DE102017117666A1 - Method for producing a metallic component - Google Patents

Abstract

A method for producing a metal component (10) is characterized by the following steps: producing the component (10) by a generative manufacturing method to form at least one chamber (14) in the component interior and at the same time producing a temporary support structure (22, 24) passing through the chamber (14) to interconnect opposing walls (18, 20) of the component, wherein between the support structure (22, 24) and the wall (18, 20) at the same time in the manufacture of component (10) and Supporting structure (22, 24) is formed immediately adjacent to the wall (18, 20) transition region (26, 28) having an outer surface (A) / volume ratio (V) A / V of ≥ 0.5, and initiating Energy into the component (10) to dissolve, liquefy or volatilize the material in the transition region (26, 28).

Description

The invention relates to a method for producing a metallic component using a generative manufacturing method.

Such generative manufacturing methods are known in the art, not only for the production of plastic parts, but also for the production of metal parts. Here, for example, arbitrarily shaped metallic components can be produced by liquefying metal powder by means of a laser beam and applying it in layers to previously cooled sections. Such components are increasingly being used, for example, in the aviation industry, in particular in turbine construction, since the mechanical finishing is eliminated and since the complicated structures can be carried out in lightweight construction.

In the manufacture of such metallic components, hollow chambers are created which sometimes require web or rib-like temporary support structures which pass through the chambers and temporarily stabilize the opposite chamber walls. These support structures are co-manufactured in generative manufacturing, so that they merge integrally into the adjacent walls. But these support structures should then be removed from the chamber, which is not mechanically possible because the chambers are not accessible laterally via tools. This lack of accessibility is the reason why the generative manufacturing process is superior to the previous manufacturing process. Chambers and support structures can be placed in areas that can not be reached with mechanical processing tools and thus placed in locations that are particularly suitable for saving weight.

The state of the art is currently the use of chemical processing methods in which these so-called support structures are dissolved by the use of aggressive chemicals. However, these methods do not selectively affect only the support structures, but on the entire component.

The object of the invention is to provide a method by which such known metallic components can be made even easier and faster.

1. a) Herstellen des Bauteils durch ein generatives Fertigungsverfahren unter Bildung wenigstens einer Kammer im Bauteilinneren und unter gleichzeitigem Herstellen einer temporären Stützstruktur, die die Kammer durchzieht, um gegenüberliegende Wände des Bauteils miteinander zu verbinden,
2. b) wobei zwischen der Stützstruktur und der Wand gleichzeitig bei der Herstellung von Bauteil und Stützstruktur ein unmittelbar an die Wand anschließender Übergangsbereich erzeugt wird, der ein Außenoberflächen- / Volumenverhältnis A/V von ≥ 0,5 hat, und
3. c) Einleiten von Energie in das Bauteil, um das Material im Übergangsbereich aufzulösen, zu verflüssigen oder zu verdampfen.

The method according to the invention is characterized by the following steps:

1. a) producing the component by a generative manufacturing process to form at least one chamber in the component interior and at the same time producing a temporary support structure, which passes through the chamber to connect opposite walls of the component with each other,
2. b) wherein between the support structure and the wall at the same time in the manufacture of the component and support structure, a transition wall immediately adjacent to the wall is created, which has an outer surface / volume ratio A / V of ≥ 0.5, and
3. c) introducing energy into the component to dissolve, liquefy or volatilize the material in the transition region.

The special feature of the method according to the invention is, inter alia, that not the entire support structure is provided with perforations, but that exactly the transition region to the wall is greatly weakened, so that this area is destroyed by the subsequent dissolution, evaporation or liquefaction. In the previous methods, the idea was to destroy the entire support structure as evenly as possible. The invention takes a different approach, it provides to release the support structure of the wall. Subsequent steps to completely remove the previously released support structure may then be removed in a possibly more appropriate method or in another station. Moreover, by releasing the support structure, the channel cross-section can be abruptly increased, which can facilitate the insertion of tools (e.g., cathodes) in a subsequent process step. Another possibility is that the remaining pieces of the support structure can fall out, be blown out or washed out via the supply and / or outlet channels. The outer surface of the transition region is, of course, not measured at the microstructure in the case of porous materials, but at the envelope, via which the dimensioning of the transition region also takes place. Likewise, the volume is correspondingly measured as the interior of the envelope. If the transition region has deliberately produced holes, in particular through-holes or corresponding channels, then their channel wall must be added to the outer surface, and their volume does not enter the total volume.

