Method of forming a component from a green part

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.

1 . A method of forming a component from a part in a green state, the method comprising:
 selecting at least one first portion of the part to undergo a different local volume reduction from at least one second portion of the part to obtain the component;   providing the part in the green state, including:
 the at least one first portion having a first volume of powder material V P1  and a first volume of binder V B1 , the at least one first portion having a first solid loading defined as V P1 /(V P1 +V B1 ), and 
 the at least one second portion having a second volume of powder material at least one second portion V P2  and a second volume of binder V B2 , the at least one second portion having a second solid loading defined as V P2 /(V P2 +V B2 ), the first and second solid loadings having different values from one another; and 
   debinding and sintering the part to obtain the component, the different values of the first and second solid loadings producing the different local volume reduction in the at least one first portion with respect to the at least one second portion.   
     
     
         2 . The method as defined in  claim 1 , wherein a difference between the values of the first and second solid loadings is at least 0.01. 
     
     
         3 . The method as defined in  claim 1 , wherein a difference between the values of the first and second solid loadings is at most 0.06. 
     
     
         4 . The method as defined in  claim 1 , wherein providing the part in the green state includes molding the at least one first portion from a first feedstock having the first solid loading and molding the at least one second portion from a second feedstock having the second solid loading. 
     
     
         5 . The method as defined in  claim 1 , wherein providing the part in the green state includes molding the at least one first and second portions with a same feedstock having the second solid loading, and vaporizing part of the binder in the at least one first portion until the first solid loading is obtained in the at least one first portion. 
     
     
         6 . The method as defined in  claim 5 , wherein vaporizing the part of the binder includes heating the at least one first portion with a laser. 
     
     
         7 . The method as defined in  claim 1 , wherein the component is a shroud segment for a gas turbine engine, the at least one first portion being defined in retention elements of the shroud segment, the at least one second portion including a platform of the shroud segment, the first solid loading being greater than the second solid loading. 
     
     
         8 . The method as defined in  claim 7 , wherein selecting the at least one first portion includes:
 comparing a desired shape of the component with a shape of the component after sintering when produced with a part having a uniform solid loading corresponding to the second solid loading; and   selecting the at least one first portion to correspond to each section of the component produced from the part having the uniform solid loading deviating from the desired final shape by more than a predetermined threshold.   
     
     
         9 . The method as defined in  claim 1 , wherein sintering the part is performed with a surface of the part placed against a shaping surface of a setter, the surface of the part not conforming to the shaping surface, the surface of the part defined by the at least one second portion, the first solid loading being greater than the second solid loading such that the at least one first portion undergoes a smaller local volume reduction than the at least one second portion during sintering to deform the part to conform the surface to the shaping surface of the setter. 
     
     
         10 . The method as defined in  claim 9 , wherein the component is a heat shield for a gas turbine engine. 
     
     
         11 . The method as defined in  claim 1 , wherein the at least one first and second portions include the same powder material and the same binder. 
     
     
         12 . A method of forming a component using powder injection molding, the method comprising:
 determining a resulting final shape obtained from debinding and sintering a green part having a uniform first volumetric proportion of binder;   selecting at least one first portion of the green part requiring a different local deformation than that producing the resulting final shape to obtain a desired final shape;   providing the green part with the at least one first portion including a second volumetric proportion of binder different from the first volumetric proportion of binder, the green part including at least one second portion having the first volumetric proportion of binder; and   debinding and sintering the green part to obtain the component with the desired final shape.   
     
     
         13 . The method as defined in  claim 12 , wherein a difference between values of the first and second volumetric proportions of binder is at least 0.01. 
     
     
         14 . The method as defined in  claim 12 , wherein a difference between values of the first and second volumetric proportions of binder is at most 0.06. 
     
     
         15 . The method as defined in  claim 12 , wherein providing the green part includes molding the at least one first portion from a first feedstock having the first volumetric proportion of binder and molding the at least one second portion from a second feedstock having the second volumetric proportion of binder. 
     
     
         16 . The method as defined in  claim 12 , wherein providing the green part includes molding the at least one first and second portions with a same feedstock having the second volumetric proportion of binder, and vaporizing part of the binder in the at least one first portion until the first volumetric proportion of binder is obtained in the at least one first portion. 
     
     
         17 . The method as defined in  claim 16 , wherein vaporizing the part of the binder includes heating the at least one first portion with a laser. 
     
     
         18 . The method as defined in  claim 12 , wherein the component is a shroud segment for a gas turbine engine, the at least one first portion being defined in retention elements of the shroud segment, the at least one second portion including a platform of the shroud segment, the first volumetric proportion of binder being smaller than the second volumetric proportion of binder. 
     
     
         19 . The method as defined in  claim 12 , wherein sintering is performed with a first surface of the part placed against a shaping surface of a setter, the first surface not conforming to the shaping surface, the first surface defined by the at least one second portion, the first volumetric proportion of binder being smaller than the second volumetric proportion of binder such that the at least one first portion undergoes a smaller local volume reduction than the at least one second portion during sintering to deform and conform the first surface to the shaping surface of the setter. 
     
     
         20 . The method as defined in  claim 12 , wherein the at least one first and second portions are made from the same materials.