Vibration Characteristics of maskless exposure module in PCB manufacturing system

초록

This paper presents vibration characteristics of maskless exposure module in Printed Circuit Board (PCB) manufacturing system. In order to complete exposure process in PCB, masking type module has been widely used in electronics industries. However, masking process confronts some limitations of application due to higher production cost for masking as well as lower printing reso-lution. Since Digital Micromirror Device (DMD) is initially introduced by Texas Instruments in 1987, Digital Light Process (DLP) which adopts maskless exposure process is considered as an al-ternative method to overcome these challenges. Therefore, maskless exposure module is started to be in the spotlight for flexible production system to meet the needs of fabrication in variable pat-terns at low cost. Since maskless exposure process adopts direct patterning to PCB, vibration prob-lems become more critical compared to conventional masking type process. Moreover, movements of exposure engine as well as stage generate vibration sources in the system. Thus, it is imperative to analyze the vibration characteristics for the maskless exposure module to improve the quality and accuracy of PCB. In this study, vibration analysis using the Finite Element Analysis is conducted to identify the critical structural parts deteriorating vibration performance. Modal analysis is also per-formed to find the optimal solution of design for desired vibration damping performance in mask-less exposure module. Experimental investigations are also conducted by single/dual encoder meas-urement process under the operating module speed. Measurement points of vibration are selected by three places, which are base of stage, exposure engine and top of stage, to check the effect of vibra-tion from the exposure engine. Comparisons between analysis results and experimental measure-ment are conducted to confirm the accuracy of analysis results including the developed FE model. Finally, this studies show feasibility of optimal