EP2741875B1 - Die casting machine and die casting method - Google Patents

Description

The present invention relates to a die casting machine with a die, which is intended for die casting possibly complicated castings from liquid molten metal.

It has already created so-called hot chamber die casting machines in which the existing of a die and a Druckgießkolben Gießgarnitur is in the heated metal bath. The die casting machine and the holding furnace required to keep the metal bath warm form one unit. In such hot chamber die casting machines, the liquid metal is sucked out of the metal bath by means of the upwardly moving die casting piston. During the subsequent downward movement of the pressure casting piston, the inlet opening coming from the metal reservoir is closed and the liquid metal is shot at high pressure and high speed into the mold cavity located in the die. As a result of the high inflow velocity of the liquid metal, porosities and oxides, ie air pockets and oxides, are often found in the interior of the castings Impurities. In addition, the castings have mechanical properties that appear to be in need of improvement. In the prior art die casting machines, the mold parts of the die are traversed along guide columns forming part of the die casting machine, with the guide columns and hydraulic cylinders sized to hold the mold parts together even under high operating pressures of the die. Since the known die casting machines should also be usable in conjunction with larger die casting molds and since the guide columns and hydraulic cylinders are still to withstand the stresses that occur during the process and holding together of the mold parts, the known die casting machines are correspondingly bulky in design and production , elaborate and expensive.

From the EP 2 319 638 A2 is already a metal die casting machine with a die known, whose mold cavity is intended for pressing and solidification of a molten metal. By means of a gate valve, which closes the inlet opening provided in one of the mold parts and completely closes off the mold cavity of the mold from the supply, pressure can be exerted on the molten metal in the mold and permanently maintained during the solidification phase. The mold has a fixed base, a top, and relatively movable side members which are held in place by the clamping forces of the die casting machine applied to the mold during the casting process.

Another die casting machine with one, also from several, during the casting process by appropriate Zuhaltekräfte in position to each other parts to be held existing mold is also from the WO 03/020459 A2 known. It is therefore an object to provide a die casting machine and a die casting method of the type mentioned above, with which larger castings can preferably be produced in an improved quality, the die casting machine according to the invention should still be much smaller and cheaper to produce.

In the die casting machine of the type mentioned above, the solution according to the invention consists in the features of the valid patent claim 1.

The die casting machine according to the invention has a die which has at least one fixed first casting part, at least one second casting part movable along guide columns and at least two casting side parts which are movable relative to each other transversely to the travel path of the at least one second casting part. In this case, there are locking pins on at least two mold side parts which, in the closed position, engage behind the fixed first mold part and the movable second mold part such that the travel of the second mold part is limited in the direction away from the at least one first mold part. The mold parts and the mold side parts of the die are thus mechanically interconnected so that the die is capable of withstanding high pressures in its closed or locked state. Since the mold parts and mold side parts are mechanically connected to each other, the guide columns and the associated units are required only for moving the at least one second mold part relative to the at least first mold part. At the Holding together the pressure die occurring pressures particularly well between the mold parts and mold side panels to transfer and distribute evenly, is provided according to the invention that the at least two mold-side parts projecting locking pin, the at least one fixed first mold part and the at least one second movable Behind the mold part. Since the guide columns and required for the process associated aggregates no longer need to be sized so as to hold the die together even under high operating pressures, the die casting machine according to the invention can be even smaller, more compact and cost-effective dimensioned, even if they are also for the production of larger castings should be usable. With the die casting machine according to the invention, therefore, considerable energy savings can also be achieved.

Thus, a possibly different temperature-induced expansion when joining the Gießformteile and mold side panels can be compensated, it is advantageous if the at least one movable second mold part is movable at least with a portion in the space bounded by the mold side panels gap.

For this purpose, preferred embodiments according to the invention provide that at least one locking pin is movable in the longitudinal direction of the pin and / or that the at least one locking pin should be movable against a restoring force. In this case, there is a particularly simple and inexpensive proposal according to the invention is that the restoring force is designed as a return spring and in particular as a compression spring. It is also possible that at least one hydraulic, pneumatic or electromechanical Force transmitter serves as a restoring force.

