Deep drawing stainless steel sink bowls - using two draws and tools preventing tearing of the steel sheet

摘要

Deep drawn hollow parts are made in two successive drawing operations, esp. stainless steel sinks consisting of a draining board contg. at least one sink bowl. In the first draw, the steel sheet is forced through a die plate, and the second draw produces the final shape. The first draw produces a large radius on the sink rim and an inward bulge on the sink base; then, in the second draw, the bulge provides the material needed to finish the deep sink, and the rim radius is reduced to its final size. One pref. set of tools includes a stationary punch and a die contg. an elastic insert made e.g. of polyurethane, employed in the first draw; the second draw again uses a stationary punch with an expanding sleeve used to reduce the radius on the sink rim. Similar tool sets are pref. for mfg. double-sink units, several tool sets being included in the claims. Method avoids tears during drawing, without the need for an intermediate anneal between the two drawing operations.