Wednesday, December 15, 2010
Weak current College】 【ultrasonic cleaning the printhead skills】.
<br> <br> Use ultrasonic cleaner cleaning the print head, is a good approach to use effect is good, then we take a look at ultrasonic cleaning machine works. Ultrasonic cleaning is done outside the cavitation effect, ie in the cleaning liquid bubble .formed in the countless quickly and promptly implosion. The resulting impact will be immersed in a liquid inside and outside surface of the workpiece in the dirt to peel off. With the ultrasonic frequencies increase, the increase in the number of bubbles and blasting impact weakened, .therefore, high-frequency ultrasonic special applies to small particles of dirt cleaning without breaking the workpiece surface. Bubble is in a liquid in high-frequency (ultrasonic frequency), high intensity of the sound wave. Therefore, any ultrasonic cleaning system must have three .basic components: blooming cleaning liquid grooves, the electrical energy into mechanical energy of transducer and produce high-frequency electrical signal of ultrasonic generator. In theory, analysis, burst of cavitation bubble will produce more than 10,000 psi of pressure and 20,000 ° F (11,000 .° C) temperature, and a burst of transient wave radiates quickly. A single cavitation bubble released by energy is very small, but there are millions per seconds of cavitation bubble burst at the same time, accumulated effect is very strong, the powerful impact of .dirt on the surface of the workpiece, this is all the characteristics of ultrasonic cleaning. If the ultrasound energy is large enough, cavitation phenomenon will produce around in cleaning fluid, ultrasonic cleaning tiny effectively cracks and holes. Cavitation effect also contributed to the chemical reaction .and accelerates the surface membrane of dissolved. However only in a certain area of liquid pressure is below the air bubble within the gas pressure is in the region have empty phenomenon from a transducer generates an ultrasonic amplitude is large enough to meet this condition. Generate cavitation .minimum power is called cavitation threshold. Different liquid exists different cavitation threshold, the ultrasonic energy must exceed the critical point to achieve the cleaning effect. In other words, only energy greater than the critical point to generate cavitation bubble for ultrasonic cleaning. When the operating .frequency is low (in human auditory range) will produce noise. When the frequency is below 20kHz, noise at work not only to become very large and may exceed occupational safety and health law or other regulation required safety noise limits. In need high power and .remove dirt without considering the application of surface damage, usually choose from 20kHz to 30kHz range lower cleaning frequency. The frequency range of cleaning frequency are often used in cleaning of large and heavy parts or high density material artifacts. Jie Kang company provides 20KHz magnetic transducer .and 25KHz of piezoelectric transducers. High frequency is usually used in cleaning of smaller, more precise parts, or clear the small particles. High-frequency has also been used is not allowed to damage the workpiece surface. Using high-frequency can be accessed from .several ways improved cleaning performance. As the frequency increases, the number of cavitation bubble is linear increase, resulting in a more intensive Shockwave enabled it to enter into a smaller aperture. If the power remains the same, cavitation bubble gets smaller, its release of .energy reduced, effectively reducing the damage on the workpiece surface. High frequency of another advantage consists in reducing the sticky boundary layer (mooring Nuri effect), making ultrasonic to 'discover' very small particles. This is similar to the lower water levels in the .stream you can see the river bottom of small stones..