So that the locking pins mechanically connect the mold parts and the mold side parts and can distribute the forces acting on these components of the die well, it is expedient if the locking pins are integrated into the at least two mold side parts and / or if the locking pin in the closed position an associated abutment engage behind the at least one mold part. Here, a structurally particularly simple embodiment according to the invention provides that the at least one locking pin associated abutment is formed as a protruding on a mold part flange.

The thermally induced dimensional changes of the die can be compensated particularly well when the locking pins taper towards their free pin ends such that their adjacent abutment facing side surface forms a ramp, and that provided at least on a mold part counter bearing preferably a complementary casserole counter-slope having.

In order to solidify the molten metal in the die under pressure and thereby accelerate the solidification process and counteract possible porosities in the later casting, it is advantageous if at least a second mold part has two mold sections, which can be brought apart at a distance. While the upper mold section is connected to the mold side parts via the locking pins engaging its counter bearing, the lower mold section can be spaced such that the volume available as mold cavity is reduced and the pressure on the molten metal in the mold cavity is substantially increased ,

The volume reduction of the metal occurring during the metal age is compensated by the permanent pressure and can not lead to porosities.

In this case, the mold sections can be brought by means of at least one hydraulic, pneumatic or electro-mechanical force transmitter or any other suitable means at a distance. A highly loadable construction according to the invention provides that the mold sections of the at least one second mold part are displaceably guided into each other and preferably spaced apart by pressurization of at least one separating surface located between them.

In order to combine the mold parts and the mold side parts in the closed or operating position of the die, it is advantageous if the at least one mold side part by means of a side member drive is movable transversely to the travel of the second mold part and when the return movement of the side part Drive the at least one mold side part is mechanically blocked.

In this case, a preferred embodiment according to the invention provides that each side member drive is associated with at least one locking bolt which is movable between an open position and a locking position, in which locking position of the locking bolt, a stopper surface connected to a mold side part applied in such a way that a Resetting movement of the side member drive is blocked. With the help of this locking bolt, the mechanical locking of the die used in the invention in its closed or operating position is accomplished and ensured in this area.

With the help of the locking bar thermally induced dimensional changes can be well compensated when the locking bar taper towards its free end of the latch when the adjacent mold side part facing side surface forms a ramp, and if the stopper surface connected to the mold side part a complementary casserole Counter-slope.

A particularly simple yet resilient embodiment according to the invention provides that the / the side member drive (s) is / are designed as a hydraulic cylinder.

In order to achieve a laminar, oxide-free and gas-free inflow of the molten metal into the die, it is advantageous if the mold parts and the mold side parts define at least one mold cavity, in which mold cavity at least one air suction opening and at least one preferably central inlet opening for the molten metal empties.

In order to seal the at least one, located in the die mold cavity tight and at the same time to hold the molten metal immediately in front of the inlet opening, it is useful if at least in the movable second mold part at least one locking slide is displaceably guided in a closed position at least one, preferably central inlet opening tightly closes.

The molten metal is particularly easy to hold in front of at least one inlet opening, without unfavorable influences of the ambient air are to be feared on the molten metal, if for subsequent casting operations required molten metal supply is preferably immediately below the die or is arranged.

It is expedient if the die casting machine has at least one molten metal pump, with which the molten metal from a molten metal reservoir via the at least one inlet opening in the at least one mold cavity of the die is conveyed.

The compact design of the die casting machine according to the invention is favored when the guide columns protrude beyond the stationary first mold part or a machine plate of the die casting machine carrying the first mold.

Further developments according to the invention will become apparent from the following description of preferred embodiments in conjunction with the claims and the drawings.

The invention will be described in more detail below with reference to preferred embodiments.

Fig.1:

eine teilweise längsgeschnittene Druckgießmaschine mit einer Druckgießform, die ein erstes feststehendes Gießformteil, ein entlang von Führungssäulen verfahrbares zweites Gießformteil sowie quer zum zweiten Gießformteil bewegbare Gießform-Seitenteile hat, wobei die Gießformteile und Gießform-Seitenteile hier in ihrer mechanisch verriegelten Schließ- oder Betriebsstellung dargestellt sind.

