The market for medical electronics is huge and growing. The astounding capabilities of digital technology and broadband connectivity are “a perfect storm,” enabling doctors to diagnose more accurately and offer therapies more precisely than ever before. They also offer labor-saving benefits that are important in these days of tight medical budgets. For example, products and systems that reduce costs and enable patients and families to do more for themselves — collectively called “wellness management” — are exciting new business opportunities. Remote patient monitoring systems can replace the need for expensive hospital stays. Modern electronics clearly can both improve care and reduce costs. Because of these advantages, the global medical electronics market is expected to reach $4.4 billion by 2022, growing more than 5 percent per annum over the next decade.

With this growth comes the need to ensure that these devices work effectively and reliably. But with the increasing use of complex miniature components with ever-tighter tolerances, managing faults can be problematic. Quality cleaning can make a big difference.

No Room for Error

The operations of a vapor degreaser are very simple. The solvent is heated to around 40 °C in the “boil sump, “which is the primary cleaning chamber. Solvent vapors (which are equivalent to steam from boiling water) rise from the boil sump and are trapped at the top of the machine. There, they cool and condense back into a liquid state. This fresh, pure condensate is used to rinse parts in the rinse sump, which overflows back into the boil sump to complete the loop. The solvent never wears out, and the system inherently recycles the solvent, saving resources and money.

Companies designing, manufacturing, and certifying medical electronics face a host of challenges unfamiliar to the makers of traditional consumer electronics. Consumer electronics (CE) cannot be compared to medical electronics (ME). Consumer electronics are all about “good enough” manufacturing. In contrast, medical device companies value safety, quality, and predictability in order to maximize performance and minimize liability. Unexpectedly, many challenging production and performance issues can be minimized with proper post-assembly cleaning of the printed circuit boards (PCBs) and mechanical assemblies used in these systems.

Cleaning is critical for PCB manufacturers as smaller, more densely populated circuit boards become a standard feature in the medical electronic industry. Without it devices will not function as they should and will not stand up to the rigorous regulations put in place by governing bodies.

Consumer electronics can be built to some very generalized standards. The most commonly used are promulgated by the Institute of Printed Circuits (IPC), which defines the manner in which PCB assembly should be performed. This may sound rigorous, but for the medical world it’s not nearly good enough.

The processes used in the development and manufacture of medical electronics offer no room for error. This risk-averse strategy drives the need for products to pass tough regulatory requirements because patient safety is always the priority. Therefore, cleaning should be top of the checklist for manufacturers.

The benchmark standard for medical devices is provided by the International Electrotechnical Commission (IEC) in a document called IEC 60601-1. This standard is applicable to any “electrical equipment having an applied part or transferring energy to or from the patient or detecting such energy to or from the patient.”

There is also ISO 10993. This standard evaluates devices within a risk management framework to ensure they are safe. Bioburden, pyrogens, and sterility are all assessed with this process.

Cleaning is critical to ensure that medical electronic devices work as they should and meet the relevant standards and regulations. However, the increasing use of miniature components and complex PCBs make it a challenge.

Mission-Critical Cleaning Methods

Jay Tourigny, MicroCare senior vice president and Venesia Hurtubise, a chemist with the company, develop a cleaning protocol for a large metal casting in a Branson vapor degreaser. There are numerous factors that can be tweaked in vapor degreasing to optimize cleaning results, throughput, or costs, depending on the goals of the organization.

The computing power and functionality of modern medical devices is directly proportional to the processing power of the PCBs within them. That power is the result of smaller, more densely populated PCBs that are hard to clean. Better cleaning enables engineers to specify stronger, more active fluxes, which results in better solder joints. Failing solder joints cause a huge percentage of PCB failures, so cleaning is key to their success. Problems with “cold joints,” insufficient wetting, bridging, and shorts also can be avoided. In short, better cleaning means better PCBs, which means better medical electronics.

Plus, it’s not just fluxes that companies need to be concerned about. Adhesives, conformal coatings, fingerprint residues, etc. all need to be removed. This variety of contamination makes cleaning complex.

In decades’ past, aqueous cleaning was acceptable as it was cheap and worked with the PCBs of the time. But as electronic devices become smaller and hotter, with intricate shapes and delicate parts, many manufacturers are opting for solvent cleaning because it delivers better cleaning, more consistently, more quickly, and at a lower cost.

In previous decades, vapor degreasing was the default cleaning process for most industries. In the 1990s, aqueous cleaning became more popular as a “greener” option. Many young engineers today have never seen a vapor degreaser and are unfamiliar with the thermodynamics involved. When the performance and operations of vapor cleaning are explained the whole process seems like magic, especially when compared with the familiar but large, wet and noisy aqueous cleaning systems with which they are familiar.

So, here’s the punchline engineers need to realize: advances in solvent technology have changed the game. Innovations are leading to environmentally acceptable cleaning options that outperform aqueous cleaners on today’s modern electronics. Modern, nonflammable, environmentally progressive solvent cleaning can make a substantial and relatively inexpensive enhancement to the performance, reliability, and longevity of medical devices. For example, solvents can greatly minimize bioburden issues. Many manufacturers and engineers are discovering that a properly designed and maintained vapor degreaser can be both more effective and more environmentally friendly than an aqueous-based cleaning system, and lower costs at the same time.