Patent Application
20240017340
The present invention generally regards wire arc additive manufacturing (WAAM) systems that print in horizontal print orientations.
Wire arc additive manufacturing (WAAM) is a production process used to 3D print and/or repair metal parts. WAAM is a process where a metal wire is provided from a tip of a welding robot while heat energy is applied to the metal wire and the heat energy melts the wire to allow it to be layered in the desired shape of the component being manufactured. Print orientation for WAAM is ordinarily vertical, such that each layer is stacked one on another in a height-wise direction (e.g., in a direction from the floor toward the ceiling). Vertical orientations are commonly assumed to be the only viable printing configuration for WAAM, in part, because gravity generally acts on each point of a layer uniformly.
Systems and methods in accordance with embodiments of the invention implement a horizontal print orientation for WAAM, such that each layer is stacked one on another in a length-wise direction (e.g., generally parallel to the floor). Horizontal WAAM 3D print systems can include a metal 3D printing system or a set of systems in a horizontal orientation with one or more WAAM robots operating concurrently on a work piece using one or more wire feeds and a rotating, horizontal build plate. The robots may be constrained to a linear rail and/or operate from a mobile platform that can be manually and/or autonomously guided.
One embodiment of the invention includes a wire arc additive manufacturing system comprising: a build plate defining a vertically oriented build plane and having a center point and a build axis oriented perpendicular to the build plane, wherein the build plate is configured to rotate on the build axis about center point; and at least one robot comprising at least one print head configured to deposit a molten material onto the build plate in a series of layers disposed along the build axis to form a part.
In another embodiment, the build plate rotates at a speed from 0.5 inch per minute to 600 inch per minute.
An additional embodiment further comprises a positioner, wherein the build plate is attached to the positioner and a motor on the positioner drives the build plate to rotate.
In a further embodiment, the build plate has a circular shape and a diameter from 5 feet to 18 feet.
In yet another embodiment, the print head is placed at a position at 90-degree or 270-degree from a top of the build plate circumferentially around the center point.
In a further yet embodiment, a build plate rotation speed and a print head deposition rate are coordinated such that the print head is at a constant location during printing.
In a further embodiment again, the print head is positioned at one end of an extendable arm of the at least one robot such that the print head extends to reach a desired location to print.
In another further embodiment, the at least one robot is mounted on a rail arranged in a print direction such that the rail moves the at least one robot as the part prints.
In yet another embodiment again, the at least one robot is mounted on a first mobile platform comprising a riser; wherein the at least one robot moves freely horizontally and vertically.
An additional embodiment further comprises a laser tracking system to position the at least one robot at a desired location for printing.
In another embodiment again, the mobile platform is a manually guided vehicle or an autonomously guided vehicle.
Yet another embodiment further comprises a second robot supported on a second mobile platform comprising a riser; wherein the second robot moves freely horizontally and vertically.
In an additional further embodiment, the second robot comprises an end effector assembly configured to attach a tool selected from the group consisting of: a print tool, a weld tool, a machining tool, an inspection tool, and an imaging tool.
Another embodiment further comprises a laser tracking system to position the second robot at a desired location.
In a further embodiment again, the second mobile platform is a manually guided vehicle or an autonomously guided vehicle.
In yet another embodiment, the part has a cylindrical shape or a dome shape.
Another further embodiment comprises a second build plate defining a vertically oriented build plane and having a center point and a build axis oriented perpendicular to the second build plane, wherein the second build plate is configured to rotate on the build axis about center point; and a third robot comprising at least one print head configured to deposit a molten material onto the second build plate in a series of layers disposed along the build axis to form a second part.
In yet another embodiment, the second build plate rotates at a speed from 0.5 inch per minute to 600 inch per minute.
In a further embodiment again, the build plate and the second build plate align along the build axis, the build plane of the build plate faces an opposite direction from the build plane of the second build plate.
In an additional embodiment again, the third robot is mounted on a rail arranged in a print direction such that the rail moves the third robot as the second part prints.
In another further embodiment, the third robot is mounted on a mobile platform comprising a riser; wherein the third robot moves freely horizontally and vertically.
Another embodiment further comprises a positioner, wherein the build plate is attached to one end and the second build plate is attached to an opposite end of the positioner.
In a further yet embodiment, the second part has a cylindrical shape or a dome shape.
Another embodiment includes a method for wire arc additive manufacturing, comprising printing a part with a wire arc additive manufacturing system comprising: a build plate defining a vertically oriented build plane and having a center point and a build axis oriented perpendicular to the build plane, wherein the build plate is configured to rotate on the build axis about center point; and at least one robot comprising at least one print head configured to deposit a molten material onto the build plate in a series of layers disposed along the build axis to form a part.
In a further embodiment, the build plate rotates at a speed from 0.5 inch per minute to 600 inch per minute.
In an additional embodiment, the build plate has a circular shape and a diameter from 5 feet to 18 feet.
In yet another embodiment, the print head is placed at a position at 90-degree or 270-degree from a top of the build plate circumferentially around the centerline.
In another further embodiment, a build plate rotation speed and a print head deposition rate are coordinated such that the print head is at a constant location during printing.
In a further yet embodiment, the print head is positioned at one end of an extendable arm of the at least one robot such that the print head extends to reach a desired location to print.
In yet another embodiment, the at least one robot is mounted on a rail arranged in a print direction such that the rail moves the at least one robot as the part prints.
In another embodiment again, the at least one robot is mounted on a first mobile platform comprising a riser; wherein the first robot moves freely horizontally and vertically.
An additional further embodiment comprises a laser tracking system to position the at least one robot at a desired location for printing.
