Description:
TECHNICAL FIELD
Present disclosure relates in general to a field of manufacturing. Particularly, but not exclusively, the present disclosure relates to a wire arc additive manufacturing. Further, embodiments of the disclosure discloses a method for manufacturing thick-walled tubes by the wire arc additive manufacturing method.

BACKGROUND OF THE DISCLOSURE

Manufacturing of components has evolved over time. Conventional methods of manufacturing such as injection moulding, machining, forming etc. require mass production to even out the overhead cost of tooling, labour, and overall production costs. Further, creating complex mechanical constructions via traditional manufacturing requires precision, skill and complex machinery. Multiple parts are often manufactured separately and are further assembled to form assemblies and sub-assemblies.

With advancements in technology, methods such as 3D printing or additive manufacturing is becoming increasingly relevant in the field of manufacturing. Additive manufacturing is the process of using a suitable equipment to produce a component, layer by layer. The component is printed by the equipment which is communicatively coupled to a computer. Additive manufacturing offers some unique advantages such as the cost of manufacturing of one item stays the same irrespective of the quantity. Consequently, manufacturing components of low quantity and increased shape complexity is significantly cheaper when compared to traditional manufacturing methods which require mass production to even out the overhead cost of tooling, labour for assembly, and production as mentioned above. Unlike conventional manufacturing methods where multiple parts are individually manufactured and are painstakingly assembled to manufacture a component with complex structures, additive manufacturing enables the creation of both and individual component as well as the entire assembly in a single manufacturing process. Additive manufacturing is extremely resource efficient when compared with traditional production processes where complex shapes can be formed in a single manufacturing process with a very high raw material yield in the vicinity of 100%. The above-mentioned aspects make additive manufacturing, an extremely appealing method of manufacturing additive manufacturing is gaining traction in recent times.

Additive manufacturing utilizes 3D-modeling (Computer-Aided Design or CAD) software, computer-controlled additive-manufacturing equipment, and raw materials in powder or semi-molten form. Additive manufacturing encompasses a wide variety of technologies and incorporates a wide variety of techniques, such as, for example, laser deposition, direct metal deposition, laser metal deposition, laser additive manufacturing, stereolithography, selective laser sintering etc.

Conventionally, in the field of additive manufacturing, there have been many attempts to produce a tube-shaped structure. The setup starts with a powdered layer of metal alloy particles laid on a flat surface. A computer-controlled, high-powered laser beam then advances back and forth across the surface. Particles bombarded by the laser melt and fuse together. The surface then drops down a step, and another layer of powder is added, and the laser heating process repeats, binding the newly melted material to the layer below. On a microscopic level for additive manufacturing in the above-mentioned method, the printed steels are usually highly porous. Consequently, the components are weak and are prone to fracture. There have been several attempts to create dense steel tubes with large thickness.

One example of an additive-manufacturing system suitable for manufacturing steel tubes is a wire arc-based additive manufacturing (WAAM) technique. The technique involves utilizing an electric arc as a heat source in combination with a metallic wire as the feed source. A power source is used to create the electric arc which extends from an electrode to the base material. The arc quickly heats and melts the metallic wire at the base material. The wire itself may be used as a consumable electrode as in the case of gas metal arc welding. The heat source and the feed source may be mounted on a robotic arm and the robotic arm may be configured to traverse in a pre-determined three-dimensional space. The robotic arm may be computer-controlled and may traverse in accordance with the inputs or programs fed in the computer. The molten material may be deposited on a base plate as the robotic arm traverses over the base plate. The robotic arm may be configured to traverse multiple times to deposit multiple layers of molten material until the required component is obtained. Also, components can be printed at faster deposition rates.

Further, there are practical challenges involved in producing thick-walled steel tubes. As the diameter to thickness ratio increases, the steel may lead to cracking during forming or welding process. Conventionally, manufacturing thick-walled steel tubes by WAAM caused the tube to buckle and deform under its own weight when a layer of significant thickness is deposited. In some of the conventional methods metal is deposited in zig-zag pattern along the circumference of the tube to obtain the desired thickness. However, the zig zag pattern of depositing material causes the steel tube to have a pours microstructure. Consequently, the imitation and propagation of cracks through the steel tube increases and the overall operational life of the tube reduces drastically.

