Selective soldering on printed circuit boards with endogenous induction heat at appropriate susceptors

Abstract

In this work, methods for the endogenous heating of printed circuit boards (PCBs) by means of inductive losses in built-in susceptors are presented. Two basic types of inductive heating were studied, the heating in the transversal field and the heating in the longitudinal field. Elementary test stands were constructed and characterized for both field geometries. These setups were then used to analyze various susceptor materials like copper and aluminum for the transversal field heating and nickel and iron for the longitudinal field heating. To demonstrate the soldering processes by means of inductive heating, exemplary processes were conducted on both test stands by emulating a standard solder reflow profile. The limitations of using induction heating on printed circuit boards are illustrated by component lead frames, which also heat up in the inductive field and can hence be damaged. In short, this paper presents a selective heating method, based on induction heating, for printed circuit boards. Furthermore possible setups for implementing this heating method are described.