In an additional embodiment again, the first mobile platform is a manually guided vehicle or an autonomously guided vehicle.
In yet another embodiment, the system further comprises a second robot supported on a second mobile platform comprising a riser; wherein the second robot moves freely horizontally and vertically.
In a further embodiment again, the second robot comprises an end effector assembly configured to attach a tool selected from the group consisting of: a print tool, a weld tool, a machining tool, an inspection tool, and an imaging tool.
In another further embodiment, the system further comprises a laser tracking system to position the second robot at a desired location.
In another embodiment again, the second mobile platform is a manually guided vehicle or an autonomously guided vehicle.
In a further embodiment again, the part has a cylindrical shape or a dome shape.
Another further embodiment comprises printing a second part with the system, wherein the system further comprises a second build plate defining a vertically oriented build plane and having a center point and a build axis oriented perpendicular to the build plane, wherein the second build plate is configured to rotate on the build axis about center point; and a third robot comprising at least one print head configured to deposit a molten material onto the second build plate in a series of layers disposed along the build axis to form the second part.
In an additional further embodiment, the second build plate rotates at a speed from 0.5 inch per minute to 600 inch per minute.
In yet another further embodiment, the build plate and the second build plate align along the build axis, the build plane of the build plate faces an opposite direction from the build plane of the second build plate.
In another embodiment again, the third robot is mounted on a rail arranged in a print direction such that the rail moves the third robot as the second part prints.
In a further embodiment, the third robot is mounted on a third mobile platform comprising a riser; wherein the third robot moves freely horizontally and vertically.
In yet another embodiment, the second part has a cylindrical shape or a dome shape.
Further features and advantages, as well as the structure and operation of various embodiments, are described in detail below with reference to the accompanying drawings. It is noted that the specific embodiments described herein are not intended to be limiting. Such embodiments are presented herein for illustrative purposes only. Additional embodiments will be apparent to persons skilled in the relevant art based on the teachings contained herein.
The description will be more fully understood with reference to the following figures. The figures include example embodiments of the invention and should not be construed as a complete recitation of the scope of the invention.
Turning now to the drawings, systems and methods for horizontal WAAM are described. Horizontal WAAM 3D print systems can include a metal 3D print system or a set of systems in a horizontal orientation with one or more WAAM robots operating concurrently on a work piece using one or more wire feeds and a rotating, vertically oriented build plate that is oriented perpendicular to the floor so that structures printed on the build plate extend horizontally, generally parallel to the floor. The robots may be constrained to a linear rail and/or operate from a mobile platform that can be manually and/or autonomously guided.
Additive manufacturing for industrial use may need the ability to print fast and/or at large scale. Prior WAAM systems print in a vertical orientation. In such prior WAAM systems, the build plate is parallel to the floor, so that a printed part extends vertically, in a direction from the floor toward the ceiling. Prior system designers generally viewed such “vertical” printing to be the only viable method of WAAM printing, in part because it allowed gravity to act the same way on every point in a layer for a regular object.
The inventors recognized drawbacks to vertical printing, however. Some of these drawbacks revealed themselves through the inventors' attempts to print large parts at high speed. First, the size of print objects when manufactured in vertical orientations may be limited by the external environment. When printing a tall object (for example, with a height of at least 20 feet), vertical orientation printing may be limited by the print enclosure (e.g., the height of the ceiling). The inventors realized that, to accommodate printing large scale objects, expanding the enclosure vertically or constructing new sites may be needed, which would increase printing cost and time. In addition, they realized that vertical orientation printing may require special facilities (such as a special lift) to access the large-scale printed objects for printing and/or inspection. In addition, when printing in vertical orientations using WAAM, the effect of the force of gravity depends on the nature of the part geometry, such as the presence of an overhang or underlying layer. In particular, they discovered that gravity can affect the melt (weld puddle) and cause unevenness in the build layers. Print parameters may be changed to counter the effect of the gravity force, but it can add complexity to the print processes and may need extra time to achieve good print qualities. Moreover, printing in vertical orientations are typically constrained to one print robot per build on a linear track, leading to longer print time. And they realized that vertically oriented print systems lack the flexibility to accommodate multiple print robots operating simultaneously around the build platform.
In the horizontal WAAM systems described herein, the inventors proceeded contrary to conventional understanding and configured the build plate to be generally perpendicular to the floor, so that a printed part extends horizontally and generally parallel to the floor. Horizontal WAAM 3D print systems, in accordance with many embodiments, enable metallic additive manufacturing of large structures with a higher component throughput than prior WAAM 3D print systems and methods. The inventors unexpectedly discovered that horizontal WAAM systems enable faster print speed, better print qualities, and the flexibility to accommodate large scale objects. They also realized that horizontal printing does not require a tall construction site and removes the constraints associated with vertical print orientations. They realized that horizontal print orientations enable better accessibility to the printed objects and do not require special facilities to access or inspect the printed products.
In several embodiments, horizontal WAAM systems implement rotatable horizontal build plates to provide substrates for printing. In this specification “horizontal build plate” refers to a build plate that is configured for use in a horizontal print system. The build plate itself is not horizontal. Rather, its vertical meridian is perpendicular to the floor so that a part printed off the build plate extends horizontally, parallel to the floor. Print robots can be held at specific print positions due to the rotatable horizontal build plates such that the effect from the gravity force is consistent during printing. Many embodiments include the inventive realization that some horizontal print orientations can achieve better surface finish and print qualities for parts than those printed with vertical print orientations because the gravity force can pull the melt (weld puddle) down in a consistent fashion. Several embodiments provide that multiple robots can be deployed simultaneously during printing. The robots can be supported on fixed rails and/or on mobile platforms controlled manually or autonomously. The horizontal WAAM systems allow multiple concurrent manufacturing operations to be performed simultaneously including (but not limited to) material deposition, tool changes, detailed machining operations, part inspections, and corrections. In a number of embodiments, the horizontal WAAM systems implement mobile specialist robots that enable concurrent machining of secondary features on a work piece while the print operation is in progress. The inventors realized that the size and modularity of the horizontal WAAM 3D print systems can reduce the overall time required to manufacture large-scale metal 3D printed products.
