RU2264277C1 - Method for pressing powdered elongated articles and press-mold for performing the same - Google Patents

Abstract

FIELD: powder metallurgy, namely processes for pressing elongated complex-shape articles, possibly in machine engineering.

SUBSTANCE: method is used for pressing elongated articles of powder in press-molds with die having horizontal parting. Method comprises steps of pouring powder to lower part of die, drawing together upper and lower parts of shaping die; shifting powder by moving lower punch to upper part of die and pressing it. At extraction article from press-mold its upper part is released due to opening upper part of die along one or several planes passing along (or parallel to) vertical and(or) inclined axis of upper part of pressed article. Simultaneously upper and lower parts of press-mold are opened along horizontal parting plane.

EFFECT: enhanced quality of article, enlarged manufacturing possibility at making complex-shape articles.

3 cl, 3 dwg

Description

The invention relates to the field of powder metallurgy, and in particular to the process of forming lengthy products of complex shape from powder materials on press machines with a floating matrix plate, and can be used in mechanical engineering.

There is a method of pressing articles of complex shape from powders in molds having a matrix with a horizontal connector, according to which the powder is poured into the lower part of the matrix, the upper and lower parts of the matrix are closed to form a closed molding cavity, the powder is forcedly moved under the action of the lower punch to the upper part matrix and pressed to achieve the desired density of the product, including under the action of the upper punch, upon completion of pressing open the horizontal connector between the upper and lower hours Strongly moldable matrix, wherein the upper pressing should be free from the upper tool spontaneously due to its performance in the form of a cone (AS USSR №1694343, Cl. B 22 F 3/02, 1991).

A mold for implementing this method is also known, containing a matrix with a horizontal connector, the upper and lower parts of which, when closed, form a closed molding cavity, while the molding cavity of the upper part of the matrix has a conical shape, the lower part of the matrix is installed in the floating matrix of the press, in the upper part of the matrix is the upper punch, performing only powder pressing during the process, and the lower part, the lower punch, performing powder pressing and lowering s part of the compact from the bottom of the matrix (AS USSR №1694343, Cl. Bed and 22 F 3/02, 1991).

The disadvantage of this invention is that it cannot be used for pressing powder products having the shape of the upper part, different from the conical or any other, providing its spontaneous release from the upper tool when the molding cavity is opened. For example, if the upper part of the powder product is made in the form of a cylinder, then when the molding cavity is opened, it will be torn off from the lower part of the product located in the lower part of the matrix in a pressed state, since it will experience tensile stresses from the force that must be applied to the upper parts of the compact in order to overcome the friction holding force between it and the upper tool, and these stresses significantly exceed the compressive strength. For the same reason, this method has a limitation in application in the area for which it is intended for the admissible minimum taper value, which provides free extraction of powder products with a conical shape of the upper part.

The closest to the proposed invention in terms of technical essence and the achieved result is a method of pressing long products, according to which the powder is poured into the lower part of the matrix, the upper and lower parts of the mold die are closed, forming a closed volume, the powder is distilled into the closed punch with respect to the closed matrix its upper part and pressed to the desired density of the product, including under the action of the upper punch, upon completion of pressing, open the horizontal connector waiting for the lower and upper parts of the matrix, the upper part of the pressed product located in the last is forcibly pushed out by the upper punch-ejector, and then the lower part of the product is pushed out of the lower part of the die by the action of the lower punch (AS USSR No. 1556815, Cl. B 22 F 3 / 02, 1990).

The closest to the proposed invention, the design of the mold in technical essence and the achieved result is a well-known mold for pressing long products from powder, comprising a housing, a forming matrix with a horizontal connector, the upper part of the matrix is mounted on the body, and the lower part of the matrix is floating matrix plate, upper and lower pushers-pushers (AS USSR No. 1556815, Cl. B 22 F 3/02, 1990).

