Apparatus for forming tubular risers and manifolds including tubular

Abstract

A manifold for a heat exchanger is formed by placing a blank having a siamesed pair of tubular passages supported by a first mandrel into a die cavity which receives the blank and defines at least one riser channel extending from the cavity. Each riser channel includes a core such that when a punch forces the blank into the die cavity, the blank is formed as desired and a portion of the blank is forged into the riser channel and around the core. The portion of the sidewall of the blank adjacent to the tubular risers is thickened such that the sidewall of the resulting manifold is substantially uniform after forging. After forging, the blank is removed from the die and the first mandrel is removed. The manifold is completed by inserting a second mandrel including holes in substantial alignment with the tubular risers and forcing punches into the tubular risers to remove the remaining material which separates the risers from the passages. The cores include sharp forming edges between terminal end surfaces and forming surfaces extending around the cores to define the forming heads. Recesses, depressions, patterns of grooves or the like are formed in the end surfaces of the cores. The cores include forming heads with the remainder of the cores and/or riser channels being relieved to facilitate removal of the risers from the riser channels. The riser channels and/or cores can be shaped to form defined distal ends on the tubular risers.