Venting device for a casting mould for casting metallic components

Abstract

A venting device for a casting mold for the production of metallic components comprises a first chill block half and a second chill block half, each with opposing venting surfaces. The venting surface of the first chill block half has a plurality of protrusions, while the venting surface of the second chill block half has a plurality of depressions. When the chill block halves interact, the protrusions of the venting surface of the first chill block half extend into the depressions of the venting surface of the second chill block half, forming a wave-like gap between the two venting surfaces along the longitudinal direction of the venting device. The majority of the protrusions and the majority of the depressions exhibit an asymmetrical shape in longitudinal section relative to the shape of each individual protrusion or depression, respectively.

Description

[0001] The invention relates to a venting device for a casting mold for producing metallic components.

[0002] Casting molds for the production of metal components must be coupled with a venting system to allow the air contained within the component cavity to escape when filling. Forced venting systems or vacuum valve systems are used for this purpose. Forced venting, also known as a chill vent or "washboard" vent, consists of two vent blocks with a gap between them through which the air displaced from the component cavity can escape, and the trailing melt is decelerated and cooled until solidification.

[0003] Venting the component cavity is an important factor in reducing structural defects (e.g., porosity) in the component. The performance of the forced venting system therefore plays a central role in component manufacturing. The required air must be expelled from the component cavity as quickly and completely as possible (i.e., high venting performance), while preventing the melt from splashing out of the forced venting system. Other important criteria for forced venting include the smallest possible explosion area, high mechanical resistance of the venting device against wear and damage in harsh foundry operations, high process reliability under extreme thermal cycling, and good suitability for demolding.

[0004] DE 10 2019 133354 B3 describes a venting device for venting a casting mold with a sawtooth-shaped flow gap between two mold halves for better demoldability of the sprue.

[0005] CN 108 838 368 A describes a venting device for venting a casting mold with a flow gap between two mold halves, the gap width of which decreases with increasing distance from the inflow of the flow gap.

[0006] JP S56 62669 A describes a venting device for venting a casting mold with a flow gap having trapezoidal extensions.

[0007] DE 195 00 005 A1 describes a forced venting device for permanent molds with one or more gaps, the gaps of which have almost parallel surfaces or may locally deviate from the parallel formation.

[0008] JP 2008 080391 A describes a venting device for venting a casting mold with a flow gap folded at an intermediate height of an elevation between two mold halves.

[0009] One object underlying the present invention can be seen in the creation of a venting device highly suitable for practical foundry operations. In particular, problems of conventional systems during the demolding process are to be overcome. Further aspects of the disclosure are aimed at achieving high venting performance.

[0010] According to one aspect of the invention, the problem is solved by the features of the independent claim. Further aspects and embodiments of the invention are the subject of the dependent claims and the description.

[0011] The scope of the present invention is defined by independent claim 1, and further embodiments of the invention are set out in dependent claims 2-13.

[0012] The asymmetrical shape of the protrusion and the recess ensures that the venting gap between the protrusion and the recess is also asymmetrical, i.e., it does not have the property of being reflected back onto itself by a mirror image along an axis. This asymmetry makes demolding of the melt solidified in the venting gap much easier and, if necessary, allows self-demolition or pre-demolition to occur during the cooling process. The reason for this is that, due to the asymmetrical shape, the melt is unable to "cling" to both sides of the protrusion to the same extent during solidification and shrinkage, making demolding difficult. This is because the asymmetrical wave design reduces the uniform shrinkage of the metal and, due to the different geometries on both sides of the protrusion, leads to partial dissolution or pre-demolition during solidification.This supports the demoulding and ejection process and significantly increases the process capability of the venting device.

[0013] Another beneficial effect of the asymmetrical shaft design is the reduction of tensile stresses during melt solidification between the venting device and the component. This stabilizes the venting device and thus prevents the casting material solidified in the venting device from cracking or tearing.

[0014] The asymmetrical shape of a depression can be characterized, for example, by the apex of the elevation being located off-center of the elevation's longitudinal extension. The elevation then has a different shape on its rising flank than on its falling flank.

[0015] For example, the apex of the elevation may lie within the first two-fifths or the first third of the elevation's longitudinal extent. In this case, the rising flank of the elevation has, at least on average, a greater steepness than the falling flank.

[0016] For example, the angle difference between the vertical angle of the rising flank and the vertical angle of the falling flank can be equal to or greater than 10°. With this angle difference, it can be safely assumed that there is a positive demolding effect due to more favorable shrinking conditions and a "forced" pre-demolition or detachment during solidification.

[0017] A variety of different shapes are possible for the rising flank and the falling flank. For example, the falling flank can have a first flank section beginning at the apex of the elevation and extending to a kink, which has a larger vertical angle than a second flank section extending further downward from the kink. In this case, the falling flank has an upper "sliding area" with a low steepness, which makes it difficult or even impossible for the melt to "claw" in this area.

