Ultrasonic Cleaning in the Aeronautics Industry — Complete Guide

The aeronautics and aerospace industry operates under the most demanding safety and quality standards. From turbine blades and fuel nozzles to hydraulics, heat exchangers, actuators, and avionics housings, any residue can compromise performance and reliability. Ultrasonic cleaning delivers precise, repeatable, and non-destructive results that traditional methods struggle to match — all while reducing water and chemical consumption, labor time, and total cost of ownership.

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Why Aerospace Chooses Ultrasonic Cleaning

1. Precision Cleaning: Cavitation-driven microbubbles remove oils, greases, carbon deposits, hydraulic fluids, polishing pastes, and particulate from complex geometries and micro-crevices found in engine components, turbine blades, fuel nozzles, heat exchangers, and landing gear.
2. Enhanced Safety & Reliability: Consistent cleanliness lowers risks of blockages, hot spots, corrosion, and premature wear, improving system integrity and MTBF.
3. Non-Destructive Method: No abrasive action or dimensional changes — crucial for sensors, actuators, and avionics.
4. Efficiency & Time Savings: Batch processing shortens turnaround time versus soak/scrub-only methods and minimizes downtime in MRO and production lines.
5. Material Compatibility: Tunable frequency, power, temperature, and chemistry support aluminum, titanium, nickel alloys, stainless steel, composites, elastomers, and ceramics.
6. Environmentally Responsible: Lower water and chemistry use helps meet sustainability targets and reduces waste.

In a sector where safety is crucial, ASONIC equipment is ideal for cleaning hydraulic systems, engine parts, heat exchangers, injection pumps, and blades without degrading materials.

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How Ultrasonic Cleaning Works

Ultrasonic cleaning uses high-frequency sound waves (commonly 28–80 kHz, and up to 100 kHz for delicate tasks) to generate and collapse microscopic bubbles in a liquid bath — the cavitation effect. When these bubbles implode near a surface, they release localized jets and energy that lift contamination from pores, blind holes, fine channels, and intricate surfaces.

Cavitation Explained

Alternating high/low pressure cycles create tiny cavities that expand during the low-pressure phase and implode during the high-pressure phase. This implosion delivers focused energy that dislodges soils such as oil, pigment, rust, grease, algae, fungi, bacteria, lime, soot, and wax — even from areas unreachable by manual cleaning. Suitable materials include metal, plastic, glass, ceramic, and rubber.

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Process Parameters that Matter

• Frequency: 28 kHz for heavy soils and robust parts; 40 kHz for general aerospace components; 80–120 kHz for delicate features and complex capillaries.
• Temperature: Typically 40–60 °C to improve wetting and cavitation. Stay within substrate and seal limits.
• Time & Power: Tailor to soil load and geometry (e.g., 5–20 minutes). Validate via cleanliness metrics.
• Degas Mode: Pre-run to remove dissolved gases and stabilize cavitation for consistent results.
• Fixturing: Basket/rack positioning prevents “shadowing” and ensures full immersion and line-of-sight to transducers.

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Validated Aerospace Workflow (Step-by-Step)

1. Pre-Inspection: Assess alloy/coatings, soil type, and critical features; mask sensitive areas if needed.
2. Bath Preparation: Fill with deionized water; add approved concentrate at target dilution; degas the bath.
3. Loading: Fixture parts securely; avoid contact points that trap air; maintain spacing for uniform cavitation.
4. Ultrasonic Cycle: Set frequency, temperature, and time appropriate to the part and soil load.
5. Rinsing: Rinse with clean/DI water (single or multi-stage); consider an ultrasonic rinse for capillary features.
6. Drying: Hot air or vacuum drying with filtered air; verify dryness in cavities and channels.
7. Verification & Documentation: Use water break tests, particle counts, gravimetric residue, or surface energy tests; log all parameters for traceability.

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Cleaning Concentrates

ASonic ultrasonic cleaning concentrates have specialized formulations that boost cavitation, emulsify soils, and protect sensitive substrates. Select the chemistry that matches soils and materials, and follow dilution and temperature guidance.

Cleaner	Type of impurity	Cleaning material	Dilution %	Recommended temp.
AS-MLP	Oil, grease, dust, general impurities	Metals, alloys, plastics, rubber, ceramic or glass components	2%	40–60 °C
AS-GEN	Oil, grease, dust, general impurities	Metals, alloys, plastics, rubber, ceramic or glass components	5%	40–60 °C

Cleaner	Type of impurity	Cleaning material	Dilution %	Recommended temp.
AS-CARB	Carbon, grease, heavy deposits	Engine parts; brass, aluminium and sensitive alloys	10%	50–60 °C
AS-OXI	Oxidation, general impurities, carbon & grease	Iron, copper, tin, aluminium, stainless steel	10%	40–60 °C
AS-SENS	Oils, lubricants, light grease (sensitive parts)	Brass, aluminium, tin and mixed alloys	10%	50–60 °C

Best practice: Monitor bath life (conductivity/titration), filter particulates, and change solutions on schedule to maintain validated cleanliness.

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Compliance & Quality Control

The aerospace sector requires adherence to OEM specifications and internal quality plans. Establish acceptance criteria (e.g., particle size/count, non-volatile residue, water break) and maintain auditable records of bath parameters, chemistry life, process time/temperature, and verification results. Where needed, validate with witness coupons and repeatability studies.

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Selecting the Right Ultrasonic System

• Tank size & power density: Match basket volume and mass to ensure uniform cavitation.
• Frequency options: 28 kHz for heavy-duty carbon removal; 40 kHz for general work; 80–120 kHz for delicate geometries.
• Process modules: Multi-stage lines (pre-wash, ultrasonics, DI rinses, passivation, drying) improve outcomes and throughput.
• Controls & data: Temperature stability, power control, Degas, timers, and data logging for traceability.

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FAQ — Ultrasonic Cleaning for Aeronautics

Will ultrasonics change tolerances?
No. Properly set parameters provide non-abrasive cleaning without dimensional change.

Is it safe for coated or plated parts?
Yes — when frequency, time, temperature, and chemistry are validated to the coating and OEM guidance.

Can I clean additive-manufactured parts?
Yes. Ultrasonics is effective for removing unfused powder and support residues from internal channels; validate per alloy and geometry.

How do I prove cleanliness?
Use standardized tests: water break, particle/gravimetric residue, ionic contamination, or surface energy measurements per your quality plan.

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Conclusion

Ultrasonic cleaning is a cornerstone technology for aerospace manufacturing and MRO. It provides precision, repeatability, and sustainability for everything from propulsion components to avionics hardware. With the right ASONIC system design, approved chemistry, and validated workflow, you can shorten turnaround times, elevate quality, and reduce environmental impact.

Need help specifying a validated ultrasonic process? Contact us at order@asonic.si or explore the ASONIC PRO Series.

Watch: Ultrasonic Cleaning Overview