Method and apparatus for manufacturing finished parts as composite bodies from pulverulent rolling materials

A method for manufacturing composite moldings from at least two materials in a press-molding apparatus having a matrix having an upper end surface, and at least two axially displaceable bottom plugs each of which has a pressing surface, the matrix defining a mold cavity and the apparatus also including at least two top plugs opposite the bottom plugs and having a pressing surface corresponding to the pressing surface of the respective opposite bottom plug and which, along with the bottom plugs, are configured for vertical displacement within the mold cavity, said method comprising the steps of:

• a) partially retracting a bottom plug from the mold cavity to create a void therein for receiving a powder material;
• b) filling the void created in step (a) with the powder material;
• c) pressing the top and bottom plugs relative to the matrix towards one another in the part of the mold cavity filled by the powder material in step (b) to form a pre-compacted partial molding having an upper end surface;
• d) making the upper end surface of the partial molding flush with the upper end surface of the matrix;
• e) repeating steps (a) through (d) using a next adjacent bottom plug to create an adjacent void for filling with another powder material, steps (a) through (d) being repeated as many times as necessary to make a composite molding having the desired number of layers composed of different materials with the proviso that after the introduction of another powder material in step (b) and before the pre-compacting thereof in step (c), the top and bottom plugs corresponding to the pre-compacted partial molding are so displaced together in regulated manner, resting against the end surfaces of the partial molding, until the center of gravity of the partial molding has reached a position in height relative to the center of gravity of the powder column of the other powder material, which corresponds to the desired position in height of the two centers of gravity with respect to each other in the finally compacted molding, and that only thereupon is the pre-compacting effected, the top and bottom plugs corresponding to the column of powder of the other powder material being moved in each case by the same path into the column of powder;
• and
• f) after the last layer of powder material has been pre-compacted, subjecting all of the pre-compacted partial moldings as a whole, to final compaction by pressing the top and bottom plugs toward one another.