Fig. 2:

die Druckgießmaschine aus Fig. 1 in einem Detail-Längsschnitt im Bereich der Druckgießform,

Fig. 3:

die Druckgießmaschine aus Fig. 1 und 2 bei Beendigung eines Druckgießvorganges und unmittelbar vor Entnahme des fertiggestellten Gußstückes,

Fig. 4:

eine mit Fig. 1 bis 3 vergleichbare Druckgießmaschine, deren Druckgießform hier jedoch zur Herstellung mehrerer Gussstücke auch mehrere Formnester hat,

Fig. 5:

die Druckgießmaschine aus Fig. 4 in einem Detail-Längsschnitt im Bereich der Druckgießform,

Fig. 6:

die Druckgießmaschine aus Fig. 4 und 5 in einem vergrößerten Detail-Längsschnitt in dem in Fig. 5 mit "X" eingegrenzten Bereich im Bereich einer mittels eines Schwerschiebers verschließbaren Zulauföffnung der Druckgießform,

Fig. 7:

den längsgeschnittenen Teilbereich der bereits in den Fig. 4 bis 6 gezeigten Druckgießform im Bereich der Zulauföffnung, wobei sich der Sperrschieber hier in einer Offenstellung befindet,

Fig. 8:

den in Fig. 4 gezeigten Teilbereich der Druckgießform im Bereich der Zulauföffnung, wobei sich der Sperrschieber hier in einer Schließstellung befindet, und

Fig. 9:

den ebenfalls längsgeschnittenen und bereits in den Fig. 7 und 8 gezeigten Teilbereich der Druckgießform im Bereich der Zulauföffnung, wobei das zumindest eine, in der Druckgießform vorgesehene Formnest derart komprimiert wurde, dass auch der dargestellte Sperrschieber zusätzlich in die ihm zugeordnete Zulauföffnung eintaucht.

It shows:

Fig.1:

a partially longitudinally slotted die casting machine having a die casting mold having a first fixed die part, a second die part movable along guide posts, and movable die side parts movable transversely to the second die part, wherein the die parts and mold side parts are shown here in their mechanically locked closing or operating position ,

Fig. 2:

the die casting machine off Fig. 1 in a detail longitudinal section in the area of the die,

3:

the die casting machine off Fig. 1 and 2 upon completion of a die casting operation and immediately prior to removal of the finished casting,

4:

one with Fig. 1 to 3 comparable die-casting machine, the die of which, however, also has several mold cavities for producing a plurality of castings,

Fig. 5:

the die casting machine off Fig. 4 in a detail longitudinal section in the area of the die,

Fig. 6:

the die casting machine off Fig. 4 and 5 in an enlarged detail longitudinal section in the in Fig. 5 with "X" limited area in the area of a closable by means of a slide valve inlet opening of the die,

Fig. 7:

the longitudinally cut portion of the already in the 4 to 6 shown die casting in the region of the inlet opening, wherein the gate valve is here in an open position,

Fig. 8:

the in Fig. 4 shown portion of the die in the region of the inlet opening, wherein the gate valve is here in a closed position, and

Fig. 9:

the also longitudinally cut and already in the FIGS. 7 and 8 shown partial area of the die in the region of the inlet opening, wherein the at least one, provided in the die mold cavity was compressed so that the illustrated gate valve also dips into its associated inlet opening.

In the Fig. 1 to 6 a die casting machine in two versions 1, 10 is shown. The die casting machine 1, 10 is intended for the production of metal castings 2. For this purpose, the die casting machine 1, 10 has a die casting mold 3, which encloses at least one molding cavity 4, which predetermines the outline of the casting 2.

The die casting mold 3 of the die casting machine 1, 10 has at least one fixed first casting part 5, at least one second casting part 7 movable along guide columns 6 and at least two casting mold side parts 8, 9 movable transversely to the travel path of the second casting part 7. The fixed first mold part 5 is fixedly mounted on a machine plate 11 of the die casting machine 1, 10. The movable second mold part 7 is held on at least one hydraulic cylinder 12, which serves as a travel drive. The here vertically oriented hydraulic cylinder 12 is held with its second mold part 7 facing away from the portion at a distance above the machine plate 11 at the free end portions of the guide columns 6. So that the casting mold side parts 8, 9 are movable relative to one another transversely to the travel path of the second casting part 7, all casting side parts 8, 9 are held displaceably on the machine plate 11 by means of at least one hydraulic cylinder 13 serving as a side part drive.