The relatively large ratio A / V ensures that, on the one hand, a high surface area is available for the chemical dissolution of the transition region and, on the other hand, a very high electrical, but also thermal resistance is present, which upon introduction of energy leads to liquefaction, preferably evaporation of the transition area.

Furthermore, it has been found that the transition region should have a significantly higher electrical and / or thermal resistance than the wall and the support structure. In particular, the resistance should be at least the factor 2 , in particular at least the factor 5 higher than the support structure. Also, this factor ensures that the support structure and the wall are not attacked, but the transition area is destroyed very quickly.

The ratio A / V of the outer surface to the volume of the transition region should in particular be ≥ 1, it may be in the range of 1-1.5, but in particular greater than or equal to 2.

An embodiment of the invention provides that the transition region is formed by a plurality of connecting webs. These individual connecting webs make it possible to provide no material between the connecting webs, so that the connecting webs provide for a higher outer surface and a smaller volume of the transition region. This allows an even faster destruction of the transition area.

The connecting webs may have a lower density than the rest of the component or at least the support structure, which is easily realized by the generative manufacturing process.

The density of the connecting webs should be ≦ 90%, in particular ≦ 80%, more particularly ≦ 60% of the wall density.

The connecting webs preferably have a constant density over their cross-section, i. about her volume. In this case, the ratio A / V should be ≥ 1. Alternatively, however, it is possible for each tie bar to be crossed over its cross-section, i. has different densities over its volume. In this case, it may be necessary to reduce the ratio A / V, i. it is ≥ 0.5.

It is also advantageous if the connecting webs do not extend over the entire length of the support structure, wherein the length is measured transversely to the shortest connection of support structure and wall.

The connecting webs are designed in particular as a thin, elongated webs. Over the entire length of the gap between the support structure and the wall extend relatively short connecting webs with a maximum length of 5 mm in succession. In other words, the connecting webs in this direction, i. transverse to the shortest connection of support structure and wall, are interrupted again and again.

The height of the connecting webs is very low. Under the height of the connecting webs is the shortest connection of support structure and wall to understand. This should be greater than or equal to 0.5 mm, preferably ≥ 1 mm, in particular ≥ 1.5 mm.

The wall thickness of the connecting webs should be ≤ 0.5 mm, in particular ≤ 0.2 mm. The wall thickness is the third dimension in addition to the height and the extension in the longitudinal direction. Here each connecting bar has its thinnest place.

In order to increase the outer surface of each connecting webs, it may extend nonlinearly between the supporting structure and the wall, for example in a wavy or zigzag shape.

In order to achieve the destruction of the connecting webs as quickly and uniformly as possible, according to a variant of the invention, they have largely identical A / V ratios, which vary at most in the region of 10%, that is to say ± 5%. The planning of the connecting webs is thus simplified. For a connecting bridge, for example, a fixed data record is simply stored in the CAD system.

One method of destroying the transition region is thermal deburring. This process is also referred to as explosion deburring and is a removal of the manufacturing process that is normally used for the removal of cantilevered ridges. In this case, a mixture of oxygen and hydrogen, natural gas or methane is introduced into the chamber and then ignited electrically, so that there is a detonating gas reaction. The resulting temperatures of over 2,500 ° C initiate the combustion of the burr with the oxygen. In the present case, so to speak, the transitional area evaporates abruptly due to the high temperature introduced. This sudden evaporation, which constitutes an option according to the invention in addition to the liquefaction, is particularly advantageous because the material of the support structure can be removed immediately.

