Disc Drive Parts Cleaning

 

Question:

My company is working with several disc drive parts manufacturers. There has been a move lately to clean with solvents in either a vapor degreaser or a vacuum-style vapor degreaser. Using one of the newer so called exotic solvents with alcohol addition seems to provide better results, including particulate removal, than DI water. Cleaning is so critical for some of these parts that water no longer is doing the job. The added density of these solvents seems to be helping remove more particulates. We would be pleased to test clean parts for C.M. (C.M. posed his question in the May 2000 issue of Products Finishing). Can you answer this? If not, just let me know. A.G.

Answer:

This is not really a question, so I can only comment on the statements. I am not so sure that the added density is increasing the cleanliness as much as the reduction in surface tension. The exotic solvents to which you refer are often the hydrofluorocarbons and hydrofluoroethers. These do not have a very low surface tension, but the addition of the alcohol significantly reduces the surface tension of the mixture. This will make the solvent mixture much more effective at removal of soils and particulates than would DI water alone in the same application.