Description:
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TECHNICAL FIELD
Present disclosure, in general, relates to a field of additive manufacturing. Particularly, but not exclusively, the present disclosure relates to a wire arc additive manufacturing. Further, embodiments of the present disclosure discloses a method of generating a tool path for wire arc 5 additive (WAAM) manufacturing.
BACKGROUND OF THE DISCLOSURE
Generally, manufacturing of articles are carried out using processes such as casting, molding, 10 machining, and the like. However, the conventional processes of manufacturing of the article have limitations with respect to the type of articles which can be manufactured based on complexity. The articles having complex shape and dimensional intricacy are difficult to be manufactured by the conventional manufacturing processes.
With advent of technology, additive manufacturing techniques have been developed to 15 manufacture articles with complex shape and dimensions. The additive manufacturing involves use of computer aided design (CAD) or 3D object scanners, map the article and build the article layer by layer, by using processes such as but not limited to a 3D printing process, wire arc and additive manufacturing (WAAM) process and the like. Specifically, custom large volume metallic structures can be manufactured in relatively less time using the WAAM process. 20
The WAAM process involves a molten metal wire to be deposited on a particular substrate using beads. Such beads are stacked together, and this creates a single layer of the metallic component to be produced. When the process is carried out several times with increasing number of layers with a robotic arm or gantry system machine, a whole metal component is built with minimum post process requirements. However, the main challenge for the WAAM process is to produce 25 high quality components with very less defects and printing articles with overhang parts with strong structural as well mechanical properties, as the material falls during the layering process. Additionally, robot singularity is a very common problem associated with a robot tool path motion when manufacturing an article having complex geometry. The robot singularity is a configuration in which a robot end-effector or a WAAM tool becomes blocked in certain directions due to the 30 requirement of printing the complex shape of the article. The robot singularity leads to down time
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during manufacturing and would require re-calibration of the robot along with a new tool path to complete the manufacturing process, which is undesired.
Present disclosure is directed to overcome one or more limitations stated above or any other limitations associated with the known arts.
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SUMMARY OF THE DISCLOSURE
One or more shortcomings of the prior art are overcome by a method as claimed and additional advantages are provided through the method as claimed in the present disclosure. Additional features and advantages are realized through the techniques of the present disclosure. Other 10 embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
In one non-limiting embodiment of the present disclosure a method of generating a tool path for wire arc additive manufacturing (WAAM) process is disclosed. The method includes generating, 15 by a computing unit, a 3D model of an article to be printed by the WAAM process. Further, the computing unit is configured to slice the 3D model into a plurality of sections in a vertical direction. Furthermore, the computing unit is configured to determine a direction of movement of a tool based on the plurality of sections of the 3D model. Additionally, the method includes adjusting a tool angle by the computing unit, based on the determined direction of movement of 20 the tool. Further, the computing unit generates the tool path based on the determined direction of movement of the tool and the tool angle for performing the WAAM process.Thus, the method of the present disclosure enables manufacturing articles with complex shapes and sizes by the WAAM process without robot singularity.
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In an embodiment, the determined direction of movement of the tool is at least one of a linear movement and a zig-zag movement.
In an embodiment, the tool is fixed to a six axis robot which is communicatively coupled to the computing unit. The six axis robot guides the tool for performing the WAAM process. 30
In an embodiment, the six axis robot includes a first actuator which is configured to actuate along a first axis. Further, the six axis robot includes a second actuator that is configured to actuate along
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a second axis. Additionally, a third actuator is configured to actuate along a third axis. Further, a fourth actuator is configured to actuate along a fourth axis. Furthermore, the six axis robot includes a fifth actuator which is configured to actuate along a fifth axis and a sixth actuator which is configured to actuate along a sixth axis.
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In an embodiment, the tool is connected to the sixth actuator in the six axis robot. Further, the tool angle is an angle between the fifth actuator and the sixth actuator relative to the fourth actuator of the six axis robot.
In an embodiment, the tool angle is in a range of 10 degrees to 90 degrees. 10
In an embodiment, the method includes operating by the computing unit, the tool to perform at least one of continuous welding and dot welding during the WAAM process.
In an embodiment, the method includes operating by the computing unit, the six axis robot along 15 the generated tool path without printing to determine a robot singularity.