The present disclosure is directed to overcome one or more limitations stated above or other such limitations associated with the conventional systems.

SUMMARY OF THE DISCLOSURE

One or more shortcomings of the prior art are overcome by an assembly and a method as disclosed and additional advantages are provided through the assembly and the method as described in the present disclosure.

Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.

In a non-limiting embodiment of the disclosure, a method for manufacturing a thick-walled tube by an additive manufacturing process is disclosed. The method includes steps of depositing a material layer by layer on a base plate oriented in a first direction by a deposition unit, to form the tube. The next step involves orienting the base plate and the tube created on the base plate to a second direction. Further, one or more layers of material are overlayed along a length of the tube to form the thick-walled tube.

In an embodiment of the disclosure, the step of depositing the material layer by layer to form the tube includes rotating the base plate at constant speed and raising the deposition unit gradually upwards relative to the base plate.

In an embodiment of the disclosure, the base plate is rotatable at constant speed and the deposition unit is maneuvered along the length of the tube for overlaying the one or more layers of material.

In an embodiment of the disclosure, the distance between a brim of the tube and the deposition unit is increased after overlaying each of the one or more layers of material along the length of the tube.

In an embodiment of the disclosure, the deposition unit is oriented perpendicular to the base plate for depositing material layer by layer on the base plate.

In an embodiment of the disclosure, the base plate is oriented to the second direction parallel to line of maneuvering of the deposition unit for overlaying the one or more layers of material along the length of the tube.

In an embodiment of the disclosure, the base plate is rotated at the speed of 0.3 RPM to 0.7 RPM and the deposition rate of material for depositing the plurality of layers on the base plate ranges from 2.20 Kg/hour to 2.30 Kg/hour. Further, the deposition rate for overlaying the one or more layers of material on the circumference of the tube ranges from 2.4 Kg/hour to 2.6 Kg/hour.

In an embodiment of the disclosure, the additive manufacturing process for manufacturing a thick-walled tube is a wire arc additive manufacturing process.

In an embodiment of the disclosure, and overlaying includes, feeding the material by a feeder unit and melting the material by a heating unit.

In an embodiment of the disclosure, the first direction is substantially a horizontal direction of the base plate and the second direction is substantially a vertical direction of the base plate

In a non-limiting embodiment of the disclosure, an additive manufacturing apparatus for manufacturing a thick-walled tube is disclosed. The apparatus includes a table defined with a plurality of mountings for fixedly accommodating a base plate. At least one actuator is coupled to the base plate for operating the base plate between a first direction and a second direction perpendicular to the first direction and for rotating the base plate. Further, a deposition unit is coupled to a robotic arm, where the robotic arm is configured to traverse the deposition unit relative to the base plate. Further, a control unit is communicatively coupled to the at least one actuator and the robotic arm, where the control unit is configured to operate the at least one actuator to orient the base plate in a first direction. The control unit also operates the robotic arm to maneuver the deposition unit for depositing a material layer by layer on the base plate and to form the tube. Further, the at least one actuator is operated to orient the base plate in a first direction. The actuator are also operated to orient the base plate and the tube created on the base plate to the second direction. Further, the robotic arm is operated to maneuver the deposition unit for overlaying one or more layers of material along a length of the inner layer of the tube to form the thick-walled tube.

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 FIGURES

The novel features and characteristics of the disclosure are set forth in the appended claims. The disclosure itself, however, as well as a preferred mode of use, further objectives, and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

Fig. 1 illustrates a perspective view of a wire arc additive manufacturing apparatus, in accordance with some embodiments of present disclosure.

Fig. 2 illustrates a perspective view of a rotating table in the wire arc additive manufacturing apparatus, in accordance with some embodiments of present disclosure.

Fig. 3 illustrates a side view of the table, tilted in a substantially vertical direction, in accordance with some embodiments of present disclosure.

Fig. 4 is a flowchart illustrating a method for manufacturing thick-walled tubes by wire arc additive manufacturing method.

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 method for manufacturing a thick-walled tube by an additive manufacturing process illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION

The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other devices for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the scope of the disclosure. The novel features which are believed to be characteristic of the disclosure, as to its organization, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.

