DECISION SUPPORT FOR THE ALTERNATIVE ASSEMBLY AND REFLOW TECHNOLOGY PROCESS

Printed Circuit Board (PCB) assembly is a multi-stage process that involves numerous steps, each of which must be well characterized in order to achieve high assembly yields. The traditional Through Hole Technology (THT), widely used in the 1980s, has been increasingly replaced by the Surface Mount Technology (SMT). However, there are many PCB assemblies that combine both technologies. The predominant soldering technique for through-hole devices is wave and/or hand soldering while reflow soldering is predominantly used for surface mount devices. The 'pin-in-paste' or the Alternative Assembly and Reflow Technology (AART) process allows for the simultaneous reflow of Through Hole Components (THCs) and Surface Mount Components (SMCs). The yield of the AART process is dependent on the print parameters used for stencil printing, the estimation of the solder paste volume that needs to be deposited and the stencil design. The paper discusses a user-friendly Decision Support System (DSS) which can help the process engineer estimate the hole fill percentage, the solder paste volume that needs to be deposited on each of the component site and the stencil aperture dimensions for each component. The structure of the software and the logic used in the DSS have been discussed in this paper. Microsoft Visual Basic 5.0 was used to develop the DSS.