JP2023511476A - Blue laser metal additive manufacturing system - Google Patents

Abstract

A high resolution additive manufacturing apparatus and method using a digital mirror device such that image segments that create an image of the entire object are projected onto a target area to deliver a working laser beam to the overall image of the object to be built. A method and system for additive manufacturing using a DMD in the laser beam path. Using a preheated laser beam in combination with a shaping laser beam with a DMD along the shaping laser beam path. [Selection drawing] Fig. 9

Description

This application subscribes to (i) the benefit of, and priority to, the filing date of U.S. Provisional Application No. 62/931,734, filed November 6, 2019, under 35 U.S.C. §119(e)(1); claims the benefit of rights, the entire disclosure of which is hereby incorporated by reference.

The present invention relates to laser processing of materials, and more particularly to laser building of materials, including laser additive manufacturing processes using laser beams having wavelengths from about 350 nm to about 700 nm.

Infrared (IR)-based additive manufacturing systems (e.g., having wavelengths greater than 700 nm, particularly greater than 1,000 nm) suffer from, among other things, two shortcomings: build volume and build speed. It has the disadvantage of limiting both build speed. In such IR systems, the build volume is limited by the scanning system and the limiting size of the spot created for a given focal length collimating and f-theta lens. For example, in such a conventional IR system, using a 14 mm focal length collimating lens and a 500 mm focal length f-theta lens, the spot size is approximately 350 μm for a diffraction-limited IR laser beam. This gives an addressable footprint of approximately 85 mm x 85 mm on the build source material, e.g. grant or prescribe a finite limitation of A second limitation on build speed for IR laser systems is the absorption of the laser beam by the material. Originally, most build materials had modestly low reflectivity for wavelengths in the infrared spectrum, but in additive manufacturing, gold, silver, platinum, copper, aluminum, and Problems were encountered with using these IR highly reflective build materials in IR additive manufacturing when metals such as their alloys began to be used. As a result, the coupling of infrared laser energy to the build raw material, e.g., powder layer or particles, with a significant portion of that energy reflected away from or back into the build raw material or deeper into the build raw material, Limited. These limitations are further linked or combined together to exacerbate the problems and shortcomings of IR lamination systems. The finite penetration depth of the infrared laser light thus determines the optimum layer thickness and consequently limits the processing resolution. Thus, IR laser systems are limited in layer thickness and thus resolution due to their reflectivity to typical build materials.

As used herein, unless otherwise specified, "UV," "ultraviolet," "UV spectrum," "UV portion of the spectrum," and like terms are to be given the broadest meaning, and are to be given the broadest meaning of about It includes light of wavelengths from 10 nm to about 400 nm and from 10 nm to 400 nm.

As used herein, unless otherwise specified, the terms "visible," "visible spectrum," "visible portion of the spectrum," and like terms are to be given their broadest meaning, ranging from about 380 nm to about It includes light with wavelengths of 750 nm and 400 nm to 700 nm.

As used herein, unless otherwise specified, the terms "blue laser beam", "blue laser", and "blue" should be given the broadest meaning and generally laser beams, laser beams, lasers Reference is made to systems providing light sources, eg lasers and diode lasers, which provide, eg propagate, laser beams or light having wavelengths from 400 nm (nanometers) to 500 nm and from about 400 nm to about 500 nm. Blue lasers include wavelengths of 450 nm, about 450 nm, 460 nm, about 460 nm. Blue lasers can have bandwidths from about 10 pm (picometers) to about 10 nm, about 5 nm, about 10 nm, and about 20 nm, as well as higher and similar values.

As used herein, unless otherwise specified, the terms "green laser beam", "green laser", and "green" should be given the broadest meaning and generally laser beams, laser beams, lasers Reference is made to systems providing light sources, eg lasers and diode lasers, that provide, eg propagate, laser beams or light having wavelengths from 500 nm to 575 nm and from about 500 nm to about 575 nm. Green lasers include wavelengths of 515 nm, about 515 nm, 532 nm, about 531 nm, 550 nm, about 550 nm. Green lasers can have bandwidths from about 10 pm to about 10 nm, about 5 nm, about 10 nm, and about 20 nm, as well as greater and similar values.

As used herein, and unless otherwise specified, the term "digital mirror device" should be given its broadest meaning and includes properties, surface features, structures, etc., for directing or redirecting light, including laser beams. Any device may be included, including a deformable mirror that can direct or redirect a laser beam by altering its surface contour, and/or reflection, refraction, or both. The term digital mirror device includes digital micromirror device (“DMD”) and microelectromechanical system (“MEMS”).

As used herein, unless otherwise specified, the terms “DMD,” “digital micromirror device,” “microelectromechanical system,” “MEMS,” and similar such terms are given the broadest meaning. In general, the device may include a large number of small reflective surfaces, such as mirrors, that can be moved or repositioned. Generally, the small reflective surface has, for example, a square, diamond-shaped, rectangular, circular, or elliptical shape and has a cross-section (maximum cross-section) of from about 1 μm to about 50 μm, typically from about 5 μm to about 25 μm, More specifically, it can be about 5 μm, about 10 μm, about 15 μm, and larger and smaller sizes can also be used. These devices have from about 10 to about 1,000,000 or more movable reflective surfaces; tens, hundreds, thousands, tens of thousands of movable reflective surfaces; Movable reflective surfaces; from about 200,000 to about 500,000 movable reflective surfaces; typically hundreds of thousands of movable reflective surfaces. Generally, each of the reflective surfaces has individually controllable tilt degrees of freedom and can have 2, 3, or more positions, as well as about ±5 degrees to about ±25 degrees from its axis. degrees, typically from about ±10 degrees to ±15 degrees, ±10 degrees, ±12 degrees, and ±15 degrees of off-axis tilt motion.

As used herein, unless otherwise specified, the term "non-macro-mechanical motion beam steering" device or system refers to a large mechanical motion beam steering device or system for directing a laser beam. Devices or systems that do not use or have devices that steer the beam in a dynamic motion, specifically devices that do not use galvo mirrors, gimbals, fast steering mirrors, Risley prisms, or rotating polygons to direct the laser beam or system.

In general, as used herein, the terms "about" and the symbol "~" are subject to ±10% variation or range, experimental or instrumental error associated with obtaining the stated values, unless otherwise specified. , and preferably larger variations or ranges thereof.

As used herein, room temperature is 25° C. unless otherwise specified. Also, the standard environmental temperature and standard environmental pressure are 25° C. and 1 atmosphere. Unless otherwise specified, all tests, test results, physical properties, and values dependent on temperature, pressure, or both are given at standard ambient temperature and pressure. can also include a viscosity of 000.

As used herein, unless otherwise stated, recitation of ranges of values herein merely serves as a shorthand method of referring individually to each separate value falling within the range. be. Unless stated otherwise herein, each individual value within a range is incorporated into the specification as if they were individually listed herein.