[0018] The rising flank, for example, can have a largely constant steepness. However, it is also possible for the rising flank to have a steadily increasing steepness over the initial course of the gradient, up to at least a quarter of the height of the elevation. In this case, a curved gap is created in the lower melt flow area of ​​the elevation, which brings about a targeted fluid-mechanical influence on the melt in a manner described in more detail later.

[0019] Another measure could be to decelerate the melt by diverting it at the weir by creating a bulge at the apex of the elevation. Such decelerating diversions allow for a larger gap and thus increase the venting performance.

[0020] The gap size at the weir can essentially correspond to the gap size in the remaining wave-shaped gap, ie in this example the weir does not cause any local widening of the gap size.

[0021] The elevations and depressions forming the wave-shaped gap can have a straight line in a transverse dimension. However, it is also possible for the elevations and depressions to have a zigzag or wave-shaped pattern in the transverse direction.

[0022] According to another example, the venting surface of the first chill block half can have an arcuate recessed section arranged in the flow path upstream of the multiple elevations. When the chill block halves interact, a complementary elevation section on the venting surface of the second chill block half engages into said recessed section, thereby forming an arcuate inlet gap. The arcuate inlet gap slows the melt as it enters the venting device, thus enabling better cooling or faster solidification of the melt. This, in turn, makes it possible to keep the length and thus also the burst area of ​​the venting device comparatively small.

[0023] According to a further embodiment, the venting device can have a self-centering arrangement acting between the first chill block half and the second chill block half. The molded self-centering arrangement allows for precise and reproducible centering of the chill block halves relative to one another, i.e., it prevents a "creeping" displacement of the chill block halves relative to one another. This ensures a process-reliable venting gap over the service life of the venting device (i.e., over a high number of cycles).

[0024] The self-centering arrangement can be achieved by a protruding engagement part with centering surfaces adjacent to the venting surface of one of the chill block halves and a complementarily shaped receiving part adjacent to the venting surface of the other chill block half. Self-centering is achieved by the interaction of the centering surfaces on the engagement part and the receiving part under pressure.

[0025] For example, the engagement part can comprise a transverse rib and the receiving part a transverse groove. The transverse extension of the engagement and receiving parts prevents longitudinal displacement of the chill block halves relative to each other. Furthermore, the self-centering function enables easy pre-alignment and low-wear centering.

[0026] In the following, exemplary embodiments and further developments as well as further aspects of the invention are explained by way of example with reference to the drawings, wherein a varying degree of detail is sometimes used in the drawings. Individual features of different exemplary embodiments and variants thereof can be combined with one another, unless this is excluded for technical reasons. The same reference numerals designate the same or similar parts. Length and angle relationships shown as examples in true-to-scale representations are disclosed in a generalizable form (e.g., in the sense of "greater than," "smaller than," "longer than," "shorter than"). Figure 1 shows a schematic sectional view of an exemplary casting tool in the closed state. Figure 2 shows a schematic sectional view of the Figure 1 The casting tool shown is open. Figure 3shows a schematic representation of the connection of an exemplary venting device to the component cavity in top view. Figure 4 shows a perspective view of two chill block halves of an exemplary venting device in the open position. Figure 5 shows a perspective view of the two chill block halves of the Figure 4 in closed position. Figure 6 shows a perspective view of an embodiment of one of the chill block halves of the Figures 4 and 5 . Figure 7 shows a longitudinal sectional view of an embodiment of a venting device. Figure 8 shows a longitudinal sectional view of a partial section of a wave-shaped venting gap between the chill block halves of an exemplary venting device. Figure 9 shows the wave-shaped venting gap in an enlarged and true-to-scale representation. Figure 10shows a longitudinal sectional view of an embodiment of a venting device. Figure 11 shows a perspective transparent representation of the Figure 10 shown venting device. Figure 12A shows a schematic sectional view of a conventional fastening of the chill block halves of a venting device to an exemplary casting tool in the closed state. Figure 12B illustrates in a longitudinal section the effect of a relative displacement of the chill block halves on the gap dimension. Figure 13 shows in perspective view an example of position centering between chill block half and tool half with fit clearance. Figure 14 shows a perspective view of an embodiment of a self-centering arrangement acting between the first and second chill block halves. Figure 15 shows a side view of the Figure 14shown exemplary self-centering arrangement.

[0027] Figure 1shows an exemplary casting tool 10 in a simplified representation. The casting tool 10 has a first tool half 12 and a second tool half 14, which lies opposite the first tool half 12. When the casting tool 14 is closed, the two tool halves 12, 14 lie against one another. Between the tool halves is a cavity 16, in which the component to be produced is cast. Furthermore, a venting device 100 is provided on the casting tool 10, which is in fluid communication with the cavity 16 in a manner described in more detail below. The venting device 100 has a first chill block half 120 and a second chill block half 140, which can be implemented, for example, as inserts in the first tool half 12 and the second tool half 14, respectively. The casting tool 10 further comprises a feed (filling chamber) 18, via which the molten metal can be introduced into the cavity 16.

