Problems on this page:
Parts not getting clean
Hits OEE: Quality
Symptoms: Residue remains on parts after the normal cleaning time.
Detergent wrong or too weak
Check the detergent type for the soil and measure its concentration.
Bath temperature too low
Heat the bath to the temperature the detergent works best at.
Parts shielded in an overloaded basket
Load fewer parts so each surface sees the liquid, and turn parts with blind holes.
Transducers not working
Run a foil test or use a cavitation meter to check activity across the tank.
Prevention: Cleaning result checked on sample parts each shift.
Weak cavitation
Hits OEE: Quality
Symptoms: A foil test shows little erosion, or parts take much longer to clean.
Transducer bonded to the tank has come loose
Have the transducers checked by the maker or service provider.
Liquid not degassed after filling
Run the degas cycle after filling or topping up the tank.
Liquid level wrong
Keep the level at the mark the maker sets.
Generator not tuned to the transducers
Have the generator frequency checked.
Prevention: Foil test or cavitation meter reading recorded weekly.
Generator fault alarm
Hits OEE: Availability
Symptoms: The ultrasonic generator stops with a fault or overtemperature alarm.
Generator overheating
Clean the generator air filter and keep its vents clear.
Transducer or cable fault
Have the transducer circuit tested by a qualified technician.
Tank run with too little liquid
Never run the ultrasonics with the tank below its minimum level.
Loose connection at the generator
Check the connectors with the unit isolated.
Prevention: Generator alarms logged with the action taken.
Parts pitted or marked
Hits OEE: Quality
Symptoms: Soft metal or coated parts come out with pitting or a frosted surface.
Cleaning time too long
Shorten the cycle to the time that cleans the part.
Parts resting on the tank bottom
Always use a basket or fixture so parts do not touch the tank.
Power too high for delicate parts
Use a lower power setting or higher frequency for delicate parts.
Detergent too aggressive for the material
Check detergent compatibility with the part material.
Prevention: Cleaning programmes set per part type.
Bath getting dirty quickly
Hits OEE: Quality
Symptoms: The bath turns dirty or oily within a short time and cleaning falls off.
Heavy oil carried in on parts
Pre-clean heavily soiled parts before the ultrasonic tank.
No filtration or skimming
Fit and maintain a filter and an overflow weir to remove floating oil.
Bath changed too rarely
Set a bath change interval based on its condition.
Rinse water carried back into the bath
Drain baskets before moving them between tanks.
Prevention: Bath condition checked daily and changes recorded.
Bath not heating
Hits OEE: Availability
Symptoms: The bath stays below its set temperature.
Heater element failed or scaled
Have the heater tested and descale it if needed.
Temperature sensor faulty
Compare the reading with a thermometer.
Thermal cut-out tripped
Find why it tripped before resetting it.
Lid left off on a cold day
Keep the lid on while heating.
Prevention: Bath temperature checked at start-up.
Tank leaking
Hits OEE: Availability
Symptoms: Liquid seeps from the bottom of the tank or from a weld.
Tank bottom eroded by cavitation over time
Have the tank inspected and replaced if the bottom is thin.
Cracked weld
Have the weld repaired by the maker or a specialist.
Drain valve leaking
Replace the drain valve seal.
Corrosive chemistry used
Use only detergents approved for the tank material.
Prevention: Tank and drain inspected at each bath change.
Spots or stains after rinsing
Hits OEE: Quality
Symptoms: Parts show water spots or detergent marks after drying.
Rinse water hard or dirty
Use clean, softened or deionised water for the final rinse.
Rinse too short
Lengthen the rinse or add a second rinse.
Drying too slow
Dry parts promptly with clean warm air.
Detergent concentration too high
Reduce the concentration to the supplier range.
Prevention: Final rinse water quality checked weekly.
Uneven cleaning across the tank
Hits OEE: Quality
Symptoms: Parts in some areas of the basket come out cleaner than others.
One transducer zone not working
Run a foil test across the whole tank to find dead zones.
Parts placed in the same spots every time
Move or rotate parts during the cycle.
Basket shielding the sound
Use an open basket made for ultrasonic use.
Sweep function switched off
Use the frequency sweep if the generator has one.
Prevention: Foil test pattern compared with the last one.
Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.
Related equipment guides: parts washer · electroplating line · deburring machine · CNC machine · conformal coating machine
Stop the same fault coming back
Recurring ultrasonic cleaner stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.
Book a Fabrico demo
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Related tools: full troubleshooting directory · OEE calculator · downtime cost · MTBF / MTTR · glossary
Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover