schematically represented in fig1 is a die casting device 10 according to the invention , which has a first , movable die half 11 and a second , fixed die half 12 , which interact in the customary way with a die closing unit that is known per se , and therefore not represented in the drawing . said closing unit comprises a movable platen and a fixed platen , which are not represented in the drawing to achieve a better overview and on each of which one of the two die halves 11 , 12 is held in a known way . by means of the die closing unit , a predeterminable closing force can be exerted on the two die halves 11 , 12 . the two die halves 11 , 12 form between them a mold cavity 14 , which has the form of a casting to be cast and into which a casting material , for example a molten metal , preferably liquid aluminum or magnesium material , can be injected . for this purpose , the mold cavity 14 has an inlet opening , which is usually referred to as the “ gate ” and in fig1 is provided with the designation 15 . by way of an inlet channel 17 , the gate 15 is in connection with a casting chamber 18 , which has a filling opening 19 and in which an injection piston 21 is displaceably mounted . the injection piston 21 is held on a piston rod 22 , which is fixed by its end that is remote from the injection piston 21 on a working piston 24 . the working piston 24 is displaceably mounted in a working cylinder 26 of a drive unit provided overall with the designation 27 . the drive unit 27 has a pressure cylinder 29 , which is hydraulically coupled to the working cylinder 26 and in which a pressure piston 30 is displaceably mounted . on its end face that is toward the working cylinder 26 , the pressure piston 30 has a thrust pin 31 , which enters the working cylinder 26 on the side of the working cylinder 26 that is remote from the piston rod 22 . the pressure cylinder 29 is in flow connection by way of a pressure line 33 with a pressure accumulator which is known per se , and therefore not represented in the drawing , and which receives pressurized hydraulic fluid . an electrically controllable control valve 34 in the form of a solenoid is connected into the pressure line 33 and can be used for opening and closing the flow connection between the pressure accumulator ( not represented in the drawing ) and the pressure cylinder 29 in a defined manner . the working cylinder 26 is in flow connection by way of an outlet line 36 with a storage tank 37 for hydraulic fluid , so that hydraulic fluid can be delivered from the working cylinder 26 to the storage tank 37 by way of the outlet line 36 . approximately midway along it in the longitudinal direction , the piston rod 22 carries a bush 39 , fixed on which is a carrying arm 40 , which at the end carries a measuring rule 41 , which interacts with a position encoder 42 . the position encoder 42 is in connection by way of a signal line 44 with an electrical control unit 46 , to which the control valve 34 is also connected by way of a control line 48 . the die casting device 10 has a gas suction device 50 , which is known per se , and therefore only schematically represented in the drawing , and which is in flow connection with the mold cavity 14 by way of a venting channel 52 extending from the mold cavity 14 , a venting unit 55 adjoining the venting channel 52 and a suction line 57 adjoining said venting unit . an outlet valve 59 , which is configured as a solenoid and is connected to the control unit 46 by way of a control line 60 , is connected into the suction line 57 . the venting unit 55 is shown enlarged in fig2 and 3 . it forms a venting block 62 with a first block part 63 , which is fixed on the movable die half 11 , and with a second block part 64 , which is fixed on the fixed die half 12 . the two block parts 63 and 64 form between them a flow channel 66 , which adjoins the venting channel 52 and is connected to the suction line 57 by way of an outlet channel 67 passing through the second block part 64 . protruding into the flow channel 66 are rib - shaped first projections 69 and likewise rib - shaped second projections 70 , which are opposite to one another and disposed offset in relation to one another in the direction of flow , engaging in one another in a comb - like manner and forming between them a flow labyrinth 72 . the first projections 69 are fixed by means of a screw connection that is known per se , and therefore not represented in the drawing to achieve a better overview , on a holding plate 74 , which is formed in the manner of a slide and is mounted displaceably in a recess 77 of the first block part 63 with the aid of a linear guide 75 , for example a dovetail guide . by way of a thrust rod 79 , the holding plate 74 is acted upon by a compression spring 80 with an elastic restoring force . the compression spring 80 is disposed in a spring housing 82 , which is fixed on the outside of the first block part 63 , on the side remote from the movable die half 11 , and is passed through by the thrust rod 79 , which at its free end carries an extension arm 83 , which interacts with an electrical position encoder 85 and in the first end position of the holding plate 74 , represented in fig2 , lies against a switching contact 86 . the position encoder 85 and the switching contact 86 are connected to the control unit 46 by way of respective signal lines 87 and 88 , which are only shown in part in the drawing to achieve a better overview . disposed between the spring housing 82 and the extension arm 83 is an arresting mechanism 90 , which is passed through by the thrust rod 79 . the arresting mechanism 90 has in a way known per se , and therefore not represented in the drawing , arresting means , for example tensioning means , with which the thrust rod 79 , and thereby also the holding plate 74 and the first projections 79 , can be arrested in any position desired . the holding plate 74 is acted upon by the compression spring 80 with a spring force in the direction of the movable die half 11 . in the position represented in fig2 , the holding plate 74 lies with an end face 92 remote from the thrust rod 79 against an adjustable stop in the form of an adjusting screw 93 , which predetermines the position of the holding plate 74 , and consequently also the position of the first projections 69 . a temperature measuring sensor 95 , which is connected to the control unit 46 by way of a signal line 96 , enters the first block part 63 . the second projections 70 are immovably fixed on the second block part 64 , it likewise being possible for a screw connection that is known per se , and therefore not represented in the drawing , to be used to fix them . the holding plate 74 , and consequently also the first projections 69 , are displaceable back and forth between the first end position , represented in fig2 , in which the holding plate 74 lies with its end face 92 against the adjusting screw 93 , and the second end position , represented in fig3 , in which the end face 92 assumes a distance from the adjusting screw 93 . in the first end position , the first projections 69 assume a relatively great distance from the second projections 70 , so that the flow labyrinth 72 has a relatively large flow cross - section . with increasing displacement of the holding plate 74 into its second end position , the flow cross - section of the flow labyrinth 72 is reduced . this is particularly clear from fig3 . to produce a casting , a molten metal is injected into the mold cavity 14 by means of the injection piston 21 . at the beginning of the casting operation , the injection piston 21 assumes a withdrawn position , in which it exposes the filling opening 19 , so that the molten metal can be filled into the casting chamber 18 . subsequently , the injection piston 21 is pushed into the casting chamber 18 by means of the drive unit 27 . the path covered by the injection piston 21 can be sensed by means of the position encoder 42 . at first , the liquid casting material is transported up to the gate 15 by means of the injection piston 21 and at the same time air and casting gases are extracted from the mold cavity 14 by means of the gas suction device 50 by way of the venting channel 52 , the flow labyrinth 72 , the outlet channel 67 and the suction line 57 , with the outlet valve 59 being open . once , according to the signal of the position encoder 42 , the injection piston 21 has reached a position in which the molten metal has reached the gate 15 , the drive unit 27 is activated by the control unit 46 by way of the control valve 34 in such a way that the injection piston 21 is pushed at high speed further into the casting chamber 18 within a very short time and the previously evacuated mold cavity 14 is completely filled with liquid casting material . the liquid casting material 100 finally reaches the inlet 98 of the flow labyrinth 72 and is first deflected by a second projection 70 , to subsequently impinge on a first projection 69 . this is represented in fig2 . the liquid casting material 100 thereby impinges at very high speed on a first projection 69 , to which a considerable momentum is transferred as a result . this has the consequence that the first projection 69 is displaced together with the holding plate 74 counter to the action of the compression spring 80 in the direction away from the adjusting screw 93 , so that the initially considerable flow cross - section of the flow labyrinth 72 by way of which gas is extracted from the mold cavity 14 is reduced . the successive deflections that the liquid casting material 100 undergoes within the flow labyrinth 72 have the effect of slowing the casting material 100 . at the same time , heat is dissipated from the liquid casting material 100 to the block parts 63 and 64 as well as to the projections 69 and 70 and to the holding plate 74 , so that the temperature of the casting material 100 is greatly reduced and it finally solidifies within the flow labyrinth 72 , still before the casting material 100 reaches the outlet 99 of the flow labyrinth 72 . the casting material 100 hardening in the mold cavity 14 can be subjected to a very high pressure by the injection piston 21 for the secondary compression of the casting material 100 . once the casting operation has taken place , the mold cavity 14 can be opened by displacing the movable die half 11 , the flow labyrinth 72 also being opened at the same time , since the first block part 63 , fixed on the movable die half 11 , is brought along with the movable die half 11 to a distance from the second block part 64 . the casting material 100 that has hardened within the flow labyrinth 72 can consequently be easily removed from the flow labyrinth 72 . to make the removal easier , the holding plate 74 can be arrested together with the first projections 69 in their second end position , represented in fig2 , by means of the arresting mechanism 90 , so that the casting material 100 that has hardened in the flow labyrinth 72 is not subjected to any force by the first projections 79 . after removal of the solidified casting material 100 from the flow labyrinth 72 and removal of the casting from the mold cavity 14 , the first block part 63 together with the movable die half 11 can be moved again in the direction of the second block part 64 , or in the direction of the fixed die half 12 , so that a renewed casting operation can subsequently be carried out . the movable mounting of the first projections 69 allows the flow labyrinth 72 to have a considerable flow cross - section at the beginning of a casting operation , so that the mold cavity 14 can be reliably evacuated by the gas suction device 50 . however , to avoid liquid casting material 100 being able to flow through the flow labyrinth 72 during the casting operation , the flow cross - section thereof can be reduced on account of the movable mounting of the first projections 69 , the first projections 69 being displaced by the casting material 100 that enters the flow labyrinth 72 . this dispenses with the need for electrical , hydraulic or pneumatic control of the movement of the first projections 69 .