FIELD OF THE INVENTION:
The present disclosure generally relates to additive manufacturing process for a turbo-machinery component. Particularly relates to manufacturing of impellers for centrifugal compressors, centrifugal pumps or turbo expanders using powder-bed fusion technology. More particularly relates to a process to additively manufacture a turbo machinery impeller using Direct Metal Laser Sintering (DMLS) 3D printing with a heat treatment cycle.
BACKGROUND OF THE INVENTION:
Background description includes information that may be useful in understanding the present invention.
Turbo-machinery impellers such as Centrifugal compressor impellers, with shroud and hub, have a complex geometry and are difficult to manufacture and also for narrow gap impellers i.e. when the gap between hub and shroud is very less using conventional processes due to plurality of curved or aerodynamic profiles vanes. In the conventional process, the 2D impellers have two-piece construction i.e. hub (bottom part) and shroud (top part) that are joined (fused) using external or internal welding processes. These two parts are machined from raw material using machines like CNC milling machines, which is a subtractive manufacturing process where material wastage is a huge concern. Manufacturing 2D impellers through the conventional processes has disadvantages such as long set-up time, long process time and rework.
The patent number US6854960B2 discloses an impeller is manufactured by providing a mold for one angular segment containing one vane of an impeller and corresponding hub and rim portions, injection-molding fiber-reinforced polymer composite resin material into the mold to produce a plurality of substantially identical segments, and assembling the segments into an impeller by bonding corresponding mating end surfaces of the hub and rim portions of the segments.
The patent number US20150017013A1 discloses a method of manufacturing a turbo-machine impeller which includes a hub and a plurality of blades using powder material in an additive-manufacturing process. The method also includes applying energy to

the powder material by way of a high energy source and solidifying the powder material. At least one bulky portion of the hub is irradiated such that the powder material solidifies in a lattice structure surrounded by an outer solid skin structure enclosing the lattice structure.
The aforementioned prior art and conventional method often suffers from the problem of manufacturing an impeller having a complex geometry and is difficult to manufacture using conventional processes which has some disadvantages such as long set-up time, long process time and rework.
Hence, there is a need of a process to employ additive manufacturing process for turbo-machinery components such as impellers for centrifugal compressors, centrifugal pumps or turbo expanders in a single piece.
OBJECTS OF THE INVENTION:
It is therefore the object of the present invention is to propose a process employing additive manufacturing process for turbo-machinery components such as impellers for centrifugal compressors, centrifugal pumps or turbo expanders in a single piece using Direct Metal Laser Sintering (DMLS) 3D printing.
Another objective of the invention is to propose a post heat treatment cycle of the turbo-machinery components to achieve required metallurgical and mechanical properties.
SUMMARY OF THE INVENTION:
One or more drawbacks of conventional systems and method of manufacturing a turbo-machinery component through additive manufacturing process to meet the functional requirement are overcome, and additional advantages are provided through the process as claimed in the present disclosure. Additional features and advantages are realized through the technicalities of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered to be part of the claimed disclosure.
The process facilitates the manufacturing of a turbo-machinery component with a post heat treatment process.

A method employing additive manufacturing process for a turbo-machinery component such as impellers for centrifugal compressors, centrifugal pumps or turbo expanders, in a single piece, primarily using powder-bed method by high power LASER source.
With the intention of simplifying the manufacturing process, reducing the expense of manufacturing a turbo-machinery component and also post heat treatment process to meet the functional requirement, the present invention is advantageous.
Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
It is to be understood that the aspects and embodiments of the disclosure described above may be used in any combination with each other. Several of the aspects and embodiments may be combined to form a further embodiment of the disclosure.
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of apparatus that are consistent with the subject matter as claimed herein, wherein:
Figure-1 illustrates an isometric view of the compressor impeller according to an embodiment of the present invention.
Figure-2 illustrates an isometric view of the cross section of the compressor impeller according to an embodiment of the present invention.
Figure-3 illustrates another isometric view of the compressor impeller according to an embodiment of the present invention.

