The technology of ultrasonic soldering

The technology of ultrasonic soldering

ultrasonic soldering

Ultrasonic soldering is a virtually flux-free soldering process that uses ultrasonic energy without chemical solder materials. It can be achieved with difficult-to-solder metals such as glass, ceramics, and composites and cannot be soldered using conventional devices. Ultrasonic soldering as a flux-free soldering process is increasingly used in the soldering of metals and ceramics, from solar photovoltaic cells and medical shape memory alloys to specialized electronics and sensor packages.

Ultrasonic soldering is a virtually flux-free soldering process that uses ultrasonic energy without chemical solder materials. It can be achieved with difficult-to-solder metals such as glass, ceramics, and composites and cannot be soldered using conventional devices. Ultrasonic soldering as a flux-free soldering process is increasingly used in the soldering of metals and ceramics, from solar photovoltaic cells and medical shape memory alloys to specialized electronics and sensor packages.

Ultrasonic solder equipment

Ultrasonic soldering uses an ultrasonic soldering iron or ultrasonic dip soldering equipment as described above. In these devices, piezoelectric crystals generate high frequency (20 – 60 kHz) sound waves in the molten solder layer or batch to mechanically destroy the oxides formed on the molten solder surface. The tip of the ultrasonic soldering iron is also connected to the heating element to prevent deterioration of the piezoelectric element, which will thermally isolate the piezoelectric crystal.

Ultrasonic soldering irons

Ultrasonic soldering irons generate heat when mechanically oscillating at frequencies of 20 – 60 kHz (up to 450°C). This soldering head melts the solder metal when acoustic vibrations are induced in the molten solder pool. The vibration and cavitation in the molten solder then wet the solder and adheres to many metal surfaces. The acoustic energy generated by the soldering tip works through the cavitation of the molten solder, which mechanically destroys the solder layer itself and the oxide layer on the surface of the metal being joined.
Conventional soldering irons do not have the help of ultrasonic energy to destroy the oxide layer on the solder and metal surfaces, leading to poor soldering during the soldering process. In addition, conventional soldering irons require flux in the soldering process, which can also affect the effectiveness of the soldering.

ultrasonic soldering iron

ultrasonic soldering iron

Ultrasonic dip soldering equipment

The cavitation produced by ultrasonic dip welding is very effective in destroying oxides on many metals. Still, it is ineffective when welding to ceramics and glass, which are themselves oxides or other non-metallic compounds because they are the base and therefore cannot destroy the material. In direct soldering to glass and ceramics, it is necessary to modify the filler metals for ultrasonic welding with active elements such as In, Ti, Hf, Zr, and rare earth elements (Ce, La, and Lu). The solders alloyed with these elements are called “active solders” because they act directly on the glass and ceramic surfaces to form a bond.

Glass and ceramics are inherently oxidized, making them difficult to join with conventional soldering devices. The cavity effect of ultrasound produces a cavity that absorbs oxygen when collapse while releasing heat energy. It is believed that this energy can be effectively used to form covalent bonds on the surface of the glass, etc., using oxygen absorbed by metallic elements that are highly oxyphilic in the molten state as a carrier. Under the vibration of ultrasonic waves, the molten solder gets thoroughly stirred, the tin at the solder interface absorbs oxygen more efficiently and may form a stronger covalent bond. Moreover, its geometric properties, chemical properties, and bond strength are no less than those of ordinary solder.

Ultrasonic dip soldering equipment

Ultrasonic dip soldering equipment

Summary

The use of ultrasonic soldering is expanding because it is clean and flux-free and incorporates reactive solder designated for joining components where corrosive fluxes may trap or disrupt operations or contaminate clean production environments dissimilar materials, metals, ceramics, glass, etc., are present for incorporation. The active solder’s incipient oxide needs to be destroyed and well-suited for ultrasonic agitation to adhere effectively to the surface. In applications with small or narrow solder joint areas, soldering with 1 – 10 mm soldering iron tips is very effective because the molten metal is small and can be effectively stirred by the 1 – 10 mm iron.

 

HCSONIC

Website:

Leave a Reply

邮箱地址不会被公开。 必填项已用*标注