Selecting the Right Cleaner for the Job
Cleaning is an essential step prior to most metal finishing and heat treating operations. Here are eight basic questions that must be answered in order to choose the best cleaner for the job.
1. What is the overall process?
Typical processes requiring cleaning include black oxide, plating, phosphating, heat treating, anodizing, and chromating just to name a few. Different degrees of cleanliness will be required depending on the process. For instance, decorative plating cleanliness requirements are more stringent than those for black oxide.
2. What metals are to be cleaned?
Steel, cast iron, copper, nickel and titanium can be cleaned with any alkaline cleaner, but aluminum, brass, bronze and zinc must be cleaned with an inhibited cleaner.
3. What are the soils to be removed?
There are numerous types of soils that can be present including oils, greases, cutting fluids, rust preventatives, drawing compounds, buffing compounds, smut, oxides and scale.
4. What equipment will be used?
Equipment can vary from soak, spray, electrolytic, agi-lift, ultrasonic, vibratory, etc. Cleaners are formulated specifically for how they are applied. For example, a soak cleaner would not be an appropriate choice to be used in spray wash equipment.
5. Are there any process limitations?
Is there a maximum temperature? Can cleaning time vary or is it set as in the case of an automated line? Is there a rinse after the cleaner?
6. What is the water quality?
Cleaners used in hard water areas should contain a sequestrant to tie up calcium and magnesium ions. This will prevent the formation of insoluble soaps and other compounds that would otherwise decrease the effectiveness of the cleaner.
7. Are there any product requirements?
Perhaps there is a preference over a powder or a liquid product. In some processes it may be advantageous to have a cleaner that will split oil while in others it will be better to have an emulsifier.
8. Are there any restrictions?
Some areas do not allow phosphates due to eutrophication. Silicated cleaners are not a good choice when ultrafiltration is used. Certain chelators may cause problems in waste treat.
Sharing the answers to these questions with your chemical supplier is the first step to ensuring that the proper cleaner is recommended for your process.
Submited by Diana St Jacques – Chief Chemist
Click Here to view Heatbath products for metal cleaning.Return to the List of Articles.