In the Fig. 2 and 4 It can be seen that on at least two mold side parts 8, 9 projecting locking pins 14 which engage behind in the closed position at least the movable second mold part 7 such that the travel of the second mold part 7 is limited in the direction away from the first mold part 5 direction. The embodiments 1, 10 of the die casting machine shown here have locking pins 14 on all their casting side parts 8, 9, which engage behind both the first and the second casting mold parts 5, 7. By means of the locking pins 14, the mold parts 5, 7 and the mold side parts 8, 9 can be mechanically locked in such a way that the pressure casting mold in its closed position also uses high operating pressures of the inside of the pressure casting mold Molten metal can withstand.

For this purpose, the return movement of the movable respectively by means of a side member drive transverse to the travel of the second mold part 7 mold side parts 8, 9 is also mechanically blocked. For this purpose, each side member drive at least one locking bar 16 is associated, which is movable between an open position and a locking position. In the locked position, the locking latches 16 engage a stop surface 17 connected to a casting side part 8, 9 in such a way that a return movement of the side part drive is blocked. Also, the locking bar 16 taper towards its free end of the bolt out such that their side facing the adjacent mold-side part 8, 9 side surface forms a ramp 18. Since the abutment surfaces connected to a mold side part 8, 9 have a complementary casserole counter-bevel, thermally induced dimensional deviations during the assembly of the pressure casting mold 3 can also be well compensated in this region.

The locking pins 14 protruding from the mold side parts 8, 9 are held movably on the mold side parts 8, 9 in the journal longitudinal direction against a restoring force. This restoring force is generated here by a respective compression spring, which compression springs act on their associated locking pin 14 back. However, it is also possible that the restoring force acting on the locking pins 14 is generated in each case by a hydraulic, pneumatic or electro-mechanical force transmitter. In the closed position of the die, the locking pins 14 engage behind a serving as an abutment flange 21. At each mold part 5, 7 is a flange 21 before. The locking pins 14 taper here to their spigot end in such a way that its side surface facing the adjacent flange forms a ramp 22. On the flanges 21 complementary casserole slopes are provided. Due to the movable configuration of the locking pin 14 and by the run-up bevels corresponding to 22 bevels 22 which occur during assembly of the die 3 due to temperature deviations can be well balanced.

The mold parts 5, 7 and the mold side parts 8, 9 enclose in their closed position at least one mold cavity 4, in which the required for the production of the casting 2 molten metal can be poured. In order to be able to pressurize the molten metal cast in the at least one mold cavity 4, the movable second mold part 7 has two mold sections 23, 24 which can be brought apart at a distance from one another. While the upper mold section 23 carries the behind engaged by locking pin 14 and serving as an abutment flange 21, the lower mold section 24 in contrast, in the space bounded by the mold side parts 8, 9 intermediate space. The mold sections 23, 24 have slidably into each other guided portions, which can be brought here by pressurizing the separating surfaces lying between them at a distance. By pressurizing the molten metal present in the at least one mold cavity 4 during the cooling and solidification process, the quality of the casting 2 is favorably influenced, its mechanical properties are significantly improved, the cooling process is accelerated and the cycle times are shortened.

The mold parts 5, 7 and the mold side parts 8, 9 define in the closed position of the die 3 at least one

Mold cavity 4. In order to be able to pour the molten metal into the at least one mold cavity 4 in a laminar fluid flow, at least one air suction opening 25 and at least one inlet opening 26 opens in each mold cavity. The air enclosed in the mold cavity 4 can be sucked off via the air suction opening 25 the molten metal is poured or fed via the at least one inlet opening 26. In the movable second mold part 7, at least one locking slide 27 is displaceably guided, the at least one inlet opening 26 closes tightly in the closed position, such that the molten metal reservoir 28 can still be present immediately behind the gate valve 27.

In the Fig. 1 to 5 It can be seen that the molten metal reservoir 28 required for subsequent casting operations is present below the die casting mold 3. Thus it is avoided that the ambient air can adversely affect the quality of the molten metal supply required for subsequent casting operations. In this case, at least one metal melt pump 29 is integrated into the molten metal reservoir 28, by means of which the molten metal can be conveyed via the at least one inlet opening 26 into the at least one mold cavity 4 of the pressure casting mold 3.

