Method for additively manufacturing a tip structure on a pre-existing part

Abstract

A method for additively manufacturing a tip structure on a pre-existing part includes: a) placing the part in a build space of a beam-assisted additive manufacturing setup and below a transparent aligning plate, b) engraving a top contour of the part onto the aligning plate with an energy beam of the setup, c) aligning a top surface of the part such that the top surface coincides with the engraved contour, d) removing the aligning plate from the setup, and e) additively manufacturing the tip structure according to a predefined geometry on the top surface.

Claims

1. A method for powder-bed-based additive manufacture of a tip structure on a pre-existing part comprising: a) placing the pre-existing part in a build space of a beam-assisted additive manufacturing setup and below a transparent aligning plate, b) engraving a top contour of the pre-existing part onto the transparent aligning plate with an energy beam of the setup, c) aligning a top surface of the pre-existing part such that the top surface coincides with the engraved top contour, d) removing the transparent aligning plate from the setup, and e) additively manufacturing the tip structure according to a predefined geometry on the top surface, wherein the engraved top contour mates with the top surface, and with an initial layer of the tip structure, wherein the aligning plate is made of an optically permeable material being susceptible to be engraved by an energy beam in order to image the contour of the tip structure.

2. The method according to claim 1, wherein the pre-existing part is a pre-machined part, and wherein an extent of premachining is adjusted to the predefined geometry of the tip structure.

3. The method according to claim 1, wherein the top surface of the pre-existing part is aligned horizontally.

4. The method according to claim 1, wherein the tip structure is manufactured by selective laser melting or electron beam melting.

5. The method according to claim 1, wherein the pre-existing part constitutes a section of a component, or a turbine blade or burner root, and wherein the tip structure constitutes a tip to be manufactured for the refurbishment of the component.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features, expediencies and advantageous refinements become apparent from the following description of the exemplary embodiment in connection with the Figures.

(2) FIG. 1 shows a schematic side view of an apparatus according to the present invention.

(3) FIG. 2 shows a schematic perspective view of the apparatus in a different state.

(4) FIG. 3 shows a further schematic perspective view of the apparatus.

(5) FIG. 4 shows a further schematic perspective view of the apparatus.

(6) FIG. 5 indicates a schematic flow chart of method steps of the present invention.

DETAILED DESCRIPTION OF INVENTION

(7) Like elements, elements of the same kind and identically acting elements may be provided with the same reference numerals in the Figures.

(8) FIG. 1 shows an additive manufacturing setup 100. The setup is advantageously a beam-assisted setup or device suitable for performing a selective laser melting or electron beam melting process.

(9) The setup 100 comprises a build plate A. On top of the build plate A, a component or part to be manufactured can be placed for its manufacture.

(10) The setup 100 further comprises an apparatus 20. Instead of the setup, the build plate A may be comprised by the apparatus 20.

(11) The apparatus 20 further comprises a frame D which is arranged on top of the build plate A, thereby defining a build space 30 for an additive build process. In a top view of the setup 100 and/or the apparatus 20, the frame D advantageously fully spans a covers the build plate A.

(12) The frame may be any stable metal frame, advantageously being open at an upper end such that an energy beam (see numeral 101) from the setup 100 can enter the build space 30 without any hindrance (cf. as well FIG. 2).

(13) The build plate A advantageously carries the frame D. The frame D may as well be rigidly fixed to the build plate A.

(14) The setup 100 further comprises an aligning plate E. The aligning plate E is attachable to the top of the frame D. The aligning plate E is advantageously even in shape and further removable from the setup 100, i.e. easily attachable to and removable from e.g. the frame D of the setup 100 as indicated by the double arrow in FIG. 1.

(15) The aligning plate E is advantageously made of glass or plastics and configured to image paths of a laser or electron beam 101 for the presented method. The aligning plate E is particularly configured such that it is susceptible to be engraved by the mentioned radiation, e.g. to image a contour or cross-section of a manufacturing plane of a part F the additive manufacture shall start from.

(16) In case of a laser beam-assisted additive manufacturing method the aligning plate E is advantageously suitable for imaging a region of it which has already been exposed with a laser beam. The same holds mutatis mutandis for a process assisted by an electron beam, i.e. electron beam melting.

(17) The part F advantageously represents a pre-machined part, wherein an extent of pre-machining is adjusted to the predefined geometry of the tip structure G, as shown in FIG. 1. The part F may further constitute a section of a component 10, such as a turbine blade or vane or a root of a turbine burner, wherein the tip structure G constitutes a tip to be manufactured onto the part F e.g. for a refurbishment of the component 10.

