Plastic and nonmetallic article shaping or treating: processes – Forming articles by uniting randomly associated particles
Patent
1997-04-18
2000-08-08
Theisen, Mary Lynn
Plastic and nonmetallic article shaping or treating: processes
Forming articles by uniting randomly associated particles
264123, 425344, 425352, 425356, B29C 4302
Patent
active
060997729
DESCRIPTION:
BRIEF SUMMARY
FIELD OF INVENTION
This invention relates to presses and toolsets for producing compacted parts out of powder material. More specifically it relates to a split die toolset.
BACKGROUND OF THE INVENTION
Devices to compact parts out of powder material for sintering are well known to those persons skilled in the art. In some cases, the compacted part has an undercut which prevents removal of the part or blank from the dies by linear or axial displacement.
Tool sets with split dies are known in powder material compaction to press parts into shapes that have an undercut in the compacting direction.
For example, U.S. Pat. No. 3,773,446 teaches a device for moulding parts to be sintered by compressing powdered material held between a fixed die and moveable die. A pair of punches extending through the dies compresses the powder material. A pressure plate operated by the punch extending through the moveable die engages the moveable die and is also locked to the fixed die during the compression so as produce a part having an undercut.
U.S. Pat. No. 3,752,622 teaches a device for moulding blanks with undercut parts to be sintered by compaction of powder material.
The prior art teaches that both parts of the die are tied together while filling with a feed box that moves across the top of the dies for purpose of filling the cavity with powdered material. After compaction the upper part of the die moves away together with the top punch to eject the part.
One of the disadvantages of the known systems as referred to above relates to the fact that the upper part of the die has to be tied mechanically to the lower part of the die and the upper punch in an alternating mode, thus making a complicated tool rig necessary.
It is therefore an object of this invention to provide a device that is simpler to construct and more efficient to operate than heretofore known by the prior art.
It is another object of this invention to provide a tool system with a split die where both parts of the die remain tied to one part of the rig during the entire cycle.
In a first aspect of the invention there is provided a toolset for a powder molding machine comprising a pair of opposed die and punch sets each having a die and a punch co-operating therewith to define respective chambers, the sets being movable relative to one another from an open position in which the sets are separated, to a closed position in which the sets abut, with the chambers in closed communication to form a closed mold cavity, one of the punches being movable from a filling position, in which the respective chamber has a volume sufficient to receive a charge of powder to fill the cavity, to a transfer position in which the respective chamber has a reduced volume, movement of the punch between the filling and the transfer positions thereby transferring powder to the other of the chambers to fill the closed cavity.
In another aspect of the invention the pair of die and punch sets constitutes a first die and punch set and a second die and punch set; the one punch being a first punch of the first die and punch set, the die with which it co-operates being a first die of the first die and punch set, and the first die and punch set having, additionally, at least a second punch; and the first and second punches are slidably nested within the first die.
In still another aspect of the invention the dies and punches of the pair of die and punch sets are further movable to compaction and ejection positions, and, in each of the filling, transfer, compaction, and ejection positions each of the punches is in sliding engagement within the die with which it is co-operating.
In yet another aspect of the invention the die and punch sets are movable in a direction of reciprocation, and, in the closed position, one of the chambers is offset transversely to the direction relative to the other of the chambers.
In a further aspect of the invention, the dies and punches of the pair of die and punch sets are further movable to compaction and ejection positions, and, in each of the filling, trans
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Buckley-Golder Keith
Haiko Mark
Hinzmann Gerd
Ma Frank
Round Robert
Stackpole Limited
Theisen Mary Lynn
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