Horizontal WAAM systems in accordance with many embodiments allow large overall volumes of the printed products. In some embodiments, the horizontal WAAM systems can print objects with at least one dimension of at least 15 feet; of at least 16 feet; of at least 18 feet; of at least 20 feet; of at 22 feet; of at least 24 feet; of at least 26 feet. Unlike objects printed with a vertical WAAM system, the size of a part printed with a horizontal WAAM system is not limited by the height of the ceiling in which the printer is located. The horizontally printed objects in accordance with some embodiments can have at least one component with a shape of a rectangular, square, cylinder, circle, eclipse, dome, triangle, polygon, pentagon, hexagon, octagon, cube, sphere, hemisphere, cone, pyramid, and any combinations thereof. Several embodiments provide that the horizontal WAAM systems can operate with an operating volume equivalent to a cylinder of a diameter of at least 50 inches; of at least 55 inches; of at least 1 foot; of at least 5 feet; of at least 10 feet; of at least 15 feet; of at least 20 feet; of at least 25 feet. Many embodiments provide that reduced backlash of the horizontal WAAM systems allow a machine accuracy of about 0.040 inch; or higher than about 0.040 inch; or lower than about 0.040 inch. The reduced backlash can achieve a machine repeatability of lower than about 0.003 inch; or higher than about 0.003 inch. The WAAM systems can include at least one horizontal build plate with a rotational speed of about 5.7 revolutions per minute, or higher than about 5.7 revolutions per minute, or lower than about 5.7 revolutions per minute.
Horizontal WAAM systems have various setups to mitigate environmental effects such as (but not limited to) wind, exhaust, moving subjects (machines or human). Examples of such setups include (but are not limited to) enclosures surrounding horizontal systems, fences, real time motion detection and/or alert systems.
Horizontal WAAM systems have various safety setups: E stop buttons and/or keys can be strategically laid out around horizontal WAAM systems; automatic locks to doors and/or panels; lighting; real time motion detection and/or alert systems. Support structures can be used for safety and seismic prevention.
Many embodiments implement a horizontal print orientation for WAAM processes. Contrary to conventional understanding, the inventors realized not only that horizontal printing is a viable alternative to vertical printing but also that it provides benefits over vertical printing in some embodiments. Such benefits over vertical printing for WAAM include (but are not limited to) increased print speed, increased structural stability (reduced “waviness” in final product), and reduced wasted or parasitic mass. Parasitic mass refers to the mass that does not have a beneficial contribution to the function of a component.
Prior WAAM processes print in a vertical orientation, e.g., in a direction from the floor toward the ceiling. The recognized advantages of vertical print include heritage, good wall thickness control/weaving, the implementation of multiple print heads, and relative ease of handling complex geometries. The inventors realized, however, that vertical printing can be difficult to achieve out-of-position printing, such as printing a dome or printing ribs structures inside of a cylinder. They also recognized that part accessibility can be more prone to waviness for vertical printing. They also discovered that vertical printing may have slower print speeds than horizontal print. They recognized that vertical printing can be limited by the height of the print enclosure when printing a tall object, e.g., limited by the height of the ceiling.
Contrary to the system in
Horizontal WAAM print orientation, in accordance with several embodiments, allows for the use of mobile platforms to allow for improved robot positioning with reduced mechanical complexity relative to vertical print orientations.
Horizontal WAAM print orientations in accordance with some embodiments also enable higher robot density per print cell than achievable with vertical print orientations.
Thermal stresses can cause about 0.5 inches deflection in vertical and/or horizontal print orientations. An about 18-foot diameter cylinder at about 0.300-inch wall thickness and printed to about 18 feet in length, horizontally mounted to a theoretically infinitely rigid surface, deflects about 0.005 inch. Deflection caused by the riser, the tabletop, the positioner, etc.) adds an additional about 0.045 inch of deflection, for a total horizontal deflection of about 0.05 inch. Additional supports are not necessarily required to compensate for such deformation. Changing print parameters or build parameters can change print part wall thickness such that the stiffness of the part can be modified. Several embodiments may correct such mild deformations by controlling the build parameters.
In several embodiments, however, part retention designs may be utilized with horizontal printing, either instead of selecting appropriate build parameters or in conjunction with selecting appropriate build parameters. Some embodiments use external support systems including (but not limited to) carts, stands, fork lifts, scissor lifts, and/or crane lifts, to support print parts. Various sizes of supporting systems can be used to support the print parts depending on a variety of attributes of the print parts such as (but not limited to) sizes, weights, geometries, strengths, and any combinations thereof. In some embodiments, supporting systems can be used to support the print parts during print. In certain embodiments, carts can be used to support print parts in case they may suffer a failure and fall from the build plate. Such supporting systems are not necessarily serving as structural supports, but rather a safety measure or catastrophic failsafe.