In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings 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 terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a system that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such mechanism. In other words, one or more elements in the device or mechanism proceeded by “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the mechanism.

As used in the description below, the phrase “thick-walled tube” refers to tube walls that are dense or wide. In an embodiment, diameter to wall thickness ratio of the thick-walled tube may be smaller than 20. The above-mentioned diameter to wall thickness ratio of the thick-walled tube is generally inferred and the same must not be considered as a limitation. As used in the description below the term “horizontal orientation” refers to the alignment of a table and a base plate mounted on the table in the horizontal direction. As used in the description below the term “vertical orientation” refers to the alignment of a table and a base plate mounted on the table in the vertical direction.

Embodiments of the present disclosure discloses a method for manufacturing thick-walled tubes by an additive manufacturing process. Conventional method of manufacturing thick-walled tubes often leads to cracking during forming or welding process. The conventional methods often causes the tube to buckle and deform under its own weight when a layer of significant thickness is deposited. There have been several methods for manufacturing thick-walled steel tubes where, the metal is deposited metal in zig-zag pattern along the circumference of the tube However, the zig zag pattern of depositing material causes the steel tube to have a pours microstructure. Consequently, the initiation and propagation of cracks through the steel tube increases and the overall operational life of the tube reduces drastically.

Accordingly, the present disclosure discloses a method for manufacturing a thick-walled tube by an additive manufacturing process. The method includes steps of depositing a material layer by layer on a base plate oriented in a first direction by a deposition unit, to form the tube. The base plate is rotated at constant speed as the material is deposited on the base plate. The next step involves orienting the base plate and the tube created on the base plate to a second direction. Further, one or more layers of material are overlayed along a length of the tube to form the thick-walled tube. The deposition unit traverses along the length of the tube at constant speed and the base plate also rotates at constant speed as the material is overlayed on the surface of the tube. The distance between a brim of the tube and the deposition unit is increased after overlaying each of the one or more layers of material on the tube. Multiple layers of material may be overlayed on the tube until the desired thickness of the tube is achieved.

The following paragraphs describe the present disclosure with reference to Figs. 1 to 3.

Fig. 1 illustrates a perspective view of a wire arc additive manufacturing apparatus (100). The apparatus (100) may include a robotic arm (3). The robotic arm (3) may further include a plurality of linkages and may be operable in a pre-determined three-dimensional space. The robotic arm (3) may be a 6-axis robot that is maneuverable in X, Y, Z, X’, Y’ and Z’ axis. The robotic arm (3) may include multiple actuators for facilitating the movement of the robotic arm (3) to be maneuvered along the six axis. One end of the robotic arm (3) may be coupled to a deposition unit (4) and a heating unit (5) whereas, the other end of the robotic arm (3) may be firmly mounted or housed on a floor. Further, the apparatus (100) may also include a power source (1) and a feeder unit (2). The feeder unit (2) is connected to the deposition unit (4) at the end of the robotic arm (3). The feeder unit (2) may supply or feed metallic wires including, but not limited to steel as raw material to the deposition unit (4). The deposition unit (4) that is coupled to the end of the robotic arm (3) may traverse with the robotic arm (3) and may act as an intermediate material transfer member between the heating unit (5) and the feeder unit (2). The feeder unit (2) may supply steel wire to the deposition unit (4) with a diameter ranging from 1 mm to 1.4 mm. The above-mentioned dimensions of the wire supplied as raw material must not be construed as a limitation and any wire with larger or smaller dimensions may also be used based on the required deposition parameters including the deposition metal size. The feeder unit (2) and the deposition unit (4) may supply wire at a deposition rate ranging from 2.20 Kg/hour to 2.6 Kg/hour. The above-mentioned deposition rate must not be construed as a limitation as it is obvious to a person skilled in the art that the same may be varied by changing the various operational parameters of the apparatus (100). The deposition may be initiated in a cold metal transfer mode where, the material is fed from the feeder unit (2) to the deposition unit (4).

