Why Use Ultrasonic Cleaning ?
Ultrasonic cleaning has become increasingly popular for Casted Aluminum Components. One reason is that it's an environmentally friendly process capable of replacing some vapor degassing processes. The second reason is that it enhances aqueous cleaning processes in many applications. The ultrasonic cleaning action is able to infiltrate the smallest crevices and hard-to-reach surfaces, penetrating areas normally inaccessible to other cleaning methods.
Can ultrasonic cleaning damage my parts ?
With certain cautions, ultrasonic cleaning is considered safe for most parts. While the effects of thousands of explosions per second are very powerful, the cleaning process is safe since the energy is localized at the microscopic level. The most important cautionary consideration is the choice of cleaning solution. Potentially adverse effects of the detergent on the material being cleaned will be enhanced by the ultrasonics. Ultrasonic cleaning is not recommended for the following gem stones: opal, pearl, emerald, tanzanite, malachite, turquoise, lapis and coral.
How do I get the best ultrasonic cleaning ?
There are many considerations important to ultrasonic cleaning. Optimizing these variables will produce the best cleaning. The most important decisions to be made are choosing the proper cleaning solution, cleaning at the right temperature for the correct amount of time, and choosing the right size and type of ultrasonic cleaner.
What is "direct" and "indirect" cleaning ?
Direct cleaning occurs when the parts are cleaned in a cleaning solution which fills the cleaner, usually inside a perforated tray or mesh basket. The limitation of direct cleaning is that a solution must be chosen that will not damage the ultrasonic cleaner. Indirect cleaning involves placing the parts to be cleaned in an inner non-perforated tray or beaker that often contains a solution that the user may not want directly filling the ultrasonic tank. When choosing indirect cleaning, make sure that the water level inside the tank itself is maintained to the fill line (about 1" from the tank top) at all times.
Why is a special solution required for cleaning ?
Soils adhere to the parts... if they didn't, the soil would just fall off the parts! The purpose of the solution is to break the bonds between parts and their soils. Water alone has no cleaning properties. The primary purpose of the ultrasonic activity (cavitation) is to assist the solution in doing its job. An ultrasonic cleaning solution contains various ingredients designed to optimize the ultrasonic cleaning process. For example, increased cavitation levels result from reduced fluid surface tension. An ultrasonic solution will contain a good wetting agent or surfactant.
What cleaning solution should I use ?
Modern ultrasonic cleaning solutions are compounded from a variety of detergents, wetting agents and other reactive components. A large variety of excellent formulations are available, designed for specific applications. Proper selection is crucial for acceptable cleaning activity and to preclude undesirable reactivity with the part being cleaned. Transonic can help you to identify either the optimal 'stock' cleaning formula, or likely candidates to test and evaluate.
When should solutions be changed ?
Cleaning solutions should be replenished when a noticeable decrease in cleaning action occurs, or when the solution is visibly dirty or spent. A fresh batch of solution at each cleaning session is usually not required.
Why must I keep solution at the tank's level indicator ?
The solution level should always be maintained at the level indicator in the tank, with trays or beakers installed. The ultrasonic cleaning system is a 'tuned' system. Improper solution levels will change the characteristics of the environment, can affect the system frequency, decrease effectiveness, and potentially damage the cleaner. Maintaining the proper solution level provides optimum circulation of solution around parts, and protects heaters and transducers from overheating or stress.
What is the length of cleaning time ?
Cleaning time will vary, depending on such things as soil, solution, temperature and the degree of cleanliness desired. Highly visible removal of soils should start almost immediately after the ultrasonic cleaning action begins. Cleaning time adjustment is the easiest (and most often misapplied) factor used to compensate for process variables. Although new application cycle an experienced operator can approximate duration, it usually must be validated by actual use with the chosen solution and the actual soiled parts.
How do I perform the "foil" test ?
Cut three small pieces of aluminum foil about 4" x 8" each. Fold each piece over a rod that you will use to suspend the foil in the tank. A clothes hanger works well. Your cleaner should be filled with an ultrasonic cleaning solution, degassed, and brought up to normal operating temperature. Suspend the first "square" in the center of the tank and the other two a couple of inches from each end of the tank. Make sure that the tank is filled to the fill line, and turn on the ultrasonics for about ten minutes. Remove the foil and inspect: All three pieces of aluminum foil should be perforated and wrinkled to about the same degree.
Why must trays or beakers be used ?
Items being cleaned should never be placed directly on the tank bottom. Transducers (which produce the ultrasound) are bonded to the bottom of the tank. Items resting directly on the tank bottom can damage the transducers and/or reduce cavitation. Additionally, a tray or beaker will position the item within the optimal cleaning zone of the tank. The tray or beaker will also hold the load together and allow for easy, no-touch removal, draining and transport of the items to the next step in the cleaning process.
What is the optimum cleaning temperature ?
Heat usually enhances and speeds up the cleaning process, and most detergent solutions are designed to work best at an elevated temperature. The best way to find the optimum temperature, which will give you the fastest, cleanest and safest results, is to run tests. Usually, the best results are within the 50¡C to 65¡C range.
Is rinsing required after cleaning cycles ?
Rinsing is recommended to remove any chemical residue, which could be harmful to the part. Parts can be rinsed right in your ultrasonic cleaner, using a clean water bath, or in a separate tub containing tap, distilled or de-ionized water.