A second option for vaporizing or liquefying, in particular for vaporizing, is that an electric current is applied in step c) to the component which flows through the transition region. The electrical resistance is so high in this area that this area is heated strongly and thus the transition area is liquefied or preferably immediately evaporated. As an alternative to both options, an electrochemical removal process can also be used.

The removal of the remaining support structure after step c), for example, by the fact that the support structure is dissolved in the chamber itself, which can be done by an electrochemical process, or that the support structure is displaced by applying an axial force from the channel.

The support structure preferably has a honeycomb structure, ie it is hollow and can thus easily be dissolved or removed. In addition, the cost of materials for the production of the support structure is reduced.

• - 1 einen Querschnitt durch ein durch das erfindungsgemäße Verfahren hergestelltes metallisches Bauteil vor Zerstören des Übergangsbereichs, wobei das Bauteil in einer entsprechenden Vorrichtung aufgenommen ist,
• - 2 eine Schnittansicht durch das Bauteil nach 1 im Bereich der Stützstruktur längs der Linie II-II in 1,
• - 3 eine Längsschnittansicht durch einen Flügelabschnitt einer Turbinenschaufel, die durch das erfindungsgemäße Verfahren hergestellt wird,
• - 4 einen Längsschnitt durch den Flügelabschnitt längs der Linie IV-IV in 3,
• - 5 einen Schnitt durch den Flügelabschnitt längs der Linie V-V in 3,
• - 6 eine vergrößerte Ansicht des Übergangsbereichs, der in 5 zu sehen ist,
• - 7 eine zur 6 alternative Ausführungsform des Übergangsbereichs, und
• - 8 ein Träger, auf dem mehrere erfindungsgemäß hergestellte Bauteile angebracht sind.

In particular, several components are placed on a support in a corresponding device, in which then suddenly all transition areas are destroyed on all components simultaneously. Such carriers are in particular plates to which the components are attached. For example, the carriers are produced by a generative manufacturing process together with the components. The connection of components to the carrier is effected by means of a transition region, which may also have the aforementioned properties, individually or in any combination. This ensures that when the energy is introduced into the carrier and thus into the components and the transition areas between the components and the common carrier are destroyed. Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. In the drawings show:

• - 1 a cross section through a metallic component produced by the inventive method before destroying the transition region, wherein the component is accommodated in a corresponding device,
• - 2 a sectional view through the component after 1 in the area of the support structure along the line II - II in 1 .
• - 3 a longitudinal sectional view through a wing portion of a turbine blade, which is produced by the inventive method,
• - 4 a longitudinal section through the wing portion along the line IV - IV in 3 .
• - 5 a section through the wing section along the line V - V in 3 .
• - 6 an enlarged view of the transition area that is in 5 you can see,
• - 7 one to 6 alternative embodiment of the transition region, and
• - 8th a carrier on which a plurality of components produced according to the invention are mounted.

In 1 is a manufactured by a generative manufacturing process component 10 shown in section, which is a closed circumferential wall 12 owns a chamber 14 encloses. The chamber 14 is not accessible to mechanical manufacturing processes, it has only one or more inlet or outlet ports 16 and thus supply and outlet channels through which, for example, liquid or compressed air or generally gas can be introduced.

The component 10 is manufactured for example by laser sintering.

1. a) Der/die Übergangsbereiche hat bzw. haben ein Außenoberflächen-Volumenverhältnis A/V von ≥0,5, insbesondere ≥ 1, weiter insbesondere von 1-1,5, vorzugsweise jedoch ≥ 2, wobei A die Außenoberfläche und V das Volumen des Übergangsbereichs ist,
2. b) der Übergangsbereich 26, 28 ist deutlich dünner als die angrenzende Stützstruktur 22, 24, wenigstens um den Faktor 4, insbesondere um den Faktor 10, siehe 1,
3. c) der Übergangsbereich 26, 28 ist wesentlich schmäler als die angrenzende Stützstruktur und hat Verschmälerungen 27, um in diesem Bereich wenigstens um den Faktor 2, insbesondere wenigstens um den Faktor 5 (siehe 2) kleiner als die Stützstruktur 22, 24 zu sein,
4. d) der Querschnitt des Übergangsbereichs 26, 28 ist wesentlich geringer als der der Stützstruktur 22, 24, gemessen senkrecht zur Längsrichtung der Stützstruktur 22, 24, insbesondere wenigstens um den Faktor 10,
5. e) im Übergangsbereich 26, 28 sind zahlreiche Löcher 30, die auch Langlöcher sein können (siehe 2), vorhanden, die den Querschnitt des Übergangsbereichs noch einmal weiter herabsetzen, wobei die Löcher 30 vorzugsweise Durchgangslöcher unter Bildung von Kanälen sind,
6. f) die Dichte des Materials im Übergangsbereich 26, 28 ist deutlich geringer als im Bereich der Wand 18, 20, und beträgt maximal 90 %, insbesondere maximal 80 %, vorzugsweise sogar maximal 60 % der Dichte der Wand 18, 20.

