SU1526910A1 - Die-casting mould for compacting articles from powder - Google Patents

Abstract

The invention relates to powder metallurgy, in particular to molds for pressing articles from powder. The purpose of the invention is to simplify the design. Before pressing, the punch 1 is retracted to the extreme upper position, the punch 2 is inserted into the hole 7. After powder filling, two-sided pressing of the powder in the threaded part of the matrix is carried out. Then the punch 1 is retracted to the upper position, the punch 2 is withdrawn from the pressing zone. After filling a portion of the powder, it is pressed while simultaneously pushing the compacted powder from the threaded part of the die into the outlet 7. Making part of the working cavity of the upper part 3 of the matrix with multiple non-self-braking cuts and setting the upper part 3 of the matrix stationary relative to its lower part 4 makes it easier matrix design, while retaining the possibility of shear stresses in the compression material due to its rotation in the threaded part of the matrix. 1 il. 1 tab.

Description

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Punch 2 is removed from the press zone. After filling a portion of the powder, it is pressed and simultaneously pressed through the compacted powder from the threaded part of the die into the outlet 7. The part of the working cavity of the upper part 3 of the die is filled with multiple non-self-brakes 04

Splicing and setting in the upper part 3 of the matrix stationary relative to its lower part k allows to simplify the design of the matrix, while retaining the possibility of shear stresses in the pressed material due to its rotation in the threaded part of the matrix. 1 ill., 1 tab.

The invention relates to powder metallurgy, in particular to molds for compressing articles from powder.

The aim of the invention is to simplify the construction with

The drawing on the left side shows the relative position of the elements at the end of the compaction of the material in the threaded part of the die, and on the right side the relative position of the elements when pushing the material during the pressing process.

The mold contains the upper 1 and lower 2 punches and the die containing the upper 3 and lower k parts, which are fixedly connected with each other. The lower part of the working cavity of the upper part 3 of the matrix is made with multiple non-braking screw thread 5, while the diameter of the screw thread cavities is equal to the diameter of the inlet 6 of the upper part of the matrix 3, and the diameter of the screw threads 5 is equal to the diameter of the matrix 4.

The mold works as follows.

Before pressing, the upper punch 1 is retracted to the extreme upper position, and the lower punch 2 is inserted into the outlet 7 of the lower part of the matrix, after which powder is loaded into the cavity of the matrix. Then, by pressing the punches 1 and 2 two-sidedly, the powder is compacted into the threaded part of the matrix. After that, the punch 2 is removed from the die and retracted from the pressing zone, and the punch 1 is retracted to the extreme upper position. Then a portion of the powder is poured into the inlet 6 and the punch 1 is pressed with simultaneous pushing of the compacted powder located in the threaded part of the matrix into the outlet 7 of the lower part of the matrix. At the same time, the pressed powder in the threaded part and the die outlet, held in them by friction forces, performs the function of the lower punch 2, i.e. it creates a back pressure

During the pressing process, the powder located in the inlet 6 and the outlet 7 moves progressively, and in the threaded part of the matrix from plane A to plane B the powder performs both translational and rotational motion (helical motion). In this case, intense shear deformations occur in planes A and B, contributing to its compaction. After the extrusion of a portion of the powder loaded into the inlet 6 with pushing it into the threaded part of the die, the punch 1 is retracted to its extreme upper position and another portion of the powder is poured into the inlet.

The compaction is then repeated.

Thus, the installation of the upper part of the die stationary relative to its lower part and carrying out in the lower part of the working cavity of the upper part of the matrix a multiple non-braking spindle thread, the diameter of the cavities of which is equal to the diameter of the inlet, and the diameter of the protrusions — the diameter of the outlet of the matrix by eliminating a large number of interconnected moving elements that require a drive. This allows the material in the threaded portion of the die to rotate relative to the material in the inlet and outlet, resulting in intense shear deformations

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Example. The mold was tested by pressing cylindrical billets of 50 mm from refractory powders and powders based on tungsten carbide, and the pressing force was 1000 kN. After pressing, the billet was heat treated at 1300 ° C for 1 h in vacuum.

The results of the tests are given in the table, where K is the inequality coefficient, and P is the density,

As follows from the data presented in the table, the use of the proposed mold allows to obtain products of approximately the same quality as is known with a simultaneous reduction in the cost of its manufacture by 30-35

The mold powder Brand Sample K,% P,

Claims (1)

Invention Formula A mold for pressing articles from powder, comprising a composite matrix consisting of upper and lower parts, and upper and lower punches, characterized in that, in order to simplify the design, the upper part of the matrix is fixedly fixed relative to its lower part, the lower part , the working cavity in the upper part of the matrix is made with multiple non-self-braking screw thread, the diameter of the cut-in cavities is equal to the diameter of the inlet of the upper part of the matrix, and the diameter of the cutting projections is equal to the diameter of the output hole The bottom of the matrix.