The disadvantages of the known method and design of the mold are the inability to extrude products that do not allow forced expulsion by the pusher on their upper part due to configuration or insufficient strength, impaired quality of the pressed product during forced expulsion of it from the upper part of the matrix, since at the final moment of separation from the molding tool, the free upper part of the product is sandwiched between the ejector and its lower part, pressed in the lower part of the matrix , is in the loaded state of uniaxial compression with a sufficiently large force under the action of the ejector, which is necessary to extrude the long part of the product from the upper part of the matrix, which contributes to the formation of cracks, delaminations and even destruction of this part of the product can occur.

The aim of the invention is to expand the functionality of obtaining compacts of long powder products of complex shape, improving the quality of products.

The goal is achieved in that in the proposed method, when removing from the mold, the entire upper part of the compact is released from the molding tool by connecting the upper part of the matrix along one or more planes passing along / or parallel to the vertical and / or inclined axis of the upper part of the compact, and synchronously with the connector of the upper and lower parts of the mold on the horizontal plane of the connector.

In the proposed method, the upper part of the pressing is released from the forming tools of the upper part of the mold without any external influence, which allows you to fully maintain the quality achieved by pressing.

The proposed method allows to expand the range of powder products pressed on automatic presses, since due to the additional connectors of the upper part of the matrix along vertical or horizontal tilted planes to remove the upper part of the press from it, it becomes possible to press products having steps with a bent or inclined to horizontal (deviating from the vertical) axis, as well as products with a curved side surface. Configuration examples of such powder products are shown in FIG. 3.

In addition, since the filling of the upper part of the mold with powder is carried out by force by moving it to the upper part under the influence of the lower punch, the proposed method opens up the possibility of pressing very small powder products having small cross sections on the press machines, which do not allow free filling of the powder into shape, and insufficient strength for forced ejection from the mold, for which it is proposed to develop a method according to which everything is molded in the upper part of the matrix and the entire product, and in the lower part of the matrix, a press residue is formed with cross-sectional dimensions that allow powder to be filled into the mold by free flowing, or using vibration, and exceeding the cross-sectional dimensions of the product itself, which is formed during pressing in the lower parts of the matrix and the product itself, the press residue is separated from the product by further processing, for example, by machining or cutting in a die after sintering the product.

Figure 3 shows examples of configurations of powder products that can only be obtained by the proposed method, namely:

- in figa, the product has a large step length with a small diameter (h / d> 5) and an even smaller diameter end step, ending with a sphere, which makes it impossible to manufacture it in the traditional way, since when removing its upper part from the forming tools using the ejector will be destroyed by the applied ejection force;

- on figb, 3c and 3g of the product have a curved configuration of the upper part, which cannot be removed from a solid forming tool by a known method of manufacturing compacts by pushing;

- Fig.3d shows a powder product with a small diameter d, which cannot be obtained on a press machine in a known manner due to the impossibility of loading the mold with powder by free filling. According to the proposed method, a product is pressed with a press residue (in Fig. 3d, the left view is marked as the “removable part"), in which the step, molded in the lower part of the matrix, where the powder is filled, has a size ⌀ D that satisfies this requirement. On fig.3d, right view - shows the finished powder product after removal of the press residue.

A mold for implementing the proposed method, comprising a housing, a forming matrix with a horizontal connector, the lower part of the forming matrix fixed in a floating plate of the matrix, the upper and lower punches, equipped with a spring-loaded additional plate mounted on the housing with the possibility of vertical movement, and the upper part of the matrix is made detachable along one or several planes passing along / or parallel to the vertical and / or inclined axis / axes of its forming cavity, its parts are fixed in the creeps, which are installed Credited an extra plate with the possibility of horizontal movement, have a wedge surface interacting with introduced into the structure and affixed to the housing wedges, and provided with an elastic element ensuring their dilution.

The method is as follows (see diagram in figure 1).

The pressed powder on the press machine with the feeder 16 is poured into the lower part of the matrix 1 installed in the floating plate of the block of the press machine (step 1).

