Claims:We claim:
1. A system (100) to produce a complex three-dimensional structure from powder material, the system (100) comprising:
a. a build platform (101) to print three-dimensional structures from powder material;
b. a build plate (102) disposed on the build platform (101) for accumulating powder material;
c. a dispenser module (103) coupled to the build platform (101), wherein the dispenser module (103) is configured to deposit powder material on the build plate (102) which is disposed on the build platform (101);
d. a recoater arm (104) to transfer powder material from the dispenser module (103) to the build plate (102) which is disposed on the build platform (101);
e. a collector module (105) disposed adjacent to the build platform (101), wherein the collector module (105) is configured to collect the excessive powder material from the build platform (101);
f. a laser source (106) disposed above the build platform (101) for sintering powder material by directing multiple laser beams from the laser source (106).

2. The system (100) as claimed in claim 1, wherein the build plate (102) is denoted by a dense lattice of voxels for an adaptable laser source (106) path.

3. A method (200) for producing a complex three-dimensional structure from powder material, the method (200) comprising the steps of:
a. designing a model and preparing data of a three-dimensional structure to be manufactured from a design interface;
b. loading files from the design interface to a system (100) in a sliced manner;
c. calibrating the process parameters of the components in an additive manufacturing process;
d. securing the build plate (102) on the build platform (101) and heating the build plate (102) to a pre-defined temperature;
e. loading powder material in the dispenser module (103);
f. scanning for the gap between the recoater arm (104) and the build platform (101);
g. depositing powder material on the build plate (102) using the recoater arm (104);
h. analyzing and controlling the path of the laser source (106) to sinter powder material, wherein the path of the laser source (106) is controlled by employing an integer based calculation(s);
i. moving the laser source (106) to the subsequent location corresponding to the build platform (101).

4. The method (200) as claimed in claim 3, wherein the height of the build platform (101) is adjusted based on the distance between the recoater arm (104) and the build platform (101).

5. The method (200) as claimed in claim 3, wherein an inert gas is introduced into the build platform (101) for removing dust particles in powder material deposited on the build plate (102).

