DE1235113B - Process for cold punching high-alloy steel - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

PEUTSCHES

PATENT OFFICE

EXPLOITATION PAPER 1235113 Int. Cl .:

B 21 j

German class: 49h-2

Number: 1235 113

File number: M 547981 b / 49 h

Filing date: November 14, 1962

Opened on: February 23, 1967

The invention relates to a method for cold punching high-alloy steel by means of a cylindrical, conical piercing mandrel for the finished production of tubular workpieces or for the production of starting products for non-cutting further processing, with the the same piercer is first pre-punched to a shallow depth, dry, powdered lubricant, in particular tungsten or molybdenum disulfide, is introduced, perforated and the remaining slug is pressed out against resistance.

Such a method is known in particular for the manufacture of piston pins. It allowed at high punching speed, the production of relatively long workpieces is more excellent Surface quality, as it ensures favorable lubrication of the piercer. To carry out the known method, it is necessary when punching the matrices or at least their bottom parts to be replaced, as a special training for pressing out the residual slug against resistance of the lower part of the die is provided. It is also possible to carry out the three stages of the process, namely the production of the pre-perforation, the actual perforation and the pressing out of the remaining slugs to be carried out against resistance at the same time, including a revolver table and three press mandrels of the same design Can be used, which are arranged in such a way that they are at each companionway to one in each case going down different and progressively increasing height. The performance of such However, the device leaves something to be desired, which is due to the fact that between the Receiving matrices arranged on the turret table and attached to the fixed frame part Bottom parts of the dies, which are opposite the three spikes, ensure an absolute seal have to be.

The aim of the invention is to simplify this method and, in particular, to save the expenditure of time which is caused by the separate process of producing the pre-perforation of shallow depth, which is used to hold the lubricant. At the same time, the need to use two different matrices should be dispensed with, as a result of which an additional simplification can be achieved. For this purpose, the procedure according to the invention is that a blank pre-perforated on both sides with different hole diameters and a not yet pre-perforated blank are jointly inserted into the die and the remaining slugs of the pre-perforated blank are pressed out, a process for cold perforating
of high-alloy steel

Applicant:

Industrial de Precision Marti -1. P. M., S. A.,

Vieux-Charmont, Doubs (France)

Representative:

Dipl.-Ing. W. Scherrmann, patent attorney,

Eßlingen / Neckar, Fabrikstr. 9

Named as inventor:

Frederic Marti,

Vieux-Charmont, Doubs (France)

Claimed priority:

France of December 29, 1961 (883 537) -

at the same time the counter pre-punching is produced on the opposite side of the unperforated blank.

The fact that now on its own, separate operation for producing the pre-punching and the use of a separate, different die for piercing and the corresponding one Formation of the residual slug can be dispensed with, the result is a substantial rationalization of the whole manufacturing process, for example of cold-pressed piston pins, the price of which remains the same Quality can thus be lowered.

The creation of two pre-holes on the opposite sides of the blank, which is used for Production of a hollow body to be punched in a cold way is known per se. In which known procedure is used for pre-punching a divided die without a base, in which Pre-piercing mandrels can penetrate on both sides, which act on the blank at the same time. Apart from that from the fact that this is the prepunching as part of a separate operation before the actual perforation takes place, this measure is not used to create an opening or a cavity Inclusion of a lubricant, but rather to it, in conjunction with a special one Design of the pre-hole die a preform of the

709 510/306

3 4

To produce blank, so that when it is inserted, proper lubrication of the peripheral surface

in a closed die, which ensures the piercing mandrel for punching.

finds application, is exactly centered. Of course it is possible from the start

Very simple relationships arise when producing a small number of blanks that Method according to the invention in the manner durchge- 5 lists a recess for the solid lubricant is that the pre-punched blank to pass through, in order to make it possible in this way punch with the reverse insert position compared to its each retraction of the piercer at the same time Pre-punching is used in the die. This means that two workpieces can be inserted into the die without the Gegenvorlochimg, which is geometrically pretty that it would be necessary to use the exactly certain shape can be given, with the io lower blank of the previous operation Punch facing towards the piercer and to be used for filling,

of the lubricant determined by the piercer. For further explanation, the inventive

methods effectively enclosed in the cavity formed in this way are described on the basis of an example,

can be. It is further advantageous to show through in the drawing

Guide the counter pre-punching a counter pre-punching 15 Fig. 1 a die with two inserted work mandrels to use with a tapered forehead shape, pieces before punching,

which is designed in such a way that the in F i g known per se. 2 the die according to FIG. 1 with the two

Counter pre-piercing workpieces arranged on the ejector after the downward drop of the piercing mandrel,

a slightly smaller opening angle of the front tip Fig. 3 the die according to Fig. 1 with a new

and a slightly larger diameter than the 20 inserted workpiece on which the during the

Has perforated mandrel. This results in a blank obtained in the preceding operation

was set very favorable for the absorption of the lubricant, at the moment of the attack of the

Shape of the pre-punching. In the production of z. B. piercer on the upper blank and

Hollow rivets with heads have already become a head compression. 4 the die according to FIG. 1 in a Darste! -

matrix is used, the bottom of which is mainly of 25 lung according to FIG. 2.

a conical which is also used as an ejector. The die 1 has a in its lower part

Perforated mandrel is formed. A full comparison to this is Ejector 2, which is the bottom portion of the die

not possible; nevertheless this detail forms and in the middle a conical counterpart

no independent meaning. pre-piercing mandrel 3 carries.

