阅读说明：本技术 具有全向构建路径的激光热丝增材沉积头
(Laser hot wire additive deposition head with omnidirectional construction path
) 是由 克里斯多佛·D·阿戈斯蒂
M·D·莱特萨
W·T·马修斯
凯尔·G·史密斯 于 2019-07-16 设计创作，主要内容包括：披露了集成式激光热丝沉积头的实施例。在一个实施例中,所述沉积头包括结构框架、激光加工子系统、送丝装置、以及导电管。所述激光加工子系统安装在所述结构框架内,以沿纵向定向的方向将单束路径激光束朝向有待增材制造的基材或零件递送。所述送丝装置和导电管安装在所述框架内,以将可消耗填充焊丝相对于所述纵向定向的方向成一定角度地朝向所述基材或零件给送。在运动控制系统的引导下,所述沉积头可以相对于所述基材或零件全向移动来对所述零件进行增材制造,而无需从所述纵向定向的方向有角度地改变所述单束路径激光束的取向或旋转所述沉积头。(Embodiments of an integrated laser hot wire deposition head are disclosed. In one embodiment, the deposition head includes a structural frame, a laser processing subsystem, a wire feeder, and a conductive tube. The laser processing subsystem is mounted within the structural frame to deliver a single beam path laser beam in a longitudinally oriented direction toward a substrate or part to be additively manufactured. The wire feeder and contact tube are mounted within the frame to feed consumable filler wire at an angle toward the substrate or part relative to the longitudinally oriented direction. Under the direction of a motion control system, the deposition head may be moved omni-directionally relative to the substrate or part to perform additive manufacturing of the part without the need to angularly reorient the single-path laser beam from the longitudinally-oriented direction or rotate the deposition head.)
1. An integrated laser hot wire additive deposition head, the deposition head comprising:
a structural frame;
a laser machining subsystem comprising a laser focusing device mounted within the frame and configured to deliver a single beam path laser beam in a longitudinally oriented direction toward a substrate or part to be additively manufactured; and
a wire feeder and a contact tube mounted within the frame and configured for feeding consumable filler wire toward the substrate or the part at an angle of between 1 ° and 30 ° relative to the longitudinally oriented direction,
wherein, under the direction of a motion control system, the deposition head is configured for additive manufacturing of the part with omnidirectional movement relative to the substrate or the part without:
angularly changing the orientation of said single-path laser beam from said longitudinally oriented direction, or
Rotating the deposition head.
2. The integrated laser hot wire additive deposition head of claim 1, wherein the angle is manually adjustable between 1 ° and 30 °.
3. The integrated laser hot wire additive deposition head of claim 1, wherein a distance between a first location where the laser beam converges with the base material or the part and a second location where a tip of the consumable filler wire converges with the base material or the part is manually adjustable.
4. The integrated laser hot wire additive deposition head of claim 1, wherein the single beam path laser beam does not split or recombine within the integrated laser hot wire additive deposition head.
5. The integrated laser hot wire additive deposition head of claim 1, further comprising a nose cone, universal hoses and conduits, and a water cooled contact block.
6. The integrated laser hot wire additive deposition head of claim 1, wherein the wire feeder comprises a motor and a drive roller.
7. The integrated laser hot wire additive deposition head of claim 1, wherein the consumable filler wire approaches a conductive tube within the deposition head at a first angle of about 30 degrees or less from the longitudinally oriented direction and then exits the conductive tube at a second angle of about 1 to 5 degrees from the longitudinally oriented direction.
8. The integrated laser hot wire additive deposition head of claim 1, wherein the laser focusing device operates in the infrared spectrum to provide an output power of up to 15 kilowatts.
9. The integrated laser hot wire additive deposition head of claim 1, wherein deposition rates of up to about 10.0 kilowatts per hour can be achieved.
10. The integrated laser hot wire additive deposition head of claim 1, wherein the laser focusing apparatus comprises at least one of a laser light focusing optics module, a focusing optics secondary gas inlet, an imperforate focusing optics lid slide, and a focusing optics exit tip.
11. An integrated laser hot wire additive deposition head, the deposition head comprising:
a structural frame;
a laser machining subsystem comprising a laser focusing device mounted within the frame and configured to deliver a single beam path laser beam in a longitudinally oriented direction toward a substrate or part to be additively manufactured; and
a contact tube mounted within the frame and configured to accept consumable filler wire from an external wire feeder and direct the consumable filler wire toward the substrate or the part at an angle of between 1 ° and 30 ° relative to the longitudinally oriented direction,
wherein, under the direction of a motion control system, the deposition head is configured for additive manufacturing of the part with omnidirectional movement relative to the substrate or the part without:
angularly changing the orientation of said single-path laser beam from said longitudinally oriented direction, or
Rotating the deposition head.
12. The integrated laser hot wire additive deposition head of claim 11, wherein the angle is manually adjustable between 1 ° and 30 °.
13. The integrated laser hot wire additive deposition head of claim 11, wherein a distance between a first location where the laser beam converges with the base material or the part and a second location where a tip of the consumable filler wire converges with the base material or the part is manually adjustable.
14. The integrated laser hot wire additive deposition head of claim 11, wherein the single beam path laser beam does not split or recombine within the integrated laser hot wire additive deposition head.
15. The integrated laser hot wire additive deposition head of claim 11, further comprising a nose cone, universal hoses and conduits, and a water cooled contact block.
16. The integrated laser hot wire additive deposition head of claim 11, wherein the consumable filler wire approaches a conductive tube within the deposition head at a first angle of about 30 degrees or less from the longitudinally oriented direction and then exits the conductive tube at a second angle of about 1 to 5 degrees from the longitudinally oriented direction.
17. The integrated laser hot wire additive deposition head of claim 11, wherein the laser focusing device operates in the infrared spectrum to provide an output power of up to 15 kilowatts.
18. The integrated laser hot wire additive deposition head of claim 11, wherein deposition rates of up to about 10.0 kilowatts per hour can be achieved.