[0028] The two tool halves 12, 14 can be multi-part and, for example, each be constructed from a mold frame and a mold insert containing a cavity contour surface (not shown). The two tool halves 12, 14 can be mounted on machine plates 22, 24 of a casting machine (not shown) and can be moved towards each other in the normal direction to the plate extension into the closed position (see Figure 1 ) or moved away from each other. For example, machine plate 24 may be a stationary plate of the casting machine, while machine plate 22 represents the movable machine side.

[0029] The casting tool 10 can, for example, be a die casting mold (HPDC, High Pressure Die Casting) for casting metallic components, e.g., a casting tool for aluminum die casting. Components made of aluminum, magnesium, or zinc alloys can be manufactured using die casting.

[0030] When filling the cavity 16 (casting mold) via the filling chamber 18, the air in the cavity 16 is displaced by the molten metal flowing into the cavity 16 and removed from the cavity 16 via the venting device 100. This means that the venting device 100 (forced venting) has the task of completely venting the component cavity 16 in a short time in order to avoid quality losses of the component.

[0031] The venting is achieved by discharging the air into a gap between the two chill block halves 120, 140 of the venting device 100. The trailing melt is significantly decelerated and cooled in the gap via a wave-shaped surface geometry of the first and second chill block halves 120, 140 that runs transversely to the flow. This causes the melt to solidify between the two chill block halves 120 and 140. The challenge is to control the deceleration process through the decelerating wave geometry of the gap surfaces in such a way that, on the one hand, a high venting performance is achieved and, on the other hand, the melt is prevented from splashing out of the casting tool 10 (i.e., from the venting device 100).In other words, the gap between the chill block halves 120, 140 should have a cross-section sufficient for venting and at the same time ensure that the melt "runs dead" in the venting gap.

[0032] Conventional forced venting devices made of steel use a gap of less than 1.2 mm, as otherwise the melt could shoot through, i.e., pass through the chill block without solidifying. On the other hand, the gap must be greater than 0.8 mm, as otherwise sufficient venting performance cannot be achieved. If the tool halves 12, 14 are made of a material with better thermal conductivity than steel, larger gaps can sometimes be achieved. However, if such materials (e.g. copper or copper-tungsten alloys) are less durable and therefore have shorter service lives and are less suitable for harsh foundry operations. These materials are sensitive, crack, wear out more quickly, cannot be repaired, and have a limited service life (only around 80,000 castings). Furthermore, they cannot be coated with PVD hard coatings, or can only be coated with difficulty.

[0033] An important aspect when dimensioning the venting device 100 is that the venting device 100 is added to the blasting area of ​​the casting. The blasting area is the casting area projected into the parting plane of the die casting mold, to which the solidified material in the chill block is also added. This means that lengthening or widening the first and second chill block halves 120, 140, i.e., increasing the longitudinal and transverse dimensions of the gap, requires a higher clamping force of the casting machine. Larger and more complex casting machines must then be used, making the entire system significantly more expensive. In this respect, the base area of ​​the venting device (i.e., its length and width) should not be increased if possible, or should be kept as small as possible. In contrast, increasing the gap does not increase the blasting area of ​​the casting.

[0034] After the casting process, the casting tool 10 is opened so that the component 200 can be removed. As in Figure 2 As shown, the casting material 210 solidified in the venting device 100 is located on the component 200.

[0035] Various problems can arise during demolding of the component 200 together with the casting material 210. The wave-shaped, solidified casting material 210 can cling to the surfaces of the chill block halves 120, 140 and is then not ejected, or not completely ejected, from the venting device 100. The casting material 210 or parts thereof can tear off and fall into the cavity 16, thus damaging the system or blocking the venting device 100. Furthermore, the casting material 210 can tear off or break away from the component 200 in the area where the venting device 100 connects to the cavity 16. Figure 3shows a schematic representation of venting channels 310, which run between the component cavity 16 and the gap in the venting device 100 (between the chill block halves 120, 140). The short arrows indicate the stress directions occurring during the solidification process. In the venting device 100, shrinkage stresses occur in both directions, in the component the shrinkage only leads one-sided to stresses. In particular, particularly high tensile stresses occur at points P, which can lead to the casting material in the feed channels of component 200 (lower arrows P) or the casting material 210 (upper arrows P) tearing or breaking off.

[0036] The venting device 100 can be installed both vertically and horizontally. Furthermore, more than one venting device can be provided, ie, for example, two or three venting devices can be connected to the component 200.

[0037] Figure 4 illustrates in perspective the two chill block halves 120, 140 of an exemplary venting device 100 in the open state. The chill block halves 120, 140 are also referred to in the art as chill blocks. The venting surface 120A (see Figure 6 ) of the first chill block half 120 has several elevations 122, which create a wave geometry running transversely to the flow of the melt. The flow direction of the melt is in Figure 6 represented by the arrows S.

