SU1271652A1 - Injection die for pressing powder articles - Google Patents

Abstract

The invention relates to the field of powder metallurgy, in particular to molds for the pressing of articles made of metal powders. The aim of the invention is to improve the quality of the extruded products. Powder is poured into matrix 6 of the mold, then it is brought in contact (L 35 U1

Description

a top assembly, made to the powder, made in the form of a housing 3 and hydraulic cylinders with platforms 4 and plungers 5 for compacting the powder in zones in the radial direction. Oil is fed into the channel made in the housing 3, the plungers 5 are inserted into the powder and the latter is sealed in zones from the central to the peripheral zone. Then the drive of movement of the punches is turned on, the period of the final double-sided pressing as peripheral is carried out.

as well as the central zones, as the pressing force increases, the plungers 5 begin to force the oil out of the housing 3 and occupy the original assembled position. The upper seal assembly is retracted to the extreme upper position, and the further stroke of the punch 2 pushes the article out of the die. The described constructional design of the mold allows to obtain products with a higher density, while reducing the inequality of the products 2 times. 2il. 1 tab.

one

The invention relates to powder metallurgy, in particular to molds for pressing a product from metal powders,

The purpose of the invention is to improve the quality of the pressed products,

Figure 1 presents the proposed mold at the initial moment of work; Fig. 2 - the same at the time of the preliminary and final pressing process.

The mold contains the top 1 and bottom 2 punches. On the punches on the side of the cavity for loading the powder, units are placed for compacting the powder in zones in the radial direction. Each node consists of a hollow body 3 with staggered cylindrical bores of equal depth on the side of the cavity and telescopic hydraulic cylinders, the working areas of 4 plungers of which increase from the central plunger to the peripheral one, and their lengths respectively decrease in arithmetic progression. The drive of the punches 1 and 2, as well as the control of the plungers 5, is carried out from the hydraulic system of the press (not shown). The matrix 6 of the mold is installed on the table 7 of the press.

The operation of the device is carried out in the following manner.

At the initial moment, the upper and lower nodes for compacting the powder in the zones in the radial direction are respectively in the extreme

upper and lower positions. In the matrix 6 fall asleep powder. Then, the upper assembly is brought in to seal until the end working surfaces of the plungers 5 (Fig. 1) touch, and the hydraulic drive system of the upper 1 and lower 2 punches, i.e. lock the oil in the hydraulic cylinders drive the punches. Thereafter, oil is supplied from the hydraulic system through a channel made in each housing of the seal assembly, which leads to pushing the plungers 5 and introducing them into the powder to be pressed, while pre-consolidating mainly the central part of the workpiece is carried out. After pre-pressing is completed, the plungers 5 occupy the position shown in Fig. 2. The force P (1) generated by the powder compacted zones by zones is controlled by setting the relief valve (not shown) and is 0.5 of the main pressing force P. Then the drive of the movement of the punches 1 and 2 is turned on and the final two-side pressing is performed both peripheral and central areas of the product. As the pressing force increases, the plungers 5 begin to force the oil out of the housing 3 to occupy the initial assembled position. The force P on the sides of the upper and lower plungers reaches its maximum. The upper seal assembly is retracted to its highest position, and the distance3

the lowest stroke of the lower punch 2 push the finished product.

Performing the pressing unit in the form of a telescopic hydraulic cylinder with plunger working areas increasing from central to peripheral, allows, during the pre-pressing period, to carry out the process of compacting the workpiece separately with separate annular microvolumes, displacing the powder from the peripheral zones to the central one. waste plungers powder from the peripheral zone also tends to fill mainly the central zone of the workpiece, which allows for more evenly aspredelit powder compressibility.

Claims (1)

Thus, the use of the proposed mold reduces the porosity in volume and unevenness of products by about two times, which leads to an increase in the quality of finished products. DETAILED DESCRIPTION OF THE INVENTION A mold for pressing powder articles, comprising a matrix of punches and a unit for compacting the powder in zones in the radial direction, characterized in that. 716524 Making the plungers of length, decreasing from central to extreme exponentially, and stepped cylindrical bores 5 of equal depth in the housing allows to obtain a product with flat ends due to the fact that the lower ends of the plungers are installed in one plane at the final moment of pressing. The properties of products with dimensions d-h 100 50 mm, obtained by pressing iron powder in the known and proposed molds, are presented in the table (pressing pressure of 1000 kN), where G is the tensile strength of the pressed blanks; Szzd - flexural strength; K inequality coefficient by the volume of the workpiece, P is the porosity of the preform. 35 56 15.2 that, in order to improve the quality of the pressed products, the node for compacting powder in zones in the radial direction is made in the form of a hollow body with a channel and with stepped cylindrical bores of equal depth from the side of the cavity and telescopic hydro cylinders whose working plunger areas increase from the central plunger to the peripheral one, and their lengths correspondingly decrease exponentially. Pi -L. ± ra 1J