When the press slider moves down, the upper part of the mold goes all the way to the bottom (the horizontal connector of the upper and lower parts of the matrix is closed) and stops from the counteraction of the springs of the floating plate of the matrix (not shown conventionally in the diagram), and the casing 11 continues to move down and acting through the structural elements installed on it on the upper part of the mold, closes the upper parts of the matrix 2 and 3 along the plane of the connector 15, a closed mold cavity of the mold is formed, while the powder is still in the lower parts of the matrix (stage 2).

Under the action of the ongoing downward stroke of the press slide, the casing 11 overcomes the force of the spring-loaded matrix plate, lowers it down and, with the lower punch 4, first distills the powder into the upper cavity of the mold, and then compacts it to the desired density of the product (step 3). When lowering, the compression force of the springs of the matrix plate increases, under its action and the force of pressing the product, the closing force of the matrix connectors (horizontal and vertical) automatically increases and thereby ensures reliable retention of the mold from the connector under the action of the compacted powder.

When the press slider moves upward, the entire mold in the closed state rises up until the matrix plate reaches the initial level (reaches the stop) and stops, and the casing 11 continues its movement together with the press slider up and through the structural elements installed on it acts on the upper part of the mold, simultaneously and simultaneously opens the mold on the vertical and horizontal planes of the connector, while simultaneously releasing the entire upper part of the mold from the forming tools in rhney part of the matrix (step 4).

With a continued upward stroke of the press slide, the lower punch rises by the press mechanism and pushes the lower part of the compact from the lower part of the die. Due to the elastic aftereffect, the compact increases in the transverse size and releases the lower punch, which drops down to the position for filling the powder, and the compact remains on the mirror of the lower part of the matrix (step 5). By the subsequent movement of the powder filling feeder, the compact is removed from the pressing zone, the manufacturing process of the compact on the press machine is completed, powder filling is again started and the next compact manufacturing cycle is started.

Figure 2 shows the proposed mold at the final moment of compaction of the powder, General view.

The mold contains the lower part 1 and the upper parts 2, 3 of the detachable matrix, forming in a closed state a cavity for molding the powder, the lower punch 4 located in the lower part of the matrix and fixed through the mounting elements on the mechanism of the press ejection (not shown conventionally in the drawing) . The lower part 1 of the matrix is also fixed through mounting elements in the matrix plate of the press block mounted on the press machine and which is its accessory, which is spring-loaded from below and has the ability to fall down under the influence of a force exceeding the spring force. The upper parts 2 and 3 of the matrix are fixed respectively in the left and right sliders 5 and 6, which are placed in the guides (not shown conventionally in the drawing) of the additional plate 7 with the possibility of horizontal movement and interact with it through the elastic element 8. The sliders 5 and 6 have wedge the surfaces with which they interact respectively with the wedges 9 and 10, mounted on the housing 11, and are in constant contact under the action of the elastic elements 8. An additional plate 7 is installed using screws and columns (not shown) on orpuse 11 is vertically movable and biased downward elastic member 12. The housing 11 via the mounting members secured to the top plate of the press unit, connected to the slide press machine (not shown).

The spring force of the floating matrix plate should exceed the force of the connector of the upper and lower parts of the matrix on the horizontal plane that occurs when powder is pressed, plus the total force from compression of the elastic elements 8 and 12 of the mold. To fulfill this requirement, additional elastic elements 13 and 14 are installed in the press block, which increase the back pressure of the floating matrix plate.

The proposed mold can be applied on any press machine or press having a press block with a floating matrix plate.

The mold works as follows.

The powder is poured into the cavity of the lower part of the matrix 1, after which the working stroke of the press slider begins. When the press slider moves down, the additional plate 7 of the upper part of the mold is lowered until the upper parts 2 and 3 of the matrix come into contact with the lower part 1 and stops from the resistance of the elastic element of the floating matrix plate, while the downward movement continues to compress the elastic element 12 through the wedges 9 and 10 acts on the creepers 5 and 6, closes the upper parts 2 and 3 of the matrix, compressing the elastic elements 8, a closed cavity is formed for molding the powder product, the upper part of the mold gets a rigid fixation of all important elements and begins to lower the matrix plate, overcoming the force of its springing, while all the connectors of the matrix are reliably closed. With continued lowering of the floating plate of the matrix and the entire mold, the stationary lower punch 4 distills the powder from the lower part of the matrix 1 to the upper part of the matrix and compacts it in a closed forming cavity to the desired density of the powder product. The movement of the press slider down and the molding of the powder product is completed.

