Simple & Effective Ways to Protect Your Aluminum Parts
Instructor: Eric Bromley
Are you seeing white spots?
What are your thoughts on using a rinse aid in the final rinse tank to help with parts spotting? Rinse aid will help with some spotting. It does work to help with the larger sheeted pieces. A couple of things to caution with that is that you need to maintain the percentage at a relatively low percentage because if you do get a high concentration of the rinse aid in your rinse tank, that in itself can cause some spots and streaking. Also, if you do have a cascading rinse, be aware that as the rinse is being replenished, it is also going to be taking out some of the rinse aid so it takes a little bit of balancing, but it is certainly worth evaluating for your application. It doesn’t work with all applications, but it is worth a test.
You mentioned pH can sometimes cause spotting, can you elaborate more? Sure! A lot of times, especially coolants, they have a pH that can be very aggressive in some cutting metals as well because of the job they have to do. Not only in the machining process, but also in the stamping and the forming processes. The pH itself can affect some of the softer aluminums where it can start to etch the surface. This is not only important for aesthetic, but also any areas that have a flat mating surface for seal, be it a pump or compressor, it’s very important the surface stays pristine. You need to be aware of that as being potential for some problems.
You talked mostly about the wash and rinse processes, how important is the drier operation with preventing spotting? That is an important step. I didn’t mention it on purpose because the drier is importer because you need to align the manifolds and the pressure so that it sheets the water off and away from the product. Its also important to get into any cupping areas, so maybe some rotation during drying is necessary, but drying is important to get the water spots off the parts prior to letting them air dry or to move to the next process. That is an important step for sure.