SU1284688A1 - Apparatus for pressing bulky blanks from powder materials - Google Patents

Abstract

The invention relates to powder metallurgy, in particular, to devices for pressing large-sized blanks of powder materials. The aim of the invention is to increase the reliability of work and improve the quality of the pressed blanks. When pressing cylindrical blanks with a height of 70 mm and a diameter of 70 mm from carbon-graphite powder materials and from

Description

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In the case of an iron-based tallic powder, the inner element 4 of the punch is introduced into the empty matrix 2 of the mold placed on the bed 1, and the powder is poured into the space between the blades 6 through the feed hopper 12. From the actuator 11, the matrix is rotated at a constant angular velocity, the hydraulic cylinders 16 are driven to move the outer 3 punch element, the powder is precompressed to a density of 20-25%, in the lower cavity of the hydraulic cylinder 18 they create pressure while creating a counterpressure in its upper cavity implementation of the slow rise of the internal 4 elements

a punch and maintaining a pressure on this element of 0.3-0.4 of the maximum pressing pressure applied to the outer element of the punch. After the extrusion cycle has been completed, a flat end of the blank is obtained by the same lengths of the slits of the outer element of the punch and the blades of the inner element. The described device provides improved reliability by eliminating sticking of the powder mass between the blades and improving the quality of the blanks by eliminating delamination of the material of the blanks. 3 il. 2 tab.

The invention relates to powder metallurgy, in particular, to devices for pressing large-sized blanks of powder materials.

The purpose of the invention is to increase the reliability of work and improve the quality of pressed blanks.

Figure 1 shows the device, a general view; figure 2 - section aa in figure 1; Fig; 3 - section BB in Fig.1.

A device for pressing large-sized blanks consists of a bed 1, a mold containing a matrix 2 and a composite punch consisting of an outer 3 and an inner 4 elements, the outer element 3 having radial slots 5 in which the blades 6 of the inner element enter , made in the form of an asterisk, while the length of the slits 5 is equal to the length of the blades 6 (asterisks) HI Hg.

A mandrel 7 is rigidly fixed in the central part of the table of the bed 1. On the table 8 of the bed I in the supporting 9 and the sliding 10 bearings, a matrix 2 is installed with the possibility of rotational movement from an individual drive 11. The powder is loaded into the matrix through a funnel 12 mounted on the matrix 2.

The ejection of the finished billet is effected by the pushers 13 through the washer 14 from the hydraulic cylinder (not shown).

The outer 3 and inner 4 punch elements are mounted on the slider 15, with the outer 3 punch element being driven from the hydraulic cylinders 16 through the rods 17, and the inner 4 element from the hydraulic cylinder 18 mounted on the slider 15.

The device works as follows. Previously, the inner element 4 of the punch is introduced into the empty matrix 2, and the powder is poured through the loading funnel 12 into the space between the blades 6 (Fig. 2). Then, from the actuator 11. The die 2 is connected with rotational motion with a constant angular velocity, and the drive of the hydraulic cylinders 16 for moving the outer 3 punch element is activated. The oil from the upper cavity of the hydraulic cylinder 18 goes freely to drain, the period of preliminary pressing of the powder to a density of 20-25% begins, after which the hydraulic system (not shown) creates pressure in the lower cavity of the hydraulic cylinder 18 while simultaneously creating back pressure in its upper cavity of the hydraulic cylinder 18. It is calculated that the inner 4th element of the punch performs a slow rise and there remains a certain pressure on it equal to about 0.3-0.4 of the maximum pressing force applied to the outer element of the plunger on.

There is a continuous mixing and pressing of the powder over the entire height. After the extrusion cycle is completed, the flat end of the blank is obtained by using the same lengths of the slits of the outer element of the punch and the lengths of the blades (asterisk) of the inner element of the punch.

When the pressing is completed, the cylinders 16 from the slider 15 lift the elements 3 and 4 to the extreme upper position, and the pushing bars 13 push the finished billet through the washer 14 from the hydraulic cylinder.

The device is tested when pressing cylindrical blanks with a height of 70 mm and a diameter of 70 mm from carbon-graphite powder materials of the ATMI, GM-3 and PZHCHM2 metal powders containing various binders with different percentages. The test results are shown in Table. one.

Table 1

As can be seen from the data given in table. 1, the time interval between the next cleaning of the punch slots for further pressing on a known device depends on the binder and its percentage in the pressed material.

With an increase in the viscosity of the binder and its percentage, sticking of the powder mass onto the punch is more intense, which reduces the reliability of the device and reduces productivity by reducing the intervals of the well-known

As can be seen from the data given in table. 2, the mechanical properties of the products obtained by pressing on the proposed device improve by an average of 18% rupture, an average of 25% flexural strength.

Therefore, the proposed device allows to increase the mechanical properties of the products, and consequently, the quality by increasing the adhesive forces between the individual powder particles in the cross section.

Thus, the use of the proposed invention allows to increase the reliability of work and the quality of the pressed blanks due to the fact that the punch is made composite.

Making the inner punch with the blades in the shape of an asterisk and installing it in the slots of the outer punch with the possibility of reciprocating variable

Change between the next cleaning of the punch slots.

In the proposed device, this period of time is unlimited, since during the pressing process the adhesive mass is squeezed in the slot of the punch and the powder is pressed out by the protrusions of the punch.

The pressed blanks are sintered at 1000 ° C for 30 minutes, after which they are tested for mechanical strength (bending, breaking).

The test results are shown in Table. 2

table 2

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prevents the sticking of the powder mass between the paddles and, consequently, their blockage, because in the process of pressing the pressed powder mass is squeezed out by the protrusions of the external punch, and also allows to improve the quality of the pressed blanks due to continuous mixing with simultaneous continuous pressing under pressure throughout the height billet, which eliminates the possibility of stratification of the billet, and the length of the cuts of the outer punch equal to the length of the blades, the inner punch allows at the end of the press nor get a flat end of the workpiece. An increase in the reliability of the device leads to an increase in its production by about 10% due to a reduction in the loss of time spent on cleaning the punch slots during the period of sticking of the powder mass.

Claims (1)

Invention Formula A device for compacting large-sized blanks of powder materials, comprising a frame, a mold with a punch having radial slots, and a matrix that is rotatably mounted, in order to increase reliability and improve Powder Editor N. Margolin Order 7494/12 Compiled by L. Gamayunova Tehred I. VeresKorrektor M. Demchik Circulation 739 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, ul. Project, 4 the quality of the pressed blanks, the punch is made of external and internal forming elements, the latter being made in the form of an asterisk with blades, each of the elements has an individual drive and the length of the external punch slots is equal to the length of the internal punch blades. Aa in - BFig.2 Fig.Z