I present to industry on a regular basis, about the importance of “Process over Product” when it comes to getting clean parts in your metal finishing operation. This was reinforced to me more than ever, during an onsite cleaning trial at a new customer this week.
In this particular case we are cleaning a critical aluminum part, and a improved cleaner was needed. But it is only part of the solution. In fact, regardless of how good the cleaner chemistry performed in the tank, without significant improvements to other parts of the process, the desired cleanliness levels can’t be obtained. So, here is what I saw, and what I recommended to solve the pain.
Ultrasonic transducers are only good if they are used properly. This process has, and requires, the use of ultrasonic energy to facilitate proper cleaning. Poor fixturing of the parts relative to the position of the transducers in the tank and improper power settings contribute to poor cleaning results. Once these conditions were corrected, dramatic improvements in removal of the soils are seen. The tool is only effective if used properly.
Good rinsing REALLY does matter. The best cleaner you can find still does not matter, if you can’t rinse it and the contaminates it removes off the surface of your parts. In some cases, cleaner residues can be more detrimental than the soils themselves. Allowing hot aqueous cleaner solution to dry on parts almost guarantees a poor result. Get the parts from the cleaner tank to the rinses as quickly as possible. If drag-out of the solution is a concern, utilize a tank in between steps to recapture and recycle the solution.
Let me say it one more time… Good rinsing REALLY does matter! If you want clean parts you have to rinse with clean water. In this case, the customer has a zero discharge rinse water recycle system that is believed to return clean water to the rinse tank. In reality, his system can only remove solids, and does not remove any organic contaminates, such as residual surfactants, and the water soluble lube carried into the tank. So, as these materials build up in the rinse tank, they only re-soil the surface. The practice of recycling water is great, but only if the water is truly clean. The addition of a media bed that can remove the organics will produce clean water. Another great method for insuring clean rinses, is installing a counter flow rinse system. With the addition of just one extra rinse tank, counter flowing clean water into the first, you can dramatically improve rinsing. This method will also improve your ability to use a water recycling system.
Let me conclude this blog, by saying that I truly believe in the holistic approach to solving the really difficult cleaning challenges. So challenge me, and the other experts at Hubbard-Hall to solve yours today.
Director of Cleaning Technologies & Product Development