In an embodiment, the method includes generating by the computing unit, coordinates based on the plurality of sections of the 3D model and the determined direction of movement of the tool for operating the tool in the tool path. 20
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. 25
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
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 30 thereof, will best be understood by reference to the following detailed description of an illustrative embodiments 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:
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Fig. 1 is a flowchart illustrating a method of generating a tool path for wire arc additive manufacturing (WAAM) process, according to an exemplary embodiment of the present disclosure.
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Fig. 2 is a perspective view of a six axis robot, according to an exemplary embodiment of the present disclosure.
Fig. 3 is a front view of the sliced 3D model with a plurality of sections, according to an exemplary embodiment of the present disclosure. 10
Fig. 4 is a schematic view of a direction of movement of the tool in a zigzag path, according to an exemplary embodiment of the present disclosure.
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in 15 the art will readily recognize from the following description that alternative embodiments of the system and method illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION 20
The foregoing has broadly outlined the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which forms the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that, the 25 conception and specific embodiments disclosed may be readily utilized as a basis for modifying other methods, materials, and processes for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that, such equivalent method do not depart from the scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristics of the disclosure, to the method, together with further 30 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.
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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. 5
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 in detail 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, 10 equivalents, and alternatives falling within the scope of the disclosure.
The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusions, such that a method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such method. In other words, one or more elements in a method proceeded by 15 “comprises… a” does not, without more constraints, preclude the existence of other elements or additional elements in the method.
Reference will now be made to the exemplary embodiments of the disclosure, as illustrated in the accompanying drawings. Wherever possible, same numerals have been used to refer to the same 20 or like parts. The following paragraphs describe the present disclosure with reference to Figs. 1-2.
Fig. 1 is a flowchart depicting a method of generating a tool path for wire arc additive manufacturing (WAAM) process. The WAAM process is a manufacturing process configured to 3D print or repair metal parts. The WAAM process may be executed by depositing layers of metal 25 on top of each other, until a desired 3D shape is created. The manufacturing or production of components or articles using WAAM may be carried out by a robot or a robotic arm which may be integrated with a power source. Referring now to Fig. 2, in an illustrated embodiment, the robot may be a six axis robot (200). The six axis robot (200) may include a first actuator positioned in a first arm (1), which may be configured to actuate along a first axis. Further, the six axis robot (200) 30 may include a second actuator which may be positioned in a second arm (2) coupled to the first
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arm (1). The second actuator may be configured to actuate along a second axis. Additionally, the six axis robot (200) may include a third actuator which may be positioned in a third arm (3) that may be coupled to the second arm (2). The third actuator may be configured to actuate along a third axis. Furthermore, the six axis robot (200) may include a fourth actuator which may be positioned on the fourth arm (4). The fourth arm (4) may be coupled to the third arm (3). The 5 further fourth actuator may be configured to actuate the fourth arm (4) along a fourth axis. Further, the six axis robot (200) may include a fifth actuator which may be positioned in a fifth arm (5) that may be coupled to the fourth arm (4) and may be configured to actuate along a fifth axis. Furthermore, the six axis robot (200) may include a sixth actuator which may be positioned in a sixth arm (6). The sixth arm (6) may be coupled to the fifth arm (5) and may be configured to 10 actuate along a sixth axis. In an embodiment, the actuators in the six axis robot (200) may be including but not limited to a rotary actuator, a linear actuator and the like. That is, the tool which may be attached to the sixth arm (6) (adapted to actuate the tool along the sixth axis of the six axis robot (200), may be adapted to actuate with six degree of motion, for example, in the x-axis (positive& negative), in the y-axis (positive& negative) and z-axis (positive& negative). Further, 15 the six axis robot (200) may be communicatively coupled to a computing unit (CU). The computing unit (CU) may be configured to operate the six axis robot (200) based on requirement to perform the WAAM process.
In an embodiment, the WAAM process may be carried out by employing a tool. For example, the tool may including but not limited to a welding torch, a welding electrode and the like. The tool 20 may be fixed to the six axis robot (200) to perform the WAAM process. In an embodiment, the tool may be connected to the sixth arm (6) of the six axis robot (200).
The method is now described with reference to the flowchart blocks illustrated in Fig. 1.
