| 摘要 |
PURPOSE:To stabilize the normal contact state by a method wherein the lead deforming process by the contact operation between the lead and a pad is computed in the state wherein the rear surface of a package is bonded onto a printed substrate so that the lead shape making a specific angle of the pad with the lead junction surface may be decided. CONSTITUTION:Within the title lead deformation tolerance computing method, a lead as a cantilever having the side of a package body as a supporting part is to be successively deformed since the lead end previously making an angle of about +70 deg. with a pad is brought into contact with the pad so as to compute the press down amount K1 as the lead deformation amount when the angle of the lead junction surface made with the pad is leveled with the pad (53-55). Furthermore, the heel part of the lead is pushed upward so as to compute the pushed, up amount K2 when the lead junction surface is paralleled with the pad surface (56-58). Finally, this position is further pushed upward so as to compute the pushed up amount K3 when the angle of the lead junction surface made with the pad becomes -7 deg. (59-61) thereby enabling the lead deformation tolerance to be computed by the following formula i.e. z=(K+(k2+3)). |
