The Role of Uncertainty in Liquidity Breakdown

A method is provided for forming a ball at a lower end of a material solder wire which is arranged generally vertically. The method comprises the steps of: forming an upward stream of an oxygen-free gas surrounding the solder wire; bringing a lateral flame of combustion to a ball forming position adjacent to the upward gas stream but short of the solder wire to thermally melt the lower end of the solder wire into a ball; and causing the lower ball end of the solder wire to solidify in the upward gas stream.