The test method described in IEC 62137-1-4:2009 applies to surface mount components with a thin and wide basal plane, such as QFP and BGA. This test method evaluates the endurance of the solder joints between component leads and lands on a substrate by cyclic bending of substrate. This test also evaluates the effects of repeated mechanical stress, such as key pushing in cell phones, the strength of the solder joint between component terminals and lands on a substrate.