Normally, the audible frequency of sound to human is from 16KHz to 20KHz, thus we name sound in frequency over than 20KHz as ultrasonic (or ultrasound). However, most animals is more sensitive to sound than human, such as cat which can hear sound in about 64KHz. Reported by Biology Report on internet, most kinds of moth can hear sound in frequency as high as 300KHz, then it says that moth has the most sensitive ear. So far as we know that the bat can make sound in frequency about 212KHz,which is more than ten times of that human can hear. The sound made by bat is in ultrasound frequency area. What should be noted is that, for application in engineering, some sound in frequency audible to human is called ultrasonic by us, such as we call plastic welding machine in frequency of 15KHz as ultrasonic plastic welder.
Ultrasonic System Applied in Industries
Ultrasonic applied in industries normally is 15~100KHz, mostly applied is 15KHz, 20KHz, 28KHz, 30KHz, 35KHz, 40KHz, 60KHz,80KHz, etc. It applies ultrasonic generator(also called as ultrasonic power supplier, can be IC circuit type and IGBT type) transform 50/60Hz electric power into 15KHz or over than it to supply to ultrasonic transducer (also called ultrasonic converter). Ultrasonic transducer transform the supplied electrical power into mechanical energy in the same frequency and then transmit the energy to booster to enhance the wave amplitude by fixed times, after which the energy will be transmitted to ultrasonic horn (mould) to have it enhanced again, after which then energy will be forced to objects to process.
Ultrasonic Industrial Application
Ultrasonic is widely applied in both military area, industry area or in people living, such as ultrasonic detection, ultrasonic attack, ultrasonic metal inspection, ultrasonic health examination or health treatment, ultrasonic welding (plastic welding or metal welding), ultrasonic cutting, etc. This article will describe some application of ultrasonic in plastic industry only.
Ultrasonic Plastic Welding
ress two pre-assembled plastic halves together by ultrasonic horn under high pressure, and ultrasonic horn transmits energy to the welding area through the one plastic half touched by ultrasonic horn, by which friction cased of internal of plastic material to generate high temperature to melt the plastic material at the welding area, then ultrasonic stops but keep plastic halves pressed together by ultrasonic horn under pressure until re-solidification of plastic part, then ultrasonic plastic welding finishes.
This application of ultrasonic is popular in automotive industry, motorbike industry, house-held applicant industry, electronics industry, toy industry, etc. It is with advantages of firm welding strength, leak-proof welding performance and high production capacity, etc.
Zhejiang Zhenbo Precision Machinery Co. Ltd.
No 217, Weiqi Road, Yueqing Economic Development
Zone, WenzhouZhejiang, China