The cleaning strength of PCB cleaners is usually measured by an industry benchmark called Kb (Kauri Butanol) value. the greater the Kb value is usually better, meaning that the cleaner has more cleaning power. But there are trade-offs - stronger solvents may have compatibility issues with plastics, coatings, inks and other ingredients. Smart engineers check the Kb values of the products they clean and make sure they avoid costly surprises.
Contamination-related failures are increasing in the electronics industry. As smaller components and more densely assembled circuit boards become the norm, fault management and device quality assurance issues are important.
An effective cleaning process is critical to the life of electrical components, but it is very challenging. Many manufacturers choose solvent cleaning, finding it more effective, more flexible and less expensive than other methods such as water cleaning. Before deciding which cleaning agent to use, it is important to study the Kb value because it is a good benchmark and starting point for analysis.
The cleaning strength of solvent cleaners is usually calculated by the Kauri-Butanol (Kb) test standardized by the International Society for Testing and Materials (ASTM). This is a simple process that is performed using a standardized test material called butanol, which is a thick and flexible rubber. Under controlled conditions (e.g., temperature, pressure, etc.), it is soaked in a solvent for a period of time. The remaining butanol is then measured to determine the amount of material dissolved by the solvent. A value of 10 is very mild, while anything above 70 is a corrosive solvent. This indicator is used to determine the relative cleaning ability of the solvent, which is a good indicator when choosing a cleaning solution for PCBs.
The Kb value can be found in the solvent technical data sheet. This will show a number that allows you to gauge the strength of the cleaner and suitability for the contaminant to be removed. solvents with lower Kb values will dissolve grease but will not handle ions and solder. solvents with higher Kb values may be fast and effective cleaners, but may attack plastic parts. For this reason, it is important to consider the components to be cleaned and their housing materials. Depending on the level of contamination, ensure that the solvent has the "horsepower" to dissolve contamination and clean effectively without affecting the components themselves.
Although the Kb value is a good indicator of the strength of the cleaning agent, but there are other factors need to be considered. The Kb value test has some limitations. For example, the test must be conducted at 25 ℃ and an atmospheric pressure. Testing under other conditions will produce different results. It is important to use cleaning solvents from reliable suppliers who will perform the test under standardized and regulated conditions. There are also solvents that cannot be evaluated by the Kb method because it dissolves butanol gum almost immediately.
Choosing a cleaning agent with the best Kb value is a balancing act, while other factors that affect cleaning performance need to be considered. The technician must also check surface tension and density, toxicity and flammability, as well as the cost of cleaning each part. Let's also not forget the regulations on the environmental friendliness and safety of solvents. Your choice must be sustainable and not compromise cleaning performance.
Today, many engineers will not only focus on Kb values, but will also use systematic testing procedures that provide a realistic picture of the solvent composition, contaminants and cleaning process in a rigorous manner. Without testing it is difficult to predict the cleaning effect of the fluid. The effect of the cleaning process may vary depending on the contaminants, the solvent selected, the application, the cleaning system and the physical shape of the parts being cleaned.
Reliable cleaning solvent suppliers should provide a "cleaning test". Here the test in order to clean the components and contaminants to choose the correct cleaning fluid. The results are analyzed to select the correct critical cleaning solvent and the required process, weighing all the necessary factors to find the right "perfect" cleaning solution. Often, the results are surprising: some mild solvents may clean as well or better than those with high Kb values, maintaining good material compatibility. Importantly, solvents can be tailored to have a wide range of Kb values, which gives them very versatile cleaning performance.
When considering Kb values, remember to be thorough and seek professional advice on critical cleaning requirements.
Zhejiang NeoDen Technology Co., Ltd. has been manufacturing and exporting various small pick and place machines since 2010. Taking advantage of our own rich experienced R&D, well trained production, NeoDen wins great reputation from the world wide customers. with global presence in over 130 countries, the excellent performance, high accuracy and reliability of NeoDen PNP machines make them perfect for R&D, professional prototyping and small to medium batch production. We provide professional solution of one stop SMT equipment.
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