Compared to a conventional die casting machine, the die casting machine 1 shown here is characterized by a much more compact design. Since the hydraulic cylinder 12 is needed only for moving the second mold part 7 and the mold parts 5, 7 does not hold together, this hydraulic cylinder 12 and the second mold part 7 supporting guide columns 6 can be designed correspondingly smaller. Since thus lower forces required to operate the die casting machine shown here are, can be achieved with the die casting machine 1, a significant energy savings.

From a comparison of Fig. 7 to 9 , which show the die 3 of the die casting machine 10 in a detailed view in the region of the inlet opening 26, it becomes clear that the gate valve 27, after filling the at least one mold cavity 4 provided in the die 3, moves from its open position Fig. 7 in its closed position according to Fig. 8 moves, in which closed position the metal melt located in the at least one mold cavity 4 separated from the required for subsequent casting operations molten metal reservoir 28 and the inlet opening 26 is sealed. In the now following solidification phase, the casting mold sections 23, 24 are hydraulically spaced and the metal melt in the at least one mold cavity is pressurized, so that the locking slide 27 is additionally immersed in its associated inlet opening 28 (cf. Fig. 9 ). But it is also possible to bring the mold sections 23, 24 pneumatically, electro-mechanically or in any other suitable manner at a distance.

The high operating pressures required during the compression mold 3 during the solidification of the molten metal are collected and transmitted solely by the mechanical locking of the mold parts 5, 7 and the mold side parts 8, 9. The filling of the die 3 with molten metal takes place at high pressure-tight locked mold. At the same time 29 pressure is applied to the molten metal 29 by means of the molten metal pump 29, while in the die 3, a vacuum is generated. In this way, a fast, laminar, oxide and gas-free filling of the mold 3 is possible. Like from one Fig. 8 becomes clear, immediately after completion of the Mold filling by means of the locking slide 27, the inlet opening 26 is closed and thus the molten metal in the die 3 thermally and pressure-safe from the molten metal reservoir 28 separated. Upon onset of solidification of the metal in the mold cavity 4, pressure is applied both by means of the casting mold sections 23, 24 of the casting mold part 7 and with the central hydraulic cylinder 12. The application of the pressure takes place evenly on the mold cavity 4 located in the casting 2 until its complete solidification. Due to the high pressure results in an accelerated heat exchange with the die 3, whereby the solidification process is significantly shortened. The high pressure and short solidification times enable the casting of metals and alloys that were previously not castable by gravity casting, such as wrought aluminum alloys or forged alloys.

From a comparison of the in the FIGS. 1 to 3 illustrated embodiment 1 and the machine version 10 according to 4 to 6 It is clear that the die casting mold 3 of the die casting machine 10 can also have a plurality of mold cavities 4 for simultaneously producing a plurality of castings 2. While the die casting machine 1 according to the Fig. 1 to 4 a die-casting mold 3 having only one mold cavity 4, in which mold cavity 4, for example, a light metal impeller can be produced, are in the die 3 of the die casting machine 10 according to Fig. 5 several mold cavities 4 are provided, which are used here for the simultaneous production of, for example, several pistons.

LIST OF REFERENCE NUMBERS

1

die casting machine

2

casting

3

die

4

cavity

5

first fixed mold part

6

guide columns

7

second mobile mold part

8th

Mold-side part

9

Mold-side part

10

die casting machine

11

machine plate

12

Hydraulic cylinder (for the second mobile mold part 6)

13

Hydraulic cylinder (the mold side parts 8, 9)

14

locking pin

16

safety catch

17

Stop surface (on the mold side parts 8, 9)

18

approach ramp

21

flange

22

Ramp (on locking pin 14)

23

lower mold section

24

Upper mold section

25

air exhaust

26

Inlet opening (for the molten metal)

27

Gate valve (in the second mold part 7)

28

Molten metal stock

29

Molten metal pumps

Claims (19)

