Manufacturing method

Abstract

The present disclosure relates to a method of forming a component and at least one support structure joined to the component by additive layer manufacturing, wherein the support structure has a reduced density and/or increased porosity relative to the component. The method then comprises a subsequent heat treatment step at increased pressure on the component and support structure to separate the component and at least one support structure.

Claims

1. A method of forming a component, the method comprising: forming the component and at least one support structure joined to the component at a join by additive layer manufacturing, at least a portion of the support structure having at least one of a reduced density and increased porosity relative to the component; subsequently carrying out a heat treatment at increased pressure on the component and the at least one support structure to at least partially separate the component and the at least one support structure by consolidating the at least one support structure and causing the support structure to separate from contact with the component; and forming a weakened portion at the join between the component and the at least one support structure by using a reduced energy density parameter when consolidating a powder material at the join, or leaving the powder material at the join partly unconsolidated by not exposing one or more layers of the powder material at the join to the heat treatment, wherein the heat treatment comprises hot isostatic pressing.

2. The method according to claim 1, comprising forming a plurality of support structures, each support structure having at least one of a lower density and greater porosity than the component.

3. The method according to claim 1, comprising forming the at least one support structure of a material having at least one of a lower density and increased porosity relative to the component.

4. The method according to claim 1, comprising forming at least one encapsulated pocket or void in the at least one support structure, the at least one encapsulated pocket or void having a reduced density relative to the component.

5. The method according to claim 1, comprising forming at least one notch on the at least one support structure adjacent to the join with the component.

6. The method according to claim 1, comprising forming the at least one support structure with at least one anchor, wherein the at least one anchor is denser than a surrounding support structure.

7. The method according to claim 6, wherein the at least one anchor extends from a base plate upon which the component and the at least one support structure are formed by additive layer manufacturing into the at least one support structure.

8. The method according to claim 6, wherein the at least one support structure bridges two surfaces of the component and the at least one anchor extends from one of the surfaces into the at least one support structure.

9. The method according to claim 1, wherein a bonding between a base plate upon which the component and the at least one support structure are formed by additive layer manufacturing is enhanced towards the center of a join between the base plate and support structure.

10. The method according to claim 1, wherein consolidating the at least one support structure includes consolidating the support structure into a more dense structure with an associated reduction in volume.

11. The method according to claim 1, wherein consolidating the at least one support structure includes consolidating the support structure into a more dense structure with an associated reduction in volume greater than a reduction in volume of the component.

12. The method according to claim 1, wherein a bonding between a base plate upon which the component and the at least one support structure are formed by additive layer manufacturing is enhanced towards the center of a join between the base plate and support structure by increasing an energy density of the heat treatment or exposing a powder material to the heat treatment multiple times during formation of the bonding.

13. A gas turbine component manufactured according to claim 1.

14. A gas turbine engine comprising a component according to claim 13.

15. A method of forming a component, the method comprising: forming the component and at least one support structure joined to the component by additive layer manufacturing, at least a portion of the support structure having at least one of a reduced density and increased porosity relative to the component; and subsequently carrying out a heat treatment at increased pressure on the component and the at least one support structure to at least partially separate the component and the at least one support structure by consolidating the at least one support structure and causing the support structure to separate from contact with the component, wherein the heat treatment comprises hot isostatic pressing, and a bonding between a base plate upon which the component and the at least one support structure are formed by additive layer manufacturing is enhanced towards the center of a join between the base plate and support structure by increasing an energy density of the heat treatment or exposing a powder material to the heat treatment multiple times during formation of the bonding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments will now be described by way of example only, with reference to the Figures, in which:

(2) FIG. 1 shows a component with associated support structures prior to heat treatment;

(3) FIG. 2 shows the component of FIG. 1 with the associated support structures after heat treatment;

(4) FIG. 3 shows the formation of notches at component/support structure join;

(5) FIGS. 4a and 4b show a support structure having encapsulated voids before (5a) and after (5b) heat treatment;

(6) FIGS. 5a and 5b show a support structure having an anchor to a base plate before (6a) and after (6b) heat treatment;

(7) FIGS. 6a and 6b show a support structure having an anchoring pin extending to the base plate before (6a) and after (6b) heat treatment; and

(8) FIGS. 7a and 7b show a support structure having an anchoring pin extending to a second surface of the component before (7a) and after (7b) heat treatment.

