SU1715494A1 - Method of pressing-out pressed articles with holes - Google Patents

Abstract

The invention relates to methods for pressing out molded products with holes, preferably from powder abrasives with non-central holes. After pressing, the product is released by removing the cage from the split matrix, then the shape of the side surface of the product is fixed and the rods forming the holes in the product are removed, after which the product is removed from the matrix. 3 il. § v) c

Description

This invention relates to powder metallurgy, in particular to methods for repressing articles.

The known method repressive products, implemented during operation of the mold. It involves popping the rod and releasing the compressed headers from the die.

The disadvantage of this method ow. In the case of pressing blanks with small holes, the ejection of the rod is a very laborious operation. At the same time, mechanical damage to the pressed workpiece is often difficult.

There is also known a method for pressing out products, which is realized when the mold is in operation, including pulling the rod and releasing the pressed workpiece from the die.

The disadvantage of this method is that at a certain diameter of the hole in the pressed billet and high pressing pressures, the strength of the rod does not allow it to be pulled out of the billet. v In this case, the complexity of the rod removal process increases dramatically. In this case, the workpiece is often subjected to mechanical damage, which leads to scrap.

Closest to the present invention is a method of repressing, which includes releasing the product by removing the clip from the split matrix, removing the rod and removing the product from the matrix.

The disadvantage of this method is the low yield of products, mainly from abrasive powders.

four

with

four

with central hole. This is due to the fact that when pressing products from a diamond-containing charge, the process of setting the pressed material with mold parts takes place (especially when using the method of hot pressing at t 850 ° G, the material of the mold is HN77TYUR GOST 5632 steel -72), as well as the process of pressing a solid diamond powder into a much less hard core of the mold. These processes are the reason that even after clearing the billet from the die (despite its some elastic expansion), removing the rod from the latter requires the use of press equipment. In the case of non-central location of the rod, the forces required for its extrusion increase, since the elastic aftereffect is uneven. In the process of extruding a rod from a workpiece freed from a matrix, its plastic deformations in height can occur. In this case, the external dimensions and shape undergo a change, and in the case of using ceramic ties, the workpiece is often destroyed.

The purpose of the invention is to increase the yield of products.

The goal is achieved by the fact that in the method of pressing out pressed articles with holes, mainly from abrasive powders with non-central holes, which include releasing the product by removing the cage from the separable matrix, removing the rod and removing it from the matrix, before removing the rod, fix the shape of the side surface products.

Fixing the shape of the side surface of the product, while removing the rod from it, allows to eliminate mechanical damage (plastic deformation and fracture) on the product.

Figure 1 shows the first stage of repressing; figure 2 - the second stage; n

Aig.Z - the third stage.

The press-form, by which the proposed method of repressing is realized, consists of the matrix 2 covered by the holder 1, inside which the intermediate ring 3 and the off-center rod 4, the lining 5 of the punch 6, the stand 7, the hub 8 of the distributor ring 9 and the limiting plate 8 are installed

0

0

five

bodies 10. Matrix 2 is composite in structure and has vertical connector planes. The essence of the repressing process is as follows.

After pressing, the mold is set as shown1 on 1; A compression ring 9 is put on the holder 1 and, applying a pressing force to it, the matrix 2 is released from the holder 1. As a result of this, the accumulated stresses and elastic expansion, i.e. increase in linear dimensions. However, despite this, the rod 4 continues to be held firmly enough in the workpiece. Therefore, it cannot be manually removed. The reason for this is that during the extrusion process, the compressible material seizes with the mold parts, as well as the solid diamond powder is pressed into the much less hard core of the mold. Elastic aftereffect only weakens the interaction of the pressed product with the rod.

After the implementation of the elastic stresses, the pressed billet is surrounded by the elements of the composite matrix 2, on which the holder 1 is put on (FIG. 2). Since when compressing powders of plastic metals, elastic aftereffects are not significant (0.2%), the shape of the billet differs little from the shape of the forming cavity of matrix 2. In the case of more significant elastic aftereffects (ceramic bonded product) for fixing the shape of the lateral the surface of the product can be used. The matrix, the cavity diameter of which exactly corresponds to the outer diameter of the workpiece after the elastic stresses in it.

Further distribution occurs as follows. The mold is installed on the stand 7. The pins of the stand 7, the passage through the holes made in the lining 5Ј interact with the intermediate ring 3. On the lining 5 through the corresponding. holes in the cage 1 install the plug 8 and, applying to it. the force of the press, lower the lining 5 along the pins of the stand 7. Since the back fastener 5 interacts with the rod 4, the latter comes out of

(Reg. 2

Claims (1)

Claim A method of extruding pressed articles with holes, mainly from abrasive powders with off-center holes, including releasing the product by removing the clip from the split matrix, removing the rod and removing the product from. matrix, characterized in that, for the purpose, increase yield of products, before removing the rod carry out the fixation of the form. side surface of the product. ------------- I .......... · 1 I at <L of FIG. g Fig.Z