DE2229558A1 - PROCESS FOR ISOSTATIC DEFORMING - Google Patents

Description

Dipl.-Ing. H. MITSCHERLICH 8 MUNICH 22, Dipl.-Ing. K. GUNSCHMANN ^, Dr. rer. not. W. KORBER l6 ₀ Junil 972 PATENT LAWYERS

DIRECTED BY NATIONALE DES USINES RENAULT 8/10 Avenue Emile Zola
Billancourt (Seine) France

and

AUTOMOBILE PEUGEOT

75, avenue de la Grande Arme * e

Paris, France

Patent application

Method of isostatic deformation

The invention relates to a method for deforming metal parts by forming using a high isostatic pressure,

It is known that the mechanical properties, in particular the ductility and the flowability of materials improved if they are exposed to high isostatic pressures during a deformation process,

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This working technique has been used in several processes, e.g. hydrostatic extrusion and hydrostatic Deforming, whereby the parts to be deformed were enclosed in a vessel that was filled with an incompressible Liquid was filled, on which a high pressure was exerted.

In hydrostatic extrusion, the fluid pressure itself provides the thrust and ejection of the part by the pulling device.

In the case of hydrostatic deformation, the workpiece is in the usual way by the action of pressure between its two Molds deformed. The container with the high pressure liquid picks up the workpiece and the matrices and compensates for its decrease in volume as the two matrices approach on the workpiece in that the excess liquid is drained through a drain line in which a Valve is arranged that controls the flow rate of the draining liquid and consequently the resulting hydrostatic Pressure regulates.

The further development of this working technique is impaired by two major disadvantages:

- The maximum pressure is limited by the strength of the seals in the high pressure chamber, in particular the seals limited between the movable die (punch) and the walls of the high pressure chamber. To absorb the high pressures To be able to do so, the space is generally cylindrical and surrounded by steel bands. The circular Seals are attached to the punch. They can only be used for a very short time, often only once, because with the prevailing high pressure creeping and congestion

the sealing material occurs.

- Working in a high-temperature container is not favorable for a quick change and for tactical work in an industrial production "

The method according to the invention eliminates these two disadvantages and at the same time enables a simplification of the means used,

The procedure is that

a) the blank is surrounded by a material of suitable plasticity, which in normal surroundings is a solid forms, the dimensions of which are slightly below those of a pressure chamber,

b) the blank inserted into the mentioned pressure chamber ' whose bottom is formed by the embossing of the lower die, and that the pressure chamber above the blank is closed by lowering a stamp into the pressure chamber, the stamp surface being the embossing surface represents for the workpiece,

c) the excess between the two embossing surfaces during the lowering of the punch and the deformation of the blank on the covering material by pressing out the material between the outer surface of the punch and the wall surface of the pressure chamber is led away because the game between the stamp and the pressure chamber and the Plasticity of the wrapping material are chosen so that the extrusion pressure is the required isostatic Corresponds to the deformation pressure for the blank,

d) workpiece and envelope out of the pressure chamber and

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are removed from the punch and a new, previously wrapped blank is introduced into the pressure chamber,

This process is therefore comparable to the steps involved in deforming on a conventional press, because the previous one Wrapping of the raw part and the removal of the workpieces and the remnants of the material wrapping them are independent of this, independent processes.

By eliminating liquids, the sealing problems are based and the only static seal between the lower die and the pressure chamber do not cause any pressure maintenance problems. Between the stamp and the pressure chamber are, in contrast to the known facilities, no seals.

By adjusting the play of the punch in the pressure chamber and by adjusting the plasticity of the wrapping material the required isostatic pressure can be set precisely. One can also use the isostatic pressure according to a given The program can be varied by changing the punch cross-section and thus the extrusion pressure as a function of the immersion depth of the stamp varies.

This possibility, in particular, allows the isostatic pressure to be adjusted as a function of the extent of the deformation of the workpiece increased during the deformation process. In this way, the pressure concentrations on the workpiece and the corresponding extrusion areas decreased. This also results in better regulation and a more economical use of energy. The means used remain very simple and cannot be adjusted.

The ejection of the deformed workpiece and the pressed

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th wrapping is done by simply pulling back the Stamp to which they adhere as a result of the deformation pressure and from which they are then removed by a stripping plate the punch continues its upward movement. Coatings on the stamp and on the pressure chamber walls can help facilitate these withdrawals to be provided *

The production of a workpiece according to the method according to the invention is described below with reference to the drawings which represent the following:

Fig. 1 is a schematic representation of the steps of Treatment of the blank by wrapping and then inserting it into the pressure chamber of the press;

2 shows the attack of the ram when the pressure chamber is closed;

3 shows the start of upsetting a blank and the simultaneous extrusion of the wrapping material;

Figure H shows the plunger at the end of its downward movement after completion the deformation of the blank;

5 shows the removal of the casing and the workpiece Retraction of the punch through a stripping plate, as well as gripping a new, wrapped blank and introducing it into the pressure chamber, the Raw part was fed by the gripper that removed the previous workpiece,

Fig. 1 shows a conventional, reshaped blank 1, which with a plastic material '2 is enveloped, so that an ins-

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total cylindrical pressed part is created, the diameter of which is slightly smaller than the diameter of the pressure chamber 3 into which the pressed part is to be inserted.

The envelope is made by casting, pressure spraying, compaction or any other means depending on the type of material chosen; A synthetic resin or a wax can be used as the material, which may contain a filler material to adjust the plasticity, or an alloy with a low melting point, for example with a content of tin, lead and bismuth The latter substance, which melts at a temperature of around 70 ^° C., is particularly suitable.