The material or the wire from the deposition unit (4) is conveyed to the heating unit (5). The power source (1) may be connected to the heating unit (5) and the power source (1) may provide the required energy for the operation of the heating unit (5). The heating unit (5) may include but not be limited to a metal inert gas (MIG) welding system. In an embodiment, the heating unit (5) may be a cold metal transfer inert gas welding system and may generate an electric arc at temperatures suitable to melt the wire form the deposition unit (4). The composition of the inert gas in the MIG welding system may be mixture of argon and carbon dioxide in a ratio of 82% and 18% respectively. The electric arc generated in the heating unit (5) may melt the wire that is fed from the deposition unit (4). The heating unit (5) may further be connected to nozzle (9) of suitable dimensions and the molten metal from the heating unit (5) may be conveyed through the nozzle (9) onto a base plate (7).

In an embodiment, the intensity of the electric arc generated by the heating unit (5) may be varied based on the raw material. For instance, if the wire that is fed by the feeder unit (2) is aluminum, then the intensity of the electric arc may be varied to a temperature equal to or greater than the melting temperature of aluminum. In an embodiment, the feed rate from the feeder unit (2) and the deposition unit (4) may also be varied. The heating unit (5) may be coupled to a control unit and the control unit may be connected to an I/O interface (not shown in the figure). The control unit may include a memory unit and parameters such as the feed rate, intensity of the electric arc etc. for a wide variety of metals may be fed through the I/O interface to be stored in the memory unit. An operator may select the operational parameters based on the stored data through the I/O interface. For example, if a tube of steel is to be manufactured, the operator may select a corresponding option conveying steel as the raw material. The feed rate and the intensity of the electric arc suitable for steel may be subsequently be implemented to the feeder unit (2) and the heating unit (5) respectively. Further, the movement of the robotic arm (3) within the pre-determined three-dimensional space may be pre-programmed by any of the methods known in the art. The operational parameters may be implemented in a variety of computing systems, such as a laptop computer, a desktop computer, a Personal Computer (PC), a notebook, a smartphone, a tablet, e-book readers, a server, a network server, a cloud-based server, and the like.

Fig. 2 illustrates a perspective view of a rotating worktop (101) in the vicinity of the wire arc additive manufacturing apparatus (100). The worktop (101) may include a table (6) defined with a plurality of mountings for fixedly accommodating a base plate (7) [seen form Fig. 1]. In an exemplary embodiment, the diameter of the base plate (7) may range from 450 mm to about 500 mm and the diameter of the base plate (7) must not be considered as a limitation as the same may be varied based on the required diameter of the tube (8) that is to be manufactured. The table (6) may be configured to rotate about a first axis (A-A). The table (6) may be coupled to at least one actuator [not shown] for rotating the table (6) along the first axis (A-A). The table (6) may be operated between a first direction and a second direction. The first direction may be a horizontal direction and the second direction may be a vertical direction of the table (6). The table (6) may also include an actuator for imparting a rotary movement to the base plate (7). The actuator may cause the table (6) and the base plate (7) mounted to the table (6) to rotate at a pre-determined speed. The table (6) and the base plate (7) may rotate about an axis which is perpendicular to the first axis (A-A). It is also important to note that the rotatable table may be substituted with another other greppable means that imparts controlled rotary motion. In an embodiment, the rotational speed of the table (6) may be varied based on the orientation of the table (6). For instance, the table (6) may be operated by the actuator to rotate at a first pre-determined speed when oriented in the first direction and the table (6) may be rotated at a second-pre-determined speed when oriented in the second direction. In an embodiment, the rotational speeds may be varied based on the viscosity of the molten metal form the heating unit (5). For instance, when the molten metal is of greater viscosity, the table (6) may rotate at lower speeds so that the viscous molten metal is uniformly deposited on the base plate. Further, when the molten metal is of lower viscosity with better free flowing characteristics, the table (6) may be rotated at higher speeds so that accumulation or excessive deposition of the molten metal at a single given point on the table (6) is prevented. The rotational speed of the table (6) may be pre-determined and may be stored in the memory unit of the control unit. The rotational speed of the table (6) may be determined based on viscosity of the molten metal for any given the material and the viscosity of the molten material may be determined by the composition of the material and the intensity of the electric arc. Further, the deposition unit (4) may initially be positioned in a direction perpendicular to the base plate (7) and the molten material from the heating unit (5) may be deposited on the base plate (7) of the table (6). Multiple layers of molten material may be sequentially deposited to manufacture the tube (8). The method of manufacturing the thick-walled tube (8) is explained in detail below.