1. Die casting machine (1, 10), comprising a die casting mould (3) having at least one stationary first casting mould part (5), at least one second casting mould part (7) which is movable along guide pillars (6), and at least two lateral casting mould parts (8, 9), which are movable relative to one another transversely with respect to the travel path of the at least one second casting mould part (7), wherein locking pins (14) protrude from at least two lateral casting mould parts (8, 9), and engage behind at least the stationary first casting mould part (5) and the movable second casting mould part (7) so that the travel path of the at least one second casting mould part (7) in the direction away from the at least one first casting mould part (5) is limited.
2. Die casting machine as claimed in claim 1, characterised in that at least a partial region of the movable second casting mould part (7) is movable in the intermediate space defined by the lateral casting mould parts (8, 9).
3. Die casting machine as claimed in claim 1 or 2, characterised in that at least one locking pin (14) is movable in a longitudinal direction of the pin.
4. Die casting machine as claimed in any one of claims 1 to 3, characterised in that the at least one locking pin (14) is movable in the longitudinal direction of the pin against a return force.
5. Die casting machine as claimed in claim 4, characterised in that the return force is configured as a return spring and in particular as a compression spring or is effected by means of at least one hydraulic, pneumatic, or electromechanical force transmitter.
6. Die casting machine as claimed in any one of claims 1 to 5, characterised in that the locking pins (14) are integrated into the at least two lateral casting mould parts (8, 9).
7. Die casting machine as claimed in any one of claims 1 to 6, characterised in that, in the closed position, the locking pins (14) engage behind an associated counter support on at least one casting mould part (5, 7).
8. Die casting machine as claimed in claim 7, characterised in that the counter support associated with at least one locking pin (14) is formed as a flange (21) protruding from a casting mould part (5, 7).
9. Die casting machine as claimed in any one of claims 1 to 8, characterised in that the locking pins (14) taper towards a free pin end thereof such that the side face of the locking pins (14) facing the adjacent counter support forms a guide bevel (22), and in that the counter support provided at least on a casting mould part (5, 7) has a complementary mating guide bevel.
10. Die casting machine as claimed in any one of claims 1 to 9, characterised in that the second casting mould part (7) has two casting mould part pieces (23, 24) which can be moved to a spaced interval from one another, and in that the upper casting mould part piece (23) preferably carries the counter support.
11. Die casting machine as claimed in any one of claims 1 to 10, characterised in that the casting mould part pieces (23, 24) of the second casting mould part (7) are guided so as to be displaceable one inside the other and can be moved to a spaced interval from one another by applying pressure to at least one separating surface located therebetween.
12. Die casting machine as claimed in any one of claims 1 to 11, characterised in that the at least one lateral casting mould part (8, 9) is movable transversely with respect to the travel path of the second casting mould part (7) by means of a lateral part drive, and in that the return movement of the lateral part drive of the at least one lateral casting mould part (8, 9) can be blocked mechanically.
13. Die casting machine as claimed in any one of claims 1 to 12, characterised in that the lateral part drive is assigned at least one blocking catch (16), which is movable between an open position and a blocking position, in which blocking position the blocking catch (16) acts upon a stop surface connected to a lateral casting mould part (8, 9) such that a return movement of the lateral part drive is blocked.
14. Die casting machine as claimed in any one of claims 1 to 13, characterised in that the blocking catches (16) taper towards a free catch end thereof such that a side face thereof facing the adjacent lateral casting mould part (8, 9) forms a guide bevel, and in that the stop surface (17) connected to the lateral casting mould part (8, 9) has a complementary mating bevel.
15. Die casting machine as claimed in any one of claims 1 to 14, characterised in that the lateral part drive(s) is/are formed as hydraulic cylinders (13).
16. Die casting machine as claimed in any one of claims 1 to 15, characterised in that the casting mould parts (5, 7) and the lateral casting mould parts (8, 9) define at least one mould cavity (4), wherein at least one air extraction opening (25) and at least one preferably central inflow opening (26) for the molten metal issue in said mould cavity (4).
17. Die casting machine as claimed in any one of claims 1 to 16, characterised in that at least one blocking slide (27) is displaceably guided in the movable second casting mould part (7), said blocking slide closing the at least one preferably central inflow opening (26) in a leaktight manner in a closed position.
18. Die casting machine as claimed in any one of claims 1 to 17, characterised in that the die casting machine (1, 10) has at least one molten metal pump (29), by means of which the molten metal is conveyed out of a molten metal reservoir (28) via the at least one inflow opening (26) into the at least one mould cavity (4) of the die casting mould (3).
19. Die casting machine as claimed in any one of claims 1 to 18, characterised in that the guide pillars (6) protrude beyond the stationary first casting mould part (5) or beyond a machine plate (11) of the die casting machine (1, 10), said plate carrying the first casting mould part (5).

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