1. Power selection

Ultrasonic Cleaning effect is not necessarily proportional to (power × cleaning time), sometimes with small power, it takes a long time to remove dirt.However, if the power reaches a certain value, the dirt is sometimes removed quickly.If the selection power is too high, The cavitation intensity will greatly increase, The cleaning effect is improved, But at this time, the more precise parts also have corrosion points.The gains do not make up for the losses, And the cavitation at the vibrating plate at the bottom of the cleaning cylinder is serious, Water pitting corrosion also increases.When using organic solvents such as trichloroethylene, there is basically no problem, but when using water or water-soluble cleaning solution, it is easy to be corroded by water pitting.If the surface of diaphragm has been scarred, cavitation corrosion at the bottom of water is more serious under high power, so ultrasonic power should be selected according to actual use.When selecting ultrasonic cleaning equipment, if the height of the workpiece is generally less than 30cm, then when the height of the inner groove of the selected ultrasonic cleaning equipment is about 40cm, a single vibrating plate at the bottom can be selected, and the power can be kept at 0.3 ~ 0.5 W per square centimeter.If the workpiece is too large, or the amount of cleaning is too large each time, the height of the tank body we choose is above 40cm, which is generally calculated according to the lifting power, and is generally selected at 11W/L..

2, the choice of frequency

In the cleaning process of ultrasonic cleaning machine, the frequency of ultrasonic wave has a very important relationship.If the frequency is lower, the cavitation valve of ultrasonic cleaning machine is lower.To put it simply, under the condition of low frequency, the liquid will be compressed or thinned to a certain extent, and there will be a longer time interval, so that the bubbles can reach a very long size, and the empty talk intensity will be enhanced, which is more conducive to cleaning.Therefore, the low-frequency ultrasonic cleaning machine is more suitable and plays a great role in cleaning large parts.This also has the disadvantage that it is not suitable for cleaning objects with high surface glossiness, because it has the effect of corroding the surface, and it also has the disadvantage of loud noise.At the frequency of about 40 KHZ, under the same sound intensity, the number of cavitation bubbles is more than that at the frequency of 18KHZ, and the penetrating force is strong.It is suitable to clean the workpiece with complex surface shape or blind hole, and the cavitation noise is small, but the cavitation intensity is low, which is suitable for cleaning the occasion where the adhesion between dirt and the surface of the cleaned piece is weak.High frequency ultrasonic cleaning is suitable for fine cleaning of computers and microelectronic components; MHz ultrasonic cleaning is suitable for cleaning integrated circuit chips, silicon wafers and wave films, and can remove micron and sub-micron dirt without any damage to the cleaned parts.Therefore, the frequency of ultrasonic cleaning machine is generally selected in the range of 80KHZ from the perspective of cleaning effect and economy.Of course, it is very important to select the correct frequency, and the selection of specific and appropriate working frequency needs to be obtained by certain experiments.Ultrasonic cleaning frequency ranges from 28kHz to 120kHz.Physical cleaning force caused by cavitation when using water or water cleaning agent is obviously beneficial to low frequency, generally about 28-40kHz is used.For parts with small gap, slit and deep hole, it is better to clean with high frequency (generally above 40kHz), even hundreds of kHz.When cleaning clock parts, use 400kHz.If wideband FM cleaning is used, the effect is better.

3, the use of cleaning baskets 

When cleaning small parts and articles, the net basket is often used, and special attention should be paid to the ultrasonic attenuation caused by the mesh.When the frequency is 28khz, it is better to use a mesh over 10mm.

4.  the selection of cleaning liquid temperature 

The most suitable cleaning temperature of water cleaning liquid is 40-60 ℃, especially when it is cold, if the temperature of cleaning liquid is low and the cavitation effect is poor, the cleaning effect is also poor.Therefore, some cleaning machines are wound with heating electric heating wires outside the cleaning cylinder to control the temperature.When the temperature rises, cavitation is easy to occur, so the cleaning effect is better.When the temperature continues to rise, the gas pressure in the bubble increases, which causes the impact sound pressure to decrease, reflecting the multiplication of these two factors.