19. The integrated laser hot wire additive deposition head of claim 11, wherein the laser focusing apparatus comprises at least one of a laser light focusing optics module, a focusing optics secondary gas inlet, an imperforate focusing optics lid slide, and a focusing optics exit tip.
20. The integrated laser hot wire additive deposition head of claim 11, further comprising at least one of a thermal/electrical insulation plate, a wire entry adjustment unit, a nose cone locking collar, and a supplemental gas/tip cooling gas conduit.
Technical Field
Embodiments of the present invention relate to systems and methods related to additive manufacturing (often synonymously referred to as 3D printing), and more particularly to laser hot filament additive deposition heads that allow for omnidirectional build paths.
Background
Conventionally, additive manufacturing processes are capable of manufacturing near net shape parts with relatively low deposition rates, where each part is built layer by layer. However, the orientation of the deposition apparatus may have to be continuously adjusted when depositing, for example, a layer of metallic material. Such constant adjustments may involve complex path planning and robotic manipulation. Furthermore, the laser optics in certain laser filament embodiments can be quite complex, requiring splitting and then recombining the laser beams. Such complex optical implementations can be quite expensive.
Disclosure of Invention
Embodiments of the invention include systems and methods related to a laser hot wire deposition head for additive manufacturing that allows for the creation of an omnidirectional build path. One embodiment includes a deposition head including a laser focusing device, a wire feeder, and a filler wire contact tip or tube integrated into a single deposition head. The configuration of the deposition head provides a longitudinally oriented laser beam with the filler wire fed at an angle of 30 degrees or less (e.g., 12 degrees in one embodiment) from the longitudinal axis of the laser beam. The longitudinal (lengthwise, linear) axis corresponds to the directional vector of the laser beam path in free space towards the surface of the substrate or part to be additively manufactured. Such a configuration allows the deposition head to move in any translational direction or path (e.g., relative to a cartesian plane) without changing the angle of the deposition head or rotating the deposition head perpendicular to the path plane. The laser beam generated and delivered to the processing site follows a single path in the deposition head. For example, the laser beam is not split into multiple paths and then brought together again. With the available software typically used for layering and path planning of additively manufactured parts, the complexity of the machining increases significantly when it is necessary to adjust the rotational orientation of the deposition apparatus. Furthermore, if the rotational orientation of the deposition apparatus must be taken into account, the winding and unwinding of the apparatus and the supporting umbilicals of the process hoses and utilities must also be taken into account, in some cases making it significantly more difficult, more expensive, more time intensive, or substantially impossible to produce additively manufactured parts having moderately complex geometries. For these reasons and others not mentioned in the context of this document, a deposition apparatus having a rotational orientation that is directionally dependent on the path may be less advantageous for certain applications and may be less versatile for general use.
In one embodiment, an integrated laser hot wire additive deposition head includes a structural frame, a laser processing subsystem, a wire feeder, and a conductive tube. The laser processing subsystem includes a laser focusing device mounted within the frame and configured to emit a single beam path laser beam in a longitudinally oriented direction toward a surface of a substrate or part to be additively manufactured. The single beam path laser beams are not split or recombined within the integrated laser hot filament additive deposition head. The wire feeder and contact tube are mounted within the frame and configured for feeding consumable filler wire toward the substrate or the part at an angle of between 1 ° and 30 ° relative to the direction of longitudinal orientation. The angle is manually adjustable between 1 ° and 30 ° via a conductor tube assembly equipped with an angular pivot joint. In particular, the contact tube is integrated into a spherical ball and socket swivel and coupled to a flexible wire conduit that is subsequently attached to a rigidly mounted wire feeder, thereby enabling angular adjustment and repositioning of the welding wire as it enters the path of the laser beam. Under the direction of a motion control system, the deposition head is configured for omni-directional movement relative to the substrate or the part to additive-fabricate the part without the need to angularly reorient the single-beam-path laser beam from the longitudinally-oriented direction (the direction established for additive-fabrication of a current portion of the part) or rotate the deposition head. In one embodiment, a distance between a first location where the laser beam converges with the base material or the part and a second location where a tip of the consumable filler wire converges with the base material or the part is manually adjustable. Fine tuning of the convergence of the welding wire as it enters the path of the laser beam is accomplished via a two-axis linear cross slide (cross-slide) module that holds the hot wire contact block and the conductive tube assembly. In one embodiment, the integrated laser hot wire additive deposition head includes a nose cone, a universal hose and conduit, and a water cooled hot wire contact block. In one embodiment, the wire feeder includes a motor and a drive roller. In one embodiment, the consumable filler wire approaches a contact tube within the deposition head at a first angle of about 30 degrees or less from the longitudinally oriented direction and then leaves the contact tube at a second angle of about 1 to 5 degrees from the longitudinally oriented direction (e.g., because the contact tube is bent). In one embodiment, the laser device operates in the infrared spectrum to provide an output power of up to 15 kilowatts. In one embodiment, deposition rates of up to about 10.0 kilowatt-hours may be achieved. In one embodiment, the laser focusing apparatus includes at least one of a laser light focusing optics module, a focusing optics secondary gas inlet, an imperforate focusing optics cover slide, and a focusing optics exit tip.
