Technical Articles

Technical Articles

Additional environmental product to the Electrolube Safewash Range

Tags: Safewash, Electronic and General Purpose Cleaning, Environment, Cleaning

Safewash Total

Electrolube have an additional product, Safewash Total, to their well established water based cleaning range. Safewash Total is a specially formulated blend of non-flammable solvents which form a micro-emulsion when mixed with water. Designed for removal of a wide range of residues and contaminants from printed circuit boards with all types of application methods, including dishwasher, in-line pressure systems, ultrasonic and spray under immersion.

Cleaning has been an essential stage within electronics manufacturing processes for many years, to remove potentially harmful contaminants that could lead to PCB failure. Such contaminants include flux, solder and adhesive residues, and other more general contaminants such as dust and fingerprints present from various stages of manufacture. As the developing electronics market sees modern assemblies getting smaller and smaller, the requirement for high performance and reliability is stronger than ever. In order to achieve good insulation resistance, and ensure adhesion of conformal coatings and encapsulants, cleanliness of the electronic assemblies is essential.

With environmental concerns at an all time high many electronics manufacturers are moving away from traditional solvent cleaners with ozone depleting chemicals and high VOC content, and replacing them with safer alternatives. Although many solvent cleaners allow a convenient single stage process, water-based cleaners have several advantages including non-flammable properties, low odour, low/non-VOC and very low toxicity. Recent improvements in water-based technologies allow changes to be made with full confidence that assembly performance and reliability will not be compromised, and can in fact be improved.

In the past, the specific choice of cleaner has been dependant on the equipment choice, whether it be ultrasonic, spray under immersion or dishwasher type application. The use of Safewash Total now allows the use of a single product for all types of processing. Versatility is partially due to the cleaner being supplied as a concentrate, allowing flexibility in terms of the application concentration in addition to temperature. At approximately 20% concentration the solution has low foaming properties, particularly at the elevated temperatures commonly used during spray application such as dishwasher and in-line cleaning. Used in immersion applications such as ultrasonic, Safewash Total will remove residues from screens, stencils, boards and accessories at concentrations as low as 10%.

In addition to the process versatility, Safewash Total has been formulated to remove a wide range of contaminants, including residues from leaded, lead-free and no-clean fluxes, pastes and adhesives, as well as general dust and debris. The product is also easy to rinse and can be used in conjunction with Safewash Defoamer when cleaning residues which can cause extensive foaming in dishwasher applications.

A further advantage of Safewash Total is that although it is supplied as a concentrate to allow process flexibility and minimize transport costs, it also contains a non-silicate corrosion inhibitor to enable safe use on sensitive metals such as copper, silver, and aluminium. Generally, water based cleaners that contain inhibitors have previously only been supplied at a ready-to-use concentration. While being convenient for the user, this means transporting a large amount of water within the product which is costly in both financial and environmental terms. Safewash Total is classified as non-hazardous for transport, and once diluted to the in-use concentration is completely unclassified, making it one of the safest cleaners available.

There is a variety of solution control methods that can be used for monitoring the concentration and contamination level of Safewash Total through its extensive lifetime; the most suitable for a specific application will however depend on the type of residue being removed. Acidic flux residues will generally lower the pH and increase the conductivity, while being relatively unaffected by variations in concentration.

Graph showing pH values of SWAT at various concentrations. Graph showing conductivity of SWAT concentrations at 20 degrees. Graph of SWAT BRIX values.

Refractive index, or BRIX, gives a measurement of the solids level in the cleaner. Although this can give some indication of contamination level, changes in refractive index over time are more likely to be as a result of variations in the concentration of the solution, often affected by drag out of the cleaning solution into the rinsing cycle. All these methods are simple and require the use of a relatively inexpensive meter.

Graph of SWAT cloud temperatures.

Cloud temperature measurement is another alternative method to control the solution. Simply warming a small sample of the cleaning solution and noting the temperature at which it becomes cloudy will indicate if the solution has become highly contaminated or the concentration has dropped due to drag out.

Electrolube Safewash range is the most effective family of aqueous cleaning products available. It is currently in use by major manufacturers in a wide variety of cleaning machines and cleans to both military and commercial standards, at minimal financial and environmental cost. The addition of Safewash Total has ensured that the range continues to provide superior cleaning performance, allow process flexibility and meet the environmental goals of modern electronics manufacturers.

Electrolube is a leading manufacturer of electro-chemicals for electronics, automotive and industrial manufacturing. R&D, quality and environmental concerns are fundamental to the Electrolube philosophy of providing the highest level of customer service. The continued global expansion of Electrolube and its innovative range of environmentally friendly products proves that the total capability and dedication to customer care combine to create a winning formula.

 


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