6. The method (200) as claimed in claim 3, wherein the laser source (106) is moved to a desired location by varying the dimensions of the voxel which converts the continuous path of the laser source (106) to a computationally efficient discretized path.
, Description:PREAMBLE TO THE DESCRIPTION
[001] The following specification particularly describes the invention and the manner in which it is to be performed:
DESCRIPTION OF THE INVENTION
Technical field of the invention
[002] The present invention relates to a system and method to produce a complex three-dimensional structure from powder material by controlling the path of a laser source in an additive manufacturing process.
Background of the invention
[003] The additive manufacturing process involves adding up of layers to form a complex three-dimensional structure of a material. The powder/slurry material are fused together in a layer by layer pattern to create a three-dimensional structure. The additive manufacturing process is categorized as binder jetting, directed energy deposition, material extrusion, material jetting, powder bed fusion, sheet lamination, and vat photopolymerization. The additive manufacturing process is categorized based on the type of materials and energy source.
[004] The traditional manufacturing technique involves removal of materials from the workpiece to obtain a required shape. The manufacturing technique involves milling, turning, grinding, threading and other machining operations to obtain required shapes. The subtractive method reduces the material dimension incurring loss of materials and the range of shapes achieved is limited to the design of the tool. Hence, the additive manufacturing process is widely employed to obtain complex three-dimensional shapes by addition of parts to form the required structure. The additive manufacturing process performs complex operations to obtain required shape of the material.
[005] Though additive manufacturing method aids in the formation of complex three-dimensional shapes, the traditional additive manufacturing process provides limited movement of the energy source thereby resulting in a reduction of the production efficiency. Consequently, many attempts have been made to make the additive manufacturing process more accurate and precise.
[006] The US Patent Application No. US5155324A titled “Method for selective laser sintering with layer wise cross-scanning” relates to an apparatus and method for producing parts by selective laser sintering. The disclosed method selectively sinters a first layer of heat-fusible powder by directing a laser beam so that it scans the first layer in a first direction to sinter a first cross-section of the part. A second layer of the heat-fusible powder is then disposed over the first layer, and the next cross-section of the part is selectively sintered by the laser being scanned in a different direction from the first direction, for example in a direction perpendicular to the first direction. The cross-scanning resulting from scanning in different directions provides parts with structural strength which is not dependent upon orientation, with more uniform surfaces and textures, and with reduced distortion. In addition, each of the layers may have its outlined traced prior to the scanning, to further define the edges of the cross-section.
[007] Another Chinese Patent Application No. CN108527855A titled “Systems and methods for fabricating component with at least one laser device” discloses a controller for use in an additive manufacturing system including at least one laser device configured to generate at least one melt pool in a powdered material includes a processing device and a memory device. The controller is configured to generate at least one control signal to control a power output of the at least one laser device throughout at least one scanning path across the layer of the powdered material, and the scanning is path generated at least partially based on a functional relationship between a plurality of points of a generating path and each point of a plurality of points of the scanning path. The controller is further configured to generate a non-uniform energy intensity profile for the scanning path and transmit the control signal to the laser device to emit at least one laser beam to generate at least one melt pool.
[008] Hence, there is a need for an additive manufacturing process which yields accurate and precise results.
Summary of the invention
[009] The invention relates to a system and method to produce a complex three-dimensional structure from powder material by controlling the path of a laser source in an additive manufacturing process. The additive manufacturing process comprises a build platform, build plate disposed on the build platform, dispenser module coupled to the build platform, a receoater arm which aids in transferring powder material from dispenser module to the build plate, collector module disposed adjacent to the build platform and laser source disposed above the build platform. The recoater arm deposits powder material on the build platform in a layer-wise pattern which is drawn from the dispenser module.
[0010] A design interface comprises a design model of a three-dimensional structure which is sliced and transferred to a system to produce a complex three-dimensional structure. Further, the gap between the build plate and the recoater arm is scanned thereby adjusting the level of the build platform in the system. The recoater arm collects powder material from the collector module and deposits it on the build plate subsequent to the adjustment of the build platform in the system.
[0011] The laser source emits multiple laser beams which are directed from the laser source towards the powder material disposed on the build plate thereby sintering the powder material. During the sintering process, the movement of the laser source over the build platform is controlled by an integer based calculation(s). The laser source from one particular location is moved to another location over the build platform by changing the corresponding values of a voxel grid, wherein the path of the laser source is broken into hemi quadrants corresponding to voxel grids in the build platform. The grid rotation angles beside the first hemi-quadrant may be derived by setting a base angle and changing corresponding x and y co-ordinates of the voxels. The laser source from the already formed area is transited to a new area over the build platform by altering the variables of the voxel in the additive manufacturing build requirements thereby hardening the powder material to form a three-dimensional structure.
[0012] Thus, the present invention incorporates the integrized gridding method to manufacture a complex three-dimensional structure which eliminates the floating point errors arising due to integer degree rotations. Further, the integrized gridding method converts the continuous path of the laser source into computationally efficient discrete paths thereby directing multiple laser beams on power material disposed in the build plate.
[0013] Further, the present invention provides utility in manufacturing industry to produce complex three-dimensional structure in a plurality of fields such as automotive, aerospace, medical, energy and so on. The efficient path finding method of the laser source may increase the accuracy in the sintering of powder material thereby, increasing the programming efficiency of the system. Further, multiple beams emitted from the laser source and the discretized path followed by the laser source significantly reduces the time taken to produce complex three-dimensional structures.
Brief description of drawings
[0014] FIG 1 illustrates a system to produce a complex three-dimensional structure from powder material.
[0015] Figure 2 illustrates the flowchart of a method to produce a complex three-dimensional structure from powder material.
Detailed description of the invention
[0016] Reference will now be made in detail to the description of the present subject matter, one or more examples of which are shown in figures. Each example is provided to explain the subject matter and not a limitation. Various changes and modifications obvious to one skilled in the art to which the invention pertains are deemed to be within the spirit, scope and contemplation of the invention.
[0017] The invention relates to a system and method to produce a complex three-dimensional structure from powder material. The system comprises a build platform, build plate, dispenser module, recoater arm, collector module and a laser source. The build plate, disposed on the build platform is denoted by dense lattice of voxel, wherein the powder material is deposited from the dispenser module. The laser source emits multiple laser beams to sinter the powder material which is accumulated on the build plate. During the sintering process, the path of the laser source is controlled by an integer based calculation(s). The movement of the laser source is influenced by altering the values of the voxel grid corresponding to the build platform.