(18) The mentioned contour H may represent or indicate a junction line between the part F and the tip structure G in overall component 10, wherein this contour junction mates with the top surface 11, as well as with an initial layer of the tip structure G (see FIG. 1).

(19) The aligning plate E is advantageously constructed very thin in thickness, e.g. with a thickness of at most 5 mm.

(20) The aligning plate E has advantageously a uniform thickness.

(21) Its thickness may as well amount to more than 5 mm, however advantageously less than 5 mm, such as 3 mm, 2 mm, 1 mm or even less.

(22) The apparatus 20 further comprises a clamping mechanism comprising a clamping fixture B and a clamping fixture C. The clamping fixture B is, advantageously, a translational clamping fixture, e.g. suitable for fixing the part F and vary its position in the build space 30 along e.g. the vertical or build-up direction. The clamping fixture C is advantageously a rotational clamping fixture, i.e. suitable for fixing a part, such as the part F and vary and the orientation of the part according to any spatial direction or angle i.e. advantageously along and a azimuth angle and an elevation or declination angle in the build space 30 (see angles α and β in FIGS. 2 and 4 below).

(23) In FIG. 1, a situation is shown, in which the pre-existing part F is placed in the build space 30. The part F is particularly placed below the aligning plate E.

(24) Besides the presentation of the mentioned apparatus 20, an inventive method of additively manufacturing a tip structure on the pre-existing part F is described by means of the Figures. The method comprising placing the part F in the build space 30 and below the transparent aligning plate E as described above (cf. step a) in FIG. 5).

(25) The method further comprises engraving the contour H of the part F onto the aligning plate E with an energy beam 101 of the setup 100 (cf. FIG. 1 and step b) in FIG. 5).

(26) The method further comprises aligning the top surface 11 of the part F such that the top surface 11 coincides or mates with the engraved contour H (cf. and step c) in FIG. 5). This is further explained by means of FIGS. 2 to 4.

(27) FIG. 2 shows a perspective schematic view of the setup 100, wherein the aligning plate E is shown to be partly optically permeable or translucent, such that the engraved contour H and the top surface (cf. dashed line referenced with numeral 11 in FIG. 2) shining through the at least partly transparent aligning plate E, are shown. Thus, the mentioned alignment of the top surface 11 with the engraved contour, namely such that the top surface coincides with the contour, can be easily facilitated. Therefore, the clamping mechanism B, C has to be adjusted such that the shown azimuth or separation angle α by which the contour H and the part F are misaligned, vanishes. This may be performed manually or automatically.

(28) Preferably, the top surface 11 of the part F has an even surface.

(29) A result of such alignment is shown in FIGS. 1 and 3. In the perspective view of FIG. 3, the dashed line disappeared in contrast to the indication of FIG. 2, due to the congruence of the part F or—as the case may be—its top surface 11 with the engraved contour H.

(30) As mentioned above, said aligning has advantageously been performed by a respective adjustment of the clamping mechanism B, C.

(31) As described above, the top surface 11 is advantageously aligned horizontally and/or parallel to a surface of the alignment plate E. The top surface is, advantageously, aligned such that a single recoating step in the SLM process or setup 100 covers said surface with a powdery base material (not explicitly indicated).

(32) FIG. 4 shows a situation, in which said horizontal alignment has not yet been performed and e.g. a rotational and/or a translational alignment still has to be carried out by adjustment of the respective clamping mechanism as described above. Said adjustment has to be carried out such that the indicated declination angle β becomes zero.

(33) The method further comprises removing the aligning plate E from the setup 100 (cf. step d) in FIG. 5).

(34) The method further comprises additively manufacturing the tip structure G according to a predefined geometry (cf. step e) in FIG. 5). A predefined geometry for the tip structure G is indicated in FIG. 1 by means of the dashed area. The dashed area may represent a corresponding CAD-model of the tip structure G which inherently matches to the beam tooling and particularly to the engraved contour H. Consequently and necessarily, also the top surface 11 or its contour H coincides or mates with the engraved contour H, such that an accurate alignment has been provided.

(35) Said geometry for the tip structure G is then—according to the present invention—additively manufactured on the top surface 11 of part F. This is advantageously done by means of selective laser melting or electron beam melting method and according to the predefined geometry.

(36) The scope of protection of the invention is not limited to the examples given hereinabove. The invention is embodied in each novel characteristic and each combination of characteristics, which particularly includes every combination of any features which are stated in the claims, even if this feature or this combination of features is not explicitly stated in the claims or in the examples.