EP0183648A1 - Press for processing work pieces made from metal - Google Patents

Abstract

The fineblanking tool installed in a transfer press comprises an upper part (2) with an upper tool insert (17) and a lower part (3) with a lower tool insert (18). A hydraulic block (4, 4 ') is housed both in the upper part (2) and in the lower part (3) of the fineblanking tool. The hydraulic block (4) is used with the upper tool insert (17) in a change frame (6) and the hydraulic block (4 ') with the lower tool insert (18) in another frame (6'). The hydraulic blocks (4, 4 ') are driven by pressure means (56, 19, 44) with pressure oil, these drive means (56, 19, 44) forming a separate unit. In this way, the advantages of transfer technology are combined in a single processing machine with the advantages of fineblanking technology.

Description

The invention relates to a press for processing workpieces made of sheet metal or cast or forged blanks, with at least two work stages, each of which a tool is assigned, and a device for automatically transporting the workpieces.

Completed stamped parts often require a 100% smooth cut surface at the functional points. This also applies to stamped parts with bends, cranks, reshaped pot or plate-like parts. In order to achieve a 100% smooth cut surface on such stamped parts, it is customary to subsequently finish these parts after the stamping-technical work processes by machining, such as turning, milling or broaching. However, it is also possible to cut the desired 100% smooth cut surfaces on such punched parts in a fineblanking press without cutting.

However, such a known method for producing the 100% smooth cut surface on stamped parts is disadvantageous in the sense that the finished stamped parts are used in a second machining process in a processing machine suitable for producing the 100% smooth cut surface on the stamped parts and processed there have to. This results in a loss of time and an increase in manufacturing costs.

The fine blanking process and the corresponding fine blanking tools are described in the book "Fine blanking" by J. Haack and F. Birzer, Hallwag-Verlag, Bern, 1977.

DE-OS 3,227,696 describes a progressive tool which is used in high-speed presses. Such a tool comprises a plurality of processing stations, through which one through the Tool-conveyed punched strip is processed. The processing stations are cutting, bending, bending, cranking and turning stations, which are subsequently housed in the tool.

From CH-PS 641,696 a press with a follow-up tool is also known, the eight stations of which gradually deform the workpiece. Here, the workpieces are transported by means of a device with rods driven in the transport direction with elastic grippers. By means of the rods provided with elastic grippers, formed stamped parts that have been shaped out of the sheet plane can be conveyed quickly.

With those mentioned in the two documents presses you can indeed per ram stroke a finished stamped part in rapid _K can adenz incurred, but if such a stamped part is to be additionally partially provided to the function points with a 100% strength smooth cut surface, it is, as above mentioned, to be further processed.

JP-PS 58-65526 describes a press with a single tool. In the tool, multi-stage machining of workpieces takes place in one working stroke. A hydraulic block is installed in the upper and lower part of the press. One of the processing stages can be designed as a fineblanking stage.

However, the design with a single tool cannot e.g. find application in a transfer press.

The invention specified in claim 1 has for its object to provide a press for processing workpieces made of sheet metal or cast or forged blanks, in which fineblanking operations are combined with the conventional work processes of punching and / or drawing technology in a single processing machine. This should enable to produce complicated stamped parts with 100% smooth cut surfaces quickly and inexpensively.

This object is achieved in the press mentioned at the outset in that at least one of the working stages is formed by a fineblanking tool embedded in any working stage, in the upper part and lower part of which a hydraulic block is installed as the upper or lower part of the tool insert, which hydraulic block with the responsible one Tool insert used in an upper or lower change frame and can be controlled by a drive means.

The upper interchangeable frame of the fineblanking tool can advantageously have a top plate and an upper clamping plate and the lower interchangeable frame a lower plate and a lower clamping plate, the drive means forming a separate unit from the interchangeable frames.

