Nearly all efforts at cleaning disposable medical devices require several steps during manufacturing. Each cleaning process is designed to remove contamination created during manufacturing processes, such as particulate, oils or inorganics. But achieving high quality cleaning results is a challenge in the world of medical devices because of the complex assemblies, intricate shapes, sensitive substrates and delicate parts. Many device manufacturers use water-based cleaning systems and simply tolerate the problems those machines bring. But today, many new solvent options are available. These new chemistries are highly effective, safe, environmentally friendly and affordable. In response, medical device manufacturers are once again realizing that vapor degreasing is highly effective method for critical cleaning.
The author describes the flawed decision-making criteria used by many companies when selecting cleaning equipment. All too often, companies focus on the “cost-per-liter” of the cleaning fluid as the principle life-cycle cost. This is misleading because aqueous cleaning systems generally only use their inexpensive cleaning saponifiers and surfactants once, while solvent systems recycle the cleaning fluid indefinitely — the solvent never wears out. This distinction results in substantially different cleaning costs. The model also includes indirect costs, such as maintenance, floor space, ancillary systems, and labor costs. Modern solvent cleaning usually is faster and less expensive than aqueous cleaning.
First published November 2o11
Revised June 2018
For decades, vapor degreasing was the “go to” precision cleaning technology. This came to an end in the 1990s when the ozone issue forced the phase-out of the most popular vapor degreasing solvents. Water-based cleaning systems filled some of the void. But today users of aqueous cleaners know those systems guzzle electricity, have large footprints, require significant capital investment, are maintenance intensive, and usually require extensive wastewater treatment systems. It’s time to revisit vapor degreasing.
Advancements in the electronics industry are continuously leading to more sophisticated, intricate and miniaturized circuitry, and cleaning these smaller, denser, hotter components has become a major issue. Additionally, lead-free, no-clean and halide-free flux formulations have introduced new cleaning obstacles, and the phase-out of old-style solvents has eliminated many popular choices. The purpose of this paper is to present a new cleaning chemistry and process for difficult no-clean, lead-free and high temperature flux residues on reflowed PCBs. The proposed solvents are drop-in replacements for older solvent cleaners and also are highly acceptable alternatives to complex aqueous cleaning systems. These new cleaning technologies enable high quality results with high through-put.
The authors explain the thermodynamics and operational techniques behind the working of a modern vapor degreaser. They contrasts those systems with old-style solvent degreasers as well as the complexities of aqueous cleaning systems. The pros and cons of each are explored as well as a basic shopping list of features and capabilities that will help companies keep cleaning costs low. This white paper is a great primer on the basics of vapor degreasing.
In this reprint from Finishing Today magazine, the author explores the problems inherent in aqueous cleaning processes: large footprints, require large capital investments, consume electricity at a prodigious rate, are maintenance intensive, and require expensive waste water treatment systems. Vapor degreasing resolves all of these problems but introduces certain new issues that must be considered when upgrading cleaning systems. With modern equipment and solvents, vapor degreasing is a safe, cost-effective and environmentally acceptable cleaning method.
Many companies are considering changing from their old-style aqueous cleaning systems to newer, industrial green cleaning products such as modern solvent-based vapor degreaser cleaning systems. The author explains the differences between the choices, highlights some of the myths of aqueous cleaning and shows that a modern vapor degreasers with modern, safe solvents can be more budget-friendly, planet-friendly and people-friendly than aqueous cleaners of equal capacity.
In the world of precision cleaning, there are four common process choices for engineers: hydrocarbon cleaning, aqueous cleaning, semi-aqueous cleaning, and solvent cleaning with vapor degreasers. Each method has its strength and weaknesses, but the authors suggest that the most environmentally acceptable choice for critical cleaning is vapor degreasing with modern specialty solvents. This is particularly true when energy consumption and costs are compared. The vast majority of atmospheric emissions in the world today come from the burning of fossil fuels, and much of that pollution is generated trying to produce electricity. Using electricity conservatively helps protect the planet and your budget.
Solvents can accomplish this due to the unique nature of the chemistries. For example, if a device has complex geometries, production debris can become trapped in tight spaces, making cleaning with high-boiling fluids difficult and inconsistent. Quality standards on finished components may require black light inspection, particle count, water break or other analysis to confirm cleanliness.
Cleaning with solvents has been a fine choice because they are stable and highly effective. These fluids also are low in viscosity and surface tension, which allows them to get into tight crevices and wet all the surfaces of the parts. They also offer high solvency (“Kb Value”) which allows them to rigorously clean the surface and displace stubborn soils. All of these factors combine to produce the best possible cleaning at the lowest cost-per-part-cleaned.
First Published April 2014
Revised and Updated April 2017