At block 101, the method may include generating a 3D model, by the computing unit (CU) of the article to be printed by the WAAM process. In an implementation, the computing unit (CU) may 25 be a computer and other devices capable of performing computing operations. Further, the computing unit (CU) may include specialized processing units such as integrated system (bus) controllers, memory management control units, floating point units, graphics processing units, digital signal processing units, etc. The processing unit may include a microprocessor, such as AMD Athlon, Duron or Opteron, ARM’s application, embedded or secure processors, other line 30
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of processors, and the like. In an implementation, the computing unit (CU) may include virtual software which may be configured to aid in creation of the CAD or 3D models.
At Block 102 and as seen in Fig. 3, the method may include slicing of the 3D model by the computing unit (CU) into a plurality of sections. In an embodiment, the 3D model may be sliced 5 into the plurality of sections in a vertical direction.
Further, referring to block 103, the method may include determining a direction of movement of the tool by the computing unit (CU) which may be based on the plurality of sections of the 3D model. In an embodiment, the direction of movement may be determined by the computing unit 10 (CU) based on, but not limited to the thickness of the sections of the 3D model and the number of layers of the sliced 3D model which may be determined based on the layer height. In an embodiment, the slicing thickness may be a multiplication factor of a layer height, but limited to a limit in which the singularity problem of the six axis robot (200). For example, the layer height may be predefined and may be in the range of 1mm to 100mm for the optimum processing 15 conditions. Further, the computing unit (CU) may be configured to select the direction of movement of the tool between two predefined types of directions. That is, the computing unit (CU) may be configured to select the tool directions which may be at least one of a zigzag pattern or a linear unidirectional pattern. In an embodiment, the unidirectional pattern of the tool the heat input over time along the printed material may be less, as there is a dry movement between an end of a 20 line to start point of the next line in a same layer. That is, the linear unidirectional pattern may be employed for printing the articles having thin walls or may be employed during part printing of the article. The zigzag pattern [as seen in Fig. 4] may be efficient for the WAAM process as it may require less printing time due to continuous printing over the whole layer. Additionally, the zigzag pattern or the linear unidirectional pattern which may be determined by the computing unit 25 (CU) based on the sliced section of the 3D model reduces the porosity and residual stress in the printed article.
Furthermore, at block 104, the method may include adjusting, a tool angle by the computing unit (CU) based on the determined direction of movement of the tool. In an embodiment, the tool angle may be an angle between the fifth actuator [that is the fifth actuator associated with the fifth arm 30 (5)] and the sixth actuator [that is the sixth actuator associated with the sixth arm (6)], relative to
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the fourth actuator [that is the fourth actuator associated with the fourth arm (4)] of the six axis robot (200). That is, the tool angle may be an angle which may be measured between the fifth arm (5) and the sixth arm (6), relative to the fourth arm (4) of the six axis robot (200). Further, in an embodiment, the tool angle may be in a range of 10 degrees to 90 degrees. The tool angle may be determined by the computing unit (CU) based on the sliced 3D model, particularly the height at 5 which the printing may take place based on the sliced model. In an embodiment, the tool angle may be determined depending on a Z-height of the 3D model. For example, at lower level layer which may be up to the first 10 layers, a 10 degree tool angle may be sufficient to avoid the robot singularity during printing of the 3D model. Further, with increase in Z height of the 3D model, the angle may also be increased by the computing unit (CU) to avoid robot singularity. This way 10 by changing the angle based on the height of the 3D model in sections by the computing unit (CU) may facilitate prevention of robot singularity.
Referring now to Block 105, the method may include generating the tool path by the computing unit (CU). The tool path may be based on the determined direction of movement of the tool and 15 the tool angle for performing the WAAM process.
In an embodiment, tool path planning as per the present disclosure provides a new approach to avoid robot singularity, which is a condition caused by the collinear alignment of two or more robot axes resulting in unpredictable robot motion and velocities or stoppage of robot end effector 20 in a particular direction. To avoid this, the sixth arm (6) or the end effector or tool (welding torch) has to be rotated at a certain angle with respect to fifth arm (5) of the six axis robot (200), so that at all tool path points, 4th, 5th and 6th axis may not be colinear to mitigate robot singularity.
In an embodiment, the computing unit (CU) may be configured to operate the tool to perform at 25 least one of continuous welding and dot welding during the WAAM process.