• Fig. 1 eine schematische Seitenansicht einer Transferpresse mit dem eingebauten Feinschneidwerkzeug nach der Figur 3,
• Fig. 2 eine schematische Draufsicht im Schnitt auf die Transferpresse nach der Figur 1,
• Fig. 3 einen Schnitt eines Feinschneidwerkzeuges, dessen Hydraulikblöcke mit den zuständigen Werkzeug-Einsätzen in jeweils einem Wechselgestell eingesetzt sind,
• Fig. 4 eine schematische Ansicht im Schnitt des in einer Feinschneidpresse eingebauten Feinschneidwerkzeuges nach der Figur 3,
• Fig. 5A bis 5G einzelne Bearbeitungsvorgänge in der Transferpresse nach den Fig. 1 und 2, alle im Schnitt,
• Fig. 6 einen Schnitt des Stanzteiles entlang der Linie VI-VI der Figur 7,
• Fig. 7 eine Ansicht eines feingeschnittenen Stanzteiles,
• Fig. 8a bis 8f einzelne Feinschneidvorgänge in dem in der Transferpresse nach den Fig. 1 und 2 in siebenter Arbeitstufe eingebauten Feinschneidwerkzeug nach der Fig. 3, alle im Schnitt und
• Fig. 9 eine diagrammatische Darstellung der Stössel-und Kolbenbewegungsabläufe einer Transferpresse mit eingebautem Feinschneidwerkzeug r»ch der Figur 3.

The invention is explained below with reference to the drawing, for example. Show it:

• 1 is a schematic side view of a transfer press with the built-in fine blanking tool according to FIG. 3,
• 2 shows a schematic plan view in section of the transfer press according to FIG. 1,
• 3 shows a section of a fineblanking tool, the hydraulic blocks of which are used with the responsible tool inserts in a changing frame,
• 4 shows a schematic view in section of the fine blanking tool according to FIG. 3 installed in a fine blanking press,
• 5A to 5G individual processing operations in the transfer press according to FIGS. 1 and 2, all in section,
• 6 shows a section of the stamped part along the line VI-VI of FIG. 7,
• 7 is a view of a finely cut stamped part,
• 8a to 8f individual fineblanking processes in the fineblanking tool according to FIG. 3 built into the transfer press according to FIGS. 1 and 2 in a seventh working stage, all in section and
• 9 shows a diagrammatic representation of the tappet and piston movement sequences of a transfer press with a built-in fineblanking tool from FIG. 3.

The fineblanking tool according to FIG. 3 consists of an upper part 2 and a lower part 3. The upper part 2 comprises a hydraulic block 4 which on the one hand is attached to a head plate 8 and on the other hand is connected to an upper tool insert 17 as its superstructure. The hydraulic block 4 and the upper tool insert 17 are inserted in a change frame 6 with the head plate 8 mentioned above. The upper set 42 of the upper tool insert 17 is screwed to the interchangeable frame 6 by means of fastening screws 31. In a similar way, the lower part 3 comprises a hydraulic block 4 ', which on the one hand is fastened to the lower plate 9 and on the other hand is connected to the lower tool insert 18 as its substructure. The hydraulic block 4 'and the lower tool insert 18 are inserted in an interchangeable frame 6' with the lower plate 9 mentioned above. The cutting plate 41 of the lower tool insert 18 is screwed to the interchangeable frame 6 'by means of the fastening screws 31.

Furthermore, FIG. 3 schematically shows an assembly for feeding the hydraulic blocks 4, 4 'with pressure oil, which forms a separate unit from the frames 6, 6'. The unit consists of a motor 56, a pump 19 and a memory 44. 58 is the liquid container. Each hydraulic block 4, 4 'has two piston cylinders. In the hydraulic block 4 there are cylinders 13, 14 and pistons 21, 22. In the hydraulic block 4's there are cylinders 15, 16 and pistons 23, 24. Via valves 57 and connections 5, pressure oil is supplied to the hydraulic blocks 4, 4 '. The piston cylinders 13 to 16 act independently of one another and the pressures acting in them are individually adjustable via the valves 57 and can be switched on and off individually.

The hydraulic pressures generated in the hydraulic blocks 4, 4 'take over clamping, stripping and ejection functions. But they are also used to hold the part in position or at the transport level. The piston 22 is in operative connection with a pressure pin 26 for counter-punch 32. The piston 21 is in active connection with the pressure bolt 27 for wipers 45. The piston 24 is in active connection with the pressure bolt 28 for ejector 38 and the piston 23 is in active connection with the pressure pin 29 for ejector 35 and counter-punch below 33. With 40 the guide plate in the upper tool insert 17, with 34 the inner die and 36 the Umschneidstempel designated. In the lower tool insert 18, 30 denotes the insert in the insert 41 and 43 the base. In the upper and in the lower tool insert, tuning plates 39 are provided for the precise adjustment of the inner form punch 34 and the cutting punch 36, the counter punch below 33 and the insert 30 for the purpose of tuning after the sharp cutting. The locking bolts 37 take over the securing of the position of the guide plate 40 to the lower tool insert 18. With 11 are centering pins for the tool inserts 17, 18, with 51 part position finder, with 59 ejector bolts.

