Sustainable Cleaning Fluids for Reliable Long-Term Medical Device Production

By Elizabeth Norwood, MicroCare Senior Chemist

Printed circuit boards (PCBs) are crucial components in various healthcare devices and applications, driving advancements in diagnostics, patient care, and research. With the continuous progress in medical innovation and the increasing reliance on electronic devices, the demand for PCBs in the medical industry is on the rise.

The integration of complex and miniaturized PCBs in telemedicine, wearables, medical imaging systems, and other healthcare applications is anticipated by medical device engineers to fuel the growing need for PCBs in the future. These specialized PCBs enable the development of advanced medical devices, improving diagnostic accuracy and efficiency, while miniaturization allows for compact and portable devices that enhance remote monitoring and real-time feedback. They also play a crucial role in medical imaging systems, facilitating precise data processing and transmission for high-quality imaging. Furthermore, PCBs enable the creation of wearable medical devices that monitor vital signs and track health parameters, making continuous healthcare tracking more accessible. The expanding field of telemedicine further amplifies the demand for PCBs.

When manufacturing medical devices, quality and reliability are critical. They must adhere to stringent standards to guarantee the safety, quality, consistency, and security of these products. Furthermore, additional regulations necessitate careful consideration — specifically, those pertaining to environmental sustainability.

In a medical electronics industry that is becoming more focused on environmental awareness, it is vital to use manufacturing methods that prioritize sustainability while maintaining device reliability.

Cleaning for consistency

Cleanliness is paramount in medical device manufacturing. It ensures the safety and effectiveness of the final product. PCBs are intricate components that can accumulate contaminants, such as flux residues, soldering debris, or dust particles, during the manufacturing process.

Contaminants on the PCB surface can create unintended electrical paths, leading to malfunctions, signal interference, or even electrical shorts. They can also harbor pyrogenic microorganisms or particles that may compromise patient safety.

Thorough cleaning of the PCBs ensures that the electrical connections are free from debris and contaminants, promoting reliable, accurate, and long-term operation. Therefore, today's medical device manufacturers must find a cleaning method that achieves excellent cleaning results and is environmentally sustainable, safeguarding both workers and the planet.

Green cleaning

The healthcare sectors of the United States, Canada, England, and Australia emit an estimated 748 million metric tons of greenhouse gases each year, exceeding the carbon emissions of all but six nations worldwide. The World Economic Forum stated that healthcare systems account for over 4% of global CO2 emissions on a global average basis. That figure is closer to 10% of national emissions for most industrialized nations — more than the aviation or shipping sectors. These staggering statistics call for medical electronic manufacturers to contribute to "green planning" by incorporating sustainable practices across all production areas.

Meeting stringent quality and reliability standards is critical in manufacturing medical devices. Additionally, device manufacturers must carefully consider environmentally sustainable regulations. Emphasizing sustainability in the cleaning process is vital, as cleanliness is essential for the safety and effectiveness of medical devices and their internal PCBs.

This, however, can be a challenge as PCBs become smaller, more densely packed with circuitry, and contain a combination of materials. Finding a cleaning process that effectively cleans these complex and delicate assemblies, but meets environmental regulations, may seem like an impossible task.

Vapor degreasing as an option

Vapor degreasing, when combined with advanced sustainable fluids, is a cleaning method that addresses these challenges. It is increasingly used by manufacturers within the medical electronics sector due to its compliance with emerging environmental regulations governing cleaning fluid use and worker safety. Additionally, it offers an efficient cleaning process that simplifies adherence to strict regulations like those stipulated by FDA and the International Standards Organization (ISO), which require medical device manufacturers to validate their cleaning processes to demonstrate compliance with standards and ensures that the devices meet stringent quality and safety requirements.

Vapor degreasing effectively cleans PCBs using a closed-loop system with a boil sump and rinse sump. The cleaning fluid heats in the boil sump, and the PCBs are immersed into the heated fluid for cleaning. After cleaning, the boards are either manually or mechanically transferred to the rinse sump for final rinse in more uncontaminated fluid. The PCBs are then dried and cooled within a vapor blanket. Modern cleaning fluids used in vapor degreasers easily remove particles and contaminants from tightly packed assemblies, leaving no residue or spots, making it ideal for critical applications in the medical electronics industry.

Meeting standards

Modern cleaning fluids not only clean exceptionally well, but also meet the stringent regulatory requirements imposed by the medical industry and international and regional governing bodies.