Fig. 4 is a flowchart illustrating a method for manufacturing thick-walled tubes (8). With reference to Fig. 1, the table (6) may initially be oriented in the first direction or the horizontal direction by the control unit at step 201. Subsequently, the actuators in the robotic arm (3) may be operated by the control unit and the deposition unit (4) may be maneuvered to be positioned proximal to the base plate (7) at a pre-determined point away from the center of the base plate (7). In an exemplary embodiment, the deposition unit (4) herein, is maneuvered such that the nozzle (9) lies at a distance of 100mm form the center of the base plate (7). The deposition unit (4) may be positioned such that the nozzle (9) at the tip of the heating unit (5) is at a pre-determined distance from the surface of the base plate (7). The base plate (7) and the deposition unit (4) may initially be oriented perpendicular to each other. Once, the deposition unit (4) positioned at a pre-determined point proximal to the base plate (7), the feeder unit (2) may supply the steel wire such that the deposition rate ranges from 2.20 Kg/hour to 2.30 Kg/hour. The range of the deposition rate must not be construed as a limitation as the same may vary for different metals. Further, the table (6) may be configured to rotate at a constant speed ranging from 0.3 RPM to 0.7 RPM. The table (6) is preferably rotated at a constant speed of 0.5 RPM herein. The steel wires form the feeder unit (2) are initially fed to the deposition unit (4). The deposition unit (4) further communicates the steel wire to the heating unit (5). The heating unit (5) may receive power form the power source (1) with a current of around 160 A and voltage of 15 V. The heating unit (5) may generate the electric arc to heat and liquefy the steel wire to a molten state. The molten metal may further be deposited on the rotating base plate (7) by the nozzle (9) attached to the tip of the heating unit (5) at step 202. Since, the base plate (7) is subjected to a rotary movement, the molten material is deposited on the base plate (7) in a circular manner. The deposition rate herein may range from 2.20 Kg/hour to 2.30 Kg/hour. The above-mentioned deposition rate ensures that the thickness of the deposited molten metal is 2.5 mm with a height ranging from 5 mm to 6 mm. As mentioned above, the operational parameters such the intensity of the electric arc, rotational speed of the base plate (7), the feed rate, the deposition rate etc. may be customized to the steel wire and the same may vary for a different metal.

Further, once the first layer of molten metal is deposited on the base plate (7), the same may be allowed to be cooled for a pre-determined time so that the molten metal solidifies. Subsequently, the deposition unit (4) may be maneuvered by the robotic arm (3) along the vertical direction. The deposition unit (4) may be maneuvered such that the height between the tip of the nozzle (9) and the surface of the base plate (7) increases. The height at which the deposition unit (4) is maneuvered vertically may vary based on the thickness and the height of the deposited material. Since the thickness and the height of the deposited molten material herein is 2.5 mm and 5 mm-6 mm respectively, the vertical height of the deposition unit (4) may be increased slightly beyond 6mm from the previous position of the deposition unit (4). The deposition unit (4) may subsequently stack another layer of molten metal on the already deposited layer of metal. This process of depositing a layer of molten metal and increasing the height of the deposition unit (4) along the vertical direction may be repeated unit the desired height of the tube (8) is achieved. Thus, multiple layers of metal are stacked to form a thin layer of tube (8). The thickness of the printed tube (8) may be suitably increased and the same is explained with greater detail below.