[0038] The elevations 122 are positioned when the venting device 100 is closed (see Figure 5 ) into several recesses 142 (see Figure 7) of the venting surface 140A of the second chill block half 140. The wave-shaped gap 732 of the venting device 100 extends between the two venting surfaces 120A and 140A. The gap geometry thus results from the geometry of several elevations 122 and the opposite several depressions 142 of the two chill block halves 120 and 140, respectively. As in Figure 7 As shown, the elevations 122 and the depressions 142 can be complementary in shape to one another, whereby (with ideal centering of the first and second chill block halves 120, 140 to one another) a constant gap dimension can be realized over the entire gap profile.

[0039] Figure 7 further illustrates a cooling system 720 of the first chill block half 120 and a cooling system 740 of the second chill block half 140 of the venting device 100. In the Figure 7In the example shown, the cooling systems 720, 740 can each comprise one or more cooling bores that extend longitudinally (i.e., in the direction of the arrows S) along the venting surfaces 120A and 140A of the first and second chill block halves 120, 140, respectively. The cooling systems 720, 740 effect a conventional temperature control of the venting surfaces 120A, 140A and enable rapid dissipation of heat to accelerate the solidification process of the melt flowing through them. The arrows indicate the direction of the heat flow from the elevations 122 and the depressions 142 to the respective cooling systems 720 and 740, respectively.

[0040] Figure 8 shows a partial section of the wave-shaped gap 732 between the plurality of elevations 122 of the first chill block half 120 and the plurality of depressions 142 of the second chill block half 140. Figure 9shows an enlarged and true-to-scale representation of the gap and surface profile of the chill block halves 120, 140.

[0041] Each elevation 122 has an asymmetrical shape in longitudinal section. The same applies analogously to each depression 142 and thus also to the course of the gap 732.

[0042] The asymmetry can be characterized, for example, by a vertex SP of the elevation 122 being located off-center of the longitudinal extension of the elevation 122. PL represents the period length PL of an elevation 122. For example, the vertex SP of the elevation can be located in the first two-fifths or in the first third of the period length PL.

[0043] The asymmetrical shape of an elevation 122 is characterized in that the elevation 122 has an ascending flank 122_1 and a descending flank 122_2, wherein the ascending flank 122_1 is steeper than the descending flank 122_2.

[0044] In Figure 9 the steepness of the rising flank 122_1 is expressed by the vertical angle α and the steepness of the falling flank by the vertical angle β. Both angles occur with respect to the vertical L. In the Figure 9In the wave geometry shown, α and β refer to the gradients of essentially rectilinear sections of the rising flank 122_1 and the falling flank 122_2, respectively. For example, the rising flank 122_1 comprises an initial section 122_1a and a main section 122_1b or is composed of these sections, wherein the initial section 122_1a, for example, has a continuously increasing steepness and the main section 122_1b then leads largely in a rectilinear manner from the initial section 122_1a to the vertex SP or shortly before it. The initial section 122_1a can, for example, extend over at least a quarter of the height of the elevation 122, while the main section 122_1b can, for example, make up more than half or two-thirds of the height of the elevation 122.

[0045] Regardless of the shape of the rising flank 122_1, the falling flank 122_2 can have a flat section 122_2c beginning at the apex SP of the elevation 122 and extending to a kink point K, and further comprise a main section 122_2d extending from the kink point K. The vertical angle of the flat section 122_2c can be greater than the vertical angle β of the main section 122_2d. The main section 122_2d can span more than half or more than two-thirds of the height of the elevation 122. The main section 122_2d can extend to the lower end of the elevation 122. As in Figure 9 For example, it can be straight over its entire length or it can be flattened in the lower area.

[0046] In the example of Figure 9The vertical angle α refers to the course of the main section 122_1b and the vertical angle β to the course of the main section 122_2d. However, it is also possible that the vertical angles α and β denote the average steepness of the ascending flank 122_1 and the descending flank 122_2, respectively.

[0047] The asymmetrical shape of the elevation 122 and the depression 124 results in a positive demolding effect. The asymmetry prevents equal force ratios when the solidifying melt shrinks onto the rising flank 122_1 and the falling flank 122_2. This prevents the solidifying melt from clinging to both sides of the elevation 122 with equal forces. When opening the chill block halves 120, 140, pre-demolding can occur, which reduces demolding forces overall and simplifies the feeds (see Figure 3 ) are therefore subjected to less mechanical stress.

[0048] For example, the flat section 122_2c can serve as a sliding area where pre-detachment can occur when the melt solidifies.