Further, in an embodiment, during printing of an overhang portion of the article the computing unit (CU) may be configured to employ dot-welding technique. In dot welding, the tool may be moved horizontally in the determined direction of movement in small increments following arc ON - OFF conditions, such that a very small weld puddle may be formed. The tool focus line may 30 be kept slightly above a neutral line (manufacturing line), so that due to gravity the molten metal may get deposited at the neutral position. This way one weld line may be formed in the horizontal
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direction of the object to form the overhang. Upon, printing the overhang portion, normal welding may be continued for completing the article.
In an embodiment, the method may include generating coordinates by the computing unit (CU), which may be based on the plurality of sections of the 3D model and the determined direction of movement of the tool for operating the tool in the tool path. The coordinates enables mapping of 5 the tool path which may be followed by the robot to print the article as per requirement. Additionally, the method may include operating the six axis robot (200) by the computing unit (CU), along the generated tool path without printing to determine a robot singularity. That is, computing unit (CU) may be configured to perform a trial run of the tool path in order to check for robot singularity. 10
It should be noted that in an exemplary embodiment, as seen in the Figs. 1-2 the features, steps, connections and process should not be construed as a limitation as the method may include any other type of features, steps, connections and may work with other process or any other combinations for manufacturing an article with by the WAAM process.
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In an embodiment, the method facilitates manufacturing the articles by the WAAM process with very less defects. Additionally, the method enables printing of articles having overhang parts with strong structural as well mechanical properties. Furthermore, the tool path generated by the method prevents robot singularity even when printing of complex articles.
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It should be imperative that the method and any other elements described in the above detailed description should not be considered as a limitation with respect to the figures. Rather, variation to such method should be considered within the scope of the detailed description.
Equivalents: 25
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.
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It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) 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 5 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 following appended claims 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 10 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 15 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 20 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 25 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, claims, or drawings, should be understood to contemplate the possibilities of 30
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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.”
In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group. 5
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.
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Referral Numerals:
Reference Number
Description
101-105
Flow chart blocks
200
Six axis robot
1
First arm
2
Second arm
3
Third arm
4
Fourth arm
5
Fifth arm
6
Sixth arm
CU
Computing unit (CU) , Claims:We Claim:
1. A method of generating a tool path for wire arc additive manufacturing (WAAM) process, the method comprising:
generating, by a computing unit (CU), a 3D model of an article to be printed by the 5 WAAM process;
slicing, by the computing unit (CU), the 3D model into a plurality of sections in a vertical direction;
determining, by the computing unit (CU), a direction of movement of a tool based on the plurality of sections of the 3D model; 10
adjusting, by the computing unit (CU), a tool angle based on the determined direction of movement of the tool; and
generating, by the computing unit (CU), the tool path based on the determined direction of movement of the tool and the tool angle for performing the WAAM process. 15
2. The method as claimed in claim 1, wherein the determined direction of movement of the tool is at least one of a linear movement and a zig-zag movement.
3. The method as claimed in claim 1, wherein the tool is fixed to a six axis robot (200) communicatively coupled to the computing unit (CU), wherein the six axis robot (200) 20 guides the tool for performing the WAAM process.
4. The method as claimed in claim 3, wherein the six axis robot (200) comprises:
a first actuator configured to actuate along a first axis;
a second actuator configured to actuate along a second axis; 25
a third actuator configured to actuate along a third axis;
a fourth actuator configured to actuate along a fourth axis;
a fifth actuator configured to actuate along a fifth axis; and
a sixth actuator configured to actuate along a sixth axis. 30
5. The method as claimed in claim 4, wherein the tool is connected to the sixth actuator in the six axis robot (200).
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6. The method as claimed in claim 4, wherein the tool angle is an angle between the fifth actuator and the sixth actuator relative to the fourth actuator of the six axis robot (200).
7. The method as claimed in claim 1, wherein the tool angle is in a range of 10 degrees to 90 degrees. 5
8. The method as claimed in claim 1, comprising operating by the computing unit (CU), the tool to perform at least one of continuous welding and dot welding during the WAAM process. 10
9. The method as claimed in claim 1, comprising operating by the computing unit (CU), the six axis robot (200) along the generated tool path without printing to determine a robot singularity.
10. The method as claimed in claim 1, comprising generating by the computing unit (CU), 15 coordinates based on the plurality of sections of the 3D model and the determined direction of movement of the tool for operating the tool in the tool path.