During horizontal printing, the force of gravity may induce a variable effect on weld puddles at each circumferential position around a cylindrical part. Such circumferential variability is typically not present in vertical printing systems and a reason horizontally was not generally thought to be a viable alternative to vertical printing. One challenge to increasing print speed in horizontal metal 3D printing is compensating for the variable gravity effects. For example, if all other print parameters are held constant in a horizontally oriented metal 3D print system, a print head located 180-degrees circumferentially from the top of a cylindrical build plate may produce a cylindrical product with a thicker wall than a print head located 90-degrees from the top of the build plate.
In order to overcome variable gravity effect on print parts, horizontal WAAM print systems in accordance with many embodiments position one and/or more print heads at about 90-degrees from the highest point on the build plate, when the build plate is oriented with the vertical meridian facing straight up from the floor (that is, the “3 o'clock” position, if the build plate is conceptually analogized to the face of an analog clock mounted on a wall and facing straight up), at about 270-degrees (the “9 o'clock” position), and/or at about 90- and about 270-degrees from the top of the build plate circumferentially around the build plate's centerline and normal to the build plate's build surface. The described print head locations (3 o'clock position and/or 9 o'clock position) are referred to individually and collectively as “horizontal meridian” print position(s) below. The inventors discovered that the horizontal meridian print positions can improve print stability by aligning the weld direction with gravity, enable higher deposition rate, improve surface finish, and reduce overall time required to complete a metal 3D printed product. The horizontal meridian position allows WAAM printing for large scale cylinders and/or other symmetrical parts created by rotating the build plate.
In many embodiments, horizontal WAAM print systems include rotatable build plates. Horizontal meridian systems can print cylindrical parts of various radiuses while maintaining constant print parameters because the effect of gravity on the weld puddle remains constant at each radial position in horizontal orientation. Some embodiments may use multiple print heads. Print heads can be positioned at different positions. Print heads on fixed rails can be positioned at points along the horizontal meridian so that the print head is located at the 9 o'clock and/or the 3 o'clock position on the build plate. Print heads on mobile platforms can be positioned on the horizontal meridian and/or moved to any desired locations. Print parameters of each print head can be modified and optimized at each position to address the difference in gravity effects. Print parameters such as (but not limited to) travel speed and/or wire feed speed, can be modified to achieve a desired thickness to address gravity effects. In a vertical orientation, these types of variable radius operations may require modification to the print thermal parameters which decreases part throughput.
As can be appreciated, a horizontal meridian print position may be a desirable print position for cylindrical parts such as (but not limited to) barrels. Other print positions can be implemented when printing other shapes of print parts in order to minimize irregularities caused by gravity force effects. Some embodiments use a horizontal meridian print position and other print positions when printing dome-like shapes including (but not limited to) a dome of a launch vehicle.
Several embodiments provide the inventive realization that the horizontal meridian print position can lead to better print quality than is possible in vertical print orientation. The inventors discovered that a horizontal meridian print position improves print quality by utilizing the force of gravity to pull the melt (weld puddle) down relative to the build direction. In such embodiments, the build quality of finished parts may be improved vis-à-vis vertical printing because in a vertical orientation, the melt pool is variably deformed causing unevenness in the build layers, whereas in a horizontal build orientation, the force of gravity at the horizontal meridian acts on the melt pool in a constant fashion leading to a smoother and more consistent build. Moreover, the constant orientation of the build relative to gravity, and thus constant weld parameters, obtained when printing in an orientation on the horizontal meridian in horizontal embodiments allows for more facile builds of parts that otherwise may experience variable gravitational forces when formed in a vertical orientation, such as domes or other overhanging or unsupported parts.
In many embodiments, build plates rotate to facilitate horizontal printing such that print robot (and/or print torch) can be held at constant print locations. In several embodiments, rotation speed and/or rotation rate of build plates are coordinated with deposition rate of print robots during horizontal printing. Higher build plate rotation rate can achieve a faster deposition rate of materials. Some embodiments select optimal build plate rotation rate based on deposition rate of print robots. Several embodiments select optimal deposition rate of print robots based on build plate rotation rate. Build plates can be held on positioners. In certain embodiments, driver systems of the positioners control rotation rate of build plates. Positioners can have at least one motor in the driver system to control rotation rate. Rotation rate of build plates can be selected to achieve optimal deposition rate of metallic materials and/or ensure print quality during horizontal printing. Rotation rate should be compatible with various parameters of the driver system such as (but not limited to) torque and/or gear ratio, to maintain steady operation of the build plate.