[0049] The vertical angle α of the rising flank 122_1 is smaller than the vertical angle β of the falling flank 122_2. The angular difference between the vertical angle α and the vertical angle β can be equal to or greater than 10°, i.e., α < β and, for example, β ≥ α + 10°. Preferably, angular differences greater than 15°, 20°, 25°, etc., up to a maximum of 50° can also be used. The following are concrete examples of suitable pairings [α, β] of the vertical angles: [10°, 35°], [10°, 40°], [15°, 50°], [15°, 35°], [15°, 40°], [15°, 45°], [20°, 35°], [20°, 40°], [20°, 45°], [20°, 50°]. In the Figure 9 In the example shown, the angle setting [19.71°, 38.98°] is selected. All of the above values ​​for α and β are also disclosed as range limits for larger or smaller angles of α and β, respectively.

[0050] The greater the angle difference, the stronger the positive demolding effect due to asymmetric shrinkage and forced pre-demolition or detachment during solidification. This applies both to the definition of the vertical angles α and β of the rising and falling flanks as average flank steepness and to the Figure 9 The definition given as an example is the steepness of subsections (here the respective main sections 122_1b and 122_2d) of the ascending flank 122_1 and the descending flank 122_2. As already mentioned, the main sections 122_1b and 122_2d can be sections that make up more than half or two-thirds of the height of the elevation 122 and / or that run largely in a straight line and / or represent the steepest sections of the ascending flank 122_1 and the descending flank 122_2.

[0051] A further measure for improving the venting performance of the venting device 100 can consist of providing a dam SS in the region of the apex SP of the elevation 122 for local swirling of the melt. The dam SS can be formed by a bulge in the region of the apex SP of the elevation 122 and by an opposite, contour-conforming bulge in the depression 142. The dam SS represents a disturbance geometry in the venting gap 732, which, for example, can manage without a variation of the gap size (i.e., the gap size can remain constant across the dam SS) or - in other embodiments - can also have a larger gap size locally.

[0052] The (optional) curved geometry of the initial section 122_1a of the rising flank 122_1 and the resulting increased steepness of the main section 122_1b can interact with the SS barrage in such a way that the melt is more effectively pressed against the opposite wall of the bulge in the depression 142. The wall of the bulge facing the melt flow thus acts as a kind of impact surface with a high deceleration effect (see the reverse arrows).

[0053] Due to the asymmetrical wave geometry, the wave height H can be increased compared to the prior art, whereby more travel per area is generated and a higher cooling capacity and deceleration of the melt can be achieved for a given size of the venting surfaces 120A, 140A (i.e. the blasting area). Alternatively, as a result of the larger wave height H, the size of the venting surfaces 120A, 140A can be reduced (i.e., the venting device 100 can be shortened), thus reducing the blasting area. At the same time, a larger gap size can be set compared to known venting devices, since the deceleration of the melt is additionally increased, for example, by the steep main section 122_1b and / or by weirs SS. As already mentioned, the blasting area and thus the required clamping force of the machine are not increased by increasing the gap size.

[0054] It should be noted that all elevations 122 (and associated depressions 142) may each have an identical shape and thus also the same period length PL. However, it is also possible for individual, several, or even all elevations 122 (and associated depressions 142) to have different shapes. For example, by changing the period length PL along the course of the venting gap 732, elevations 122 with different period lengths (and thus also different flank steepnesses) could be created. Furthermore, it is possible for the asymmetric shape as such to vary from one elevation 122 to another elevation 122. As long as there is a sufficient number of elevations, each with an asymmetric shape, along the gap, the described effects will occur to a greater or lesser extent.

[0055] Figure 10shows a sectional view of another embodiment of a venting device 1000. The venting device 1000 can include all features of the venting device 100, which is why reference is made to the above description to avoid repetition.

[0056] Furthermore, the venting device 1000 has a cooling system 720 in the first chill block half 120 and / or a cooling system 740 in the second chill block half 140. The cooling system 720 can have one or more cooling geometries (e.g., cooling channels) 1722, 1724, to which transverse channels 1722_1 and 1724_1, 1724_2 are connected. This achieves surface cooling of at least a partial section of the venting surface 120A. The transverse channels 1722_1 and 1724_1, 1724_2 can, for example, each run within a raised portion 122 and thereby bring about effective, contour-close flank cooling transversely to the flow direction S of the melt through the venting gap 732. The cooling geometries 1722, 1724 and / or the transverse channels 1722_1 or 1724_1, 1724_2 can, for example, have round or square cross-sections.

[0057] Analogously, the cooling system 740 in the second chill block half 140 can be provided with one or more cooling geometries (e.g., cooling channels) 1742, 1744, which are each in coolant communication with transverse channels 1742_1, 1742_2, or 1744_1 in the same manner as described above. This achieves surface cooling of at least a partial section of the venting surface 140A. The transverse channels 1742_1 and 1742_2 can, for example, run in regions between the depressions 142 and therefore enable effective, contour-close flank cooling of the depressions 142 in a direction transverse to the flow direction S of the melt. The cooling geometries 1742, 1744 and / or the transverse channels 1742_1, 1742_2, or 1744_1 can, for example, have round or square cross-sections.

