Cleaning finely machined parts with ultrasonic energy avoids damage by abrasive compounds and mechanical scrubbing to remove grinding dust, metal shavings, lubricants, cutting and coolant fluid residues. That’s why ultrasonic cleaners are widely used to prepare machined parts for final assembly or for further processing steps such as electroplating and powder coating.
Ultrasonic cleaning machined parts avoid surface damage while eliminating time-consuming soaking then scrubbing parts with potentially dangerous solvents.
Ultrasonic Energy, the Fast, Clean way to Clean Machined Parts
Ultrasonic cleaners, as noted below, are offered in sizes from benchtop to floor-mounted industrial units. They use biodegradable cleaning solution concentrates such as elma tec clean A4 universal degreaser to quickly and safely remove all forms of contaminants from finely finished machined parts.
Another cleaning solution formulation, elma clean 260, is designed for aluminum, laser machined parts and light metal alloys. It removes aqueous cooling emulsions, greases, oils, fingerprints, dust and lime soaps.
Biodegradable ultrasonic cleaning formulations greatly reduce health and disposal concerns common with solvents. Because these formulations are water-based, rust concerns are eliminated when the bath contains a rust inhibitor such as elma-KS, also offered as a concentrate.
How Ultrasonic Cleaners Work
Cleaning action is produced by the unit’s ultrasonic generator, which is connected to ultrasonic transducers bonded to the bottom of the cleaning tank.
When the unit is activated the transducers create hundreds of thousands of microscopic vacuum bubbles in the cleaning solution. These implode when they come in contact with parts being cleaned to quickly and safely blast away contaminants including those in tiny crevices and blind holes impossible to reach by manual scrubbing.
This force, called cavitation action, quickly strips away all contaminants without damaging the parts.
Selecting an Ultrasonic Cleaner for Machined Parts
As noted above, ultrasonic cleaners are offered in several sizes. When selecting your unit consider the size of machined parts you will be cleaning. Two selection points come into play. First is the size of the cleaning tank, second is the size of the cleaning basket in which parts are placed without stacking or crowding.
Baskets are required because they place parts at the correct level in the tank and they allow safe placing and removal without reaching into the tank.
For example, the 4.7 gallon Elmasonic Select 180 ultrasonic cleaner has tank dimensions 12.9 x 11.8 x 7.9 inches deep. The recommended basket for this cleaner is 11 x 9.8 x 4.5 inches deep. Select units are available in 11 tank sizes from 0.75 to 24 gallons.
For more on tank dimensions and baskets check the videos on our ultrasonic cleaner learning center.
If you run long cleaning cycles or are cleaning very large parts consider a benchtop or floor mounted industrial unit.
Examples of benchtop industrial units are found in the Elmasonic x tra TT units offered in 4 tank capacities from 0.79 to 4.8 gallons. These units are designed to operate continuously up to 8 hours.
For cleaning larger parts on an industrial scale, evaluate Shiraclean ultrasonic cleaners in 5 tank capacities from 25 to 110 gallons or a custom made unit. Large part cleaning can be accomplished by lowering them into the tank from an overhead support and/or resting them on specially fabricated ridges on the tank bottom.
Useful Features for Cleaning Machined Parts
A quick search will reveal that ultrasonic cleaners are available in a wide price range with features ranging from a simple on-off switch to highly programmable units. When you are cleaning machined parts here are some features that will prove useful.
- Timers let you set the length of the cleaning cycle. Experience will soon enable you to develop optimum cleaning cycle time, then you can set and forget the operation while attending to other matters.
- Heaters warm the cleaning solution to the temperature recommended by the manufacturer.
- A degassing mode removes entrained air from new cleaning solutions that otherwise interferes with the cavitation process. Degassing can also be accomplished by running the unit without a load for a number of minutes (depending on tank capacity) but a degas mode does it faster.
- A sweep mode produces a slight ±variation in ultrasonic frequency that avoids what are called hot spots, or intense cavitation, and dead zones with no ultrasonic action. In short, sweep helps assure a uniform cleaning action.
- A pulse mode produces intermittent blasts of higher ultrasonic frequency and is useful for removing stubborn contaminants.
- Ultrasonic frequency determines the size of cavitation bubbles. A common frequency is 37 kHz or 37,000 cycles per second, and is satisfactory for most applications for cleaning machined parts. Highly finished parts and parts of softer metals such as polished aluminum may require a higher frequency such as the 80 kHz offered on the dual-frequency Elmasonic P line. Equipment operating at other frequencies is available.
For more suggestions on evaluating equipment check our ultrasonic cleaner FAQs.
Maintaining Your Ultrasonic Cleaning Bath
Contaminants removed by ultrasonic cleaning remain in the bath and over time will cause cleaning efficiency to drop off.
Oily contaminants removed when cleaning machined parts with elma tec clean A4 float to the top of the solution. Floating contaminants can be skimmed off and set aside – although some ultrasonic cleaners are equipped with skimmers and weirs to direct these contaminants to a holding container.
Solid contaminants fall to the bottom of the tank where, if allowed to remain, will damage the tank unless it is equipped with filters.
Eventually, however, cleaning efficiency will drop, signaling it is time to replace the solution. Drain the tank and dispose of the solution, along with skimmed off contaminants following local regulations.
Take the time to clean the tank according to the instruction manual. Fill the tank with fresh solution, degas it and you are ready to resume cleaning.
For additional helpful information on selecting an ultrasonic cleaner for machined parts, check our post ultrasonic cleaners and how they work.
Then contact the scientists at Tovatech for unbiased recommendations on equipment, cleaning solution formulations and operating suggestions.