These innovative cleaning fluids align with the exacting standards outlined by the Environmental Protection Agency (EPA) and the EU's Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) program. They are unlike older legacy solvents like trichloroethylene (TCE) perchloroethylene (Perc), and n-propyl bromide (nPB), which present environmental or health concerns. Modern vapor degreasing fluids, based on Hydrofluoroolefin (HFO) technology, possess a zero ozone deleting potential (ODP), and feature low volatile organic compound (VOC) content minimizing harmful emissions. These fluids also exhibit a low global warming potential (GWP), contributing to efforts in mitigating climate change. Furthermore, modern vapor degreasing fluids are not hazardous air pollutants (HAP) and do not require National Emission Standards for Hazardous Air Pollutants (NESHAP) permits.

By employing these progressive cleaning fluids, the medical manufacturing industry can adopt environmentally sustainable practices without compromising cleaning performance.

Reducing energy use

The reduction of energy use is crucial in the medical device manufacturing industry, as it is one of the most energy-intensive sectors. Sustainable efforts become even more significant in this context. By reducing energy consumption, manufacturers contribute to environmental preservation and could cut costs. Medical device manufacturers should prioritize sustainability and focus on strategies to help minimize energy usage. Implementing energy-saving measures not only lowers their carbon footprint but also improves their financial performance by reducing operational costs.

Vapor degreasing stands out as an advantageous cleaning process compared to other methods. Unlike traditional approaches, vapor degreasing eliminates the need for water, preserving this valuable non-renewable resource. Moreover, it significantly reduces energy consumption by eliminating the necessity to heat water for cleaning purposes, avoiding the use of energy-intensive air knives or fans for drying PCBS, and minimizing the energy required for treating and purifying wastewater.

Thanks to the low boiling points and heat of vaporization of vapor degreasing fluids, the energy needed to heat the cleaning solution within the machine is reduced, making the cleaning process more efficient. Additionally, PCBs emerging from the vapor degreaser are completely dry, eliminating the need for energy-intensive drying methods like blowers. This leads to reduced electricity usage, lower fossil fuel consumption, and diminished greenhouse gas emissions, contributing to a more environmentally friendly and sustainable manufacturing process.

Recycle, reuse

Sustainable vapor degreasing fluids can be recycled and reused hundreds of times within the machine before requiring replenishment, making them both cost-effective and environmentally friendly cleaning agents. Since these cleaning fluids do not necessitate stabilizers, scavengers, or weekly acid acceptance testing often required for chlorinated or brominated cleaning solvents, they are easily recyclable onsite. New cleaning fluids can be recycled by distillation in the vapor degreaser, increasing their production floor service life, reducing overall maintenance costs, and minimizing the generation of hazardous waste.

Staff safety

When seeking sustainable cleaning solutions, prioritizing worker safety is of utmost importance. Supporting health and safety through greener cleaning practices is vital. It is crucial to avoid chemistries that may be harmful or under regulatory scrutiny and seek alternative solutions.

Advanced vapor degreasing fluids boast excellent safety profiles. They exhibit non-flammable properties, enhancing their safety credentials. Many modern vapor degreasing fluids have favorable toxicity profiles and high threshold limit values (TLVs), making them safer for exposed workers.

Meeting the quality and sustainability challenge

Cleaning plays a vital role in maintaining the reliability of devices and meeting quality and regulatory standards in the production of medical electronic components. However, it is equally important to focus on the sustainability of the cleaning process. Manufacturers can effectively balance device reliability and environmental responsibility by giving priority to green cleaning methods, including the utilization of advanced fluids in vapor degreasing.

By adopting green cleaning practices, manufacturers can achieve several benefits. Firstly, advanced fluids used in vapor degreasing offer superior cleaning performance, ensuring that the components are free from contaminants. This contributes to the overall reliability and functionality of the devices, reducing the risk of malfunction or performance issues.

Secondly, green cleaning methods prioritize environmental sustainability by minimizing the negative impact on the ecosystem. Advanced fluids used in vapor degreasing are engineered by chemists to have low GWPs and zero ODPs, which means they have reduced environmental footprint compared to traditional solvents. They have a lower potential for air pollution and can be easily recycled or reclaimed, further reducing waste generation.

Furthermore, green cleaning methods require less energy and water consumption, leading to additional sustainability benefits. By minimizing resource usage, manufacturers can reduce their carbon footprint and conserve natural resources.

In addition to the immediate environmental advantages, adopting green cleaning practices can enhance a manufacturer's reputation and appeal to environmentally conscious consumers and regulatory bodies. Many organizations and consumers today value sustainability and eco-friendly practices. By prioritizing green cleaning, manufacturers can demonstrate their commitment to environmental responsibility.

About the author:

Elizabeth Norwood is a senior chemist at MicroCare, which offers precision cleaning solutions. She has been in the industry more than 25 years and holds a Bachelor of Science in Chemistry from the University of St. Joseph. Norwood researches, develops, and tests cleaning-related products. She currently has one patent issued and two pending for her work.

For more information, visit www.microcare.com.