[0058] In other words, the transverse channels 1722_1, 1724_1, 1724_2, 1742_1, 1742_2 allow effective and uniform cooling of the elevations 122 and the depressions 142, for example, across almost their entire transverse dimension, i.e., across almost the entire width of the venting surfaces 120A and 140A, respectively. The cooling geometries 1722, 1724 and 1742, 1744, respectively, are supplied with cooling medium during operation. Efficient heat dissipation makes it possible to use large gap dimensions and keep the blast surface of the venting device 1000 comparatively small.

[0059] The cooling system 720 or 740 with cross-channel cooling can, for example, cool only a portion of the venting surface(s) 120A or 140A, respectively. For example, an inlet-side portion can be cooled with a number of elevations 122 or depressions 142 equal to or less than 2, 3, 4, 5, 6, ... or greater. Cooling is particularly efficient in the inlet-side portion.

[0060] Figure 10 1 further illustrates a feature that may be present in all embodiments of venting devices 100, 1000, and consists in the fact that the venting surface 120A of the first chill block half 120 may have an arcuate recessed section arranged in the flow path in front of the plurality of elevations 122, into which, when the chill block halves 120, 140 interact, a complementary elevation section on the venting surface 140A of the second chill block half 140 engages, thereby forming an arcuate inlet gap (at reference numeral 1050). The arcuate inlet gap 1050 acts as an inlet-side "brake arch," which causes the melt to slow down / decelerate even before it enters the wave-shaped venting gap 732. For this purpose, a transverse channel 1744_1 may be provided specifically for tempering (cooling) the arcuate inlet gap 1050.

[0061] First and second chill block halves 120, 140 with transverse cooling channels can be manufactured, for example, by additive manufacturing using a powder (see, for example, WO 19233962 A1) using a powder bed process. Additive manufacturing processes include PBF (Powder Bed Fusion), SLS (Selective Laser Sintering), EBM (Electron Beam Melting), or DMD (Direct Metal Deposition). Furthermore, hybrid manufacturing is also possible, in which a conformal surface cooling system as well as the elevations and depressions of the venting surface are printed onto a plate with existing cooling holes. A wide variety of steels, particularly hot-work steels, can be suitable materials.

[0062] According to one aspect of this disclosure, the described cooling system 720, 740 with transverse cooling channels, which enable contour-close surface cooling and, for example, extend into the elevations 122 or between the depressions 142, can also be provided in any venting device with a wave-shaped gap between chill blocks. This means that, in particular, this disclosure also encompasses venting devices that have any desired (e.g., even symmetrical) shape of the individual elevations 122 and the individual depressions 142 in longitudinal section and are equipped with a cooling system with transverse cooling channels. The other features described above can optionally also be implemented in embodiments of such a venting device.

[0063] In practice, a variation in the gap dimension that occurs due to an undesirable relative displacement of the first and second chill block halves 120, 140 can have a serious negative impact on the venting performance of a venting device.

[0064] Conventional venting devices are attached to the respective tool halves 12 and 14 via screw connections 1222, 1224 and position centering devices 1212, 1214, see Figure 12A. Screw connections and position centering are not form-dependent dimensions (definition according to DIN 1680 Part 1), with which centering is achieved "from the outside". The position centering (for example, tongue and groove) between the tool halves 12, 14 and the respective chill block halves 120 and 140 is intended to ensure the dimensional accuracy of the gap across the mold separation. However, a poorly controlled heat balance or structural separation jumps can lead to a relative displacement of the first and second chill block halves 120, 140. This results in a Figure 12B shown modified gap size 1210, 1220 and a reduction in the required ventilation capacity.

[0065] Even small relative displacements (offsets) of, for example, 0.1 mm can lead to a loss of venting performance of more than 25% in the venting gap 732. This change immediately leads to quality and process problems. Gaps 732 that are too narrow (see gap dimension 1220) no longer allow sufficient air to pass through and can thus lead to the failure of the venting device 100, 1000. Since wider gaps would lead to the melt "splashing out" or "shooting through," conventional venting devices result in a narrow, error-prone process window.

[0066] A remedy applicable to all venting devices is a self-centering arrangement acting between the first chill block half 120 and the second chill block half 140. The self-centering arrangement prevents the Figure 12shown displacement between the chill block halves 120, 140 and thus ensures a process-reliable venting gap 732.