Fig. 3 illustrates a side view of the table (6), tilted in a substantially horizontal direction. Once, the tube (8) of desired height is printed, the thickness of the tube (8) may be increased by overlaying a plurality of molten metal layers the surface of the tube (8). The surface of the tube (8) is further referred to as an inner layer or a first layer (11) of the tube (8). The control unit may engage the actuators of the table (6) and may orient the table (6) to the second direction that is substantially perpendicular to the first direction i.e., along the vertical direction at the step 203. The base plate (7) and the table (6) may be tilted by 90 degrees and may be positioned along the vertical direction. Consequently, the tube (8) may extend from the base plate (7) along the horizontal direction. After the base plate (7) is oriented along the vertical direction, the deposition unit (4) may be maneuvered by the robotic arm (3) and may be positioned proximal to the first layer (11) of the tube (8). The deposition unit (4) may be positioned in a direction perpendicular to a central axis (A-A) of the tube (8) or in a direction parallel to the second direction of the base plate (7). The deposition unit (4) may be positioned such that the nozzle (9) at the tip of the heating unit (5) lies proximal to the point where the tube (8) comes in contact with the base plate (7). The deposition unit (4) may also be positioned such that the distance between the surface of the first layer (11) of the tube (8) and the tip of the nozzle (9) is around 100 mm. Further, the robotic arm (3) may maneuver the deposition unit (4) to traverse in a direction parallel to the central axis (A-A) of the tube (8). The robotic arm (3) may maneuver the deposition unit (4) and the nozzle (9) along the horizontal direction and the robotic arm (3) may be configured to traverse the length of the tube (8) along the central axis (Z-Z) of the tube (8). Further, the table (6) may be configured to rotate at a constant speed ranging from 0.2 RPM to 10 RPM. The table (6) is preferably rotated at a constant speed of 0.5 RPM herein. Like in the previous step, the steel wires form the feeder unit (2) are fed to the deposition unit (4). The deposition unit (4) further communicates the steel wire to the heating unit (5). The heating unit (5) may receive power form the power source (1) with a current of around 150 A and voltage of 21 V. The heating unit (5) may generate the electric arc to heat and liquefy the steel wire to a molten state. The molten metal may further be overlayed on the first layer (11) of the tube (8) by the nozzle (9) attached to the tip of the heating unit (5) at the step 204. The molten meatal is overlayed on the first layer (11) or along the circumference of the tube (8) as the deposition unit (4) and the nozzle (9) traverse the length of the tube (8) along the central axis (Z-Z) of the tube (8) in the horizontal direction. The deposition unit (4) may traverse at a constant speed along the length of the tube (8) and the base plate (7) may also rotate at a constant speed while the material is being overlayed on the first layer (11) of the tube (8). Consequently, the molten material that is overlayed on the surface of the first layer (11) may be uniform throughout the first layer (11). Further, the deposition rate during overlaying is slightly higher and may range from 2.4 Kg/hour to 2.6 Kg/hour. The higher material deposition rate during the overlaying process also translates to faster overlaying process for the manufacturing of the thick-walled tube (8). The deposition unit (4) may traverse from the point where the tube (8) comes in contact with the base plate (7) to the tip of the tube (8) and the material may simultaneously be overlayed on the first layer (11) of the tube (8).

Once, the layer of molten metal has been overlayed over the first layer (11), the robotic arm (3) may maneuver the nozzle (9) and deposition unit (4) along the vertical direction. The deposition unit (4) may be maneuvered such that the height between the tip of the nozzle (9) and the surface of the first layer (11) increases. The height at which the deposition unit (4) is maneuvered vertically may vary based on the thickness and the height of the overlayed metal. The deposition unit (4) may subsequently stack another layer of molten metal on the already overlayed layer of metal. The robotic arm (3) may maneuver the deposition unit (4) from the tip of the tube (8) back to the point where the tube (8) comes in contact with the base plate (7) as the new layer of metal is being overlayed. This process of overlaying a layer of molten metal and increasing the height of the deposition unit (4) along the vertical direction may be repeated until the desired thickness of the tube (8) is achieved.

In an embodiment, the above-mentioned method of manufacturing the tube (8) enables the production of thick-walled tubes without need of special tools and equipment’s.

In an embodiment, the above-mentioned method of manufacturing the tube (8) reduces the formation of cracks and improves the overall operational life of the tube (8).

In an embodiment, the above-mentioned method of manufacturing the tube (8) ensures the tube (8) does not buckle or deform under its own weight while manufacturing the tube (8). Consequently, tubes (8) of large thickness can be manufactured.

Equivalents

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding the description may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated in the description.

