Removal of flux with vegetable oil and soap
Brüel & Kjær earlier used freon for removing flux residue from metal parts. Now, the parts are soaked in vegetable oil and then washed with mild detergent in an industrial automatic dishwasher. This substitution ensures a more efficient cleaning than with freon.
Description of the substitution
Brüel & Kjær previously used freon to remove flux residues from metal components. In connection with the Law of 01.07.1993 which prohibited use of freon for this purpose, a collaboration with Danfoss was initiated to find an alternative. The idea was adopted from the graphics industries' use of vegetable-based cleaners. During the last 10 years, Brüel & Kjær has effectively removed flux residues using the following method: The objects are soaked at room temperature for at least 10 mins in the product "Naturen" (a vegetable oil containing cocoa fatty acid esters) . The chamber is equipped with a flow system such that the oil flows past the objects, is filtered and recirculated. Next, the objects are lifted out and transferred to an industrial dishwasher. Here they are washed at 50-70 degrees Centigrade. The product "Nordchem 215" is used as the washing agent. Next, the objects are dried in a drying cabinet using hot air.
The dishwasher has a drain leading directly to the sewage system. The oil bath only needs replacing as required (about every 3 months depending on how often the bath is used) because the flux agents precipitate out.
The method is more effective than freon cleaning. Approximately 0.2-0.3 micrograms NaCl/cm2 are used. 0,2 - 0,3. The method is cheaper than freon cleaning (environmental aspects, waste, procurements),
but, detailed calculations of this have not been made.
Considerable OCH&S benefits as well as a reduced fire hazard.
The example includes
Safety and health at work:
Technical requirements the product must fulfil
What problems made you look for a substitution?
Use of freon prohibited after 01.07.1993.
Technnically, freon cleaning was satisfactory.
What substance or product did you use before?
What solution did you find?
Vegetable oil based on cocoa fatty acid ester - "Naturen"
Washing in dishwashers using the soap "Nordchem 215" caused local irritation.
Assessment of the solution
Degree of cleanliness measured - better than freon.
Better working environment
Reduced fire hazard
What other solutions did you try/assess?
Danfoss has even used vegetable oil products with a lower viscosity than "Naturen" with satisfactory results.
A wide range of mild soaps/detergents can be used for the afterwash in the dishwasher.
Further information or literature
Minutes of the Experiences meeting:
Background for selection of substitution for cleaning flux with ARKLONE mixtures.
Breakdown into industries
Iron and metal, electronics and automotive industries
Who entered the example?
Brüel & Kjær
Thursday, November 01, 2007