Indirect ultrasonic cleaning explained

Indirect ultrasonic cleaning explained

I get a lot of questions about this – mostly from people who don’t know what to call it. Indirect ultrasonic cleaning refers to the practice of taking an ultrasonic tank, filling it with water or cleaning chemistry, then inserting a solid container into the tank. The solid container is usually a solid tray or a beaker held in a beaker cover. The container is then filled either with a different liquid, or the same liquid.

The physics of the setup are simple. Ultrasonic energy is transmitted from the transducers which are usually bonded to the bottom of the tank. The wavefront propagates through the water in the tank until it encounters a physical object, the side of the tank, or the air/water interface at the top of the tank. If a solid container filled with another liquid is encountered, the ultrasonic energy will pass through the container wall into that liquid, and sonify that liquid as well.

Makes sense – but why would anyone want to do that?

• You can fill your main tank with clean water, and keep all the soil inside your solid tray or beaker.
  
• This means your tank will never have to be cleaned.
  
• You can do multiple batches of small parts in different cleaning solutions without cross-contamination.
  
• Using a stainless steel or glass beaker will allow you to clean using caustic or other harsh liquids that you do not want your tank exposed to.
  
• You can clean with expensive solutions and limit the amount of chemistry you need to buy.
  
• Clean the same part in multiple solutions as an experiment to determine your most effective cleaning process.