Pressure self-adapting ultrasonic fine welding method and device

Abstract

The invention discloses an ultrasonic fine welding method and device, belonging to polymer fine device assembling technology field. The ultrasonic vibration is provided by an ultrasonic emitter and an ultrasonic transducer with more than 60 kHz. The stepping motor drives the rectilinear movement unit to drive an ultrasonic tool head for longitudinal shift. A pressure sensor is installed on a base for supporting the fine device. A micro displacement sensor is arranged at the lower part of a platform for bearing the ultrasonic tool head and determines the thickness of the link layer based on the location difference. A leveling mechanism is arranged on the base. Before welding, an initial pressure is provided for the fine device to restrict ultrasonic heat production in the interface and the ultrasonic vibration is applied. The ultrasonic tool head moves upwards slowly and stops after achieving the critical welding pressure which is able to soften the interface and the welding is finished after pressure maintaining. The invention realizes the accurate control for the ultrasonic energy in the fine welding process and solves the problem of welding repetitiveness owing to the fine device surface characteristic difference and reduces the influence of the parameter to the welding quality.

Description

technical field [0001] The invention belongs to the technical field of polymer MEMS assembly, and relates to a pressure-adaptive ultrasonic precision welding device and a use method thereof, which are applied to the assembly and sealing of polymer MEMS devices. Background technique [0002] With the application of polymer materials in the field of MEMS, the assembly of polymer micro-functional devices has become an important research topic. Traditional joining methods such as thermal welding and adhesive bonding have defects such as low efficiency, low strength, and poor long-term stability; sealing methods that have been studied in recent years, such as infrared welding and laser welding, have limitations in material selection. Ultrasonic welding has the advantages of high welding strength, high efficiency, local heating, and a wide range of applicable materials. It can overcome the problems existing in other technologies and methods and solve the problems in the assembly o...

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Problems solved by technology

[0005] Precision welding technology is aimed at the precise connection of small-sized devices with microstructures. It is necessary to solve the problems caused by size reduction, to ensure that the microstructures are not deformed and damaged during the welding process, and to control the small size more precisely. Ultrasonic energy applied to the welding surface, excessive or insufficient welding energy will significantly reduce the welding quality

However, due to the slight difference in roughness of the surface to be welded, there will be slight differences in parameters such as friction coefficient, surface hardness, and thermal conductivity, which will have a greater impact on the welding of small-sized micro devices. There is a problem with traditional ultrasonic welding methods. The problem of poor welding repeatability

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