Typically, the methods currently employed in additive manufacturing use an infrared laser and a galvanometer to scan the laser beam in a predetermined pattern over the surface of the powder bed. The IR laser beam is of sufficient intensity to cause a keyhole welding process that melts and fuses the liquefied powder to the underlying layer or base. This approach has several limitations that limit the speed of processing. For example, a single laser beam is used to scan the surface and the build speed is limited by the galvanometer's maximum scan speed (7 m/s). Manufacturers have tried to make heavy use of IR technology, typically believing it to be the only visible wavelength, and thus by incorporating two or more IR lasers/galvanometers into the system, the two work in tandem. Attempts to overcome this limitation by either printing a single part or being able to operate independently to print multiple parts in parallel have met with limited success. do not have. These efforts, aimed at improving the throughput of additive manufacturing systems, have focused exclusively on IR, have met with limited success, and have not met the long-standing need for improved additive manufacturing. do not have.

Another example limitation in IR processes is the volume limit that can be accommodated by the IR laser/galvanometer system. In a fixed head system, the build volume is determined by the focal length of the f-theta lens, the scan angle of the galvanometer, the wavelength of the IR laser, and the beam quality of the infrared laser. For example, with a 500 mm f-theta lens, an IR laser produces a spot size of about 50 μm for a diffraction limited infrared laser. When the laser beam is operating at 100 watts of optical power, the intensity of the beam is greater than that required to initiate the keyhole welding mode. The keyhole welding mode produces a plume of vaporized material that must be removed out of the path of the laser beam by cross jets or the laser beam will be scattered and absorbed by the vaporized metal. Also, the keyhole mode of welding forms a hole in the surface of the liquid metal, and the hole is maintained by the vapor pressure of the vaporized metal, thus expelling material other than the vaporized metal from the keyhole. This material is called spatter and results in molten material depositing elsewhere on the build plane, which can cause defects in the final product. Manufacturers of additive manufacturing systems have had limited success in developing rapid prototyping equipment to meet long-standing demand and meet the demands necessary to manufacture commercial or real-world parts. not. Achieving this requires a breakthrough in component patterning methods not achieved prior to the present invention.

In general, a problem and drawback with IR processes and systems is the requirement or desire to fuse powders in a keyhole welding mode. This is typically due to the use of a single beam to process the powder. When the laser beam is operating at 100 watts of optical power, the intensity of the beam is greater than that required to initiate the keyhole welding mode. The keyhole welding mode produces a plume of vaporized material that must be removed out of the path of the laser beam by cross jets or the laser beam will be scattered and absorbed by the vaporized metal. Also, the keyhole mode of welding forms a hole in the surface of the liquid metal and the hole is maintained by the vapor pressure of the vaporized metal so that material such as vaporized metal is expelled from the keyhole. This material is called spatter and results in molten material depositing elsewhere on the build plane, which can cause defects in the final product.

Recent work by Lawrence Livermore National Laboratories using an Optically Activated Light Valve (OALV) attempts to address these IR limitations. rice field. OALVs are high power spatial light modulators used to generate light patterns using high power lasers. The pattern on the OALV is created with a blue LED or laser light source from a projector, the output from four laser diode arrays is transmitted through a spatial light modulator and used to heat the image to its melting point, and the keyhole A Q-switched IR laser is required to initiate welding. IR lasers are used to initiate welds in keyhole mode, especially required for copper or aluminum materials when fusing these materials. This keyhole welding process typically produces spatter, part porosity, and high surface roughness. Thus, OALV systems, like typical IR systems, do not eliminate the side effect of keyhole initiation of the build process. Avoiding the keyhole welding step altogether would be nice, but the technology has not been able to overcome this problem or provide a solution to it. This drawback arises primarily because the absorption properties of many metals at IR wavelengths are very low, requiring a high peak power laser to initiate the process. Since OALVs are transparent only in the IR region of the spectrum, it is not suitable to build or use this type of system using a visible laser source as the high energy source. The cost of components for this system, especially the custom OALV, is very high.

Conventional metal-based additive manufacturing equipment either sprays a binder into the powder layer followed by a high temperature consolidation step, or scans a high power single-mode laser beam rapidly over the powder layer with a galvanometer system. , is very limited in that it is based on either Both of these systems have significant drawbacks that technology has not been able to overcome. The former system is capable of mass production of parts, but it has large tolerances due to part shrinkage during the consolidation process. The latter process is limited in build speed by the scanning speed of the galvanometer, which limits the maximum power level laser that can be used, and consequently limits build speed. Manufacturers of scan-based additive manufacturing systems have attempted to overcome this limitation by building machines with multiple scanheads and laser systems, but this has not provided an adequate solution to these problems. . This certainly increases throughput, but the scaling law is linear, in other words a system with two laser scanners can only build twice as many parts as a system with one scanner. , or can only build one part at twice the speed. Accordingly, there is a need for a high throughput laser-based metal additive manufacturing system that does not suffer from the limitations of existing systems.

The background art is intended to introduce various aspects of technology that may be related to embodiments of the invention. As such, the above description in this section provides a framework for a better understanding of the invention and should not be taken as an admission of prior art.

The present invention solves these and other problems with IR additive manufacturing systems and processes and addresses these and other long-standing and future needs so that additive manufacturing processes and systems become more widespread. . The present invention addresses these problems and needs by providing, among other things, the articles of manufacture, apparatus, and processes taught and disclosed herein.

Accordingly, there is provided an additive manufacturing system for metals, the system comprising: a laser source for providing a processing laser beam; a digital mirror device in optical communication with the laser source, the laser source being the processing laser beam; propagate along the first laser beam path to the digital mirror device; in control communication with the memory device and in control communication with the GUI; and a control system in control communication, in control communication with the laser light source, and in control communication with the stage, the memory device storing a plurality of image segments (image the stage comprises a motor and a digital mirror device; the digital mirror device is adapted to project the processing laser beam along the second laser beam path to the target area in a predetermined pattern; a predetermined pattern comprising image segments; a control system comprising instructions such that the instructions synchronize movement of the stage and projection of the image segments onto the target area; An image segment is projected onto a target area to deliver a working laser beam to the entire image of the object to be shaped to build the object from the powder.

Further provided are systems, devices, and methods having one or more of the following features. The digital mirror device is selected from the group consisting of a digital micromirror device and a microelectromechanical system; the processing laser beam has a wavelength in the range of 300 nm to 800 nm; the processing laser beam has a wavelength in the range of 300 nm to 600 nm. the processing laser beam has a wavelength in the range of 400 nm to 500 nm; the processing laser beam has a wavelength in the range of 500 nm to 600 nm; the digital mirror device is air-cooled; , a microchannel cooler, a water heat exchanger, and a Peltier cooler; further comprising a strip radiant heater for maintaining the temperature of the build chamber; and a heated build plate. further comprising a separate auxiliary laser for heating said powder layer only where the pattern will impinge; further comprising an inert atmosphere; the predetermined pattern has a power density of several kW; , a system that manipulates the beam without significant mechanical motion; the metal powder is selected from the group consisting of gold, silver, platinum, copper, aluminum, and alloys thereof.