In one embodiment, an integrated laser hot wire additive deposition head includes a frame, a laser machining subsystem, and a conductive tube. The laser processing subsystem includes a laser focusing device mounted within the frame and configured to deliver a single beam path laser beam in a longitudinally oriented direction toward a surface of a substrate or part to be additively manufactured. The single beam path laser beams are not split or recombined within the integrated laser hot filament additive deposition head. The contact tube is mounted within the frame and is configured to accept a consumable filler wire from an external wire feeder and direct the consumable filler wire toward the substrate or the part at an angle of between 1 ° and 30 ° relative to the longitudinally oriented direction. In one embodiment, the angle is manually adjustable (e.g., via welding wire entering the adjustment unit) between 1 ° and 30 °. Under the direction of a motion control system, the deposition head is configured for omni-directional movement relative to the substrate or the part to additive-fabricate the part without the need to angularly reorient the single-beam-path laser beam from the longitudinally-oriented direction (the direction established for additive-fabrication of a current portion of the part) or rotate the deposition head. In one embodiment, a distance between a first location where the laser beam converges with the base material or the part and a second location where a tip of the consumable filler wire converges with the base material or the part is manually adjustable. In one embodiment, the integrated laser hot wire additive deposition head includes a nose cone, a universal hose and conduit, and a water cooled contact block. In one embodiment, the consumable filler wire approaches a contact tube within the deposition head at a first angle of about 30 degrees or less from the longitudinally oriented direction and then leaves the contact tube at a second angle of about 1 to 5 degrees from the longitudinally oriented direction (e.g., because the contact tube is bent). In one embodiment, the laser device operates in the infrared spectrum to provide an output power of up to 15 kilowatts. In one embodiment, deposition rates of up to about 10.0 kilowatt-hours may be achieved. In one embodiment, the laser focusing apparatus includes at least one of a laser light focusing optics module, a focusing optics secondary gas inlet, an imperforate focusing optics cover slide, and a focusing optics exit tip. In one embodiment, the integrated laser hot wire additive deposition head includes at least one of a thermal/electrical insulation plate, a wire entry adjustment unit, a nose cone locking collar, and a supplemental gas/tip cooling gas conduit. Insulation plates constructed from fiber-reinforced high heat capacity polymer materials are primarily used to prevent electrical conduction back through the structural frame of the additive deposition head and through robots, controllers, or related system wiring. This uncontrolled and unexpected delivery of current typically damages the equipment and may also have a detrimental effect on deposition head processing performance. As a secondary feature, the thermal insulating properties prevent heat transfer beyond the water cooled process head contact block and to the structural frame of the head or other areas not used for active temperature control. The wire entry adjustment unit allows fine tuning of the feed angle of the deposition process, where a particular application may show slight deposition performance benefits at slightly different feed angles due to differences in the physical and thermal properties of the various different alloys employed by the process. According to one embodiment, the nose cone locking collar is a threaded collar that secures the process nose cone in place against the water cooled contact block. It also allows for removal and repair or replacement of the nose cone if damaged, and in addition, allows for installation of a nose cone of a different shape or design for a given additive manufacturing application. The make-up gas/tip cooling gas conduit supplies inert shielding gas inside the nose cone, directing a gas stream onto the tip of the wire contact tube to help cool the tip and subsequently flood the deposition site and surrounding part build area.
Many aspects of the general inventive concept will become apparent from the following detailed description of exemplary embodiments and from the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the disclosure. It should be understood that the illustrated element boundaries (e.g., boxes, groups of boxes, or other shapes) in the figures represent one embodiment of the boundaries. In some embodiments, one element may be designed as a plurality of elements or a plurality of elements may be designed as one element. In some embodiments, one element shown as an internal component of another element may be implemented as an external component, and vice versa. In addition, elements may not be drawn to scale.
Fig. 1 illustrates one embodiment of an additive manufacturing compartment with an integrated deposition head for additive manufacturing of a part;
FIG. 2 illustrates a conventional Laser Hot Wire (LHW) system using laser and filler wire in an additive manufacturing process;
FIG. 3 illustrates the relationship between the laser beam, consumable metal filler wire, contact tip/tube, shielding gas, and nose cone of one embodiment of the integrated deposition head when depositing molten metal onto a substrate/layer during an additive manufacturing process;
FIG. 4 illustrates an embodiment of an integrated deposition head oriented vertically, showing a nose cone and wire feeder;
FIG. 5 illustrates one embodiment of the internal configuration of a portion of an integrated deposition head that also provides supplemental/shielding gas via gas hoses and gas nozzles;
FIGS. 6 and 7 show two views of an embodiment of a partially assembled integrated deposition head showing a universal hose and conduit;
figures 8 to 10 show three views of an embodiment of an integrated deposition head with the cover removed and attached to the arm of the robot;
FIG. 11 illustrates one embodiment of a side of a wire feeder including drive rollers (with the cover removed);
FIG. 12 illustrates an embodiment of a nose cone end of an integrated deposition head having filler wire protruding at a steep angle relative to vertical;
FIG. 13 illustrates one embodiment of an integrated deposition head attached to an arm of a robot;
FIG. 14 illustrates a nose cone end of an embodiment of an integrated deposition head with the nose cone removed;
fig. 15 shows a first example of a plurality of metal layers deposited by one embodiment of an integrated deposition head during an additive manufacturing process to form a solid rectangular block;
FIG. 16 shows a second example of a plurality of metal layers deposited by one embodiment of an integrated deposition head during an additive manufacturing process to form a hollow cylindrical part;
figures 17 and 18 show an embodiment of a small and lightweight integrated deposition head attached to the arm of the robot;
FIG. 19 illustrates one embodiment of an example controller for use in an additive manufacturing system;
FIG. 20 illustrates two views of one embodiment of an integrated deposition head with all frames or covers unattached;
FIG. 21 illustrates one embodiment of the internal configuration of a portion of an integrated deposition head, similar to FIG. 5, showing a number of different component details;
FIG. 22 illustrates a hot wire processing subsystem of one embodiment of an integrated deposition head;
FIG. 23 illustrates a laser processing subsystem of one embodiment of an integrated deposition head;
FIG. 24 illustrates one embodiment of a laser focusing device of the laser processing subsystem of FIG. 23; and is
Fig. 25 illustrates a deposition head structural frame of one embodiment of an integrated deposition head.
Detailed Description
The examples and figures herein are merely illustrative and are not intended to limit the subject invention, which is measured by the scope and spirit of the claims. Additive manufacturing is a well known process of depositing material (e.g., in multiple layers) onto a substrate/substrate or part to produce a desired article of manufacture. According to one embodiment, a pattern of layers of a three-dimensional (3D) part to be additively manufactured is rendered and stored as digital data. The digital data may be from a CAD model or from a scanned part, for example.
