New method for calculating the necessary amount of solder paste for Pin-in-paste technology

In this paper, a new method for calculating the amount of solder paste required for Pin-in-paste technology is presented and compared to a widely used explicit expression from literature. The optimal shape of the solder profile for through-hole components is calculated with Surface Evolver, and the necessary volume is determined based on the profile calculation. The boundary conditions of the Surface Evolver calculations are the following: the solder wets until the edge of the solder pads and the contact angle is equal to the wetting angle. In the experiment, the volume is determined for different through-hole diameters and for various widths of solder pads (annular rings). The plated-hole diameter was increased from +100 μm to +750 μm compared to the diameter of a component lead, while the width of the solder ring was investigated in the range of 100 μm to 400 μm. The determined volumes were then compared to volumes calculated based on the literature expression; and a correction factor was defined.