Additionally, methods of operating any of these systems for building objects from metal powder are provided.

Further provided is a 3-D system that uses a spatial light modulator, an array of spatial light modulators, and both to form an energy pattern onto a powder layer, a plastic or nylon material. Either directly fuse or control the temperature of the area just below the melting point of the area scanned by the main laser. It is theorized that the reason for considering this approach is to improve the energy efficiency of the system. Currently, either radiant heaters, zone radiant heaters, or build plate temperature control systems are used to preheat the entire bead being processed. By reducing the size of the preheated area, the overall energy consumption of the system can be reduced.

Also, one embodiment of the present invention is based on using a digital mirror device spatial light modulator, an array of digital mirror devices, or both, with a power density of 100 W/m when operating in continuous mode. It must be limited to cm ² or less, which is sufficient to melt and flow plastics, but not enough to melt and fuse metals.

A laser and spatial light modulator, an array of spatial light modulators, and both to form an energy pattern on a powder metal layer that is fused to an underlying layer, and step-and-repeat the image across the powder layer. a gantry system for, a movement control system for, an elevator for moving the part downward as each layer is fused, a powder distribution system that allows both diffusion and compaction of the powder, and an airtight build chamber. An additive manufacturing system for metal is provided using:

Further provided are lasers, systems and methods having one or more of the following features. lasers with wavelengths in the range of 300-400 nm; lasers with wavelengths in the range of 400-500 nm; lasers with wavelengths in the range of 500-600 nm; lasers with wavelengths in the range of 600-800 nm; The laser is homogenized by a light guide, a microlens homogenizer, a diffractive element, and combinations and variations thereof; The laser is time-shared between multiple printheads or multiple printer systems; The light modulator is a digital micromirror device (DMD) array, which is an array of micromirrors; said spatial light modulator is any class of spatial light modulator capable of handling power levels from a few watts to a few kW said DMD is air cooled; said DMD is water cooled; said DMD is water cooled by a water heat exchanger such as a microchannel cooler; said DMD is cooled by a Peltier cooler a radiant heater strip for maintaining the temperature of the build chamber; a heated build plate; a thermocouple embedded in the build plate for monitoring or controlling the temperature of the build plate; software for determining the optimal build plan; separate auxiliary laser for heating the powder layer only where the pattern is irradiated; an inert atmosphere for building the part use an inert atmosphere to keep the optics in the system clean; the laser-spatial modulator combination has a power density of several W/cm ² required to fuse metals An image is produced on the powder layer.

Furthermore, a laser and a spatial light modulator for forming a pattern on a powder metal layer, using for example a conduction mode welding process with the aid of a second laser for preheating the powder layer. a laser and a spatial light modulator, an array of spatial light modulators, and both to form an energy pattern on a powder metal layer that is fused to an underlying layer by a gantry system for continuously printing the image by step-and-repeat and scrolling the image across the DMD synchronized with the movement of the head; a motion control system; and when each layer is fused. An additive manufacturing system for metal using an elevator to move the part downward to the bottom, a powder distribution system that allows both diffusion and compaction of the powder prior to fusion, and an airtight build chamber. is provided.

We also characterize build plates that include a variety of metal materials, including aluminum, anodized aluminum, titanium, steel, stainless steel, nickel, copper, combinations thereof, and other materials that may be the same or different materials as the powder. These systems and methods are provided.

Further provided are lasers, systems and methods having one or more of the following features. The laser is a blue laser at about 450 nm; the laser is a laser with a wavelength in the range of 300-400 nm; the laser is a laser with a wavelength in the range of 400-500 nm; laser with a wavelength in the range of 600 nm; said laser is a laser with a wavelength in the range of 600-800 nm; said laser is an infrared laser in the range of 800 nm-2000 nm; homogenized by a lens homogenizer; the laser is time-shared between multiple printheads or multiple printer systems; there is an auxiliary laser; the auxiliary laser is a 450 nm blue laser; , a laser with a wavelength in the range of 300-400 nm; said auxiliary laser is a laser with a wavelength in the range of 400-500 nm; said auxiliary laser is a laser with a wavelength in the range of 500-600 nm; is a laser with a wavelength in the range of 600-800 nm; said auxiliary laser is an infrared laser in the range of 800 nm-2000 nm; the auxiliary laser is time-shared among multiple printheads or multiple printer systems; the system has a spatial light modulator; the spatial light modulator is a digital micromirror device (DMD) the spatial light modulator is any class of spatial light modulator capable of handling power levels from a few watts to a few kW; the system includes a heated build plate; the system includes a pyrometer or FLIR camera for monitoring or controlling the temperature of the build plate; the system measures the temperature of the build plate including thermocouples or RTDs embedded in the build plate for monitoring or controlling; the system includes software for determining the optimal build plan; the system provides an inert atmosphere for building the part; the system uses an inert atmosphere to keep the optics in the system clean; the system produces images with power densities from a few watts to a few kilowatts on the powder layer laser-spatial modulator have a combination.

Also provided are these lasers, systems, and methods having one or more of the following features. a second laser, said second laser being used for preheating in said system and having a power density of a few Watts to several kWatts on said powder layer of said spatial filter laser system; The laser system has a powder bed with a power density of a few watts to a few kilowatts to produce an area that overlaps the image.

Additionally, a laser and spatial light modulator for forming a pattern on a powder metal layer that fuses with an underlying layer, a gantry system for stepping and repeating said image across said powder layer, and a motion control system. and an elevator to move the part downward as each layer is fused, a powder distribution system that allows both diffusion and compaction of the powder prior to fusion, and an airtight build chamber. , an additive manufacturing system for metal is provided.

In addition, these systems, subsystems, and methods are provided that have one or more of the following features. The laser is a blue laser at about 450 nm; the laser is a laser with a wavelength in the range of 300-400 nm; the laser is a laser with a wavelength in the range of 400-500 nm; is a laser with a wavelength in the range of 600 nm; said laser is a laser with a wavelength in the range of 600-800 nm; said laser is an infrared laser in the range of 800 nm-2000 nm; The auxiliary laser is time-shared between multiple printheads or multiple printer systems; The spatial light modulator is an array of micromirrors, a digital micromirror device (DMD ); said spatial light modulator is any class of spatial light modulator capable of handling power levels from a few watts to several kW; said DMD is air-cooled; water cooled by a water heat exchanger such as a microchannel cooler; the DMD is cooled by a Peltier cooler; the system includes radiant strip heaters to maintain the temperature of the build chamber; A system includes a heated build plate; the system includes a pyrometer or FLIR camera for monitoring or controlling the temperature of the build plate; the system includes a temperature for monitoring or controlling the temperature of the build plate. thermocouples or RTDs embedded in the build plate; the system includes software for determining the optimal build plan; the system scans the powder layer only where the pattern is irradiated; including a separate auxiliary laser for heating; said system uses an inert atmosphere for shaped parts; uses an inert atmosphere to keep optical components within said system clean; said system produces an image with a power density of several kW on the powder layer.