Embodiments of the additive manufacturing apparatus may include at least one of, for example, a laser-based subsystem, a plasma-based subsystem, an arc-based subsystem, an electron beam-based subsystem, or a resistance-based subsystem to deposit a metallic material, for example, by melting a metallic wire. Further, some embodiments of the additive manufacturing apparatus may include, for example, a wire feeding or feeding system to feed/deliver consumable metal wire for additive manufacturing of 3D parts on a substrate. Moreover, some embodiments of the additive manufacturing apparatus may include, for example, a motion control element (e.g., a robot) or other type of control element (e.g., an optical control element) to move a laser beam, a plasma beam, an arc, an electron beam, or a consumable metal wire relative to a substrate or 3D part being additively manufactured on the substrate.
Fig. 1 and 2, included herein, put embodiments of the integrated deposition head in context. Referring to fig. 1, fig. 1 illustrates one embodiment of an additive manufacturing compartment 10 configured with a laser hot wire apparatus for manufacturing metal parts via additive manufacturing. The laser filament apparatus of fig. 1 includes an integrated deposition head attached to an arm of a robot. The additive manufacturing compartment 10 generally includes a frame 12, a robot 14 disposed within the frame, and first and second tables 16, 18 also correspondingly disposed within the frame. The additive manufacturing cell 10 is useful for additive manufacturing parts (e.g., 22 and 24) in a manner that will be described in more detail below. In the embodiment depicted in fig. 1, the frame 12 includes a plurality of sidewalls and doors to enclose the robot 14 and tables 16 and 18. Although a generally rectangular configuration in plan view is shown, the frame 12 and compartment 10 may take a variety of configurations.
A front access door 26 is mounted to the frame 12 for access to the frame interior. Front access door 26 may take a bi-fold configuration, wherein the door includes two hinge sets: a first set of hinges attaching the door 26 to the frame 12 and a second set of hinges attaching one panel of the door to the other panel. However, the front access door 26 may take other configurations, such as a sliding door or a swinging door. Similarly, a rear access door 28 is also mounted to the frame 12. The rear access door 28 in the depicted embodiment also takes a bi-fold configuration; however, the rear access door may take on other configurations, such as those discussed with reference to the front access door 26. A window 32 may be provided on either door (depicted only on front door 26). The window may comprise a colored security screen (e.g., a screen that filters the appropriate laser wavelength) as is known in the art. According to one embodiment, the compartment 10 is a CDRH class 1 laser jacket.
A control panel 40 is provided on the frame 12 adjacent the front door 26. Control knobs and/or switches provided on the control panel 40 communicate with controls housed in a control enclosure 42 also mounted to the frame 12. The controls on the control panel 40 may be used to control operations performed in the additive manufacturing compartment 10 in a similar manner to the controls for known additive manufacturing compartments.
In one embodiment, the robot 14 is mounted on a base that is mounted on a support. The robot 14 in the depicted embodiment is centered relative to the tables 16 and 18 and includes multiple axes of movement. If desired, the base may be rotated relative to the support similar to a turret. Accordingly, some drive mechanisms (e.g., motors and transmissions (not shown)) may be housed in the base and/or in the support for rotating the robot 14.
In one embodiment, the deposition head 60 is attached to the distal end of the arm of the robot 14. For example, according to embodiments discussed below, the deposition head 60 is an integrated laser hot wire deposition head. Deposition head 60 allows for an omnidirectional build path (deposition motion) without the need to change the rotational orientation of deposition head 60 (i.e., the rotational orientation of the deposition head may remain unchanged during deposition of a layer). A flexible tube or conduit 62 is attached to the deposition head 60. Consumable metal welding wire 64 (used as a hot wire) that may be stored in a container 66 is delivered to the deposition head 60 through the conduit 62. In one embodiment, a wire feeder 68 is attached to the frame 12 (or robot 14) to facilitate delivery of the consumable metal wire 64 to the deposition head 60. In another embodiment, the wire feeder 68 is integrated into the deposition head 60 (e.g., as an on-board integrated wire feed module), as discussed below.
Although the robot 14 is shown mounted to a base or lower portion of the frame 12, the robot 14 may be mounted to an upper structure of the frame and hang downwardly into the compartment 10 if desired. In one embodiment, the power supply 72 for laser filament operation is mounted on and rests on a platform 74 that is connected to and may be part of the frame 12. The power source 72 may function as a laser power oscillator (to generate laser energy) and a welding power source to energize the consumable metal wire 64 as it passes through the deposition head 60. In another embodiment, the power source 72 may be implemented as two separate power sources, one power source serving as a laser power oscillator for generating laser energy and the other power source for heating the consumable metal wire 64 as it passes through the deposition head 60. The compartment controller 76 communicates with and controls the different parts of the laser filament apparatus of the additive manufacturing compartment 10 (including the robot 14), and rests and mounts on the platform 74. According to yet another embodiment, the laser power oscillator may be integrated into the deposition head 60 (e.g., for lower power applications).
Fig. 2 illustrates a conventional Laser Hot Wire (LHW) system 100 that uses a laser subsystem and filler wire in an additive manufacturing process. The system 100 may be present in an additive manufacturing compartment similar to the additive manufacturing compartment 10 of fig. 1. However, the system 100 of FIG. 2 does not include an integrated laser filament deposition head. The system 100 of FIG. 2 includes a filler wire feeder and an energy source. In particular, the system 100 includes a laser subsystem capable of focusing a laser beam 110 onto a substrate or part 115 to heat the substrate or part 115. The laser subsystem may be a high intensity energy source. The laser subsystem may be any type of high energy laser source including, but not limited to, carbon dioxide, Nd: YAG, Yb-disk, YB-fiber, fiber optic delivery, or direct diode laser systems (e.g., fiber coupled direct diodes).