Build plates can rotate at a rate from about 0.5 inch per minute (ipm) to about 600 ipm. Examples of build plate rotation rate can include (but are not limited to) from about 0.5 ipm to about 1 ipm; or from about 0.5 ipm to about 2 ipm; or from about 0.5 ipm to about 3 ipm; or from about 0.5 ipm to about 4 ipm; or from about 0.5 ipm to about 5 ipm; or from about 0.5 ipm to about 6 ipm; or from about 0.5 ipm to about 7 ipm; or from about 0.5 ipm to about 8 ipm; or from about 0.5 ipm to about 9 ipm; or from about 0.5 ipm to about 10 ipm; or from about 0.5 ipm to about 20 ipm; or from about 0.5 ipm to about 30 ipm; or from about 0.5 ipm to about 40 ipm; or from about 0.5 ipm to about 50 ipm; or from about 0.5 ipm to about 60 ipm; or from about 0.5 ipm to about 70 ipm; or from about ipm to about 80 ipm; or from about 0.5 ipm to about 90 ipm; or from about 0.5 ipm to about 100 ipm; or from about 0.5 ipm to about 200 ipm; or from about 0.5 ipm to about 300 ipm; or from about 0.5 ipm to about 400 ipm; or from about 0.5 ipm to about 500 ipm; or from about 2 ipm to about 600 ipm; or from about 2 ipm to about 500 ipm; or from about 2 ipm to about 400 ipm; or from about 2 ipm to about 300 ipm; or from about 2 ipm to about 200 ipm; or from about 2 ipm to about 100 ipm; or from about 2 ipm to about 90 ipm; or from about 2 ipm to about 80 ipm; or from about 2 ipm to about 70 ipm; or from about 2 ipm to about 60 ipm; or from about 2 ipm to about 50 ipm; or from about 2 ipm to about 40 ipm; or from about 2 ipm to about 30 ipm; or from about 2 ipm to about 20 ipm; or from about 2 ipm to about 10 ipm; or from about 2 ipm to about 9 ipm; or from about 2 ipm to about 8 ipm; or from about 2 ipm to about 7 ipm; or from about 2 ipm to about 6 ipm; or from about 2 ipm to about 5 ipm; or from about 2 ipm to about 4 ipm; or from about 2 ipm to about 3 ipm; or from about 4 ipm to about 100 ipm; or from about 4 ipm to about ipm; or from about 4 ipm to about 80 ipm; or from about 4 ipm to about 70 ipm; or from about 4 ipm to about 60 ipm; or from about 4 ipm to about 50 ipm; or from about 4 ipm to about 40 ipm; or from about 4 ipm to about 30 ipm; or from about 4 ipm to about 20 ipm; or from about 4 ipm to about 10 ipm; or from about 10 ipm to about 100 ipm; or from about ipm to about 100 ipm; or from about 30 ipm to about 100 ipm; or from about 40 ipm to about 100 ipm; or from about 50 ipm to about 100 ipm; or from about 10 ipm to about 20 ipm; or from about 10 ipm to about 30 ipm; or from about 10 ipm to about 40 ipm; or from about 10 ipm to about 50 ipm; or from about 10 ipm to about 60 ipm; or from about 10 ipm to about 70 ipm; or from about 10 ipm to about 80 ipm; or from about 10 ipm to about ipm; or from about 10 ipm to about 100 ipm.
Different rotation rates can be selected for build plates of various diameters. In some embodiments, build plates of about 18 feet in diameter can rotate at a rate from about 2 ipm to about 600 ipm; or from about 2 ipm to about 400 ipm; or from about 2 ipm to about 200 ipm; or from about 2 ipm to about 100 ipm. In certain embodiments, build plates of about 5 feet in diameter can rotate at a rate from about 0.5 ipm to about 200 ipm; or from about 0.5 ipm to about 150 ipm; or from about 0.5 ipm to about 100 ipm.
Many embodiments implement horizontal WAAM print cells to achieve horizontal printing. The WAAM horizontal printing can print large objects of various sizes and shapes. The printed objects in accordance with several embodiments can have one dimension of at least 16 feet; of at least 18 feet; of at least 20 feet; of at 22 feet; of at least 24 feet; of at least 26 feet. The horizontally printed objects in accordance with some embodiments can have at least one component with a shape of a rectangular, square, cylinder, circle, eclipse, dome, triangle, polygon, pentagon, hexagon, octagon, cube, sphere, hemisphere, cone, pyramid, and any combinations thereof. A horizontal WAAM cell can include (but is not limited to) a riser, a positioner, a build plate (or a horizontal build plate, or a build surface, or a turntable, or a surface plate, or a build substrate), and at least one WAAM printer (or a print robot).
Weld torch 607 is attached to the print robot 601. As can be appreciated, spindles of print robots have tool change capabilities and can be attached with a variety of tools such as (but not limited to) print heads, print torches, weld torches, machining tools, cameras, sensing devices, monitoring devices, and/or imaging devices. The spindle may have minimum quantity lubrication (MQL), temperature sensors, and/or pneumatic lock/unlock capabilities. Many embodiments provide machining capabilities for the horizontal WAAM print cells. The print robots should be able to machine barrels and domes of at least 20 feet in diameter. Mobile platforms can be incorporated to the print robots to provide machining capabilities. In some embodiments, secondary feature machining and dome machining can be achieved.
Positioners for the horizontal WAAM print cell in accordance with several embodiments can have at least one motor; or at least two motors. A greater number of motors can result in faster acceleration of build plate rotation. Acceleration to various a desired rotation speed that is less than the maximum rotation speed for a print can take less than about 0.1 second; less than about 0.5 second; less than about 1 second; less than about 5 seconds; less than about 10 seconds. Acceleration to a maximum rotation speed for a print can be less than about 0.1 second; less than about 0.5 second; less than about 1 second; less than about 5 seconds; less than about 10 seconds. Positioners can control rotation speed of build plates between about 0.5 ipm and about 600 ipm; or between about 0.003 rpm and about 0.75 rpm; and/or control revolution time between about 5 hours per revolution and about 45 hours per revolution. The positioners can have built-in backlash prevention functions. Positioners can be made with materials such as steel, carbon steel, stainless steel, metal alloys, metals, and combinations thereof. Positioners can be coated with paint.
In some embodiments, the horizontal WAAM cell can include slewing rings, bearings and/or ring gears. The slewing bearings are large-size rolling bearings that can accommodate axial, radial and moment loads acting either singly or in combination and in any direction. They can perform slewing (oscillating) movements as well as rotational movements. The slewing bearings can be mounted in vertical bearing arrangements or on horizontal support structures. The non-simultaneous raceway capacities for the slewing ring can be greater than or equal to about 0 pound, or less than or equal to about 0 pound axial load; greater than or equal to about 95,000 ft-pound, or less than or equal to about 95,000 ft-pound moment load; and greater than or equal to about 21,000 pounds, or less than or equal to about 21,000 pounds radial load. The tooth load capacities for the slewing ring can be greater than or equal to about 9,400 pounds, or less than or equal to about 9,400 pounds normal. The start-up friction can be less than about 34,000 ft-pound; operating friction can be less than about 34,000 ft-pound; and deflection from load of less than about 0.1 inch.