Further, a laser and a spatial light modulator for forming a pattern on a powder metal layer, said powder metal layer being under the assistance of a second laser for preheating said powder layer. a gantry system for stepping and repeating the image across the powder layer; a motion control system; and moving the part downward as each layer is fused. An additive manufacturing system for metal is provided that uses an elevator for movement, a powder distribution system that allows diffusion and compaction of the powder prior to fusion, and an airtight build chamber.

Still further, multiple lasers and multiple spatial light modulators for forming a large pattern on a powder metal layer that fuses with an underlying layer; A gantry system, a motion control system, an elevator to move the part downward as each layer is fused, a powder distribution system to allow diffusion and compaction of the powder prior to fusion, and an airtight build chamber. An additive manufacturing system for metal is provided using and.

Also, a plurality of lasers and a plurality of spatial light modulators for forming a checkerboard pattern of image and non-image areas on a powder metal layer that fuses with an underlying layer, and stepping the image across the powder layer. A gantry system for and-repeat, a motion control system, an elevator to move the part downward as each layer is fused, and a powder distribution system that allows the powder to be spread and compressed prior to fusing. and an airtight build chamber are provided.

still further, said exposure time for generating an image and moving said image across said DMD to generate a still image on said moving gantry system to print said pattern on said material to be fused; A combination of a laser and a spatial light modulator is provided that causes the . Still further, an additive manufacturing system for forming a metal object from a metal powder, said system comprising: a laser light source for providing a shaping laser beam along a shaping laser beam path; heating means for heating the metal powder; A digital micromirror device (DMD) on the laser beam path, the shaping laser beam adapted to be directed to the DMD, the DMD from the DMD along the laser beam path to an optical assembly. a digital micromirror device (DMD), which produces a reflected 2-D image pattern; and directs the laser beam at the metal powder such that the 2-D image pattern is transmitted to the metal powder. An additive manufacturing system is provided comprising: an optical assembly;

In addition, these systems, subsystems, and methods are provided that have one or more of the following features. said heating means is selected from the group consisting of an electric heater, a radiant heater, an IR heater and a laser beam; said heating means is a laser beam having a wavelength within the blue wavelength range; forming a layer; said laser beam having a wavelength selected from the group consisting of blue and green; said laser beam being selected from the group consisting of about 450 nm, about 460 nm, about 515 nm, about 532 nm, and about 550 nm said laser light source has a power of about 1 kW to about 20 kW; said 2-D image delivers a peak power density to said metal powder of about 2 kW/cm ² to about 5 kW/cm ² ; the DMD has a maximum average power density level; the peak power density level of the 2-D image on the metal powder is at least 500 times greater than the maximum average power density level of the DMD; said peak power density level of said 2-D image on said metal powder being at least 1,000 times greater than said maximum average power density level of said DMD; said heating means comprising: heating the powder to within 200° C. of the melting point of the metal powder; heating the powder to within 100° C. of the melting point of the metal powder; heating the powder to within 100° C. of the melting point of the metal powder; the heating means heats the powder to within 600°C of the melting point of the metal powder; the heating means heats the powder to within 400°C of the melting point of the metal powder the heating means heats the powder to within 600° C. of the melting point of the metal powder and maintains the powder at that temperature; the heating means heats the powder to the heating to within 200° C. of the melting point of the metal powder and maintaining said powder at that temperature; having a second laser light source providing a second shaping laser beam along a second shaping laser beam path; a second digital micromirror device (DMD) on a second laser beam path, wherein the second shaping laser beam is directed to the second DMD, the second DMD from the second DMD; generating a second 2-D image pattern that is reflected along the second laser beam path to a second optical assembly; the 2-D image pattern is delivered to a first area of the metal powder; A second 2-D image pattern is a second area of the metal powder. said first area and said second area are different; said first area and said second area are adjacent.

Additionally, systems, subsystems, and methods are provided having one or more of the following features. The DMD array is optimized for at least one of the following wavelengths: blue wavelength region, 400 nm, about 440 nm, 450 nm, about 450 nm, 460 nm, about 460 nm; green wavelength region, 515 nm, about 515 nm, 532 nm; Red wavelength region from about 532 nm, 600 nm to 700 nm.

Additionally, systems, subsystems, and methods are provided having one or more of the following features. The shaping laser beam has a wavelength selected from at least one of the following wavelengths. Blue wavelength range, 400 nm, about 440 nm, 450 nm, about 450 nm, 460 nm, about 460 nm, green wavelength range, 515 nm, about 515 nm, 532 nm, about 532 nm, red wavelength range from 600 nm to 700 nm.

Still further, an additive manufacturing system for forming metal objects from metal powders, the system comprising: a laser light source for providing a shaping laser beam along a shaping laser beam path; a second laser beam for providing a heating laser beam; a digital micromirror device (DMD) on said laser beam path, said shaping laser beam adapted to be directed at said DMD, said DMD extending from said DMD along said laser beam path a digital micromirror device (DMD) that produces an image that is reflected onto an optical assembly using a digital micromirror device (DMD); An additive manufacturing system is provided, comprising:

Still further, a 2-D pattern with an optimized temporal or pattern grayscale is projected onto the powder layer so that the heat transforms the molten metal puddle into sharper shape transitions and more A laser-spatial light modulator combination is provided that allows it to be manipulated into the desired build shape to produce high density parts.

1 is a perspective view of one embodiment of an additive manufacturing system according to the present invention; FIG.

1 is a cutaway perspective view of an embodiment of a laser DMD printhead in accordance with the present invention; FIG.

FIG. 4 is a chart comparing pulse width and repetition rate for a given output embodiment of the present invention; FIG.

4 is a photograph of a pattern printed using an embodiment of a laser spatial light modulator according to the present invention; 4 is a photograph of a pattern printed using an embodiment of a laser spatial light modulator according to the present invention;

1 is a chart comparing the absorption of blue light into a powder layer in an embodiment of a system according to the invention to an IR laser system;

1 is a schematic diagram of an embodiment of the superposition of a preheating beam and a shaping laser beam according to the present invention; FIG.

4 is a flow diagram of an embodiment of the timing of systems and methods according to the present invention;

4 is a flow diagram of an embodiment of the timing of systems and methods according to the present invention;

1 is a schematic diagram of an embodiment of a multi-DMD laser printer system according to the present invention; FIG.