Workpieces 1 which have a shape formed from a sheet metal plane can advantageously be produced on a transfer press 20, which is shown in FIGS. 1 and 2. The fine blanking tool according to FIG. 3 is installed in this transfer press 20 in the last, seventh working stage. With the remaining forming tools 25, the fineblanking tool according to FIG. 3 represents a tool set. In the last fineblanking stage a 100% smooth cut surface is achieved at the functional locations of the stamped part 1. The workpiece 1 is manufactured into a finely cut part 1 'in seven operations.

A punched piece is cut out of one of the material strips fed to the transfer press 20 with a ram 52 and a table 53 (FIG. 5A). In the second operation according to FIG. 5B, the workpiece 1 is trimmed (change of ridge sides in the bending zone). In the third and fourth stages (FIGS. 5C and 5D) the workpiece is bent, in the fifth operation the angle and the height of the workpiece are set (FIG. 5E). In the sixth working stage (FIG. 5F), lubricating oil for the fineblanking process is sprayed onto the workpiece 1 and in the seventh operation (FIG. 5G) the fineblanking process is carried out by means of the built-in fineblanking tool according to FIG. 3.

The built-in fineblanking tool can take over the following operations: punching, cutting, trimming, cutting and cutting. In this manufacturing method in a transfer press, the punched piece or workpiece 1 is conveyed into the individual work stages by means of bar grippers 10 with gripper tongs 12. The waste from the normal punching stages migrates down through a table opening, not shown. The waste 49 (slugs) produced during fineblanking are removed by means of swivel arms 48, which are fastened to the gripper tongs 12, via discharge plates 50.

As can also be seen from FIGS. 1 and 2, all tools 25 (cutting and forming tools) and the fineblanking tool are mounted on a single common upper base plate 46 and a single common lower base plate 47. This results in a quick change of the entire tool set in the transfer press 20. When off In the case of a work step, only the tool assigned to it has to be dismantled and readjusted. The fineblanking stage can be used at any stage position, as the optimal solution of the workpiece requires. In addition, several fineblanking tools described above can be set in different working stages of the transfer press. This is made possible by the fact that the fine blanking tool described above carries the additional hydraulics required for fine blanking.

The finely cut stamped part 1 'shown in FIGS. 6 and 7 was produced in a transfer press with the built-in fine blanking tool according to FIG. 3; the corresponding fineblanking processes are shown in FIGS. 8a-8f, which are also entered numerically in FIG. 9.

The fineblanking tool is open in the position shown in FIG. 8a. The bent workpiece 1 lies on the lower tool insert 18. The ram, not shown, of the transfer press is in the top dead center position I. The ram runs down in the position shown in FIG. 8b. The wipers 45 touch the workpiece 1, the piston 21 in the cylinder 13 is displaced upwards. The plunger is now in position II. In the position shown in FIG. 8C, the entire upper tool insert 17 is in contact with the workpiece 1, which is clamped between the upper 17 and lower 18 tool inserts. The finder 51 is inserted into the corresponding hole in the workpiece 1 and in the ejector 35 of the lower tool insert 18 and centers the part position. The pestle is in position III. In the position shown in Figure 8d, the plunger continues to run down. The piston 23 is displaced downwards. Now the bending zone of the workpiece 1 is clamped between the upper 17 and the lower 18 tool insert. The pestle can be found in position IV. The actual cutting process now begins, whereby the pistons 21 and 22 are displaced upwards and the pistons 23 and 24 downwards. At the end of this process, the plunger is in the bottom dead center position V. In the position shown in FIG. 8e, the plunger is in the bottom dead center position V. The pressure effect of the pistons 21 to 24 is switched off, the plunger moves up again back. In position VI of the plunger, the pressure of the piston 23 is switched on again, whereby the stamped part 1 is ejected upwards. In position VII of the plunger, the piston 23 pushes out the inner mold waste and the outer mold waste is stripped off by the pressure of the piston 24. This process is completed in position VIII. The ram runs back upwards, the workpiece 1 is hanging on the upper tool insert 17. In position IX, the piston 22 receives pressure and the ejection of the finely cut stamped part 1 '(stripping) begins. In position X, the stripping process of the finely cut stamped part 1 'takes place. The finely cut stamped part 1 'still hangs at the top of the bend. In position XI, the piston 21 receives pressure and begins to strip the finely cut stamped part 1 'from the bend from the upper tool insert 17 completely. This process is finished in position XII, the tool is now open again. The ram continues to its top dead center in position I. In the position shown in FIG. 8f, the finely cut stamped part 1 'is removed by means of the bar grippers 10, the waste 49 (slugs) are pushed off by the swivel arms 48 of the bar grippers 10.

