Misugi Hongoh

Temperature Rise and Welding Characteristics of Various-Frequency Ultrasonic Plastic Welding Systems

Welding characteristics and temperature increases of ultrasonic plastic welding parts over a frequency range from 27 to 94 kHz are studied. Using 27, 40, 67, and 94 kHz ultrasonic plastic welding systems, temperature increases at welding surfaces of lapped 1.0-, 2.0-, and 3.0-mm-thick polypropylene plates and polymethyl methacrylate plates are measured using 0.1- and 0.2-mm-diameter thermocouples inserted between plates, and temperature distributions at cross sections of lapped plate specimens are measured using a thermotracer. The 94 kHz vibration system used for ultrasonic plastic welding consists of a bolt-clamped Langevin-type longitudinal vibration source using four 30-mm-diameter piezoelectric ceramic (PZT) rings, a stepped horn (vibration velocity transform ratio N=3.0) and a catenoidal horn (N=3.13) with an 8-mm-diameter welding tip. The other vibration systems have similar configurations. In the case of using a higher-frequency system, increases in temperature measured at the welding parts are larger. Temperature rises are larger for lapped plate specimens than that for a one-piece specimen owing to the vibration loss of welding surfaces.

Ultrasonic plastic welding using fundamental and higher resonance frequencies.

Ultrasonic plastic welding using fundamental and higher resonance frequency vibrations simultaneously was studied. Using higher frequency, welding characteristics is improved due to the larger vibration loss of plastic materials. The 26 kHz welding tip vibrates in maximum velocity of over 4.5 m/s (peak-to-zero value) under a fundamental resonance frequency and there are several higher resonance frequencies up to 95 kHz whose vibration velocities are over one-third that of the fundamental frequency. Welding characteristics of 1.0-mm-thick polypropylene sheets are measured in the cases the vibration system are driven under combined driving voltages of fundamental and higher resonance frequencies. Welded area increases as number of driven higher frequencies increases. The welded area by three frequencies is about three to four times that of the case where only the fundamental frequency is driven. The welding characteristics of ultrasonic plastic welding are improved significantly by driving higher resonance frequencies simultaneously.

Configuration of a 30-mm-diameter 94 kHz ultrasonic longitudinal vibration system for plastic welding

Vibration and welding characteristics of a 94 kHz ultrasonic plastic welding system are studied. The 94 kHz ultrasonic plastic welding systems consist of a 30-mm-diameter bolt-clamped Langevin-type PZT longitudinal transducers with four PZT rings, a stepped horn (vibration transform ratio N = 3.0) with a supporting flange at a nodal position and a catenoidal horn (N = 3.13) with an 8-mm-diameter welding tip. Maximum vibration velocity of the 94 kHz welding tip was 3.2 m/s (peak-to-zero value) at loaded condition. The welding characteristics of the 1.0-mm-thick polypropylene sheet specimens using the 94 kHz welding system were studied. Using the 94 kHz system, a weld strength of more than 370 N per one welded area was obtained at a vibration velocity of 2.7 m/sp-0 (peak-to-zero value), welding time of 0.8 s and static pressure of 600 kPa.

Welding characteristics of 40 kHz ultrasonic plastic welding system using fundamental and higher-resonance-frequency vibrations

The welding characteristics of 40 kHz ultrasonic plastic welding system using fundamental and higher-resonance-frequency vibrations were studied. At high frequency, welding characteristics can be improved due to the larger vibration loss of plastic materials. The 40 kHz welding tip vibrates at a maximum velocity of more than 3.0 m/s (peak-to-zero value) at a fundamental resonance frequency and there are several higher resonance frequencies up to 107 kHz whose vibration velocities are more than one-fourth that of the fundamental frequency. The welding characteristics of lapped 0.5-mm-thick polyvinyl chloride and 1.0-mm-thick polypropylene sheets were measured in the cases where the vibration system was driven using combined driving voltages of both fundamental and higher resonance frequencies. The welded area and weld strength increased as fundamental and higher resonance frequencies were driven simultaneously. The welding characteristics of ultrasonic plastic welding were improved significantly by driving fundamental and higher resonance frequencies simultaneously.

Temperature Distributions in Welding Specimens for Ultrasonic Plastic Welding Systems Using Various Frequencies

Welding characteristics and temperature increases of plastic welding parts over a frequency range of 27 kHz to 94 kHz are studied. Using 27 kHz, 40 kHz, 67 kHz and 94 kHz ultrasonic plastic welding systems, temperature increase at welded surfaces of 1.0-mm-thick polypropylene plates and polymethyl methacrylate plates is measured using thermocouples inserted between plates, and temperature distributions at cross-sections of lapped plate specimens are measured using a thermotracer. The 94 kHz vibration system used for ultrasonic plastic welding consists of a bolt-clamped Langevin type longitudinal vibration source using four 30-mm-diameter piezoelectric ceramic (PZT) rings, a stepped horn (vibration velocity transform ratio N=3.0) and a catenoidal horn (N=3.13) with an 8-mm-diameter welding tip. The other vibration systems have similar configurations. Using a higher frequency system, increases in temperature measured at the welding parts are higher. The maximum temperature increase measured using thermocouples and a thermotracer was over 330°C.

Welding characteristics and temperature rises of various frequency ultrasonic plastic welding

Welding characteristics and temperature rises in plastic welding specimens over frequency range of 27 kHz to 180 kHz are studied. Using 27 kHz, 40 kHz, 67 kHz, 94 kHz, 150 kHz and 180 kHz ultrasonic plastic welding systems, tem- perature rises at welding surfaces of lapped 1.0-mm- and 3.0- mm-thick polypropylene plates are measured using thermo- couples inserted between plate specimens, and also tempera- ture rise distributions at cross sections of the lapped plate specimens are measured using a thermo-tracer. Maximum temperature rise measured was over 330 °C. Temperature rises are highest at welding surfaces compared with the other welding parts.

Configuration of a 20-mm-diameter 150 kHz ultrasonic longitudinal vibration system for plastic welding

This paper describes 20-mm-diameter 150 kHz vibration systems for ultrasonic plastic welding which were developed. Using 27 kHz to 150 kHz ultrasonic plastic welding systems, temperature rises at welding surfaces of 1.0-mm-thick polypropylene sheets are measured using thermo-couples inserted between sheet specimens and also temperature rise distributions at cross sections of the lapped sheet specimens are measured using a thermo-tracer. The maximum temperature measured was over 240/spl deg/C.

Welding characteristics of 40 kHz ultrasonic plastic welding system using fundamental and higher resonance frequency vibrations

The welding characteristics of 40 kHz welding system using the fundamental and higher resonance frequencies were studied. Using higher frequency, the welding characteristics of an ultrasonic welding system are improved due to the large vibration loss of plastic materials. The welding characteristics of the ultrasonic plastic welding system are improved significantly by driving the fundamental and higher resonance frequencies simultaneously.