In several embodiments, the horizontal WAAM cell can include at least one riser. The risers should be strong and able to support a mass extending of at least about 12 feet from the build plate.
In many embodiments, the horizontal WAAM print cell can implement horizontal build plates to enable horizontal printing. Metal and polymer 3D printers need a smooth and flat surface to start each new print. Metal 3D printers use a metallic build plate that is typically computer numerical control (CNC) machined to achieve the appropriate surface finish (smoothness) and flatness. As the size or print diameter of a metal 3D printer increases, traditional CNC machining of the build plate to achieve desired surface finish and flatness may become infeasible.
The horizontal WAAM print cell in accordance with certain embodiments can print metal structures of at least 20 feet in diameter. Building horizontal build plates using traditional CNC machining presents a significant challenge. In many embodiments, the horizontal build plates can use the machining capabilities of the metal 3D printing robot itself to achieve the required surface finish and flatness on a reusable build plate. The scale of the build plate may be constrained only by the reach of the print cell robot. The base of the build plate is constructed as a large welded assembly with loose control over the flatness and smoothness. In several embodiments, the reusable build plate can be mounted onto the positioner. In a number of embodiments, the reusable build plate can include multiple CNC machined sections that form an annular metal surface. In some embodiments, the in-cell CNC machining capabilities of the metal 3D print robots can machine the reusable build plate to the desired surface finish and flatness which may be verified by a laser scanner and/or dial indicator. At the conclusion of a print operation, the robots can machine the base of the completed part to separate it from the build plate in accordance with certain embodiments. The 3D print robots can then machine the excess material from the previous part away from the reusable build plate and prepare the surface for the next operation.
Horizontal build plates in accordance with various embodiments can remove dimensional constraints associated traditional CNC machines and enable construction of larger scale horizontal metal 3D printing systems. The horizontal build plates can increase speed of print cell construction and part production by not relying on large scale external machining operations for build plate construction or between print operations.
In several embodiments, horizontal build plates are rotatable to be compatible with the horizontal meridian print position(s). The horizontal build plate should be able to support print of barrel sections of at least 20 feet long and at least 20 feet in diameter, and a full dome structure at the end of the barrel section of at least 20 feet in maximum diameter. At about 20 feet in diameter, the overall downward deflection due to the build plate rigidity shall be less than about 0.025 inch or less than about 0.020 inch. The horizontal build plates can have the following capabilities: a) allow for access for print, part removal, part flip and/or part reinstall operations; b) support loads of a positioner emergency stop; c) interface with slewing bearing specified in positioner assembly; d) have an interface for weld current brushes or equivalent component; e) constructed out of steel sections welded to make fabrication manageable; f) machined work surfaces should allow for a clocking feature for part re-install or flip; g) machined work surfaces should have features that allow for concentric alignment; h) assembly shall have surface of at least 20 feet diameter flat enough for printing operations.
Horizontal WAAM systems can have various configurations. Several embodiments include at least one horizontal WAAM print cell in the horizontal WAAM system. In some embodiments, multiple horizontal WAAM print cells can operate simultaneously. Certain embodiments have one to four, or more than four, horizontal WAAM print cells operating side by side. Each horizontal WAAM print cell can have various configurations. In some embodiments, print robots can include various types of WAAM printing robots. In a number of embodiment, print robots can be supported with fixed rails, manually guided vehicles (MGVs), and/or autonomously guided vehicles (AGVs). In several embodiments, horizontal WAAM systems can include print robots on fixed rails; print robots on fixed rail and on MGVs or powered pusher mover; print robots on fixed rails and on AGVs; print robots on multiple MGVs and AGVs supported in parallel; and/or print robots on AGVs with no fixed rails. The horizontal WAAM capabilities include (but are not limited to) outside mold line (OML) printing, inside mold line (IML) printing, dome printing, secondary feature printing, OML machining, IML machining, dome machining, secondary feature machining, series printing, and/or parallel printing.
In many embodiments, the linear track configuration can have any number of horizontal WAAM print cells operating side by side. The print cells of the linear track configuration can have robots supported on fixed rails. In several embodiments, the robots can include at least one end effector including (but not limited to) print heads, machining heads, inspection tools, monitoring tools, and/or imaging tools. Print parts can be supported on the horizontal build plate. The horizontal build plate can rotate clockwise and/or counter clockwise relative to the robots on the fixed rails. Robots can have an arm that can travel and allow the robots to reach a sufficient area of the build plate and work on the rotating part. Robots can perform tool change to switch out various end effectors. The various end effectors enable the horizontal WAAM systems to perform various tasks including (but not limited to) material deposition, calibration, tool changes, detailed machining operations, part inspections, and/or corrections. Horizontal WAAM capabilities include (but are not limited to) OML printing, IML printing, dome printing, OML machining, IML machining, and series printing. The horizontal WAAM system with print robots on fixed rails can print a maximum diameter from about 20 feet to about 24 feet.