[0018] Figure 1 illustrates a system (100) to produce a complex three-dimensional structure from powder material. The system (100) comprises a build platform (101) to print three-dimensional structures from powder material by sintering powder material. A build plate (102) is disposed on the build platform (101) for accumulating powder material from a dispenser module (103) which is coupled to the build platform (101) in the system (100). The region of the build platform (101) is denoted by a dense lattice of voxel for an adaptable laser source (106) path. A voxel is a smallest unit volume which is represented in a three-dimensional space as discrete regions wherein the geometry of the voxel is expressed as co-ordinates along the axis. A recoater arm (104) is disposed on the build plate (102) for depositing powder material in a layer wise pattern from the dispenser module (103). A collector module (105) is disposed on the adjacent side of the build platform (101), wherein the collector module (105) collects the excessive powder material from the build platform (101). A laser source (106) is disposed above the build platform (101) for emitting multiple laser beams which are directed towards the build platform (101) for sintering powder material which is deposited on the build plate (102).
[0019] According to one or more embodiments of the present invention, a layer of powder material from the dispenser module (103) is deposited on the build plate (102) using the recoater arm (104) which deposits a pre-determined quantity of powder material on the build platform (101) by employing motors and belt drives which accumulates powder material from the dispenser module (103). The collector module (105) is disposed adjacent to the build platform (101) for collecting excessive powder material deposited on the build plate (102) which is disposed on the build platform (101).
[0020] According to one or more embodiments of the present invention, the laser source (106) emits multiple laser beams which are directed towards an optic system through an optical fibre which is a flexible fiber made up of silica. The optic system comprises a beam expander and a scanner unit for multiple laser beams to follow a pre-defined path. Multiple laser beams are directed towards the build plate (102) for sintering powder material which is disposed on the build platform (101) of the system (100).
[0021] Figure 2 illustrates a method (200) to produce a complex three-dimensional structure from powder material. The additive manufacturing process comprises a design interface for designing a model and preparing data comprising a pictorial representation of a three-dimensional structure to be manufactured as a pre-processing step, in step (201) and (202). The design interface is in a form of a computer-aided design which assists in building, modifying and analyzing the design of an object to be manufactured in an additive manufacturing process. The input from computer aided design model is converted into a stereolithography file which is sliced and loaded into the system (100) for further processing, in step (203). In step (204), the stereolithography file is converted into a numerical control programming language for calibrating the process parameters of the components in the additive manufacturing device.
[0022] In step (205), the build plate (102) is secured on the build platform (101) and heated to a preset temperature for reducing the stress in the build plate (102), in step (206). In step (207), powder material is loaded on the dispenser module (103) which is coupled to the build platform (101) in the system (100). The gap between the recoater arm (104) and build platform (101) is scanned and adjusted by altering the level of the build platform (101), in step (208) and (209). The powder material from the dispenser module (103) is transferred to the build plate (102) through a recoater arm (104) wherein the recoater arm (104) deposits powder material on the build plate (102) in a layer wise pattern, in step (210). An inert gas is introduced on to the build platform (101) to check for oxygen concentration in the build platform (101) thereby increasing the quality of the process. The laser source (106) disposed above the build platform (101) directs multiple laser beams towards the build platform (101) to sinters powder material deposited on the build platform (101), in step (211).
[0023] During sintering process, the path of the laser source (106) is analyzed and controlled by an integer based calculation(s), in step (212). In step (213), the laser source (106) from a particular location corresponding to the voxel grid is moved to a subsequent location by altering the voxel grid values.
Angle ?X ?Y Hemi-Quadrant
18? +3 +1 Base Angle, BAng
72? +1 +3 90? - BAng
108? -1 +3 90? + BAng
162? -3 +1 180? - BAng
198? +3 -1 180? + BAng
252? +1 -3 270? - BAng
288? -1 -3 270? + BAng
342? -3 -1 360? - BAng
.
[0024] The table comprises the angle representing the desired location of the laser source (106) corresponding to the voxel grid. The ‘?X’ and ‘?Y’ represents different axial values of the voxel corresponding to the build platform (101). The desired angle of rotation is achieved by moving the laser source (106) to a particular location by altering ?X and ?Y values representing the voxel in build platform (101). The positive x axis represents movement towards right side of the voxel and negative x axis towards left side of the voxel. The positive y axis represents movement towards top side in the voxel and negative sign represents movement towards lower side in the voxel. For example, for the laser source (106) to move 18 degree over the build platform (101) as shown in the table, the laser source (106) is moved towards three voxel towards right in the x axis and 1 voxel up in the y axis. The different set of grid rotation angle is achieved by changing the values and signs of x and y axis.

Base Angle, bAng (?X, ?Y) Value Tuple
0? (0, 1)
1? (57, 1)
2? (29, 1)
3? (19, 1)
4? (14, 1)
5? (11, 1)
6? (10, 1)
7? (8, 1)
8? (7, 1)
9? - 10? (6, 1)
11? - 12? (5, 1)
13? - 15? (4, 1)
16? - 21? (3, 1)
22? - 33? (2, 1)
34? - 45? (1, 1)
[0025] The list of value in the above table is used to obtain all possible grid rotations from 0° to 359°. The path of the laser source (106) is broken into hemi quadrants corresponding to voxel grids in the build platform (101). The grid rotation angles greater than the first hemi- quadrant can be derived by fixing the base angle and varying the corresponding x and y co-ordinates from the value list. The laser source (106) is transmitted to a subsequent position from the antecedent position by altering the variables of the voxel in the additive manufacturing build requirements thereby directing multiple laser beams in a desired location to sinter powder material over the build platform (101) to form a three-dimensional structure.
[0026] Thus the present invention incorporates the integrized gridding method to manufacture a complex three-dimensional structure which eliminates the floating point errors arising due to integer degree rotations. Further, the integrized gridding method converts the continuous path of the laser source (106) into computationally efficient discrete paths thereby directing multiple laser beams on power material disposed in the build plate (102).
[0027] Further, the present invention provides utility in manufacturing industry to produce complex three dimensional structure in a plurality of fields such as automotive, aerospace, medical, energy and so on. The efficient path finding method of the laser source (106) may increase the accuracy in the sintering of powder material thereby, increasing the programming efficiency of the system (100). Further, multiple beams emitted from the laser source (106) and the discretized path followed by the laser source (106) significantly reduces the time taken to produce complex three-dimensional structures.
[0028] The features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Reference numbers:
Components Reference Numbers
System 100
Build platform 101
Build plate 102
Dispenser module 103
Recoater arm 104
Collector module 105
Laser source 106