The laser subsystem includes a laser focusing device 120 and a laser power supply 130 (laser power oscillator) operatively connected to each other. The laser power supply 130 provides power to generate (e.g., in the form of optical fibers) laser energy that is provided to the laser focusing device 120. The system 100 also includes a hot filler wire feeder subsystem capable of providing at least one resistive filler wire 140 to contact the substrate or part 115 in the vicinity of the laser beam 110. The wire feeder subsystem includes a filler wire feeder 150, a contact tube 160, and a power source 170. During operation, the filler wire 140 is resistively heated by current from a power source 170 operatively connected between the contact tube 160 and the substrate or part 115. The power supply 170 may be a pulsed Direct Current (DC) power supply, but an Alternating Current (AC) or other type of power supply is also possible. The welding wire 140 is fed from the filler wire feeder 150 through the contact tube 160 toward the substrate or part 115 and extends out of the tube 160. The extension of wire 140 is resistively heated such that the extension approaches or reaches the melting point before contacting the substrate or part 115. According to one embodiment, the hot wire power supply 170 provides hot wire waveform control (actively increasing current, voltage, and shape parameters) to maintain the hot wire process and suppress arcing. The laser beam 110 may be used to melt some of the base metal of the substrate or part 115 to form a melt pool and/or may also be used to melt the wire 140 onto the substrate or part 115. The power source 170 provides the energy required to resistively melt the filler wire 140.
The system 100 further includes a motion control subsystem that is capable of moving the laser beam 110 and the resistive filler wire 140 along the substrate or part 115 in the same controlled direction 125 (at least in a relative sense) such that the laser beam 110 and the resistive filler wire 140 remain in a fixed relationship to each other. Relative motion between the substrate or part 115 and the laser/wire combination can be achieved by physically moving the substrate or part 115 or by moving the laser device 120 and wire feeder subsystem.
In fig. 2, the motion control subsystem includes a motion controller 180 operatively connected to a robot 190 having a platform 193 (e.g., a rotatable platform and/or a translatable platform). The motion controller 180 controls the motion of the robot 190. The robot 190 is operatively connected (e.g., mechanically fastened) to the substrate or part 115 via the platform 193 to move the substrate or part 115 in, for example, the current direction of travel 125 such that the laser beam 110 and the welding wire 140 effectively travel along the substrate or part 115. The robot 190 driving the platform 193 may be driven electrically, pneumatically, or hydraulically.
System 100 further includes a sensing and current control subsystem 195 operatively connected to base material or part 115 and contact tube 160 (i.e., operatively connected to the output of power source 170) and capable of measuring the potential difference (i.e., voltage V) between base material or part 115 and wire 140 and the current (I) passing therethrough. Sensing and current control subsystem 195 may further be capable of calculating a resistance value (R ═ V/I) and/or a power value (P ═ V ═ I) from the measured voltage and current. Typically, the potential difference between the wire 140 and the substrate or part 115 is zero volts or very close to zero volts (a relatively low voltage) when the wire 140 is in contact with the substrate or part 115. As a result, the sensing and current control subsystem 195 is capable of sensing when the resistive filler wire 140 is in contact with the substrate or part 115 and is operatively connected to the power source 170, thereby further being capable of controlling the flow of current through the resistive filler wire 140 (e.g., for quenching) in response to the sensing. In one embodiment, sensing and current controller 195 may be an integral part of power supply 170.
The system 100 of fig. 2 may be modified according to one embodiment of the present invention by providing a single integrated laser filament deposition head (e.g., as in fig. 1) that provides omnidirectional build path capability. In one embodiment, at least the laser focusing device, the wire feeder, and the conductive tube are integrated into a single deposition head (forming an integrated deposition head). The integrated deposition head provides a steep feed angle of the filler wire relative to the longitudinal direction of the laser beam delivered by the laser focusing device (toward the substrate or part to be additively manufactured), as discussed in detail below, thereby allowing build path omnidirectionality to be achieved. The longitudinal direction is the linear direction along which the centre line of the laser beam is directed towards the surface of the substrate or part to be additively manufactured.
The system in which the integrated deposition head is used may be the system 10 of fig. 1 or may include certain components of the system 100 of fig. 2, including a laser power supply 130, a hot wire power supply 170, a motion controller 180, and a robot 190. However, the integrated deposition head is attached to the arm of a robot (e.g., as in fig. 1), allowing the deposition head to move omni-directionally (e.g., in a cartesian (e.g., x-y) plane) relative to the substrate/part under the control of a motion controller without the need to angularly change the longitudinal or rotational orientation of the deposition head. For example, according to one embodiment, the integrated deposition head may remain in the same longitudinally-oriented position (e.g., a vertically-oriented position) without rotation during deposition of the layers. The longitudinally oriented position allows the integrated deposition head to be simply moved by a robot during deposition of a layer of a part being additively manufactured without requiring complex motion control schemes provided by motion controllers. Furthermore, having an integrated deposition head means that the separate laser subsystem and the separate filament subsystem do not need to be moved separately and in synchronization with each other.
Fig. 3 illustrates the relationship between the laser beam 310, the consumable metal filler wire 320, the contact tip/tube 330, the shielding gas 340, and the nose cone 350 of one embodiment of the integrated deposition head 300 when depositing molten metal onto the substrate/layer 360 during the additive manufacturing process. The laser beam 310 is vertically oriented and focused at a convergence point 370 where the tip of the filler wire 320 meets the laser beam 310. According to one embodiment, the laser beam 310 may be generated by a fiber optic delivery laser. However, the laser subsystem may be any type of high energy laser source including, but not limited to, carbon dioxide, Nd: YAG, Yb-disk, YB-fiber, fiber optic delivery, or direct diode laser systems (e.g., fiber coupled direct diodes).
