I have some experience with ultra sonic cleaning of AL parts. We have a 90 sec cleaning cycle. I find it very effective .

-mechantaeus

Ultrasonics can remove loose particles effectively. I have seen rusted bolts, nuts and other metal pieces that were neatly cleaned. Why can't you test a sample piece and then check for yourself?

Regards,

I used Ultra sonics for cleaning old castings from heat exchangers, The process was very effective. I found that most suppliers were willing to demonstrate their equipment to proove suitability.

When cleaning with ultrasound it is actually Ultrasonic cavitation that does the cleaning.

The basic principle is that a liquid of sorts is 'shaken' by means of some kind of actuator (ultrasonic transducers).

When the energy that is put into shaking the liquid at frequencies above 20khz reaches a point when it exceeds the adhertion forces of the liquid tiny cavities (voids) occure.

These voids grow over a few cycles of the actuator until they cannot be sustained any longer. At this point they collapse releasing huge amount of energy on super local spots. This energy is in the form of heat and pressure.

The way this process cleans is that the dirt is physically bombarded off the meterial by these millions of collapsing voids.

The energy can be enough to cause corrosion of the surface of substances like alluminium and other metals (only after long exposure). This is illustrated by the corrision of ship propellers and pump impellers.    

In summary, ultrasonic cleaning can be very effective in the cleaning of intricate components and is widely used in industry eliminating the use of harmful chemical cleaning.

I would concur with the other respondents that ultrasonics can be an effective cleaning method.  As with any cleaning operation, take a look at what "contaminant" you are trying to clean and determine if the process is appropriate.  Are your castings of a size that could be accommodated in a ultrasonic tank?  Part shape can also be a factor in how it sits relative to the transducers that produce the cavitation.  Some equipment offers frequency sweeping, bath heating and other options.  Check with various suppliers and try different bath solutions to make sure downstream (prep and paint) processes are not adversely affected.  You will also have to consider dealing with and disposing of spent bath waste.

Regards,