Tips on Checking the Performance of your Ultrasonic Cleaner

Tips on Checking the Performance of your Ultrasonic Cleaner

Checking the performance of your ultrasonic cleaner makes sense right from the beginning. While it may be a "stretch," you would not purchase a new automobile without giving it a road test to check its performance, would you? An ultrasonic cleaner investment may be considerable and you want it to do what it is designed to do.

And, as with your new automobile purchase, you'll want to develop a plan for regular checks to maintain the performance of your ultrasonic cleaner.

In this post we'll instruct you on

  • establishing an ultrasonic cleaner performance benchmark
  • monitoring ultrasonic cleaner operating features
  • spotting signs of trouble
  • avoiding factors contributing to decreased ultrasonic cleaner performance

How to Set an Ultrasonic Cleaner Performance Benchmark

Think of this as akin to a service record for your new car or your medical records kept on file by your family physician.

The Foil Test

Results of Aluminum Foil TestA widely accepted means to establish an ultrasonic cleaner performance benchmark is called the "foil test." It is simple, very effective, and should be initiated as soon as you place your new unit in service. This provides you with a baseline that allows you to monitor performance on an ongoing basis.

Conduct this test with freshly prepared and degassed cleaning solution formulations that you regularly use in your operations, and at the solution temperatures you normally use.

  1. Cut 3 strips of regular (not heavy-duty) household aluminum foil
  2. Suspend them in the cleaning solution by hanging them over a wire – one in the center and the others at each end, but not touching the tank walls or bottom. This placement lets you test the efficacy of transducers bonded to the cleaning tank.
  3. Turn on the ultrasound. In a few minutes all foil sheets should display evidence of significant pitting, dents and holes, indicating that the cleaner is working properly.
  4. Retain the strips in a plastic sleeve marked with the date and the ultrasonic cleaner number to compare results with future tests that you should schedule on a regular basis.

The Pencil Test

This simple test can be performed with a frosted glass and a No. 2 pencil. Draw an X on the frosted glass connecting the corners. Immerse the glass in the tank and activate the ultrasound. Record the time it takes for the X to disappear. This provides the benchmark for future tests.

The OK-Sonic™ Ultrasonic Bath Monitor

The OK-Sonic Bath Monitor is designed principally for testing units used for cleaning medical and dental instruments. It consists of indicator strips that monitor integrated results of the cleaning process parameters including strength of cavitation, exposure time and temperature.

Each monitor consists of two blue protein mixture soil spots on a plastic substrate. One spot is exposed and one covered by the holder. These represent open surfaces and less exposed difficult-to-clean parts of instruments.

When placed in an ultrasonic cleaner, the blue soil is slowly removed by cavitation in the cleaning bath. A detergent cleaning solution such as biodegradable MedClean C7 is recommended to expedite this process. Spots wash off completely from the substrate when exposed to sufficient cleaning cycle parameters. For more information and to order, download our OK-Sonic Ultrasonic Bath Monitor Data Sheet.

How to Monitor Ultrasonic Cleaner Operating Features

The most basic of ultrasonic cleaners have a simple on-off switch. Advanced models offer a range of features that can be checked on a regular basis. For example:

  • Check the actual temperature of the cleaning solution against the set temperature on a regular basis. Once the solution has reached the set temperature turn the unit off and use a digital thermometer to get an independent reading. This temperature should not deviate from the set temperature by more than 2 - 3˚C. If excess deviations continue to occur contact the supplier or manufacturer.
  • Check timer accuracy on a monthly basis. Set the timer for 15 minutes and switch on the unit. Use a stopwatch to measure any deviation. It should be less than 5% (45 seconds). If results are not satisfactory contact the manufacturer.
  • Check cleaning power on a regular basis. Use a wattmeter between the unit plug and the wall outlet. Operate the tank without the heater on. The wattmeter reading should not deviate from the unit’s operating instructions power by more than ± 15%. If cleaning is satisfactory you can run the unit at lower power but inspect results more thoroughly.

How to Spot Signs of Ultrasonic Cleaner Performance Problems

An absence of hissing and wave action results in slow or ceased cleaning. An electronic malfunction may be the cause. First try a reset by turning off the unit and disconnecting it from the power source. If reconnecting does not solve the problem or the malfunction continues to occur, return the unit to an authorized service point or manufacturer for repair.

Malfunctioning transducer systems can be indicated by a complete system breakdown in which case the generator turns off and all control panel diodes go dark. The unit should be returned to an authorized service point or manufacturer.

How to Avoid Factors Leading to Decreased Ultrasonic Cleaner Performance

Establish and follow a set of standard operating procedures

You'll find guidelines in the ultrasonic cleaner manufacturer’s operating and maintenance instructions.

Always degas fresh cleaning solutions. Degassing drives off cavitation-inhibiting trapped air; the amount of time required depends on the volume of the cleaning tank.

Degassing is accomplished by activating the degas mode (if so equipped) or operating the unit without a load. A uniform hissing sound, absence of large bubbles and a "blurred" solution surface indicates a degassed solution.

Clean at the recommended temperature. This is provided by the cleaning solution manufacturer. Remember that as the unit operates the temperature of the cleaning solution will increase due to ultrasonic energy. It can reach 60˚C (140˚F) or higher. If higher cleaning temperatures are required the ultrasonic cleaner’s heater thermostat can be set accordingly.

If high temperatures can damage the products the installation of a cooling coil attached to an external water supply is recommended. Contact iUltrasonic for information on this accessory.

Monitor cleaning solution levels in the tank. Each time you remove a basket of cleaned parts you remove solution coating the parts. Heat causes evaporation, which can be slowed by covering the tank during operation. This will also muffle noise. Damage can result when the tank is operating at less than capacity (either to the “fill” line or 2/3 full). Overfilled tanks will not clean satisfactorily.

Extend Cleaning Solution Effectiveness. Dirt and contaminants removed during ultrasonic cleaning remain in the solution. Over time they build up and reduce cleaning solution effectiveness. Extending cleaning solution life can be done in several ways.

A good practice is skimming off oils and other contaminants that rise to the surface. This also helps avoid contaminants adhering to cleaned products as they are removed from the bath. Some industrial-sized ultrasonic cleaners are equipped with skimmers; otherwise, it is a manual process. Solution filters are also available to remove suspended solids in industrial sized equipment.

When it is time to change the solution, it must be drained and disposed of according to local regulations. Take the time to thoroughly clean the bottom of the tank. This removes settled solids that will eventually cause serious damage. Follow the manufacturers’ tank cleaning procedures.

Always remember that if your ultrasonic cleaner performance check results prove unsatisfactory do not attempt to repair your equipment. Instead contact the iUltrasonic professionals for advice.

More About the Author

Dr. Rachel Kohn has extensive experience in developing technology-based business opportunities. Prior to founding Tovatech, she successfully built international sales of novel analytical instrumentation for Smiths Detection as a Global Account Manager in the Life Sciences division. Dr. Kohn’s prior positions include Director of Business Development at Photon-X, a telecom component start-up, Project Manager at Cardinal Health, and Business Director at the Medical Device Concept Laboratory, a nonprofit research institution focused on development of biomaterials and implantable medical devices. In addition, Dr. Kohn held various positions at Hoechst Celanese Corporation, including Marketing Manager, Project Team Leader, Business Analyst, and Senior Research Scientist. She has authored 37 patents and publications based on laboratory research in diverse fields such as advanced drug delivery systems, polymer films and membranes, optical disks, and polysaccharides. Dr. Kohn has a B.A. in Chemistry from Barnard College and a Ph.D. in Organic Chemistry from M.I.T.