Meaning
Vibrational synchronization between a welding horn and a plastic component converts mechanical energy into localized heat. This ultrasonic resonance enables the rapid joining of thermoplastic parts by concentrating friction at the interface of the joint. Achieving the correct frequency is necessary to prevent the burning of the surface or the cracking of delicate internal features.
Monitoring the power draw during the cycle provides an indirect measurement of the bond strength and the consistency of the moulding process.
Acoustic Coupling
Transmission of sound waves from the transducer to the workpiece requires a tight physical contact and a properly designed fixture. The efficiency of the weld depends on the ability of the material to transmit these vibrations to the joint area without absorbing too much energy as internal heat.
Energy Transfer
Molecular friction at the contact points melts the resin and allows the two surfaces to fuse together. This transfer is most effective when the part geometry and the material properties are tuned to the specific frequency of the ultrasonic equipment.
Welding Efficiency
Speed of the assembly process is increased when the system operates at the natural frequency of the assembly. If the ultrasonic resonance is lost due to part variation or horn wear, the resulting joint may be weak or incomplete.