The low melting point facilitates the wrapping of the blank and also the removal and recovery of this wrapping after the deformation process. The high cost price of the casing is made possible by the complete recovery, the renewed use after melting and reuse as a shell material is significantly reduced.

The enveloping block may be specially shaped, for instance with Sehragflächen, grooves etc _e be provided to facilitate the handling and the insertion of the blank.

After inserting the blank 1 surrounded by plastic material 2 in the pressure chamber 3, the walls of which are made of rings 4 and 5 are formed, while the bottom acts as a lower die 6, which rests on the foundation 7 of the press, the punch 8 downwards (see. Fig. 2); the surface 9 of the punch is embossed with the upper die.

The punch 8 can be provided with cross-sectional steps 10, which lead to a corresponding reduction in the extrusion cross-section for the wrapping material if the transverse

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sectional steps enter the pressure chamber 3, and one appropriate pressure increase. · For the same purpose can on the stamp also grooves with decreasing cross-section and decreasing depth or other comparable shapes provided that they are compatible with the need to later remove the finished workpiece.

Fig. 3 shows the blank 1 at the beginning of the pressing process, while the wrapping material 2 as a result of pressing between the punch 8 and the ring M- by the intended Gap 11 emerges.

So that the stamp receives a good guide in the ring 4, you can locally subdivide this gap by longitudinal grooves on the punch. The reliefs formed in this way on the one hand promote the adhesion of the wrapping material to the stamp surface when the stamp rises and on the other hand, the later severing of the wrapping material that has been pressed out from the top of this stamp because the. Centering ribs now form zones from which the extruded Material emerges in the form of vertical strips. The removal of the wrapping material is further facilitated by the cross-sectional step 10 of the punch 8, which is carried out in a similar manner like a chip breaker in a cutting tool, a curvature to detach from the punch in its further Immersion brings about squeezed strips.

In Fig. ¹ ^ the punch 8 has reached the lowest point of its movement and the deformation of the blank 1 is complete. Most of the wrapping material has been pressed out or fills the gap 11 between the punch 8 and the ring t.

Now the punch 8 begins its upward and backward movement takes the envelope 2 with it, and the workpiece 1, the

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closely connected to the rest of the wrapping material 2 in the gap 11 at the dies 9 and 6 because of its form burr remains, hangs on the stamp.

Of course, within the scope of the invention, you could also withdraw the stamp for yourself and then that Let the workpiece and the casing eject through the ejector. These technical details result from the available technical equipment and the workpieces to be produced.

Fig. 5 shows the punch 8 in the continuation of its return movement through a stripping plate 12, the a retaining device for the remainder of the pressed wrapping material 2 until it is separated from it The end of the punch 8 represents and the finished workpiece 1, when it is detached from the punch, on one of the Stamp 8 brought discharge table 13 sets. This can be done with an envelope 2 on the underside of the discharge table 13 provided following blank 1, which is guided over the ring 4 in the working position. By lowering the Table 13, the pressed part arrives in the pressure chamber 3. By removing the table 13 with the previously deformed pressed part the wrapped blank is stripped off and falls to the bottom of the pressure chamber 3. Now the above-described Start the deformation process again.

Patent claims:

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Claims (1)

P a t e R t a η s ρ odor: 1.Λ Method for isostatic deformation using high pressure in a plastic medium »characterized by this * draws * that a) a blank CD is surrounded by a material C2) of suitable plasticity and forms a press blank, the dimensions of which are slightly smaller than those of a ¹ pressure chamber b) the blank (1) is introduced into the pressure chamber (3) » the bottom of which is formed by the embossing of the lower die, and that the pressure chamber (3) above the blank (1) is closed by a stamp (8), the area of which the represents the upper die of the press, c) during the lowering of the punch <8) and the deformation of the blank (1) between the two embossing surfaces, the excess of the wrapping material (2) is removed by pressing out the material between the outer surface of the punch and the wall surface of the pressure chamber, because the clearance between punches and pressure chamber and the plasticity are ürohüllungsmaterials (2) chosen so that the extrusion pressure ent speaks the required deformation isostatic pressure for the blank _t d) Workpiece (1) and cover (2) from the pressure chamber (3) out- "and from the stamp <8> are removed and a 3.UVQ3 »uahealed raw part is introduced into the pressure chamber 2 € 988 3/0630 2, method according to claim 1, characterized in, that the extrusion cross-section between punch C8) and pressure chamber (3) can be changed in order to to be able to vary the isostatic pressure in the pressure chamber in a corresponding manner. 3. The method according to claims 1 and 2, characterized in that the punch (8) is provided with cross-sectional reductions (10) in the direction of its end, Process according to Claims 1 and 2, characterized in that that the punch (8) receives longitudinal ribs that centering it without play in the pressure chamber (3) guarantee. 5. The method according to any one of the preceding claims, characterized characterized that the finished workpiece and the pressed out wrapping material on the punch C8) stick while it is removed " 6 «Method according to claim S, characterized in that a stripping plate (12) removes the punch (8) from the extruded one Wrapping material (2) and the finished workpiece freed and that the material and the workpiece be taken up by a discharge table (13). 7, method according to claim 6, characterized in that 2Q9 8B3 / 0630 the discharge table (13) at the same time the following, before brings up the blank provided with a covering and brings it into the pressure chamber (3). The patent attorney 209883/0630 Blank page