Opposite walls 18 . 20 be through multiple support structures 22 . 24 bridged and supported. These support structures 22 . 24 become with the component 10 produced at the same time, namely by the generative manufacturing process, so that they are integral with the walls 12 pass. Every support structure 22 . 24 has a transition area at its end 26 . 28 , to the adjacent wall 18 . 20 , This transition area 26 . 28 is much more unstable than the wall 18 . 20 and the support structures 22 . 24 , as 1 clearly shows. This lability can be achieved by several measures that can also be used in combination:

1. a) The transition region (s) has an outer surface volume ratio A / V of ≥ 0.5, in particular ≥ 1, more particularly of 1-1.5, but preferably ≥ 2, wherein A the outer surface and V is the volume of the transition area,
2. b) the transition area 26 . 28 is significantly thinner than the adjacent support structure 22 . 24 at least by factor 4 , especially by factor 10 , please refer 1 .
3. c) the transition area 26 . 28 is much narrower than the adjacent support structure and has narrowings 27 to be in this area at least by the factor 2 , in particular at least by the factor 5 (please refer 2 ) smaller than the support structure 22 . 24 to be,
4. d) the cross section of the transitional area 26 . 28 is much lower than that of the support structure 22 . 24 measured perpendicular to the longitudinal direction of the support structure 22 . 24 , in particular at least by the factor 10 .
5. e) in the transition area 26 . 28 are numerous holes 30 , which can also be long holes (see 2 ), which further reduce the cross section of the transition area, the holes 30 preferably through-holes to form channels,
6. f) the density of the material in the transitional area 26 . 28 is significantly lower than in the area of the wall 18 . 20 , and is a maximum of 90%, in particular a maximum of 80%, preferably even a maximum of 60% of the density of the wall 18 . 20 ,

In addition, for destroying the transition area 26 . 28 , as will be explained below, a wave or zigzag shape, as in 1 based on the transition areas 28 to be seen, be beneficial. This too can be combined as desired with the above options a) to f).

In general, the transition areas 26 . 28 through connecting bridges 32 formed, as explained, non-linear or due to the holes 30 or lower thickness more labile than the support structures 22 . 24 are executed.

As based on the in 2 right side transition area 26 can be seen, a transition area 26 . 28 from several narrow and very thin, juxtaposed connecting webs 32 be composed. The above properties of the connecting webs 32 corresponds to the transition area 26 because the connecting bridges 32 together form the transition area 26 ,

The connecting bridges 32 For example, they have a constant density over their volume, so that the ratio A / V is preferably ≥ 1. At different densities the ratio A / V should be ≥ 0.5, ie it tends to be lower.

These connecting bridges 32 For example, they also run in a wave or zigzag shape.

In general, the connecting webs 32 an extremely small wall thickness d (please refer 1 ) of not more than 0.5 mm, in particular not more than 0.2 mm.

The length I the connecting webs 32 according to 2 , Measured transversely to the shortest connection of support structure 22,24 to the wall 18,20, is preferably at most 5 mm. This is also the maximum extension of the connecting webs 32 transverse to the shortest connection of support structure 22 . 24 and wall 18 . 20 measured.