DETAILED DESCRIPTION AND FURTHER OPTIONAL FEATURES OF THE DISCLOSURE

(9) FIG. 1 shows a component 1 having overhanging features which require support during manufacture to avoid distortion and enable the component to be built. The overhangs are supported by two support structures 2a, 2b.

(10) Both the component 1 and the support structures 2a, 2b are formed using additive layer manufacturing where a layer of powder material is deposited on a base plate 4 and selectively consolidated to from a horizontal cross section of the component 1 and support structures 2a, 2b. This step is repeated multiple times to form the three dimensional component 1 and the support structures 2a, 2b layer upon layer, the layers being stacked in the build direction vertically away from the base plate.

(11) The parameters used during consolidation of the powder material are varied within each layer such that the parameters used to form the horizontal cross section of the component 1 in each layer result in a more dense/less porous consolidated material (e.g. a fully dense material) than the parameters used to form the horizontal cross section of the support structures 2a, 2b.

(12) As a result, the consolidated material forming the support structure 2a, 2b is less dense/more porous that the consolidated material forming the component.

(13) The support structure 2a, 2b abut and support the overhangs of the component at joins 3a, 3b.

(14) In a subsequent step, the component 1 and support structures 2a, 2b are subjected to hot isostatic pressing.

(15) FIG. 2 shows the component 1 and support structures 2a, 2b after hot isostatic pressing. As a result of the elevated temperature and pressure, the porous, semi-dense material forming the support structures 2a, 2b is fully consolidated into a fully dense material with an associated volume change. As the component 1 is already substantially fully dense, the hot isostatic pressing does not result in any significant change in volume of the component 1 and thus the support structures 2a, 2b shrinkage away from the component 1 thus forming gaps 5a, 5b between the component 1 and the support structures 2a, 2b.

(16) FIG. 3 shows the formation of sharp notches 6a, 6b at the join between the overhangs of the component 1 and the support structures 2a, 2b. This helps provide a weakness along the joins 3a, 3b thus facilitating separation.

(17) FIG. 4a shows a support structure 2a′ supporting an overhang of a component 1′ at a join 3a′. The support structure 2a′ has a plurality of internal pockets 7 which are filled by unconsolidated powder material (e.g. with a density of 70%) and which are defined by the support structure 2a′ and the base plate 4. As shown in FIG. 4b, during hot isostatic pressing, the pockets 7 collapse to enhance the volume reduction of the support structure 2a. In other embodiments, the pockets could be emptied of powder material and then resealed (e.g. by welding) to create internal voids which would provide an even greater volume reduction during hot isostatic pressing.

(18) FIG. 5a shows a support structure 2 supporting an internal chamber within a component 1′. An anchor 9 in the form of enhanced bonding between the support structure 2 and the base plate 4 is provided so that during hot isostatic pressing, the support structure remains anchored to the base plate as shown in FIG. 5b therefore ensuring the support retracts from the component surface.

(19) Similarly, in FIGS. 6a and 6b, an anchor in the form of a pin 11 is provided extending from the base plate 4 into the support structure 2′ so that the support structure 2a is anchored to the base plate 4 during shrinkage away from the component 1″.

(20) In the embodiment shown in FIGS. 7a and 7b, the support structure 2″ bridges two surfaces of the component 1″, i.e. bridges an overhang and a vertical portion 12 of the component 1 rather than standing on the base plate 4.

(21) The anchoring pin 11 extends from the vertical portion 12 of the component 1 into the support structure 2″ so that during hot isostatic pressing, the support structure 2″ shrinks away from the overhang and is anchored to the vertical portion 12 which is more easily accessible/processable for subsequent removal of the support structure 2″.

(22) It will be understood that the disclosure is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.