5. Determination of the amount of cleaning fluid and the position of cleaning parts

Generally, the cleaning liquid level is higher than the vibrator surface by more than 100mm.Due to the influence of standing wave field, the amplitude at the node is very small, and the amplitude at the amplitude is large, resulting in uneven cleaning.Therefore, the best choice for cleaning articles should be placed at the amplitude.

6. Ultrasonic cleaning process and selection of cleaning Solution 

 Before purchasing a cleaning system, the following application analysis should be done for the cleaned parts:clarify the material composition, structure and quantity of the cleaned parts, and analyze and clarify the dirt to be removed, which are the prerequisites for deciding what cleaning method to use and judging whether to use water-based cleaning solution or solvent.The final cleaning process needs to be verified by cleaning experiments.Only in this way can we provide a suitable cleaning system, design a reasonable cleaning process and cleaning fluid.Considering the influence of physical properties of cleaning fluid on ultrasonic cleaning vapor pressure surface tension viscosity and density should be the most significant factors.Temperature can affect these factors, so it will also affect cavitation efficiency.Cleaning fluid must be used in any cleaning system.
When choosing cleaning solution, the following three factors should be considered: (1).Cleaning efficiency:When choosing the most effective cleaning solvent, you must do experiments.If ultrasound is introduced into the existing cleaning process, the solvent used generally does not need to be changed; (2).Simple operation:the liquid used should be safe, non-toxic, simple to operate and long in service life; (3).Cost:The cheapest cleaning solvent is not necessarily the lowest cost.In use, the cleaning efficiency and safety of solvent must be considered, and some factors such as the highest utilization rate of workpieces cleaned by a certain amount of solvent must be taken into account.Of course, the cleaning solvent chosen must achieve the cleaning effect and should be compatible with the workpiece material being cleaned.Water is the most common cleaning solution, so the system using water-based solution is easy to operate, low in use cost and widely used.However, for some materials and dirt, it is not suitable for aqueous solutions, so there are many solvents available.

7. different cleaning fluids, to distinguish the cleaning system

Aqueous system:usually consists of an open groove in which the workpiece is immersed.The complex system consists of multiple tanks, and is equipped with a circulating filtration system, a shower tank, a drying tank and other accessories.
Solvent system:Most of them are ultrasonic vapor phase grease removal cleaning machines, often equipped with waste liquid continuous recovery devices.Ultrasonic vapor phase cleaning oil
The grease process is completed by an integrated multi-tank system formed by solvent evaporation tank and ultrasonic immersion tank.Under the combined action of hot solvent vapor and ultrasonic agitation, oil, grease, wax and other dirt dissolved in solvent are removed.After a series of cleaning procedures, the blanked workpiece heats up, cleans and dries.

8. Handling of cleaning parts 

Another consideration in ultrasonic cleaning is the design of the loading and unloading of the cleaning parts or the tooling for placing the cleaning parts.When the cleaning parts are in the ultrasonic cleaning tank, neither the cleaning parts nor the cleaning basket shall touch the bottom of the tank.The total cross-sectional area of the cleaning element shall not exceed 70% of the cross-sectional area of the ultrasonic tank.Rubber and non-rigid plastics absorb ultrasonic energy, so care should be taken when using such materials in tooling.Special attention should also be paid to insulated cleaning parts.Even the best ultrasonic cleaning systems can be significantly less efficient if the basket is poorly designed, or if the workpiece is too heavy.Hooks, shelves and beakers can be used to support cleaning parts.

9. Cleaning time, workpiece type and quantity are clear 

Consider that the working mode of the machine is automatic, semi-automatic and manual.
Machine size, cost.

10. Others 

Cleaning a lot of dirt parts generally need to be pre-cleaned by soaking, spraying and other methods.After most of the dirt is removed, the remaining dirt is cleaned by ultrasound, and the effect is good.If the cleaning of small articles and complex shape of the articles (parts), if the cleaning net or make the cleaning material rotate, vibration while using ultrasonic radiation, can be evenly cleaned.

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