The filler wire 320 is oriented at an angle of 30 degrees or less from the longitudinal (e.g., vertical) direction 380 of the laser beam 310. The consumable metal filler wire 320 is preheated via the contact tip/tube 330 and fed into contact with the substrate/layer 360. The hot wire power supply (external to the deposition head 300) provides power to preheat the filler wire 320. According to one embodiment, the hot wire power supply provides hot wire waveform control (actively increasing current, voltage, and shape parameters) to maintain the hot wire process and suppress arcing. A laser power supply (a laser power oscillator external to the laser focusing device) generates and provides laser energy to the laser focusing device (e.g., in the form of an optical fiber), which generates a laser beam 310. Laser beam 310 melts substrate/(previous additive build layer(s) 360 and/or melts preheated filler wire 320 to fuse molten metal 390 to substrate/(previous additive build layer(s) 360. Fig. 3 shows a deposition region 362 and a dilution region 364 relative to the substrate/layer(s) 360. FIG. 3 also shows a pre-heating zone 335 of the consumable metal filler wire 320. According to one embodiment, the laser beam 310 is a single-path laser beam 310 that is not split or recombined in any way within the integrated deposition head 300.
The coaxial gas shield configuration that lowers the center of the deposition head through the optics protects the process and the deposited metal and helps to prevent debris from moving toward the laser apparatus and optics. The sacrificial focusing optic cover slider (which is not perforated) also helps protect the laser device and optics. The cover slide is not perforated because the consumable filler wire does not need to pass through the cover slide. The steep feed angle of the filler wire of 15 degrees or less provides an omni-directionality of the additive build path. That is, additive build may be achieved without changing the angle of the longitudinal or rotational orientation of the integrated deposition head. In general, the spatial relationship of the wire tip to the laser spot tends to change as the deposition head moves back and forth. This movement can be minimized by having a steep filler wire feed angle. Further, according to one embodiment, the path of the consumable filler wire up and into the integrated deposition head is relatively straight.
Fig. 4 illustrates one embodiment of a vertically oriented integrated deposition head 400 showing a nose cone 410, and a wire feeder 420 (an onboard integrated wire feed module) with drive rollers 425. The wire feeder 420 includes a servo-controlled drive (servo motor) to drive the drive roller 425 to provide a steady and precise feed of consumable filler wire. The consumable filler wire enters the integrated deposition head via a conduit. Fig. 5 illustrates one embodiment of the internal configuration of a portion of an integrated deposition head 500 that also provides supplemental/shielding gas via gas hose 510 and gas nozzle 520. Fig. 5 also shows a nose cone 550. In one embodiment, the x-y position of consumable filler wire 530 can be adjusted manually relative to laser beam 540 (i.e., how close the tip of the filler wire is to the center of the laser beam spot at the base/layer or convergence point can be adjusted). Fine tuning of the convergence of the welding wire as it enters the path of the laser beam is accomplished via a two-axis linear dovetail cross-slide module that holds the hot wire contact block and the conductive tube assembly. The cross slide employs three plates interconnected together and moving relative to each other via a linear dovetail: a base plate, a middle support plate, and an upper mounting plate. These plates allow for linear movement of the X-Y cartesian plane (along 2 vertical axes) and adjustment by using two threaded lead screws (one for each axis of movement). The substrate is attached to the insulating plate, and thus to the structural frame of the additive deposition head. A water cooled contact plate is attached to the upper mounting plate of the slider so that the position of the contact plate and contact tip can be adjusted relative to the structural frame, the laser focusing optics device just attached to the structural frame, and the laser beam path itself. In one embodiment, the steep angle between laser beam 540 and filler wire 530 is fixed. Further, according to another embodiment, the angle of consumable filler wire 530 with respect to vertical laser beam 540 may be manually adjusted (e.g., the angle may be continuously adjustable between 1 and 30 degrees). The angle is manually adjustable between 1 ° and 30 ° via a conductor tube assembly equipped with an angular pivot joint. In particular, the contact tube is integrated into a spherical ball and socket swivel and coupled to a flexible wire conduit that is subsequently attached to a rigidly mounted wire feeder, thereby enabling angular adjustment and repositioning of the welding wire as it enters the path of the laser beam. For extended use, locking set screws are used to fix and hold the angular position in a fixed position. Loosening the set screw allows the angular position of the contact tube to be changed by moving the contact tube using hand and then fixing the contact tube in a new position by re-tightening the set screw. According to an alternative embodiment, the consumable filler wire 530 approaches the contact tube within the deposition head at an angle below 30 degrees (e.g., 12 degrees) relative to the longitudinal direction of the laser beam and then exits the contact tube almost longitudinally (e.g., at an angle of 1 to 5 degrees from the longitudinal direction) due to the bending of the contact tube.
Fig. 6 and 7 show two views of an embodiment of an integrated deposition head 600 (partially assembled), showing a universal hose and conduit 610 (e.g., for welding wire, gas, water), a water cooled contact block 620, and a nose cone 630. Fig. 8-10 show three views of an embodiment of an integrated deposition head 600 having a nose cone 630 and attached to an arm 820 of a robot with the cap removed. The deposition head 600 of fig. 9 also shows a wire feeder 930, and the deposition head 600 of fig. 10 also clearly shows the water cooled contact block 620. Fig. 11 illustrates one embodiment of a side of the wire feeder 930 (with the cover removed) including the drive rollers 935. The other side (not shown) of the wire feeder 930 includes a motor for driving the drive rollers 935 and an integrated wire feeder circuit control board (see fig. 20) for controlling the motor.
