The short answer almost always is, NO, don’t do this. It can be extremely dangerous. YouTube has a number of videos showing people cleaning parts in ultrasonic machines filled with IPA alcohol. Here at MicroCare we always are amazed at this. It is absolutely not an acceptable industrial process.
Some people use IPA alcohol or “white spirits” in ultrasonic tanks to get better cleaning. This is a very dangerous choice and is not recommended. Why? Because when an ultrasonic transducer fails, it will shoot all of it’s electrical energy out of the transducer and into the cleaning fluid. If this is a flammable liquid you end up with a really nasty fireball. So if you must use ultrasonics, you must use a nonflammable solvent, and the only one that’s widely accepted for single-sump ultrasonic degreasing is water and soap.
Another risk stems from the vapors that can accumulate over an ultrasonic tank. Ultrasonic agitation heats the cleaning fluid and creates vapors above the surface of the liquid and over the machine. If the machine is not completely and properly ground, a tiny spark of static electricity can ignite those highly-oxygenated vapors. Again, fireballs are consider poor work-place hygiene. Take a look at these college kids who are able to toast bread with the the spark from static electricity. If you think static isn’t a factor in your factory, then you haven’t looked.
The one exception would be a vapor degreaser or an ultrasonic tank specifically engineered for flammable solvents. These can be expensive but extremely effective.
If your company really needs to get these parts properly and consistently cleaned, vapor degreasing with a modern, nonflammable solvent might be a better choice for you. Vapor degreasing approaches the problem completely differently and generally produces clean parts at the lowest cost per-part-cleaned.
A screen capture from a Youtube video showing the surprising power effect of static electricity. Voltages like this could set any flammable solvent in an ultrasonic tank on fire