The Design And Experiment Research Of Wire Clamp Used In Wire Bonder

Abstract:Wire bonding is a kind of well developed and widely used packaging technology. In wire bonding process, wire clamp is the key part to control the delivery of gold wire. So wire clamp’s opening and response speed not only affect the consistency of looping, but also influence the quality and efficiency of wire bonding. In this paper we study the design method and dynamic characteristics of wire clamp. What’s more, a new wire clamp with larger opening but smaller size was designed and tested. This paper included the following:1) We proposed the analysis model of wire clamp’s displacement amplification ratio and researched the influences of changing amplifier’s main geometry parameters on displacement amplification ratio; we analyzed the adjustment principle of gripping force and proposed an analysis model of wire clamp’s gripping force; the finite element model of wire clamp is created by ANSYS and its nature frequency, gripping force, displacement amplification ratio are analyzed; then, the resonant frequency and static displacement amplification ratio of wire clamp were tested, experiment results prove the accuracy of wire clamp’s analysis model and FE model.2) We design an experimental measurement platform with high speed camera to study wire clamp’s dynamic characteristics. Wire clamp’s output displacements in different driving conditions are recorded, the influences of changing PZT driver’s voltage and frequency on wire clamp’s output displacement and response speed are analyzed. Results indicate that the relationship between wire clamp’s opening to driving voltage is linear; when driving frequency is the same as wire clamp’s natural frequency, wire clamp’s open/close control become difficult.3) In the process of wire clamp’s innovation, structure design theory is summarized. Considering the three key factors-size、output displacement and response speed which are associated and mutually restricted, we invent and fabricate a new wire clamp with smaller size but larger opening. In order to improve the efficiency and service life of piezoelectric actuator, we make a new pre-tighten structure with contact plate moves parallel instead of bending to prevent offset contact between the contact plate and PZT.