[0067] For example, the self-centering arrangement may comprise an engagement part arranged adjacent to the venting surface of one of the two chill block halves (at 1410) and an engagement part arranged adjacent to the venting surface of the other chill block half (in the Figures 14 and 15 for example, the chill block half 120). As shown in Figure 14 As shown, the engagement part can comprise, for example, a transverse rib and the receiving part a transverse groove. In the closed state of the venting device 100, the chill block halves 120, 140 interlock by means of the self-centering arrangement, whereby the relative position of the chill block halves 120, 140 to one another can be determined with high precision (see Figure 15). This means that a form-dependent self-centering takes place "from the inside" via the engagement part and the receiving part (e.g. transverse rib and transverse groove). This self-centering arrangement is included in the Figures 4 to 6 also recognizable.

[0068] The engaging part and the receiving part can interact in a force-locking manner via centering surfaces. The centering surfaces of the engaging part and the receiving part can be complementarily shaped. The centering surfaces of the engaging part and / or the receiving part can be designed, for example, as inclined surfaces or round surfaces. Other shapes are also possible. The centering surfaces are shaped such that when the casting tool is closed and the engaging part and the receiving part are pressed together, self-centering occurs through a sliding movement of the chill block halves 120, 140 in the longitudinal direction (flow direction of the melt) on the centering surfaces.

[0069] The fastening of the first and second chill block halves 120, 140 of the venting device 100, 1000 to the casting tool can be carried out, for example, as in Figure 12A shown. The Figure 13 shows an example of non-form-dependent dimensions such as position centerings 1212, 1214, which are incorporated in the machine-side surfaces 120B and 140B of the first and second chill block halves 120, 140, respectively, opposite the venting surfaces 120A, 140A. The Figure 13 The position centering device shown is a round recess that interacts with a complementary extension on the opposite tool half 12 or 14; other shapes are also possible. The position centering devices 1212, 1214 must be machined with a defined fit clearance (in the longitudinal direction) so that the self-centering arrangement 1410 between the chill block halves 120, 140 can compensate for any possible displacement of the chill block halves 120, 140.

[0070] According to one aspect of this disclosure, a self-centering arrangement acting between the first chill block half 120 and the second chill block half 140 can also be provided in any venting device with a wave-shaped gap between chill blocks. This means that, in particular, this disclosure also encompasses venting devices that have any desired (e.g., even symmetrical) shape of the individual elevations 122 and the individual depressions 142 in longitudinal section and are equipped with a self-centering arrangement. The features described above can optionally also be implemented in embodiments of such a venting device.

[0071] In summary, the aspects of an asymmetric venting gap and surface cooling interact to enable a larger gap dimension due to improved deceleration of the melt and / or higher waves (i.e., more surface area for heat dissipation) and / or surface cooling (more efficient heat dissipation). In this way (or even just through one of the two measures), gap dimensions of, for example, over 1.2 or over 1.3 mm or over 1.4 mm can be achieved with venting devices made of a steel material. Furthermore, the aforementioned measures, as well as the guaranteed, defined gap dimension created by the self-centering system, increase the process reliability of the entire system. EXAMPLES

[0072] The following examples relate to further aspects of the present disclosure: Example 1 is a venting device for a casting mold for producing metallic components, wherein the venting device comprises: a first chill block half and a second chill block half with opposing venting surfaces, wherein the venting surface of the first chill block half has a plurality of elevations, the venting surface of the second chill block half has a plurality of depressions, and when the chill block halves interact, the elevations of the venting surface of the first chill block half protrude into the depressions of the venting surface of the second chill block half and form a gap between the two venting surfaces that runs in a wave-like manner in the longitudinal direction of the venting device, wherein the venting device comprises a cooling system in the first chill block half and / or a cooling system in the second chill block half, which has one or more cooling geometries to which transverse channels are connected,which effect surface cooling of at least a partial section of the respective venting surface. In Example 2, the subject matter of Example 1 can optionally comprise that the venting device has a cooling system in the first chill block half, and the transverse channels run in regions within elevations, thereby causing flank cooling of these elevations. In Example 3, the subject matter of Example 1 or 2 can optionally comprise that the venting device has a cooling system in the second chill block half, and the transverse channels run in regions between depressions, thereby causing flank cooling of these depressions. In Example 4, the subject matter of one of the preceding examples can optionally comprise that the transverse channels run across substantially the entire width of the respective venting surface. In Example 5, the subject matter of one of the preceding examples can optionally comprisethat both the first chill block half and the second chill block half have the cooling system. In Example 6, the subject matter of one of the preceding examples can optionally comprise that the venting device has a cooling system in the second chill block half, an arcuate inlet gap is arranged upstream of the wave-shaped gap, and a further transverse channel is present in the second chill block half for cooling the arcuate inlet gap. In Example 7, the subject matter of one of the preceding examples can optionally comprise that the plurality of elevations and the plurality of depressions have an asymmetrical shape with respect to the shape of an individual elevation or an individual depression in longitudinal section. Example 8 is a venting device for a casting mold for producing metallic components,wherein the venting device comprises: a first chill block half and a second chill block half with opposing venting surfaces, wherein the venting surface of the first chill block half has a plurality of elevations, the venting surface of the second chill block half has a plurality of depressions, and when the chill block halves cooperate, the elevations of the venting surface of the first chill block half protrude into the depressions of the venting surface of the second chill block half and form a gap between the two venting surfaces that runs in a wave-like manner in the longitudinal direction of the venting device, which further comprises a self-centering arrangement acting between the first chill block half and the second chill block half. In Example 9, the subject matter of Example 8 can optionally include,that the self-centering arrangement has an engagement part with centering surfaces protruding adjacent to the venting surface of one of the chill block halves and a complementarily shaped receiving part adjacent to the venting surface of the other chill block half. In Example 10, the subject matter of Example 9 can optionally comprise the engagement part comprising a transverse rib and the receiving part comprising a transverse groove. In Example 11, the subject matter of any one of Examples 8 to 10 can optionally further comprise a position centering with fit clearance provided between the first chill block half and / or the second chill block half and a tool half supporting the respective chill block half. In Example 12, the subject matter of any one of Examples 8 to 11 can optionally comprisethat the plurality of elevations and the plurality of depressions have an asymmetrical shape in longitudinal section with respect to the shape of an individual elevation or an individual depression.