1 is a schematic diagram of an embodiment of a multi-DMD laser printer system according to the present invention; FIG.

1 is a schematic diagram of one embodiment of a printing system configured with a digital mirror device in accordance with the present invention showing scrolling of an image across a target substrate when the motion system is in motion; FIG.

FIG. 11 is a photograph of one embodiment of a build pattern from a powder starting material at various power densities on the powder layer to achieve good fusing and restoration of the image in metal according to the present invention; FIG. 11 is a photograph of one embodiment of a build pattern from a powder starting material at various power densities on the powder layer to achieve good fusing and restoration of the image in metal according to the present invention;

1 is one embodiment of image segmentation used to map a single layer of a direct-to-copper printed part in accordance with the present invention;

13B is one embodiment of copper part fabrication using the mapping of FIG. 13A in accordance with the present invention;

1 is a graph showing one embodiment of blue laser light absorption versus IR laser light absorption in a copper powder build material according to the present invention.

4 is a graph showing one embodiment of build speed versus laser power for blue laser light according to the present invention.

1 is a schematic diagram of one embodiment of a control system for use in the system and method of the present invention; FIG.

Generally, the present invention relates to laser processing of materials, laser processing by matching a pre-selected laser beam wavelength to the material being processed so as to have a higher or increased level of absorption by the material, larger A system configuration that provides speed, greater efficiency, and a larger size of objects to be built, and a laser beam that has a high absorption by the starting raw material, especially when the raw material is a large structure, part, component, or article. with laser additive manufacturing.

In one embodiment of a printing system configured with a digital mirror device, an image is scrolled across the target as the stage comprising the digital mirror device is moved. In this embodiment, a 3-D image of an object (eg, a part such as a copper part) is provided to the system. The image is preferably a 3-D digital image or bitmap of the part to be built. This 3-D image is divided into a series of layers and other segments. The image segments are stored in storage associated with the controller and control system for the printing system. The image segments are ordered according to stage motion (eg, X direction, horizontal direction). The stage includes a digital mirror device in optical communication with the laser light source. Then, the image is reproduced in a predetermined manner according to the movement of the stage. That is, image reproduction is synchronized with stage motion. In this manner, segmented portions of the synchronized image are delivered to a build material, such as copper powder, to build an object in the shape of the original 3-D image.

Thus, although not limited by this example, the digital mirror device may direct image segments onto the build material as the stage is moved to shape the build material into the shape of the original 3-D image. is understood as playing back to

Figures 12A and 12B show an example of the role that proper power density on the powder layer plays in providing good fusing and restoration of the image in metal. The shaped object is a series of raised copper letters.

The printed object of FIG. 12A was printed using a 150 mm objective focus lens that demagnifies the image by a factor of 5.6. The speed of movement of the stage in the X direction and two different laser pulse lengths are shown on the right side of the photograph.

The printed object in FIG. 12B was printed using a 100 mm objective focus lens that demagnifies the image by a factor of 9. The speed of movement of the stage in the X direction and three different laser pulse lengths are shown on the right side of the picture.

A DMD of 800×600 pixels was used to build the objects of FIGS. 12A and 12B. The smallest features printed are 0.1 mm wide. The character height in FIG. 12B is about 0.65 mm.

A comparison of Figures 12A and 12B shows that the higher power density used in Figure 12B results in better speed and better quality (eg, tolerance) of the built object. Shorter focal length lenses increase the intensity of the laser image on the build material. A shorter focal length lens can reduce or eliminate the need for a preheating step, eg, a preheating laser, in some embodiments. A shorter focal length lens can provide a 4x, 5x, 6x or more improvement in speed and build object quality over a longer focal length lens.

In embodiments of the system, the preferred focal length of the focusing lens, which in embodiments is positioned after the laser beam exits the digital mirror device as a laser pattern, is about 100 mm, about 50 mm to about 150 mm, and greater or less. can be length.

Figures 13A and 13B show examples of image segmentation used to map a single layer of a direct-to-copper printed part. In Figure 13A, the image of the tensile test bar (only the top is shown) is divided into a number of different image segments. Thus, for example, section 1300 of the image corresponds to image segment 1300a, section 1301 corresponds to image segment 1301a, and section 1302 corresponds to image segment 1302a.

FIG. 13B is a photograph of a tensile test bar built by scrolling image segments as a laser beam pattern onto the build material synchronized with stage motion. Image 1350 is of a layer of tensile bars shaped along the axis. Image 1351 is of a layer of tensile bars shaped along the axis. Image 1352 is of a layer of tensile bars shaped along the axis. Parts can be shaped along a long axis, a single axis, a transverse axis, and combinations and variations thereof. Shaped along an axis means that horizontal (X-direction) motion is of the stage along that axis.

FIG. 14A shows that the blue light absorption into the powder layer is rapid with a very short mean free path, which means that when blue light is used, compared to IR light, the spot or image This means that the spread of light of high output light to the outside is small.

FIG. 14B shows build speed as a function of average power density and laser power on the DMD. For example, build rates in excess of 100 CC/hr can be achieved with peak laser powers as low as 500 Watts. The mean free path of a blue laser beam in a powder layer, eg metal powder, is much smaller than that of IR light. In this way, the blue laser beam has less heat loss due to scattering, thus allowing thinner powder layers. In this way a higher resolution can be achieved. In this way, higher build speeds can be achieved.

parts design

Images are generated and stored as monochrome bitmaps, or optionally grayscale for finer part detail or laser attenuation. Black pixels indicate high densities and correspond to laser pulses seen at least once on the powder surface at the corresponding locations.

One iteration divides the 3D model into a series of layers, which are saved as images.

image split

Image segmentation is accomplished in two stages: path definition and path ordering. In path definition, the user works with the image of the original part layer by layer. The image is divided into smaller overlapping shapes, the simplest of which is a rectangle, showing the final tool path and corresponding to the printed pattern displayed on the DMD. The parameters required to calculate the path are selected here and include, but are not limited to: stage velocity, DMD area used (height, width, offset); Laser pulse duration, laser pulse selection (ie, duty cycle), frame indication, stage ramp-up and slow-down requirements associated with timing, path length/width, overlap, timing, direction, and execution order. Additional process parameters can be selected at this point, including but not limited to laser power and laser focus offset.

Image-to-part scaling is also set during path definition. The simplest method for path selection would start with the image scaled into the space of the DMD, but this scaling could also be done elsewhere in the process. Once the path is specified, an instruction file is compiled to convert the part to real-world coordinates. The command file (G-code) contains all the information needed to run a part, layer or segment, the direction the images should be found, how they should be translated into frames, and how they should be moved to the stage. and laser pulses to display in a synchronous manner.