In the new method, the 3 ° In Fig. 3 acts in the die. 1 there are two workpieces 4 in the die 1 The blank at the bottom is used for the upper blank that has not yet been punched or pre-punched like a resilient matrix bottom; he can be in are, but simply a convenient phosphate his have upper part in the area of the base of the coating, on the slightly liquid lubricant overlying it Slightly press in the blank, while medium was applied, which the surface rend makes the downward face of the blank 35 a little greasy and superficially something of that when the piercer goes down with a pre-fixed to fill the perforation to be described on the shape of the lubricant used in the base of the die in powdered form arranged conical part is provided. That holds form.

The lower blank is then in the next step of the process shown in FIG. 2 used in its retracted position as an overhead blank, the piercing mandrel 5 shown after the 40 shown acts on the upper work-filling the lubricant into the pre-punching directly piece 4 is exposed to the action of the piercing mandrel under insufficient lubrication conditions. To be there. This has the consequence that the decline of the between the bottom of the Vorlochvmg and the piercer 5 to the in F i g. 2 shown lower end face of the piercing mandrel included lubrication position 5 α and in particular the subsequent medium can cause cracks under the action of the metal flowing from this intermediate hole during the decline of the piercing mandrel in the decline hole, which in F1 g. 2 space only along the circumferential surface of the piercer up to 6 are indicated schematically,
leak, which is thereby lubricated. As can be seen in FIG. 2, the lower work lubrication is part of the state of the art. piece 4 of FIG. ί while punching the top

The first blank on top, which was provided with two pre-holes during the 50 blank 7,

Pressing was poorly lubricated, as it did not give it the shape shown at 8 about any. on

Has a recess for solid lubricant, one side has the piercer 5 in the upper part

Over the length of its hole, a substantial pre-punching of the upper and lower workpiece is created,

surfaces damage. It is therefore considered a committee while on the other hand the conical one

considered. 55 Counter pre-piercing mandrel 3 of the ejector 2 in the raw

With each subsequent operation, ling 8 is now a conical pre-perforation in the lower part

a new workpiece inserted into the die below, has formed.

during the previous punching, the blank 8 is now turned over and inserted into the in obtained blank is placed on it, so that the F i g. 3 brought the position shown, remains under-punching of the blank seated above always with an intermediate 60 reaching out of the end face of the piercing mandrel 5 Lubrication happens while the lower space 9, in which a supply of solid lubricant Blank can be introduced during the piercing of the upper blank.

is pressed in its upper part and so that of the during the previous operation

Piercing mandrel allows concave part 10 produced below the level of the lower of piercing mandrel 5 (FIG. 3)

To penetrate the base of the upper blank, 65 is closed under the action of the piercer 5.

whereby the lower blank is reduced in its lower part with taking until after punching one

A recess for the solid lubricant results in a blank 11 which has a very small slug 12

will see which one has for the next operation, whose removal without great care

measures can be taken. The surface damage occurring when removing the slug 12 are limited to a small ridge 13, which is shown schematically in black in Figure 4 and the can be easily removed, for example by twisting off. The whole process can be done in one last work station can be carried out on the same punch press without the need for additional ones Operations would be necessary.

After the completion of the punching of the upper blank, the lower blank 8 comes from FIG. 4 off the die, provided with a pre-punching 9 similar to that in FIG. 3, in which the solid lubricant can remain enclosed below the piercer 5.

The metal in the area of the upper part 14 of the blank 8 (Fig. 3) flows upwards, where it is on the wall of the piercer 5, so that the lubricant from the recess only along can escape this wall. In fact, before starting the hole work in the upper part of the Pre-perforation for the lubricant an annular space 15 low height, which is outside the Piercing mandrel 5 runs and therefore stems from the fact that the diameter of the conical counter-pre-piercing mandrel 3 of the ejector is slightly larger than that of the piercer. The annular space 15 is not shown in FIG. 4 because the metal flows upwards on the circumferential surface of the piercer 5 is applied as soon as it begins to penetrate the metal of the blank 8.

Claims (3)

Patent claims: 1. Process for cold punching high-alloy steel by means of a cylindrical, conical shape tapered piercer for the finished production of tubular workpieces or for the Manufacture of starting products for non-cutting processing, with the the same piercer is first pre-punched to a shallow depth, dry, powdered lubricant, in particular tungsten or molybdenum disulfide, is introduced, perforated and the remaining slug is pressed out against resistance, characterized in that that one slightly pre-punched on both sides with different hole diameters and a blank that has not yet been pre-punched can be used together in the die and that the Remaining slugs of the pre-punched blank is pressed out, while at the same time on the Opposite side of the unperforated blank the counter pre-punching is created. 2. The method according to claim 1, characterized in that the pre-punched blank for Punching with the reverse insert position compared to the insert position when it was pre-punched in the die is inserted. 3. Gegenvorlochdorn for carrying out the Gegenvorlochung according to claim 1 with a acute conical end shape, characterized in that the in a known manner on the ejector (2) arranged counter pre-piercing mandrel (3) a slightly smaller opening angle of the front tip and a slightly larger diameter than the piercer (5). Considered publications:
German Patent No. 121,604;
German interpretative document No. 1 072 866;
French patents No. 1 216 322,
480. 1 sheet of drawings 709 510/306 2 67 © Bundesdruckerei Berlin