EQUILIBRIUM SHAPES OF AXISYMMETRICAL LIQUID SOLDER MENISCI AROUND A VERTICAL CYLINDER ON A HORIZONTAL SUBSTRATE

In this paper, equilibrium shapes of axisymmetric liquid solder joint menisci around a vertical cylinder on a horizontal plane substrate wer e calculated by numerically solving the Laplace equation of capillarit y. The boundary conditions are the contact angles formed with the cyli nder and with the substrate, subject to the prescribed liquid solder v olume constraint. Numerical solutions were obtained by implementing th e 4th-order Runge-Kutta technique and the Shooting Method simultaneous ly. For a given solder volume, the equilibrium shapes of axisymmetric solder menisci, the capillary height on the cylinder and the radius of the wetted circle on the substrate are sensitive to the contact angle s. Except the vertical wetted area on the cylinder, the horizontal wet ted area on the substrate and the cross-section area of the axisymmetr ic meniscus were found to be approximately linear functions of the liq uid solder volume in a small range. Finally, the effects of cylinder r adius on the equilibrium shapes and on the both wetted areas were stud ied.