Fig. 12 illustrates an embodiment of the nose-cone end of the integrated deposition head 600 having a filler wire 1210 protruding at a steep angle (less than 30 degrees) relative to the longitudinal direction (e.g., vertical). The water cooled contact block 620 prevents the nose cone 630 from becoming too hot, which could damage the nose cone 630. If not cooled, the laser reflection may be intense and heat up the nose cone 630. According to various embodiments, an active or passive water (or some other fluid) cooling system may be used. Piping (conduit 610) to the deposition head 600 provides water (or other fluid) to the water-cooled contact block 620, and other piping (conduit 610) takes water out of the water-cooled contact block 620 and deposition head 600. The water-cooled contact block 620 is also clearly shown in some other figures (e.g., fig. 6, 10, 12, and 21). Fig. 13 illustrates one embodiment of an integrated deposition head 600 attached to an arm 820 of a robot. Fig. 14 illustrates the nose cone end of one embodiment of the integrated deposition head 600 with the nose cone 630 removed. The make-up gas nozzle 1410 and the wire conduit 1420 (e.g., serving as a contact tube tip) with the filler wire 1210 extending out of the wire conduit (wire contact tube tip) 1420 can be seen. The make-up gas nozzle supplies inert shielding gas inside the nose cone, directing a gas stream onto the welding wire contact tube tip to help cool the contact tube tip and subsequently flood the deposition site and surrounding part build area. Compared to the gas jet supplied to the focusing optics arrangement against the cover slide (which may increase the temperature as it contacts the internal surfaces within the optics at elevated temperature), the supplementary gas is delivered as gas released from the pressurized tank into the hot filament nose cone at or below ambient room temperature, expanding and undergoing a temperature drop as a result. This cooler gas flow directly onto and around the contact tube tip will help transfer heat out of and away from the contact tube tip. In addition, the gas then flows out of the nose cone and surrounds the deposition point, providing additional protection for the actively deposited, molten or nearly molten metal, which is more reactive with impurities as the temperature rises. Depending on the particular application and the alloy composition of the metal deposit, this gas will most likely be nitrogen or argon, or may be some other functional inert gas. Fig. 15 shows a first example of a plurality of metal layers deposited by one embodiment of an integrated deposition head 600 during an additive manufacturing process for forming a solid rectangular block 1500. For size comparison, a ruler 1510 is shown with millimeter (mm) increments. Fig. 16 shows a second example of a plurality of metal layers deposited by one embodiment of the integrated deposition head 600 during an additive manufacturing process for forming a hollow cylindrical member 1600.
Fig. 17 and 18 show an embodiment of an integrated deposition head 1700 attached to an arm 1710 of a robot. The integrated deposition head 1700 of fig. 17 and 18 is smaller in size and lighter in weight than the deposition head 600 shown, for example, in fig. 13, and thus, may be attached to a relatively small robot 1750. In the embodiment of fig. 17 and 18, wire feeder 930 (servo-driven wire feeder) is no longer integrated into deposition head 1700, but is external to deposition head 1700 as wire feeder 1740. This helps to reduce the size and weight of the deposition head 1700. In a similar embodiment, a push-pull feeder configuration may be used in which the additive deposition head includes an integrated drive roller set and a servo motor coupled with a robot-mounted wire feeder that includes additional drive rollers and servo motors. In this embodiment, the deposition head includes an on-board, integrated, stand-alone "pull" wire feeder module having drive rollers, servo motors, and a feed control circuit board. The "push" wire feeder is mounted independently outside of the deposition head (e.g., mounted to a robot). Moreover, the aluminum substrate and the lightweight cover also help to reduce the weight of the integrated deposition head 1700 of fig. 17 and 18. In addition, active cooling may be used to allow for a smaller and lighter nose cone 1730.
Fig. 19 illustrates one embodiment of an example controller 1900 for use in an additive manufacturing system. According to various embodiments, the controller 1900 may, for example, function as a controller for a compartment controller (e.g., the compartment controller 76 of fig. 1), a motion controller (e.g., the motion controller 180 of fig. 2), a power supply (e.g., the power supply 72 of fig. 1, the laser power supply 130 of fig. 2, and/or the hot wire power supply 170 of fig. 2).
The controller 1900 includes at least one processor 1914 that communicates with a number of peripheral devices via a bus subsystem 1912. These peripheral devices may include a storage subsystem 1924 (including, for example, a memory subsystem 1928 and a file storage subsystem 1926), user interface input devices 1922, user interface output devices 1920, and a network interface subsystem 1916. These input devices and output devices allow for user interaction with controller 1900. The network interface subsystem 1916 provides an interface to an external network and couples to corresponding interface devices in other computer systems. For example, the motion controller 180 of system 100 may share one or more features with controller 1900 and may be, for example, a conventional computer, digital signal processor, and/or other computing device.
The user interface input devices 1922 may include a keyboard, a pointing device (such as a mouse, trackball, touchpad, or tablet), a scanner, a touch screen incorporated into the display, an audio input device (such as a voice recognition system, microphone, and/or other types of input devices). In general, use of the term "input device" is intended to include all possible types of devices and ways to input information into controller 1900 or onto a communication network.
User interface output devices 1920 may include a display subsystem, a printer, a facsimile machine, or a non-visual display (such as an audio output device). The display subsystem may include a Cathode Ray Tube (CRT), a flat panel device such as a Liquid Crystal Display (LCD), a projection device, or some other mechanism for creating a visible image. The display subsystem may also provide non-visual displays, such as via audio output devices. In general, use of the term "output device" is intended to include all possible types of devices and ways to output information from controller 1900 to a user or to another machine or computer system.
Storage subsystem 1924 stores programming and data constructs (e.g., software modules) that provide and support some or all of the functionality described herein. For example, storage subsystem 1924 may include a CAD model of a part to be additively manufactured and logic for identifying deposition locations to adjust the position of the integrated metal deposition head during an additive manufacturing process.
Software modules are typically executed by the processor 1914 either alone or in combination with other processors. Memory 1928 used in the storage subsystem may include a plurality of memories including: a main Random Access Memory (RAM)1930 for storing instructions and data and a Read Only Memory (ROM)1932 in which fixed instructions are stored during program execution. File storage subsystem 1926 may provide permanent storage for program and data files and may include a hard disk drive, a floppy disk drive along with associated removable media, a CD-ROM drive, an optical disk drive, or removable media cartridges. Modules implementing the functionality of certain embodiments may be stored in storage subsystem 1924 through file storage subsystem 1926, or in other machines accessible to processor(s) 1914.
Bus subsystem 1912 provides a mechanism for the various components and subsystems of controller 1900 to communicate with one another as desired. Although bus subsystem 1912 is shown schematically as a single bus, alternative embodiments of the bus subsystem may use multiple buses.
The controller 1900 may be of various types including a workstation, a server, a computing cluster, a blade server, a server farm, or any other data processing system or computing device. As the nature of computing devices and networks continues to change, the description of the controller 1900 depicted in fig. 19 is intended only as a specific example to illustrate some embodiments. Many other configurations of controller 1900 are possible with more or fewer components than the controller depicted in fig. 19.