A path order is a sequence of frames and instructions for displaying them. A frame is calculated based on the parameters described above. The frames are offset based on stage velocity, demagnification from the DMD to the powder surface, DMD mirror pitch, laser pulse duration, and delays associated with image display. Frames can be repeated when printing coarse features or when saving computing time. The original image file can be converted into frames at run time, or it can be broken down into several small steps. Those steps can include saving each path to file as a separate image, saving frames to file as images, and saving sequences to file as binary data. .

Alternatively, the DMD can be oriented in a corresponding manner utilizing built-in ordering functions such as image scrolling. In this example, the entire image for the path is loaded into memory and the . Proceed to display the appropriate part section in sync with the stage movement. Alternatively, image scrolling can be made effective for any scan direction at a low level in the DMD or printer software. This can include rotating or distorting the image stored in memory before it is displayed on the DMD.

Instead, the entire layer or component is read into memory and accessed in a manner similar to that described above.

The iteration maps stage coordinates to DMD and image coordinates. Movement of the stage over the part is synchronized with corresponding images that are displayed and printed.

Images are used to influence laser-powder interactions, leverage collected field data, bias final build properties, and address anomalies present in powders. It can be transformed or otherwise processed at any time, including at runtime. Manipulation of the image may also be based on other information about the part, environment, or process.

Program execution/process

Process environment variables including, but not limited to, powder selection, powder thickness, powder compaction, powder bed temperature, and process gas at the surface of the powder are set prior to processing.

When processing the path sequence, the laser is triggered with pulse widths contained within the display time of each frame on the DMD. A laser pulse trigger is sent directly from the DMD to the laser. The timing between the display of the frame on the DMD and the motion of the stage is adjusted so that the original image is accurately scaled to real-world dimensions within the powder.

Laser pulse and process timing are controlled to avoid DMD overheating.

The base layer is configured to aid in fusing with subsequent layers and to allow the base layer to be easily separated from subsequent layers after fabrication is complete.

Although embodiments of the system and method can use any laser wavelength, the preferred embodiment uses a pair of blue lasers and spatial light as a means to define a pattern on the powder layer to be fused. The modulators are used to print and fuse layers of parts in parallel. Laser light sources and laser beams in embodiments can have wavelengths in the blue wavelength region, preferably wavelengths of 450 nm, about 450 nm, 460 nm, about 460 nm, about 10 pm, about 5 nm, about 10 nm, about 20 nm, and It can have a bandwidth of about 2 nm to about 10 nm, and can have larger and smaller values. Laser light sources and laser beams in embodiments can have wavelengths in the green wavelength region, such as 515 nm, about 515 nm, 532 nm, about 532, 550 nm, about 550 nm, and about 10 pm, about It can have a bandwidth of 5 nm, about 10 nm, about 20 nm, about 2 nm to about 10 nm, and can have higher and lower values. Various combinations and variations of these wavelengths can be used in the system.

The print engine in embodiments of the system and method is based on a digital micromirror device (DMD) array, embodiments of which are available from Texas Instruments (TI), which print 2-D energy patterns. Generate. All DMD products made by TI are subject to this process and the DMD used to print is the DLP9500. A 2-D energy pattern refers to the image that a laser beam or laser beam pattern forms on a layer of powder to be fused. As described herein, this image is viewed as a 2-D energy pattern, ie, an image above a layer of powder, but the energy penetrates into the layer and pushes the material underneath the shaped object. As it fuses into the layers, it has depth or 3-D properties. These print engines can be used with any of the laser additive manufacturing systems and methods provided herein as well as others. A blue laser reflected from the DMD array provides a 2-D energy pattern on the powder layer with a power density of several watts to several kilowatts when re-imaged. A second blue laser is added to preheat the powder layer at the exact location where the 2-D energy pattern is imaged, and a laser-spatial light modulator pair to fuse the patterned powder to the underlying layer. can reduce the energy required for The print engine is mounted on a precision gantry system that can stitch together 2-D images to form a large 2-D image that is one layer of the part. The system preferably includes a powder diffuser that is either part of the gantry system or separate from the gantry system and an elevator as part of the build volume. The build volume is preferably very low oxygen, more preferably oxygen free, and can be filled with an inert gas such as argon or a mixed gas such as argon-CO ₂ to facilitate the fusion process. The powder bed and chamber can be directly heated by electric heaters, radiant heaters, and combinations and variations of these or other types of heaters to reduce heat loss from the part during the manufacturing process. In one embodiment, a conduction mode welding process is the preferred method for fusing the layers, which was typical in all additive manufacturing scanning laser systems prior to that embodiment taught and disclosed herein. Eliminates the spatter normally caused in the keyhole process, which was a difficult process.

Generally speaking, a digital micromirror device (DMD) is a device that uses very small mirrors made of aluminum to reflect light to create an image. A DMD is also called a DLP chip. Embodiments of these devices have dimensions of several centimeters (e.g., the side of a square, the diameter of a circle, or the long side of a rectangle; these devices may have other shapes). cm), about 1 cm to about 3 cm, about 1 cm to about 2 cm, 1 cm or less, less than 0.5 cm, less than 0.2 cm, or less. These DMDs include about 100,000 to 4 million, at least about 100,000, at least about 500,000, at least about one million, about two million, or more mirrors, each mirror comprising about 4 μm or less, about 7.56 μm or less, about 10.8 μm or less, about 10 μm or less, about 4 μm to about 20 μm, and combinations and variations of these and larger and smaller sizes. The mirrors are arranged in a given pattern, for example a matrix like a photographic mosaic, with each mirror representing one pixel.

In one embodiment, the DMD consists of a CMOS DDR SRAM chip, which is a memory cell that electrostatically tilts the mirrors to an on or off position according to its logic value (0 or 1), a heat sink, and keeps the mirrors away from dust and debris. an optical window that passes the laser while protecting it.

In embodiments, a DMD has hundreds of thousands or more microscopic mirrors on its surface arranged in a typically rectangular array corresponding to the pixels of the image to be formed and displayed. The mirrors are individually rotated to the on state or to the off state, eg ±10-12° or more or less. In the ON state, a laser from a laser source, eg, a shaping laser and a shaping laser beam, is reflected into the lens, whose pixels direct the energy of the shaping laser to the image on the powder layer. In the off state, the laser beam, eg a shaping laser, is directed elsewhere, eg a beam dump, so that the pixel does not contribute to image or powder fusion. It should be appreciated that in embodiments, the preheating laser beam can also be directed at and reflected from the DMD device to form a preheating image on the powder of the layer.

In one embodiment, which can be theorized to be similar to photographic grayscale, the mirror is switched on and off very quickly, and the ratio of on time to off time determines the amount of powder coalescence or bonding within the powder layer. decide. This makes it possible to control the laser power and the power density (eg kW/cm ² ) of the laser beam on the powder layer without changing the output beam power from the laser source. In some embodiments, more than 500 different powers and power densities, more than 700 different powers and power densities, and more than 100,000 different powers and power densities can be obtained. An alternative method of achieving the grayscale effect is to pixelate the image by omitting individual pixels whose size is small compared to the thermal diffusion distance in the material being processed. This effectively reduces the average power delivered to the image. This grayscale can be used to manipulate the melt pool into its desired shape, whether temporally or spatially.