One fixed rail can support at least one robot. The rail can be positioned for optimal reach between IML and/or OML. In some embodiments, the rails may have a travel range of about 22 feet, greater than about 22 feet, or less than about 22 feet. The rails may have about ±0.0008-inch repeatability, and have a velocity of about 6 ft/sec, greater than about 6 ft/sec, or less than about 6 ft/sec. The robots can perform various tasks by having different end effectors including (but not limited to) print tools, machining tools, inspection tools, monitoring tools, calibration tools, and/or imaging tools. Tool-changer of the linear track configuration can enable the swap of different end effectors. Examples of end effectors include (but are not limited to) build heads (such as Fronius), spindle heads (such as HSD, HiTecho, MYL, etc.), radiographic testing (RT) arms, and non-destructive evaluation (NDE) arms. The various end effectors enable horizontal WAAM systems to perform various tasks including (but not limited to) material deposition, calibration, tool changes, detailed machining operations, part inspections, and corrections in parallel and/or sequentially.
Support rails for the robots and the various machining heads of the linear track configuration of the horizontal WAAM systems enable broad machining capabilities. Multiple support rails and robots can be set up during a print such that printing and machining can take place in parallel to expedite print processes. Robots can move machining heads around the horizontal build plate for a wider reach. In addition, different machining heads can add various machining capabilities. The linear track configuration can have automated tool change capabilities. Machine spindles can machine thin wall barrels flat. Additional machining capabilities include (but are not limited to) flange facing, about ½ inch flange holes, features less than about 50 inches past print edge of 18 feet diameter barrel, and dome flange greater than about 60 inches in diameter.
The robots can travel and reach a sufficient area of the build plate and work on the rotating part. For example, a print robot can have less than about 10 feet reach, of about 10 feet reach, and greater than about 10 feet reach. In some embodiments, a print robot can have about ±0.003-inch repeatability, and may have a velocity of about 10 inch/sec; greater than about 10 inch/sec; or less than about 10 inch/sec. The print robots and the horizontal rails can have reduced backlash. Machining accuracy of each horizontal WAAM print cell of configuration 1 can achieve at least 0.04-inch accuracy and about 0.003-inch repeatability.
Support rails for print robots and various print heads of the linear track configuration of the horizontal WAAM systems enable flexible printing capabilities. Robots have arms that can travel and move the print heads around the horizontal build plate. In addition, different print heads offer various print capabilities. The print robots in accordance with several embodiments can print large-scale and complex objects including (but not limited to) large barrels with build features such as (but not limited to) ribs and domes overhangs. Printed barrels can have a diameter of at least 18 feet. Horizontal print cells can also support barrels that have less than about 8 feet in diameter with adapter plates. Printed parts can have a dome shape. Printed internal ribs can be less than about 40 inches from print edge. Print robots can use any combo of cold and/or hot wire deposition heads (See, e.g., U.S. Provisional Patent Application No. 63/371,838, filed Aug. 18, 2022, and U.S. Patent Application Publication No. 2023/0173601 A1, published Jun. 8, 2023; the disclosures of which are incorporated by reference), and can have weaving, RSI, x-restarts, contact to work distance (CTWD) control capabilities. X-restarts can include the end effector automatically aligning itself to an x-axis, as explained in U.S. Provisional Patent Application No. 63/378,975, filed Oct. 10, 2022, U.S. Provisional Patent Application No. 63/488,435, filed Mar. 3, 2023, and U.S. Provisional Patent Application No. 63/493,683, filed Mar. 31, 2023, the disclosures of each which are incorporated by reference. Printed external ribs can be anywhere along an 18 feet barrel. Raceway tabs can be anywhere along an 18 feet barrel. Internal reach for features such as iso/ortho grids can be less than 40 inches from print edge.
The linear track configuration of the horizontal WAAM systems in accordance with some embodiments can have support systems regarding (but not limited to) usability features and safety features. The linear track configuration usability features may include (but are not limited to) automated head swaps; side and front camera views of weld; manually adjustable camera view with spindle head; in-situ laser measurements; robot, welder, spindle, and environmental sensors; X-restarts capabilities; remote restarts; part removal and re-installation via bridge crane. Safety features of the linear track configuration may include (but are not limited to) proximity sensor to ensure safe tool swaps, accessible E-stops (×4), stack lights noting system state, local machine guarding, local arc protection, and easy access for consumable swaps, filing, and/or part cleaning.
Horizontal WAAM systems can be a hybrid configuration that includes robots on linear rails and mobile robots. Robots can be secured to linear rails in horizontal print cells. The linear rail may move print robots along the fixed rail during printing. Several embodiments provide mobile platforms that can be precisely positioned within the print cell to achieve desired print results. Mobile platforms can contain many, and in some embodiments, all things needed for a given print operation within reach of robots of various end effectors. The mobile systems enable manufacturing capabilities without kinematic constrains of fixed rails. Print robots of horizontal WAAM print cells can be supported by fixed rails, manually guided vehicles (MGVs), and/or powered pusher movers. MGVs can be mobile platforms that support various parts to perform horizontal printing. MGVs can host a variety of components such as (but not limited to) various robots (printing, machining, inspection, imaging, etc.), robots with various end effectors, connecting systems, power systems, scanning and feedback systems. MGVs can move around the work area and be controlled manually. Compared to linear track configurations, the hybrid configuration can have better machine specialization by leveraging separate mobile support vehicles and/or carts. Hybrid configuration can have increased workable area and increased flexibility. Due to better mobility, hybrid configurations can achieve print accuracy of less than or equal to about 0.04 inches. Mobile platforms can work in parallel with robots on fixed rails. Work capabilities of the hybrid configurations may include (but are not limited to): OML printing; IML printing; dome printing; secondary feature printing; OML machining; IML machining; dome machining; secondary feature machining; series printing; and/or parallel printing.