The lateral distance in X-direction of the connecting webs 32 is a maximum of 2.5 mm, in particular 2 mm.

The height h of the transition area 26 . 28 and its connecting bridges 32 is at least 0.5 mm, preferably at least 1 mm, but in particular at least 1.5 mm. The height h has long been the shortest connection of the support structure 22 . 24 and the wall 18 . 20 measured.

The ratios A / V for all connecting webs 32 are in particular the same, they fluctuate at most in the range of 10%.

After making the support structure 22 . 24 including peripheral wall 12 become the transition areas 26 . 28 destroyed substantially simultaneously by electrochemical removal, but in particular by evaporation or liquefaction, without the support structures 22 . 24 or the wall 12 would be destroyed or even damaged.

A first way to destroy the transition areas 26 . 28 and the bridges 32 is to perform a thermochemical deburring process. This is done via the inlet opening 16 Oxygen and hydrogen, natural gas or methane supplied and then ignited, for example, a spark in the region of the inlet opening 16 is produced. The resulting detonating gas reaction abruptly destroys the transition areas 26 . 28 and the connecting webs 32 ,

Alternatively, as in 1 indicated that an electrical current is applied to the component passing through the transition regions 26 . 28 flows, with such a current is applied that the transition areas 26 . 28 be destroyed abruptly, with immediate evaporation. Is a liquefaction of the transition areas 26 . 28 occur, the current is regulated down accordingly.

In a subsequent step, electrolyte is transferred via the inlet opening 16 introduced and completely removed by electrochemical removal. The peripheral wall 12 that is the component 10 , is doing as an anode and a tool, which, for example, via the inlet opening 16 in the chamber 14 is initiated, executed as a cathode.

Alternatively or additionally, an axial force can be applied to the support structure 22 . 24 exercise, for example by blowing compressed air. If the corresponding openings in the wall 18 . 20 big enough, can the support structures 22 . 24 remove it. In the 3-6 a further embodiment is shown in which a turbine blade 50 , also called turbine blade, is shown in sections in the area of the tip.

The previously introduced terms and reference numbers are reused for functionally identical parts or sections, so that only the differences have to be discussed below. Between the opposite walls 18 . 20 is a support structure 22 is provided in the form of a honeycomb structure, the honeycomb 52 best in 5 can be seen.

The honeycomb 52 run in the longitudinal direction of the walls 18 . 20 , Again, the support structure 22 to both walls 18 . 22 each through a transition area 26 . 28 formed in which numerous side by side extending and partly successively extending connecting webs 32 are provided. These connecting bridges 32 form the transition area 26 . 28 (please refer 5 ).

As for the properties of the transition areas 26 . 28 and its connecting bridges 32 As far as these are concerned, individually or in combination, they are identical to those previously described in relation to the introduction to the description or the 1 and 2 described properties. For example, the outer surface volume ratio A / V is as previously mentioned, that is, at least at least 1.

Also what the extension of the transition area 26 . 28 and the connecting webs 32 concerns (see length I , Height H and wall thickness d ), you can refer to the above data. The same applies to all other properties, be it density, etc.

In 4 it can be seen that the connecting webs 32 longitudinally spaced from each other, corresponding gaps 56 have a length a, which is at least 1 mm, preferably at most 10 mm.

7 shows a corresponding connection of the honeycomb structure on zigzag or wavy connecting webs 32 to the wall 18 or 20 , Again, the properties correspond to the aforementioned properties of the transition region 26 and the connecting webs 32 ,

8th shows that several components 10 on a common carrier 100 , here a plate, about transition areas 126 in the form of connecting webs 132 may be coupled together by means of a generative method.

The corresponding transition areas 126 and their connecting bridges 132 have exactly the property previously with respect to the transition areas 26 . 28 and the connecting webs 32 have been given, these properties may be present individually or in any combination.

When voltage is applied, or more generally when energy is applied, not only are the tie bars 32 but also the connecting bridges 132 liquefied, electrochemically removed, but especially directly evaporated. Again, the aforementioned methods can be used.