When the press slider moves up, the entire mold in the closed state rises up by lifting the floating plate of the matrix with its elastic element to its original position. Further, the lower part of the mold stops, and the upper part continues its upward movement, the additional plate 7 also stands while the elastic element 12 expands, and at this time, the casing 11 lifts the wedges 9 and 10, and the elastic elements 8 move apart the sliders 5 and 6 opening the upper parts 2 and 3 of the matrix and moving them away from the upper part of the powder compact in the horizontal direction, while the compact does not experience any impact from the tools that could violate its quality. Then, by continuing to raise the upper part of the mold, the housing 11 through the connecting screws (not shown) starts lifting the additional plate 7 and moves the upper parts of the matrix 2 and 3 away from the lower part 1, and by adjusting the stroke of the additional plate 7 relative to the housing 11, it is possible to achieve simultaneous connection of all parts of the matrix for horizontal and vertical connectors.

With the continued progress of the press slider up, the lower punch 4 rises up by the press eject mechanism and pushes the lower part of the press from the bottom of the die 1, the press is completely released from the forming tools and removed from the mold by a feeder (not shown) filling it with powder to perform the following work cycle.

The advantage of the proposed mold is that the design of the upper part of the matrix is made with a connector that is vertical or inclined to the horizontal plane, and each disconnectable part is mounted in a creep, which has forced movement to close from the wedge mechanism, which at the same time ensures the transmission of all the press forces at the time of pressing the product and, therefore, the reliability of the seal of this connector, and to open the upper parts of the matrix - by an elastic element, which ensures non-destructive extraction of the upper parts of the product of complex shape and low strength from the forming tool. The use of such a mold allows us to expand the range of powder products pressed on automatic presses. In particular, the proposed mold design was used for pressing a long-length step discharger of a piezo-lighter (the smallest step has ⌀2 mm, the total height is 13 mm, and the mass is 0.39 grams) on K81 press machines.

Claims (3)

1. The method of pressing long products of powder in molds with a matrix having a horizontal connector, according to which the powder is poured into the lower part of the matrix, the upper and lower parts of the mold of the mold are closed, forming a closed volume, by moving the lower punch relative to the closed matrix of the powder distilled to its upper part and pressed to the desired density of the product, including under the action of the upper punch, upon completion of pressing open the horizontal connector between the lower and upper parts of the matrix, the upper and lower parts of the molded product are separately removed respectively from the upper and lower parts of the die, characterized in that when removed from the mold, the entire upper part of the die is released from the molding tool by disconnecting the upper part of the die in one or more planes running along / or parallel vertical and / or inclined axis of the upper part of the press, simultaneously and synchronously with the connector of the upper and lower parts of the mold on the horizontal plane of the connector. 2. The method according to claim 1, characterized in that for the manufacture of powder products of very small sizes in the upper part of the matrix, the entire product is molded, and in the lower part of the matrix, a press residue is formed with cross-sectional dimensions, which allow powder to be filled into the mold by free flow or using vibration and exceeding the cross-sectional dimensions of the product itself, while the press residue formed during the pressing process in the lower part of the matrix and the product itself is separated from the product by further processing. 3. A mold for pressing long powder products of complex shape, comprising a housing, a forming matrix with a horizontal connector, the lower part of the forming matrix fixed to the floating plate of the matrix, the upper and lower punches, characterized in that it is equipped with a spring-loaded additional plate mounted on the housing with the possibility of vertical movement, and the upper part of the matrix is detachable along one or several planes passing along / or parallel to the vertical and / or inclined axis / axes of its forming olosti a portion thereof secured in polzushkah which are mounted on an additional plate with the possibility of horizontal movement, have a wedge surface which cooperates with the wedges mounted on the housing and provided with an elastic element ensuring their dilution.

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