage bacteria growth.

Non-aqueous vapour degreasing, using a solvent-based cleaning fluid eliminates the bioburden risk. The cleaning fluids are hostile to pyrogenic growth. Once cleaned, the parts exit the vapour degreaser cool and dry, further eliminating the threat of bioburden, and helping to meet the criteria needed for process validation and sterilisation.

Materials compatibility

Today's medical high-tech devices use a large variety of materials. Many combine metals like stainless steel and titanium with polymers like polypropylene, polyethylene and nylon, which can be challenging to clean without damage. Cleaning fluid must be strong enough to remove contaminant effectively, yet not cause harm to any components or coatings.

Many vapour degreasing fluids can address this problem as they can be mixed, blended or custom formulated to remove a specific soil from a specific substrate and remain compatible with sensitive or delicate materials.

Fast-drying

Modern cleaning fluids do not get trapped inside compact spaces or crevices often found on the small multifaceted parts used in medical devices. Instead, the cleaning fluid evaporates away completely without leaving residues, spots or stains. This is crucial because any residual moisture, oils, or particulates could affect the quality of the parts and result in costly rework or rejected parts.

In addition, when vapour degreasing, the cleaning and drying operations are combined, saving time. The parts leave the degreaser ready for the next step in the manufacturing process without requiring a cool-down time or extra drying process.

Documented results

Because the vapour degreasing process is consistent, it operates within established constraints that can be easily audited and documented for validation. A complete record of the cleaning can be retained to prove that all the stages defined by the cleanroom procedures and instructions were undertaken and that the outcome was as expected.

Carrier fluids for coating

In addition to providing efficient and effective cleaning, vapour degreasers can also be used to apply lubricants, specialised pharmaceutical - films onto small parts through a second step surface treatment. This coating process is completed in succession after cleaning, saving time, reducing the number of machines required and the subsequent floor space needed in the cleanroom facility. With cleanrooms costing up to £1,500 per square foot, it is an important consideration.

Coating parts using a carrier fluid deposition method is an alternative to other electrostatic or thermal coating processes that could potentially damage sensitive substrates or delicate parts.

A carrier fluid delivers and deposits a thin layer of lubricant onto complex parts. It can also be used to treat large volumes of parts or the entire completed device itself. As the carrier fluid quickly evaporates, it leaves a smooth, uniform, dry surface coating. Carrier fluids are commonly used for the application of many medical-grade lubricants, including, graphite, PTFE (polytetrafluoroethylene) and silicone. PTFE lubricant is effective for speeding the mechanical assembly of medical devices. It also helps protect metal and plastic parts that will be exposed to water, oils, chemicals, abrasion and high temperatures, as the medical devices are used in the field.

Dry lubricants also help increase the overall performance of medical devices that slide, shear, twist, rock or pivot by reducing the friction and sticking, or "stiction" when operated by a healthcare provider. This helps reduce operator hand fatigue, while helping to improve their control, accuracy and performance.

Conclusion

In conclusion, the manufacturing of medtech devices within cleanroom environments demands uncompromising standards of product quality and cleanliness. To address this along with the increasing complexity of medical devices, manufacturing techniques must also evolve.

The use of modern, non-flammable solvent-based fluids and vapour degreasers has revolutionised the industry, providing efficient and repeatable cleaning processes. These methods effectively remove contaminants, including particulate, dust, oils, and inorganic substances, ensuring compliance with strict testing and validation requirements. By eliminating the risk of bioburden, offering materials compatibility, fast-drying capabilities, and documented results, modern vapour degreasing cleaning fluids have become indispensable tools in medtech manufacturing.

Furthermore, they serve as reliable carrier fluids for coating processes, allowing for the deposition of lubricants and specialised pharmaceutical films onto intricate parts. With adherence to ISO (Organisation for Standarisation) regulations for patient safety and cleanroom validation standards, these advanced cleaning and coating machines and fluids contribute to the production of reliable, high-performance medical devices. Embrace the power of solvent-based cleaning and vapour degreasing for consistent cleanliness and enhanced medtech manufacturing outcomes.

Working with a supplier experienced in the special requirements associated with vapor degreaser cleaning and coating in a cleanroom environment ensures the utilisation of the best fluids and methods.

by Elizabeth Norwood

8 June 2023

14:00