Embodiments of DMDs for use with such systems, printheads, and print engines are available from TI and include the DLP2010, DLP3000, DLP3010, DLP4500, DLP4710, DLPA2000, DLPA3000, DLPA3005, DLPC3430, DLPC3433, DLPC3435, DLPC3438, DLPC3439, DLPC3470, DLPC3478.

FIG. 1 shows an additive manufacturing system 100 according to one embodiment. System 100 has a base 108 and a gantry system 101 mounted on base 108 . Gantry system 101 moves DMD printhead 103 . This movement is in the x-axis 102 or y-axis 102a. The system 100 has a powder layer elevator 104 (to move the part down so that the next layer is deposited on the part), a powder layer diffuser 105 and a powder roller 106 . An image 107 from the DMD printhead 103 is shown on the surface of the powder in the drawing. The system has a laminar air knife 109 and a pyrometer or FLIR camera 110 . The base 108 and gantry system 101 have wire harnesses 111 that can accommodate, for example, gantry power and control wires and optical fibers for laser beam transmission. The laser source, or part thereof, is located on the gantry and moves with the gantry in embodiments. In embodiments, the laser light source is located remote from the base, remote from the laser head, or both, eg, connected to the laser head 103 by an optical fiber, eg, placed in optical communication. The laser light source may be connected by a flying optic head design in which the laser beam propagates in free space to the printhead.

A cut-away perspective view of one embodiment of a laser DMD printhead 200 is shown in FIG. This embodiment can be used with any system of the invention, including the system of FIG. 1 and others. The laser DMD printhead 200 has a housing 230 containing optical components and also has a first laser input 201 , a second laser input 212 , and an output or exit window 209 . The laser beam propagated into the housing 230 is directed and shaped by the optics before exiting the housing 230 through the exit window 209 to form a pattern (on the powder layer, not shown in this view). do. In one embodiment, these laser inputs 201, 212 conduct a laser beam from a laser source, such as a QBH fiber optic cable connected to the laser source and in optical communication to transmit the laser beam to the printhead. connectors and fibers for The optics within housing 230 define two laser beam paths, one for an input. In the direction of laser beam propagation along the first laser beam path: input section 201, collimating lens 205, reflecting mirror 206, DMD 202 (cooled by cooler 203), (which may have a cooler) There is an off-state beam dump 204 and a DMD imaging lens 208 from which the laser beam propagates through window 209 to form image 210 . In the direction of laser beam propagation along the second laser beam path, input section 212, collimating lens 210, reflecting mirror 207 (imaging lens 208), which may or may not be in the second beam path. , a second or other imaging lens may be employed) and through a window 209 to a location on the powder bed.

In one embodiment of the additive manufacturing system, the first laser beam path is the shaping laser beam and the shaping laser beam path is the laser beam that fuses the powder to build the object. The shaping laser beam can preferably have a wavelength in the blue wavelength range of 440 nm, about 440 nm, 450 nm, about 450 nm, 460 nm, about 460 nm, for example in the green wavelength range of 515 nm, about 515 nm, 532 nm, about 532 nm. The shaping laser beam can have any power, power density, peak power, and repetition rate described herein. The second laser beam path and the second laser beam propagating along that path are preheating laser beams. It does not have to be at the same wavelength, it can be anywhere from 440 nm to 1,100 microns, or it can be the same wavelength as the shaping laser, with less, similar, or higher power on the powder layer. It has a density and is used to preheat the powder layer and to maintain the temperature of the powder layer to facilitate the ability of the build laser to fuse the powder to build an object.

In one embodiment of the printhead 230, the second laser input 212 is connected to a laser light source for preheating the layer of powder. Thus, the second laser beam path and its associated optics are for the preheating system. Thus, in this embodiment, the first beam path and components from connector 201 through window 209 to image 210 are laser beams for fusing the powder layer materials together, i.e., shaping, as described above. A laser beam or a fused laser beam is provided and the second beam path is for providing a preheating laser beam.

Although embodiments of the system and method can use any laser wavelength, the preferred embodiment uses a pair of blue lasers and a means for defining a 2-D energy pattern on the powder layer to be fused. Layers of components are printed and fused in parallel using an array of spatial light modulators in combination with an array of lasers as a. The energy pattern can be continuous or discrete when different portions of the part or separate parts are processed in parallel. By combining multiple energy patterning systems together, a higher total power can be delivered to the surface of the powder layer, resulting in the ability to print larger parts in a single pulse, increasing the efficiency of the equipment. Build speed is greatly improved. Multiple DMDs are used due to the limited output capability of DMDs. Shelf DMD systems are capable of continuously handling blue laser light from 25 W/cm ² to 75 W/cm ² depending on backplate temperature and cooling method. The larger the part being machined, the greater the total power required to completely melt the 2-D pattern across the surface. Using multiple DMDs in parallel to provide the area scaling needed to achieve the desired high build speeds, as the DMDs in embodiments can be the limiting factor for the power delivered. can be done. Additionally, the print engine is mounted on a precision gantry system that stitches together the 2-D images to form a larger 2-D image that is a single layer of the part. Embodiments of the system can include a powder diffuser as part of the gantry system or separate from the gantry, and an elevator as part of the build volume. The build volume should have reduced oxygen, preferably oxygen-free, and may be filled with an inert gas such as argon or a gas mixture such as argon- _CO2 to facilitate the fusion process. can. The energy patterned area can be preheated by an auxiliary laser source or directly heated by electric and radiant heaters to reduce heat loss from the part during the manufacturing process. The auxiliary laser or auxiliary heating source raises the base temperature of the powder bed and reduces the energy required to melt the powder by the laser/spatial modulator system, i.e. the melting or shaping laser beam or subsystem of the additive manufacturing system. Let In embodiments, a conduction mode welding process is the preferred method for fusing the layers, which eliminates the spatter normally caused in the keyhole process, which is a fundamental process in all additive manufacturing scanning laser systems.

