SU1044430A1 - Mould for hydrostatic pressing of powder articles - Google Patents

Description

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00 The invention relates to powder metallurgy and ceramics, in particular molds for the manufacture of products with side holes by hydrostatic pressing of powders. A known mold for isostatic pressing of powders, comprising a housing, a mold, an elastic shell, a bottom and a rod, the rod being hollow and equipped with a spring-loaded forming element connected to it with a cylinder of a hydraulic cylinder installed in it. The disadvantages of this mold include the inability to use it in hydrostatic presses. The closest to the proposed technical essence and the achievable result is the compress form for hydrostatic pressing of products from powders, including a perforated matrix with elastic sheath in it, a cover and a rod, the latter at the research institute is equipped with two forming elements - telescopic spring-loaded sleeves 21. The lack of a mold is the quality of pressed products with side holes caused by the wedging action of the forming elements when the hydrostatic pressure is removed. The purpose of the invention is to improve the quality of products. To achieve this goal, in a mold for hydrostatically pressing powder products, preferably with side holes, including a perforated matrix with elastic the shell, the roof and the rod, the latter is made with a slot and is provided with a profiled elastic inset installed in the slot cavity with the possibility of contacting its end parts with the surface of the shell, Rich slot configured and arr, ascheknoy to the cover portion of the rod. Fig. 1 shows a diagram of the press mold before pressing (left) and JB compression time (right); in fig. 2 is a section A-A in FIG. 1; FIG. 3 is a section on FIG. one; Fig., k is a diagram of the mold at the time that the pressure is released (left) and the pressure of the extruded compressed product (right); in fig „5, section bb in fig, f; in fig. 6 elastic insert. The mold- (Fig., 1) consists of a perforated matrix 1 with an elastic sheath 2 and a rod 3 located in it. From above, the mold is closed with a perforated cover k. with elastic sheath 5 The core 3 contains a slot facing the lid (not marked) J in ijcoTopoM is installed, a profiled elastic insert 6 in contact with the elastic sheath 2 protruding behind the insert body E, along the perimeter of which; chamfering. F facing the pressed product. The elastic insert 6 can be made integral or if necessary to form complex internal configurations in the product — composite. The technological process of forming in hydrostats working with a free matrix includes the installation of a mold c. vacuum chamber 8 (1, to the left of the axis) and then into the high pressure container 9 (Fig. 1, to the right of the axis). The mold can also be used in hydrostatic pressing plants operating in an embedded die. The mold works both ways. The perforated die assembly 1 with the elastic shell 2 and the stem 3 is mounted in the resuscitation chamber 8 (FIG. 1, to the left of the center line) J mounted on a table of a vibrating stand (not shown). In the chamber 8 create a vacuum, acting G through the perforation of the matrix 1 on the elastic sheath 2 so that the shell lines the inner surface of the matrix 1, taking its configuration. The profiled elastic insert 6 is inserted into the slot of the rod 3, while its end parts protruding beyond the insert along the entire perimeter S are in contact with the shell 2, Powder is drained into the mold, covered with the cover k with the elastic shell fixed on it 5.j

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subjected to vibrovacuum compaction and transferred to a container 9 of a high pressure hydrostatic press,

When pressing (Fig. 1, to the right of the axial line), the working fluid of the press through the holes of the matrix 1 acts on the elastic shell 2. In this case, the powder shrinks. The shaped elastic insert 6 under the action of the shell 2 also changes its configuration. Slotted rod construction

 in combination with an elastic insert, it provides the latter with the opportunity to optimally change its configuration when the pressure is isostatically applied, and the pressing forces transmitted by the press to the powder through the elastic insert 6 are the most favorable and the insert 6 is compressed in the direction of movement of the elastic shell 2 on the other hand, due to the constant volume, it expands in other directions (indicated by arrows in figure 1. to the right of the axis). This ensures compression of the -holes in the side walls and the building (pipes, cups) as well as the pressing of the bottom of the glass (if any) from the inside, which results in important parts of the products (hole and bottom) with enhanced physical and mechanical properties. The main thing is that

: free growth of the product by the value of K along the vertical axis; caused by

: the forces of elastic expansion of the product, ensured by the fact that elastic welding 6 in the process of reducing pressure (Fig. 2, the shaft from the axis) follows the sheath 2, takes its original dimensions and freely rises itself expanding the product up to the required height (k). This design eliminates the possibility of vertical pinching of the raw part. The elastic insert 6 is removed from the rod 3 together with the product and then removed from the product (Fig. 2, to the right of the axis). The configuration of the side holes is determined by the shape of the insert 6 and can be any one.

The profiling features of the elastic insert 6 are:

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that, for any shape of holes, it must be made with the end parts which protrudely protrude beyond the body of the insert, with chamfers facing the extruded product along their perimeter. The thickness of the protruding parts at the base is within 2 mm and decreases towards the periphery; at the pressing pressure, they become even thinner and leave almost no marks on the raw material, which are further reduced during the subsequent sintering of the products. 15 The purpose of making such a profile is to eliminate the splitting of the material at the exit of the holes, which occurs when inserts 6 are used without broadening at the ends.

20 In the proposed mold, in contrast to the known construction, the rod 3 is permanently fixed and it does not need to be removed from the mold together with the product, and then re-installed in the matrix. It increases productivity.

PRI me R. In the proposed mold, glasses with and side holes in the walls are pressed. The height of the glass is 600 mm, the diameter of the vertical channel is B5 mm, the cross-section of the holes in the walls of the glass is 35 cm.

The mold is installed in a vacuum chamber fixed on the table of the vibrating stand, a vacuum is created in it, while the elastic shell 2 lines the inner surface of the matrix 1. The elastic profiled insert 6 is inserted into the slot of the rod 3 so that it contacts the shell 2 with the ends. A mixture of corundum and flake graphite powders with a moisture content of 2, S% is filled up during vibrations in the mold, the mold is closed with a lid 4 with an elastic sheath 5, vacuumized, vibro-compacted and then transferred to the mold in a high pressure container, where RESS pressure of 1000 kgf / cm. Then the pressure is released, the mold is transferred to the vacuum chamber, a vacuum is created in it, the cover is removed and the product is removed together with the elastic liner 6, which then easily comes out of the product holes.

5. Holes have a high-quality smooth surface, without chips and cracks. When using a known device, the marriage of cracks and chips

is 50-55%. The strength of the material of the bottom and the walls of the holes is higher than the compressive strength of materials of other parts of the product per kgf / cm.

The processability of the process has increased due to the fact that the rod

fixed in the device permanently. This ensures its alignment. Labor productivity is increased by about 20, as the assembly and disassembly of the mold is greatly simplified.

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Claims (1)

PRESS FORM FOR HYDROSTATIC PRESSING OF POWDER PRODUCTS, mainly with side openings, including a perforated matrix with an elastic shell located in it, a lid and a rod, characterized in that, in order to improve the quality of products, the rod is made with a slot and provided with a profiled elastic an insert installed in the slot of the slot with the possibility of contacting _: its end parts with the surface of the shell, the slot being made in the part of the rod facing the cover. a "1044430>