Claims

1. A venting device for a casting mold for the production of metallic components, the venting device (100, 1000) comprising: a first chill block half (120) and a second chill block half (140) with opposing venting surfaces (120A, 140A), wherein the venting surface of the first chill block half (120) has a plurality of elevations (122), the venting surface of the second chill block half (140) has a plurality of depressions (142), and with cooperating chill block halves, the elevations (122) of the venting surface (120A) of the first chill block half (120) project into the depressions (142) of the venting surface (140A) of the second chill block half (140) and form a gap (732) between the two venting surfaces (120A, 140A) which extends in an wave-like manner in the longitudinal direction of the venting device (100, 1000), wherein the plurality of elevations (122) and the plurality of depressions (142) each have an asymmetrical shape in longitudinal section with respect to the shape of an individual elevation or an individual depression (142), and an elevation (122) has an ascending flank (122_1) in the direction of flow of the melt and a descending flank (122_2) in the direction of flow of the melt, and the ascending flank (122_1) is steeper than the descending flank (122_2).

2. The venting device according to claim 1, wherein the apex (SP) of the elevation (122) is located off-center of the longitudinal extension of the elevation (122).

3. The venting device according to claim 2, wherein the apex (SP) of the elevation (122) lies within the first two-fifths or the first third of the longitudinal extent of the elevation (122).

4. The venting device according to any one of the preceding claims, wherein α denotes the angle of the average steepness of the ascending flank (122_1) relative to the perpendicular (L) or of a main section of the ascending flank (122_1) relative to the perpendicular (L), β denotes the angle of the average steepness of the descending flank (122_2) relative to the perpendicular (L) or of a main section of the descending flank (122_2) relative to the perpendicular (L), and β ≥ α + 10°.

5. The venting device according to one of the preceding claims, wherein the descending flank (122_2) comprises a first flank section (122_2c) starting at the apex (SP) of the elevation (122) and extending to a kink (K) and a second flank section (122_2d) starting from the kink (K), wherein the angle between the first flank portion (122_2c) and the perpendicular (L) is greater than the angle between the second flank portion (122_2d) and the perpendicular (L).

6. The venting device according to one of the preceding claims, wherein the ascending flank (122_1) has a continuously increasing steepness in the initial course of the slope up to at least a height corresponding to a quarter of the height of the elevation (122).

7. The venting device according to one of the preceding claims, with a back pressure stage (SS) formed as a bulge in the region of the apex (SP) of the elevation (122) for local turbulence of the melt.

8. The venting device according to claim 7, wherein the gap dimension at the back pressure stage (SS) substantially corresponds to the gap dimension in the remaining wave-like gap (732).

9. The venting device according to one of the preceding claims, wherein the elevations (122) and depressions (142) forming the wave-like gap (732) have a rectilinear course in a transverse dimension.

10. The venting device according to any one of the preceding claims, wherein the venting surface (120A) of the first chill block half (120) comprises an arcuate depression portion arranged in the flow path upstream of the plurality of elevations (122), into which depression portion a shape-complementary elevation portion engages on the venting surface (140A) of the second chill block half (140) when the chill block halves cooperate, thereby forming an arcuate inlet gap (1050).

11. The venting device according to any one of the preceding claims, further comprising a self-centering arrangement (1410) acting between the first chill block half (120) and the second chill block half (140).

12. The venting device according to claim 11, wherein the self-centering arrangement (1410) comprises an engaging part with centering surfaces projecting adjacent to the venting surface (120A; 140A) of one of the chill block halves (120; 140) and a complementarily shaped receiving part adjacent to the venting surface of the other chill block half (140; 120).

13. The venting device according to claim 12, wherein the engaging part comprises a transverse rib and the receiving part comprises a transverse groove.

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