Claims (19)

Method for producing a metal component (10), characterized by the following steps: a) producing the component (10) by a generative manufacturing method, forming at least one chamber (14) in the component interior and simultaneously producing a temporary support structure (22, 24 b) passing through the chamber (14) to interconnect opposite walls (18, 20) of the component; b) being formed between the support structure (22, 24) and the wall (18, 20) simultaneously in the manufacture of component (10); 10) and support structure (22, 24), a transition region (26, 28) immediately adjacent to the wall (18, 20) having an outer surface (A) / volume ratio (V) A / V of ≥ 0.5 is produced and c) introducing energy into the component (10) to dissolve, liquefy or volatilize the material in the transition region without simultaneously dissolving, liquefying or vaporizing the wall and the support structure (22, 24). Method according to Claim 1 , characterized in that the transition region (26, 28) has a higher electrical and / or thermal resistance than the wall and the support structure (22, 24), in particular wherein the electrical and / or thermal resistance of the transition region (26, 28) at least by the factor 2, more particularly at least the factor 5 is higher than that of the support structure (22, 24). Method according to Claim 1 or 2 characterized in that the transition region (26, 28) has an outer surface (A) / volume ratio (V) ≥ 1 which is in the range of 1-1.5 or ≥ 2. Method according to one of the preceding claims, characterized in that the transition region (22, 24) by connecting webs (32) is formed. Method according to Claim 4 , characterized in that the connecting webs (32) have a lower density than the rest of the component (10) or at least the support structure (22, 24). Method according to Claim 5 , characterized in that the density of the connecting webs (32) ≤ 90%, in particular ≤ 80%, more particularly ≤ 60% of the wall density. Method according to one of the preceding claims, characterized in that the connecting webs themselves have a different density over their cross section or that the connecting webs have a uniform density over their cross section and the outer surface (A) / volume ratio (V) A / V of ≥ 1 is. Method according to one of Claims 4 to 7 , characterized in that numerous Connecting webs (32) are present, which are interrupted transversely to the shortest connection of the support structure (22, 24) and wall (18, 20). Method according to one of Claims 4 to 8th , characterized in that the maximum extent of the connecting webs (32) transverse to the shortest connection of support structure (22, 24) and wall (18, 20) is a maximum of 5 mm. Method according to one of Claims 4 to 9 , characterized in that the height of the connecting webs (32) measured along the shortest connection of support structure (22, 24) and wall (18, 20) ≥ 0.5 mm, preferably ≥ 1 mm, in particular ≥ 1.5 mm. Method according to one of Claims 4 to 10 , characterized in that the wall thickness of the connecting webs (32) ≤ 0.5 mm, in particular ≤0.2 mm. Method according to one of Claims 4 to 11 characterized in that the connecting webs (32) do not extend linearly between reinforcing structure (22, 24) and wall (18, 20). Method according to one of Claims 4 to 11 , characterized in that the outer surface (A) / volume ratio (V) A / V for all connecting webs (32) at most in the range of 10% varies, in particular is the same. Method according to one of the preceding claims, characterized in that in step c) of the transition region (26, 28) is evaporated by thermal deburring. Method according to one of Claims 1 to 13 , characterized in that in step c) an electrical current is applied to the component (10) which flows through the transition region (26, 28) and such a current is applied that the transition region (26, 28) is destroyed, in particular with immediate liquefaction. Method according to one of the preceding claims, characterized in that after the dissolution / liquefaction / evaporation of the transition region (26, 28) an axial force is exerted on the remaining, separated support structure to remove them from the component. Method according to one of the preceding claims, characterized in that in a subsequent step d) the support structure (22, 24) in the chamber (14) is dissolved, in particular by an electrochemical method. Method according to one of the preceding claims, characterized in that the support structure (22, 24) is a honeycomb structure. Method according to one of the preceding claims, characterized in that at least one component (10) on a support (100) is integrally mounted and the component (10) also by means of a transition region (126) on the support (100) is mounted in step c) is also dissolved, liquefied or vaporized to the at least one component (10) from the carrier (100) to solve.

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