Hybrid configurations of the horizontal WAAM systems can have increased workable areas and increased printing capabilities than linear track configurations. Mobile systems can move robots around the workable areas for better reach for printing, machining, inspection, and so on. In addition, different print heads offer various print capabilities. Hybrid configurations in accordance with several embodiments can print large-scale objects with complex features due to increased workable areas and print capabilities.
Many embodiments implement MGVs in hybrid configuration of horizontal WAAM systems. MGVs can support various types of print robots, machining robots, and any robots that may be needed to perform horizontal printing. MGVs can also include platforms such as connecting systems, power systems, scanning and feedback systems. MGVs are mobile and can be moved around and controlled manually. MGVs in accordance with several embodiments have advantages including (but not limited to) better machine specialization and/or optimization, increased workable area, increased flexibility, comparable accuracy, increased stiffness, and reduced system downtime. Design considerations of MGVs may include:
In some embodiments, print robots can be supported on the MGVs. A maximum length of the MGV with print robot can be about 12 feet and 6 inches, and a width can be about 11 feet. The print robot on MGV contains all equipment onboarded needed for printing. Machining equipment may be connected externally.
Several embodiments provide tool change capabilities with the hybrid configuration of horizontal WAAM systems. Tool change capabilities enable the hybrid configuration to perform multiple tasks with the same robot, expediting the print speed and flexibility.
Mobile platforms in accordance with some embodiments can be manufacturing platforms comprising an autonomous manufacturing robots, tools and consumables necessary for the manufacturing process, support and inspection tooling, and methods of precisely locating the mobile platforms within a horizontal print cell as to best position it for the intended operation. A custom or off-the-shelf autonomously guided vehicle (“AGV”) can lift and position the mobile platforms using a combination of coarse laser surveying or other precision locating methods. AGVs can place mobile platforms and then are free to move about the factory and execute additional operations. Keeping AGVs and mobile platform as separate systems can reduce cost and bulk of the mobile platform.
Mobile platforms in accordance with many embodiments can solve the suboptimal reach issues associated with linear rail constraints in horizontal WAAM 3D print systems. Removing rail systems allows to manufacture larger 3D printed metal structures at a higher rate with higher accuracy in the printed product by positioning the mobile platform in the optimal place for a given operation. Centralizing the manufacturing robot and its tools and consumables to the mobile platforms may avoid delays associated with tool changes and part inspections that cause operation stoppages.
In horizontal WAAM systems, various components such as (but not limited to) power, networking, data, weld equipment, and machining equipment can be connected. The umbilical strategy in accordance with several embodiments can be used to simplify cable management. When the system is connected, the robots and/or mobile platforms can be located to desired positions. The approximate location of the print can be dictated by the operation and communicated to path planner. Mobile platforms (MGVs or AGVs) can be controlled by giving them the positioner position coordinates and/or axis. Localization of robots and/or mobile platforms can be achieved using devices including (but not limited to) laser trackers and/or permanent cell fiducials. The position of the mobile platforms and/or robots with respect to permanent cell fiducials may be located using an on-board non-contact tracker. The robots can perform coordinate transformation of points in real-time. Calibration verification can be performed at the same time. Control software can pre-run the robot path. When the robots are moved into desired location (using MGVs or AGVs), print can start.
Deposition rates can be slower if processes and/or deposition are performed in serial. Many embodiments implement a decentralized architecture allowing for heterogeneous agents to self-allocate their tasks including (but not limited to) printing, inspection, and/or machining. Fully mobile configuration of horizontal WAAM systems can include multiple mobile horizontal WAAM print cells. Multiple mobile horizontal WAAM print cells can operate simultaneously. In several embodiments, the mobile configuration can include multiple MGVs, AGVs, and multiple robots, working in parallel. In some embodiments, multiple robots can be controlled for parallelizing operations or printing of complex features. One benefit of parallelizing operations is load balancing to optimize manufacturing times. This configuration can be applied to horizontal welding, which can allow multiple robots to be put anywhere to print a long horizontal structure.
As can be inferred from the above discussion, the above-mentioned concepts can be implemented in a variety of arrangements in accordance with embodiments of the invention. Accordingly, although the present invention has been described in certain specific aspects, many additional modifications and variations would be apparent to those skilled in the art. It is therefore to be understood that the present invention may be practiced otherwise than specifically described. Thus, embodiments of the present invention should be considered in all respects as illustrative and not restrictive. Notably, all references to WAAM in this application are provided as an example and should not be construed as limiting. The inventive concepts in this application are applicable to any Directed Energy Deposition (DED) 3d printing process. Appropriate feedstocks include powder or wire. Relevant energy sources are plasma, arc, laser, and others.
As used herein, the singular terms “a,” “an,” and “the” may include plural referents unless the context clearly dictates otherwise. Reference to an object in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.”
As used herein, the terms “approximately” and “about” are used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs to a close approximation. When used in conjunction with a numerical value, the terms can refer to a range of variation of less than or equal to ±10% of that numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.
Additionally, amounts, ratios, and other numerical values may sometimes be presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be understood flexibly to include numerical values explicitly specified as limits of a range, but also to include all individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly specified. For example, a ratio in the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also to include individual ratios such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, and so forth.
The current application claims the benefit, under 35 U.S.C. § 119(e), of U.S. Provisional Patent Application No. 63/368,609 entitled “Systems for Horizontal Wire Arc Additive Manufacturing and Methods Thereof” filed Jul. 15, 2022. The disclosure of U.S. Provisional Patent Application No. 63/368,609 is hereby incorporated by reference in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63368609 | Jul 2022 | US |