Figure-4 illustrates the view of the additive manufacturing 3D printing apparatus with powder bed fusion method according to an embodiment of the present invention.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and process illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
While the embodiments of the disclosure are subject to various modifications and alternative forms, specific embodiment thereof have been shown by way of example in the figures and will be described below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternative falling within the scope of the disclosure.
The drawings illustrate only those specific details that are pertinent to understand the embodiments of the present disclosure, so as not to obscure the disclosure with details that will be clear to those of ordinary skill in the art having benefit of the description herein.
In additive Manufacturing (AM) process using 3D printers in which three-dimensional solid objects of complex shapes can be made by successive deposition of powder metal layers and sintering the required powder metal in layers. The additive Manufacturing process offers for a layer-by-layer construction of complex components where a component is manufactured by dispensing or spreading a layer of powder material, which is then melted by a high power energy source and subsequently solidified. Each layer is melted and solidified only at portion which is commanded by software. This process has been used for manufacturing other turbo-machine components such as blades of axial turbines. However, these components are relatively small and have a narrow cross section.
There are several 3D printing process in additive Manufacturing (AM) technology such as stereo lithography (SLA) or fused deposition modeling (FDM) or ink jet printing

(IJP) or laminated object manufacturing (LOM) or direct metal laser sintering (DMLS) or electron beam melting (EBM) or direct energy deposition (DED).
According to an embodiment, a monolithic construction of the impeller is achieved by additive manufacturing method using the powder bed fusion technology with the use of direct metal laser sintering (DMLS) 3D printer.
In an embodiment of a process to additively manufacture turbo-machinery impeller according to figure 1, 2 and 3, a centrifugal compressor impeller (4) which is used to direct the gas flow from an axial to radial direction consists of an inlet (31), an outlet (32), a shroud (1), a hub (2) and a plurality of vanes (3).
In an embodiment according to figure 4, a direct metal laser sintering (DMLS) 3D printer (12) consists of a LASER source (5), a reflector (6) that programmatically directs the LASER beam on the metal powder to be sintered. The programmed 2D files are created from 3D file or image of the component to be manufactured. A layer of powder is spread on the target platform (11), where component is made, by means of the roller or slider (8) by taking intake powder from another platform (10) where the metal powder (9) is stored. The directed laser beam (7) sinters the powder on target platform (11) as per the coordinates sent by 2D file to the mirror (6). Once, the required parts of first layer is sintered, the second layer of powder is spread by the movement of roller (8) and the cycle repeats.
In the another embodiment, a process of heat treating the turbo machinery component manufactured using additive manufacturing process is disclosed. The heat treatment cycle is processed by heating the said component by solutionizing at a specified temperature of 1040 degree Celsius for one hour makes the microstructure altered to a fully recrystallized structure and air cool aging at 710 degree Celsius for 4 hours makes the precipitates strengthen and harden Stainless steel to produce the material with high strength, wherein the rate of heating and cooling is controlled to achieve the required hardness and other mechanical properties of the component to meet functional requirements. Heat treating the metallurgical component have a substantial impact on the microstructure to make it more homogenized.
It will be appreciated by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential

characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the invention is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.
Further, the drawings are illustrative only but not used to limit the scope of the present subject matter. It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments.

WE CLAIM:
1. A process to manufacture a turbo-machinery impeller (4) that comprises an inlet
(31), an outlet (32), a shroud (1), a hub (2) and a plurality of vanes (3), by a heat
treatment cycle using additive manufacturing method in direct metal laser sintering
(DMLS) 3D printer (12) comprising the step of:
post heat treating the turbo machinery impeller (4) by solutionizing at 1040 degree Celsius for one hour following by air cool aging at 710 degree Celsius for 4 hours.
2. A process to additively manufacture a turbo-machinery impeller with a heat
treatment cycle as claimed in claim 1, wherein said additively manufacturing method
of manufacturing the turbo machinery impeller (4) preferably uses direct metal laser
sintering (DMLS) (12) or electron beam melting (EBM) or direct energy deposition
(DED).