In Fig. 9 the movements of the plunger 52 of the transfer press 20 and the individual pistons 21 to 24 of the built in the transfer press Fineblanking tool shown diagrammatically. They are coordinated with each other. The press-in force generated by the pistons 21 to 24 is up to 75% and the counterforce up to 30% of the cutting force generated by the ram. The sequence of movements of the ram as well as the individual pistons of the hydraulic cylinders as well as the number of functions required and thus the cylinder is determined by the shape of the workpiece.

3 has, in addition to the top plate 8 and the bottom plate 9, an upper 54 and a lower 55 clamping plate. These clamping plates, which run approximately in the middle height of the top set 42 and the cutting plate 41, serve to clamp the fineblanking tool on a fineblanking press. For this purpose, a recess 60 is made in the ram 52 and in the table 53, in which recesses the head plate 8 with the hydraulic block 4 and on the other hand the lower plate 9 with the hydraulic block 4 'are accommodated. The fineblanking tool is used here on the fineblanking press for testing (see Fig. 4).

In the transfer press with the built-in fineblanking tool, the sheet metal part is produced in individual tools in individual work stages, with one finished part being produced per ram stroke. In the exemplary embodiment, the ram movement of the transfer press takes place from top to bottom, the table is fixed. The fine blanking tool described can be optimally designed as a single tool. The individual tools can be manufactured independently of one another. The blank can be optimized and used as the last tool. Each tool can be tested and optimized separately as a single tool, using a normal fineblanking machine or a single-stage press. After optimization, all tools are on a common upper and lower base plate (see Fig. 1) mounted and equipped with a set of bar grippers. If a tool fails, only this has to be dismantled and readjusted. The hydraulics are supplied by a separate unit, the switching impulses for the control come from the ram command.

Claims (5)

1. Press for processing workpieces made of sheet metal or of cast or forged blanks, with at least two work stages, each of which a tool is assigned, and a device for automatic transport of the workpieces, characterized in that at least one of the work stages by one at any stage position embedded fineblanking tool is formed, in the upper part (2) and lower part (3) of which a hydraulic block (4, 4 ') is installed as the upper or lower structure of the tool insert (17, 18), which hydraulic block (4, 4 ') used with the responsible tool insert (17, 18) in an upper or lower change frame (6, 6') and can be controlled by a drive means (56, 19, 44). 2. Press according to claim 1, characterized in that the upper change frame (6) has a head plate (8) and an upper clamping plate (54) and the lower change frame (6 ') has a lower plate (9) and a lower clamping plate (55) , wherein the drive means (56, 19, 44) form a separate unit from the change frames (6, 6 '). 3. Press according to claims 1 and 2, characterized in that it is a transfer press (20) in which the fineblanking tool is adjustably embedded by means of the top plate (8) and the bottom plate (9). 4. Press according to claim 3, characterized in that the tools are mounted in all working stages on a common upper (46) and a common lower (47) base plate, which base plates (46, 47) on the press ram (52) or press table ( 53) are spanned. (4, 4 ') comprises at least one cylinder (13, 14, 15, 16), characterized in that in each hydraulic block (4, 4' 5. A press according to claim 1, wherein each _H ydraulikblock) a plurality of independently acting piston cylinder ( 13, 14, 15, 16) are present, the pressures acting in the piston cylinders being individually adjustable via a valve (57) and being able to be switched on and off individually.

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