Patent ID: 6281466
Filing Date: 2001-08-28
Classification: B23K

Abstract:
A process for welding a projection in a first thin aluminum sheet to an adjacent second metal body, comprising the steps of:providing a first thin metal sheet of aluminum or aluminum alloy;positioning the first sheet between first and second coining dies configured to form a projection in the first sheet;contacting the first and second coining dies respectively with opposed first and second side surfaces of the first sheet;squeezing the first sheet between the first and second coining dies to cause the metal of the first sheet to cold flow radially and axially into a channel in the first coining die so as to create a projection configured as an upright annular wall which extends transversely outwardly from the first surface and which defines a hollow interior therein with said upright annular wall being backed by an annular portion of said first sheet which extends generally between said first and second surfaces and effectively constitutes an axial extension of the upright annular wall;providing a welding head assembly which reciprocally supports an electrode having a tip which is disposed in generally opposed relation to a support;positioning said first sheet and said second metal body adjacent one another and generally between the tip of the electrode and said support so that a tip of the projection on said first sheet contacts an opposed surface on the second metal body with the projection being substantially aligned with the electrode;engaging the tip of the electrode with an exterior surface of one of the first sheet and second metal body and substantially in alignment with the projection, and applying a pressing force from said electrode onto said exterior surface for holding said first sheet and said second metal body in overlapping relation between said electrode and said support;applying a welding current pulse to said electrode for transmission into said first sheet and said second metal body where they contact at said projection to effect heating of said projection; andcontinually pressing said electrode against said exterior surface throughout heating thereof by said welding current pulse so that the electrode follows up and assists in the collapse of the projection so as to create a weld nugget between said first sheet and said second metal body and to effect pressing together of said first sheet and said second metal body at said weld nugget.