Fig. 20 illustrates two views of one embodiment of the integrated deposition head 2000 with all frames or covers unattached and with an integrated wire feeder. The first view shows the deposition head 2000 from the motor side of the wire feeder 2010 with a motor 2015 and an integrated wire feeder circuit control board 2016 to control the motor 2015. In one embodiment, the plate 2016 helps control a "push-pull" wire feed operation to maintain the same feed rate. In one embodiment, the plate 2016 is also used to control a gas solenoid to control the flow of gas. The second view shows the deposition head 2000 with drive rollers 2017 from the drive roller side of the wire feeder 2010. The laser machining subsystem 2020 is shown in assembly along with a nose cone 2030 below the wire feeder 2010. According to one embodiment, the laser processing subsystem 2020 includes a laser focusing device that operates in the infrared spectrum and provides an output power of between 1 kilowatt (kW) and 15 kilowatts. For example, at 4kW, it is expected that deposition rates between 2.0 and 3.5 kW/hr may be achieved.
Fig. 21 illustrates, similar to fig. 5, one embodiment of an internal configuration of a portion 2100 of the integrated deposition head 2000 of fig. 20, showing various component details. Portion 2100 includes deposition head cladding 2101, clamp 2105, flexible shoe 2110, clamp with seal 2115, and thermal/electrical insulation plate 2120. Portion 2100 further includes wire entry conditioning unit 2125, water cooled contact block 2130, nose cone locking collar 2135, supplemental gas/tip cooling gas conduit 2140, and nose cone 2145. Portion 2100 generates and emits a laser beam 2150 and feeds a filler wire 2155. The portion 2100 also includes a wire contact tip 2160, cooling passages 2165, a wire conduit tube and liner 2170, and a hot wire process conductive lead (in the background) 2175. In one embodiment, the conductive lead 2175 provides current to the wire guide tube and liner 2170 and is water cooled, allowing the conductive lead 2175 to have a relatively small diameter. The portion 2100 further includes a focusing optic exit tip 2180, a focusing optic assist gas inlet 2185, an imperforate focusing optic cover slide 2190, and a laser light focusing optic module 2195.
The cover slide 2190 helps prevent unwanted materials/particles (e.g., spatter, smoke) from reaching the focusing optics module 2195. The gas (e.g., argon) entering the focusing optics auxiliary gas inlet 2185 also helps to prevent unwanted materials/particles (e.g., spatter, smoke) from reaching the focusing optics module 2195. The clamp 2105, clamp with seal 2115, and flexible boot 2110 help keep the gas sealed in the desired area of portion 2100, without allowing ingress of ambient air. This allows the nose cone portion of deposition head 2000 to move relative to the upper portion of portion 2100 for the purpose of moving filler wire 2155 relative to laser beam 2150. The water cooled contact block 2130 has passages 2165 within the block to allow circulation of a fluid (e.g., water) to cool the nose cone region.
The primary purpose of the insulating plate 2120 is to prevent electrical conduction back through the structural frame of the additive deposition head and through robots, controllers, or related system wiring. The wire entry adjustment unit 2125 allows for fine tuning of the feed angle of the deposition process, where a particular application may show slight deposition performance benefits at slightly different feed angles due to differences in the physical and thermal properties of the various different alloys employed by the process. The nose cone locking collar 2135 allows for the removal/installation of various nose cones (e.g., via threaded connectors). The supplemental gas/tip cooling gas conduit 2140 provides gas to help cool the contact tip region and flood the region with gas. Generally, in the region of the nose cone, the gas from the supplemental gas/tip cooling gas conduit 2140 will be cooler than the gas from the gas inlet 2185. Holes or orifices at the end of the supplemental gas/tip cooling gas conduit 2140 are used to focus the gas to form a straight gas flow. The focusing optic exit tip 2180 helps to generate bursts of gas to help prevent material/particles (e.g., spatter, smoke) from returning to the laser light focusing optic module 2195.
Fig. 22 illustrates a hot wire processing subsystem 2200 of one embodiment of an integrated deposition head 2000 having a wire feeder 2010 with drive rollers 2017. The wire processing subsystem 2200 is configured for feeding a filler wire 2155 through a wire guide tube and liner 2170 to achieve an angle relative to a longitudinal direction (e.g., vertical) as previously described herein. Fig. 23 illustrates a laser processing subsystem 2300 of one embodiment of the integrated deposition head 2000 showing a laser focusing apparatus 2350 with a laser light focusing optics module 2195, a focusing optics lid slide 2190 (not perforated), and a focusing optics assist gas inlet 2185. Laser processing subsystem 2300 is configured to generate laser beam 2150. FIG. 24 illustrates one embodiment of the laser focusing apparatus 2350 of the laser processing subsystem 2300 of FIG. 23, showing the laser light focusing optics module 2195, the focusing optics assist gas inlet 2185, the focusing optics cover slide 2190, and the focusing optics outlet tip 2180. Fig. 25 illustrates a deposition head structure frame 2500 of one embodiment of the integrated deposition head 2000 configured to surround the internal components of the integrated deposition head 2000. In one embodiment, the structural frame 2500 includes a removable cover configured to allow access to certain internal components of the integrated deposition head 2000.
Although the disclosed embodiments have been illustrated and described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the various aspects of the subject matter. Therefore, the disclosure is not limited to the specific details or illustrative examples shown and described. Accordingly, the present disclosure is intended to embrace alterations, modifications, and variations that fall within the scope of the appended claims to meet statutory subject matter requirements of 35 u.s.c. § 101. The foregoing description of specific embodiments has been presented by way of example. Given the disclosure provided, those skilled in the art will not only understand the general inventive concepts and attendant advantages, but will also find apparent various changes and modifications to the disclosed structures and methods. Accordingly, it is sought to cover all such changes and modifications as fall within the spirit and scope of the general inventive concept as defined by the appended claims and their equivalents.
