How to Select the Right Ultrasonic Metal Parts Cleaning Detergent

Ultrasonic cleaning work by transmitting ultrasonic waves into the cleaning solution where metal parts are immersed, creating ultrasonic vibration within the liquid. The internal pressure of the liquid fluctuates rapidly between sudden surges and sharp drops in a continuous cycle. When pressure plummets instantly, tiny vacuum cavities form in the solution, drawing dissolved gas inside to create micro bubbles. As pressure rises abruptly, these micro bubbles collapse violently and generate powerful shockwaves. These shockwaves strip away grime, oil stains, scale and oxide layers from metal surfaces, detaching contaminants from workpieces far faster than conventional cleaning methods.

Detergents work with chemical action to greatly improve cleaning efficiency and finish quality. Ultrasonic cleaning machines require dedicated cleaning detergents, which fall into two main categories: water-based cleaners and solvent-based cleaners. Among these, liquid water-based washer are the most widely used option. Liquid cleaning agents deliver far better cleaning performance than solid or powder formulations, plus they are easy to handle, dispense and replace.

Most cleaning agents for ultrasonic washers are liquid detergents, typically formulated with surfactants, chelating agents and functional additives. Traditional organic solvents such as trichloroethylene, trichloroethane, CFCs (ODS cleaning agents) and n-hexane were once widely adopted by manufacturers for degreasing due to their strong cleaning power and low cost. However, most of these chemicals have been officially banned by national authorities. Regrettably, some small enterprises still disregard regulatory rules and employee occupational safety by continuing to use these prohibited solvents in ultrasonic cleaning tanks, leading to annual cases of organic solvent poisoning among workers.

We promote a full range of environmentally safe alternatives, including eco-friendly hydrocarbon cleaners, n-hexane substitutes and trichloroethylene replacement solvents.

Eco-friendly hydrocarbon cleaners have gained widespread industry acceptance thanks to their non-toxicity, environmental compatibility, superior cleaning performance, low evaporation loss and excellent material compatibility. Our independently developed eco-friendly industrial mineral spirit cleaners feature powerful cleaning performance, n-hexane-free, halogen-free, low odor and eco-safe properties. They have been widely recognized and adopted across printing & packaging, optoelectronics, consumer electronics and mobile device manufacturing industries.

Upholding the social responsibility inherent to the cleaning chemical industry, our company commits to technological innovation to develop more environmentally friendly, non-toxic, safe and cost-effective cleaning agents, helping reduce occupational organic solvent poisoning incidents.

A surfactant refers to a substance that, even at low concentrations in water, can significantly reduce the surface tension between water and air, or the interfacial tension between water and other substances. Water-soluble surfactants feature an asymmetric and polar molecular structure. They tend to adsorb onto the interface between aqueous solutions and other phases, profoundly altering the physical properties of the system, especially interfacial tension across all phases.

Based on the electrical properties of their hydrophilic groups when dissolved in water, surfactants are classified into four types: anionic, cationic, non-ionic and amphoteric.

Key Considerations for Selecting Metal Cleaning Detergents

Type and Nature of Contaminants

Automotive and mechanical parts carry a wide range of contaminants, including solid grime, limescale, carbon deposits and rust, as well as liquid residues from lubricants and greases. Use RSB-103 Heavy-Duty Safe Descaler for limescale removal. For oil and grease contamination, select a targeted cleaning agent matched to the base metal material.

Corrosion Prevention

For corrosion-prone components made of copper, lead, zinc and parts of precision instruments and meters, choose near-neutral, low-corrosivity cleaning agents with strong rust inhibition performance.

Cleaning Operating Conditions

Opt for high-temperature grade cleaners if steam heating is available. Select low-temperature formulations for manual cleaning or heat-sensitive parts. Use low-foam cleaning agents for mechanical cleaning and pressure spray washing processes.

Optimal Concentration Control

Cleaning concentration directly impacts decontamination efficiency. Generally, cleaning power increases with higher concentration, yet it plateaus once reaching an optimal level. The recommended working concentration is 3% to 5%. If the standard dosage specified in the product manual fails to deliver satisfactory results, avoid over-dosing; instead, switch to a different formulated cleaner.

 Controlled Cleaning Temperature

In most cases, rising temperature enhances cleaning performance, yet excessive heat will diminish cleaning effectiveness. Every cleaning agent has an optimal temperature range—higher temperature does not always mean better results.

For non-ionic surfactants, clouding occurs when heated to a specific temperature (known as the cloud point). At this threshold, surfactant solubility drops, and key active ingredients decompose and lose efficacy, weakening cleaning power significantly. Therefore, non-ionic cleaning agents must be used below their cloud point temperature.

Service Life of Prepared Cleaning Solution

A single batch of diluted cleaner can be reused multiple times in small ultrasonic cleaning tanks. Its service life depends on the quantity of cleaned parts and the level of contamination buildup. Typically, a prepared solution remains usable continuously for 1 to 2 weeks.

To minimize consumption and maintain consistent cleaning quality, arrange cleaning sequences rationally: clean primary and lightly soiled parts first, then secondary and heavily contaminated components to extend solution service life.

Cleaning Efficiency VerificationAlways conduct practical trials when selecting the most effective cleaning solvent. When retrofitting existing cleaning processes with ultrasonic technology, the original solvent formula usually does not need replacement.

Operational Simplicity

Prioritize liquid cleaners that are non-toxic, safe to handle, easy to operate and offer a long service lifespan.

Cost-Effectiveness Evaluation

The lowest-priced solvent does not always equate to the lowest overall operating cost. Comprehensive factors must be considered: cleaning efficiency, workplace safety, and workpiece throughput per unit volume of solvent.

The selected solvent must deliver qualified cleaning results and be chemically compatible with workpiece materials. Water-based solutions are the most common option, featuring simple operation, low running costs and broad application scope. However, water-based cleaners are unsuitable for certain materials and stubborn contaminants, where specialized solvent alternatives are required.