Method of forming a component from a green part

Patent metadata

Field	Value
Publication number	US-11097343-B2
Application number	US-201916382481-A
Country	US
Kind code	B2
Filing date	Apr 12, 2019
Priority date	Mar 12, 2015
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

A method of forming a component from a part in the green state, including selecting at least one first portion of the part to undergo a different local volume reduction from at least one second portion to obtain the component. The green part is provided with the first portion(s) having a first solid loading and the second portion(s) having a second solid loading different from the first solid loading, then debound and sintered to obtain the component. The different first and second solid loadings produce the different local volume reduction in the first portion(s). The first portion(s) can be selected by determining a resulting final shape obtained from debinding and sintering a green part having a uniform first volumetric proportion of binder, and selecting the first portion(s) requiring a different local deformation than that producing the resulting final shape to obtain a desired final shape.

First claim

The invention claimed is:

1. A method of forming a jointless part of a gas turbine engine through a powder injection molding process, the method comprising:
forming a green body of the jointless part in an initial shape, including:
injection-molding at least one first sub-region of the green body with a first feedstock,
injection-molding at least one second sub-region of the green body with a second feedstock,
obtaining a gradient of volumetric proportion of binder within the green body; and

obtaining a desired final shape of the jointless part different from the initial shape of the green body by altering the initial shape via debinding and sintering the green body, wherein the at least one second sub-region undergoes a volume reduction and a change of shape such that a desired distribution of local deformations is produced to obtain the jointless part having a different geometry and size than the green body; and wherein the at least one second sub-region of the green body defines a surface of a flat shield plate prior to debinding and sintering, the surface of the flat shield plate curving during sintering to obtain the desired final shape of the jointless part after sintering.

2. The method as defined in claim 1 , wherein the gradient of volumetric proportion of binder prior to debinding and sintering the green body is provided by the first feedstock having a first volumetric proportion of binder and the second feedstock having a second volumetric proportion of binder different than the first volumetric proportion of binder.

3. The method as defined in claim 2 , wherein sintering is performed with the surface defined by the at least one second sub-region of the green body placed against a shaping surface of a setter, the first surface not conforming to the shaping surface prior to sintering, the first volumetric proportion of binder being smaller than the second volumetric proportion of binder such that the at least one first sub-region undergoes a smaller local volume reduction than the at least one second sub-region during sintering to deform and conform the surface to the shaping surface of the setter.

4. The method as defined in claim 1 , wherein the at least one first sub-region defines a retention element of the jointless part and the surface defined by the at least one second sub-region is configured to be in contact with hot gas circulating through the gas turbine engine.

5. The method as defined in claim 1 , wherein the first and second feedstocks are made of a same binder and a same powder material.

6. The method as defined in claim 1 , wherein the gradient of volumetric proportion of binder is obtained by vaporizing part of the binder in the at least one first sub-region to adjust the gradient of volumetric proportion of binder prior to debinding and sintering the green body.

7. The method as defined in claim 6 , wherein vaporizing part of the binder includes heating the at least one first sub-region with a laser.

8. The method as defined in claim 1 , wherein the first and second feedstocks have a same volumetric proportion of binder when they are being injection-molded, wherein the gradient of volumetric proportion of binder within the green body prior to debinding and sintering the green body is obtained by vaporizing part of the binder in the at least one first sub-region until the gradient of volumetric proportion of binder within the green body is reached.

9. A method of forming a finished part of a gas turbine engine from a joint free injection molded part in a green state, the injection molded part in the green state having an initial shape, the finished part having a desired final shape different than the initial shape, the method comprising:
selecting at least one first sub-region of the injection molded part to undergo a local volume reduction different than that of at least one second sub-region of the injection molded part to obtain the finished part having the desired final shape,
providing the at least one first sub-region with a first volumetric proportion of binder, the at least one second sub-region having a second volumetric proportion of binder different from the first volumetric proportion of binder, wherein a variation of volumetric proportion of binder is obtained within the injection molded part in the green state, and
debinding and sintering the injection molded part in the green state to obtain the finished part having the desired final shape, wherein the variation of volumetric proportion of binder of the injection molded part in the green state results in a desired distribution of the local volume reductions of the at least one first and second sub-regions to reach the desired final shape of the finished part after debinding and sintering, wherein the at least one second sub-region of the injection molded part in the preen state defines a surface of a flat shield plate prior to debinding and sintering, wherein debinding and sintering includes curving the surface of the flat shield plate to obtain the desired final shape of the finished part.

10. The method as defined in claim 9 , wherein sintering is performed with the surface defined by the at least one second sub-region of the injection molded part in the green state placed against a shaping surface of a setter, the first surface not conforming to the shaping surface prior to sintering, the first volumetric proportion of binder being smaller than the second volumetric proportion of binder such that the at least one first sub-region undergoes a smaller local volume reduction than the at least one second sub-region during sintering to deform and conform the first surface to the shaping surface of the setter.

11. The method as defined in claim 9 , wherein the at least one first sub-region defines a retention element of the finished part and the surface defined by the at least one second sub-region of the finished part is configured to be in contact with hot gas circulating through the gas turbine engine.

12. The method as defined in claim 9 , wherein the first and second feedstocks are made of a same binder and a same powder material.

13. A method of forming a curved platform section of a heat shield for a gas turbine engine, comprising:
forming a green body in the form of a flat panel, including:
injection-molding at least one first sub-region of the green body with a first feedstock, the at least one first sub-region defining a first surface of the flat panel, the first surface configured to receive a plurality of studs;
injection-molding at least one second sub-region of the green body with a second feedstock having a greater volumetric proportion of binder than the first feedstock, the at least one second sub-region defining a second surface opposite the first surface, the second surface configured to be in contact with hot gas circulating through the gas turbine engine;

debinding and sintering the green body in the form of the flat panel, wherein a non-uniform deformation field is obtained across the green body in the form of the flat panel, the at least one second sub-region undergoing a greater shrink than the at least one first sub-region to curve the green body in the form of the flat panel during sintering and obtain the curved platform section of the heat shield after sintering.

14. The method as defined in claim 13 , wherein sintering is performed with the second surface of the green body placed against a shaping surface of a setter, the second surface not conforming to the shaping surface prior to sintering, the at least one second sub-region deforming during sintering and conforming to the shaping surface of the setter after sintering.

Assignees

• Pratt & Whitney Canada

Inventors

• Scalzo Orlando
• Campomanes Marc Lorenzo
• Poitras Guillaume

Classifications

• Y02P10/25

  Process efficiency · CPC title

• Y02T50/60

  Efficient propulsion technologies, e.g. for aircraft · CPC title

• F01D25/246

  Fastening of diaphragms or stator-rings · CPC title

• B22F7/06

  of composite workpieces or articles from parts, e.g. to form tipped tools {(B22F7/002 takes precedence)} · CPC title

• B22F2999/00

  Aspects linked to processes or compositions used in powder metallurgy · CPC title