Referral Numerals:

Description Referral numeral
Power source 1
Feeder unit 2
Robot arm 3
Deposition unit 4
Heating unit 5
Table 6
Base plate 7
Tube 8
Nozzle 9
First layer 11
Additive manufacturing apparatus 100
Rotating worktop 101

Claims:

1. A method for manufacturing a thick-walled tube (8) by an additive manufacturing process, the method comprising:
depositing a material layer by layer on a base plate (7) oriented in a first direction by a deposition unit (4), to form the tube (8);
orienting the base plate (7) and the tube (8) created on the base plate (7) to a second direction; and
overlaying one or more layers of material along a length of the tube (8) to form the thick-walled tube (8);

2. The method as claimed in claim 1, wherein the depositing of the material layer by layer to form the tube (8), comprises:
rotating, the base plate (7) at constant speed; and
raising the deposition unit (4) gradually upwards relative to the base plate (7).

3. The method as claimed in claim 1 wherein, the base plate (7) is rotatable at constant speed and the deposition unit (4) is maneuvered along the length of the tube (8) for overlaying the one or more layers of material.

4. The method as claimed in claim 3 comprises, increasing distance between a brim of the tube (8) and the deposition unit (4) after overlaying each of the one or more layers of material along the length of the tube (8).

5. The method as claimed in claim 1 comprises, orienting the deposition unit (4) perpendicular to the base plate (7) for depositing material layer by layer on the base plate (7).

6. The method as claimed in claim 1 comprises, orienting the base plate (7) to the second direction parallel to line of maneuvering of the deposition unit (4) for overlaying the one or more layers of material along the length of the tube (8).

7. The method as claimed in claim 1 wherein, the base plate (7) is rotated at a speed of 0.3 RPM to 0.7 RPM.

8. The method as claimed in claim 1 wherein, deposition rate of material for depositing the plurality of layers on the base plate (7) ranges from 2.20 Kg/hour to 2.30 Kg/hour.

9. The method as claimed in claim 1 wherein, deposition rate for overlaying the one or more layers of material on a circumference of the tube (8) ranges from 2.4 Kg/hour to 2.6 Kg/hour.

10. The method as claimed in claim 1 wherein, the additive manufacturing process for manufacturing a thick-walled tube (8) is a wire arc additive manufacturing process.

11. The method as claimed in claim 1, wherein the deposition and overlaying includes, feeding the material by a feeder unit (2) and melting the material by a heating unit (5).

12. The method as claimed in claim 1 wherein, the first direction is substantially a horizontal direction of the base plate (7).

13. The method as claimed in claim 1, wherein the second direction is substantially a vertical direction of the base plate (7).

14. An additive manufacturing apparatus (100) for manufacturing a thick-walled tube (8), the apparatus (100) comprising:
a table (6) defined with a plurality of mountings for fixedly accommodating a base plate (7);
at least one actuator coupled to the base plate (7) for operating the base plate (7) between a first direction and a second direction perpendicular to the first direction and for rotating the base plate (7);
a deposition unit (4) coupled to a robotic arm (3), wherein the robotic arm (3) is configured to traverse the deposition unit (4) relative to the base plate (7); and
a control unit communicatively coupled to the at least one actuator and the robotic arm (3), wherein the control unit is configured to:
operate, the at least one actuator, to orient the base plate (7) in the first direction;
operate, the robotic arm (3) to maneuver the deposition unit (4) for depositing a material layer by layer on the base plate (7) to form the tube (8);
operate, the at least one actuator, to orient the base plate (7) in the first direction;
operate, the at least one actuator, to orient the base plate (7) and the tube (8) created on the base plate (7) to the second direction;
operate, the robotic arm (3) to maneuver the deposition unit (4) for overlaying one or more layers of material along a length of the inner layer (11) of the tube (8) to form the thick-walled tube (8).
15. The apparatus as claimed in claim 14 wherein, the base plate (7) is rotated at a speed of 0.3 RPM to 0.7 RPM.

16. The apparatus as claimed in claim 14 wherein, deposition rate of material for stacking the plurality of layers on the base plate (7) ranges from 2.20 Kg/hour to 2.30 Kg/hour.

17. The apparatus as claimed in claim 14 wherein, the deposition rate for overlaying the at least one layer of material on the circumference of the tube (8) ranges from 2.4 Kg/hour to 2.6 Kg/hour.