2-D energy patterning system (for 3-D fabrication)

A preferred embodiment for this system is TI's Digital Micromirror Device (DMD). This array consists of micromirrors that tilt when commanded to switch the propagating light off or on. Grayscale can be achieved by rapidly modulating the position of the mirror or the set power of the laser during the process to set the amount of energy delivered to the surface, or by randomly switching off the mirror image across the image. is achieved by reducing the average power density of Preferred DMD arrays are those optimized for use at the wavelength of the laser beam, e.g. optimized for wavelengths in the blue wavelength region, preferably 400 nm, about 440 nm, 450 nm, about 450 nm, 460 nm, about 460 nm. and optimized for wavelengths in the green wavelength region, for example 515 nm, about 515 nm, 532 nm, about 532 nm, and red wavelength regions from 600 nm to 700 nm. A typical DMD for visible wavelength light has a reflectivity of 88% at 450 nm and a diffraction efficiency of over 64%. This high transmittance allows these devices to handle average power densities of 25 W/cm2 or ^more , depending on the cooling method, and to handle shaping laser beams of blue, green, and red (visible) wavelengths. be able to. Tests performed on a DMD with a microchannel cooler have shown that it is safe to operate the device at power densities up to 75 W/cm ² . DMDs have operating power densities of about 25 W/cm ² to 160 W/cm ² , about 50 W/cm ² to 100 W/cm ² , about 25 W/cm ² to 75 W/cm ² , and higher or lower values, such as average It can have an average power density rating. The average power density rating is the continuous heat load rating for this device. Because of the high reflectivity, short pulses at low repetition rates can have power densities significantly higher than the continuous power rating of the device. Shown in FIG. 3 is a chart giving an estimate of the maximum pulse width for a given number of repetitions to maintain this average power density. Estimates are made for laser power level ratings from 150 W (watts) to 6 kW (kilowatts). At 6 kW, the instantaneous power density or peak power on the DMD device is 2.5 kW/cm ² for the DLP9500 device, more than 1,000 times greater than the average power density rating for that device. This level of power throughput is achieved because the short laser pulse width and low duty cycle do not cause the average power on the device to exceed the maximum rating. Optical coatings, in this example toughened aluminum, can sustain very high peak power levels as long as the absorbed energy does not exceed the damage threshold of the coated mirror. The damage level of aluminum optical coatings in pulsed mode is typically 10-50 MW/cm ² for short pulses, and this application of the system is well below this damage limit. The thermal mass of the mirror also serves to absorb 12% of the incident energy and determines the maximum exposure time for a given power density to keep the temperature of the mirror within the recommended operating range. As a result, the DMD system and method can deliver peak intensities capable of directly fusing metal powders to powder layers without damaging the DMD.

Thus, in embodiments of the system, the DMD device in the additive manufacturing system and method is under the influence of a laser beam and reflects the laser beam to form an image on the powder layer, the laser beam reflecting the powder layer. With peak power densities (kW/cm ² ) that are 2, 10, 100, 1,500, 100 to 1,000, and greater than the average power density ratings for DMDs above.

A photograph of the printed pattern is shown in FIGS. 4A and 4B. FIG. 4A shows a directly fused metal powder, in this example a 100 μm thick layer of copper powder, with an “N” image printed directly by the laser/spatial modulator system. It is The melting point of copper powder is 1085°C. FIG. 4B shows a second letter "U" printed directly by the laser/spatial modulator system. The powder was manually pre-positioned and heated at 100° C. to remove impurities prior to processing. The printing process begins by downloading an image of the letter N to the DMD. The blue laser system was pulsed for 4 ms with a duty cycle that maintained the recommended operating point of 25 W/ ^cm2 , delivering a peak power of 85 Watts at the surface of the powder bed, corresponding to a power density of 3.7 kW/ ^cm2 . Deliver on. A low power laser was used for this test, so the image on the moving gantry system remained stationary until enough energy was built up to heat the powder and fuse it into an image. The image has been scrolled. The image was then changed to the next letter and the process repeated. Since the powder bed was at 20° C., all energy for heating and melting the powder was provided by the laser/spatial light modulator system. The characters are approximately 500 μm high and 500 μm wide. With higher laser powers and heated layers, it is also feasible to melt the powder in a single pulse.

In one embodiment, a 6 kW blue laser source (build laser beam) was operated at a pulse width of 6.5 ms and a repetition rate of 3 Hz, which corresponds to a build speed of over 75 cc/hr using copper powder. do. A homogenizer is used to evenly distribute the laser energy across the DMD. The power density on the DMD is 2.5 kW/cm ² at 2 cm wide by 1.1 cm high. The DMD has a resolution of 1,920 mirrors by 1,080 mirrors on a 10.8 μm pitch. The reflectance of the DMD mirrors at this wavelength is about 88%, the transmission of the window of the device is 97%, the DMD's diffraction efficiency is ~62% at this wavelength, and the transmission of the imaging optics is Estimated to be 99%. Using 2:1 imaging optics, a 10 mm x 5.5 mm image was transmitted onto the powder bed with an estimated loss of ∼6 kW/cm ² from the laser-spatial light modulator combination on the powder bed. resulting in a power density, which is 1.6 times the intensity used in the tests of FIGS. 4A and 4B, and the total energy delivered is greater than 60 times. The image resolution of the "system" is about 5.04 μm, giving the system higher resolution than any other laser sintering technique. Since the published average power density of DMD chips is limited to 25 W/cm ² , a pulse width of 6.5 msec was chosen for the 6 kW laser source, which translates to about 21 Joules delivered to the powder bed. Equivalent to energy. In the experiments shown in Figures 4A and 4B, the required energy deposition was fairly low (0.34 Joules) because the irradiated area was only 0.5 mm x 0.5 mm. Assuming a bed temperature of 600° C., it is estimated that 14 Joules of energy were required to melt a volume of copper powder of 10 mm×5.5 mm×0.1 mm containing 25% voids. This analysis does not take into account heating of the substrate which drives up the required energy. The greatest energy is required when printing the first layer of the part, where the energy required to melt and fuse the powder is increased by a factor of three due to the diffusion of thermal energy into the substrate. A supplemental heating laser can be used to assist the imaging system in delivering the additional energy required in this step. As the build progresses, thermal diffusion in turn becomes a factor in the mass of the previous layer, thinner parts require less power, larger dimensions of the previous layer require more power, and the first layer is built. The highest power is required while bonding to the plate.

By resolution of a system or method it is meant that an object built by the system will have its smallest part or smallest dimension equal to the aforementioned resolution, e.g., the resolution defines the smallest dimension of an object that can be built. . Thus, by resolution of the laser system and resolution of the method, it is meant that the system and method have the ability to build a part at that resolution, i.e. have the part have features at that resolution. Thus, an example resolution of 75 μm would result in the ability to build parts with minimum dimensions of 75 μm, minimum features of 75 μm, or both. Embodiments of blue laser 3-D additive manufacturing systems, such as 3-D blue laser printers, and embodiments of blue laser 3-D additive manufacturing methods, are about 0.5 μm to about 200 μm or more, about 0.5 μm to about 100 μm , about 0.5 μm to about 50 μm, less than about 100 μm, less than about 75 μm, less than about 50 μm, less than about 25 μm, less than about 10 μm, and less than about 5 μm. The system can be capable of both large resolution, eg, greater than 200 μm, and very fine resolution of about 0.5 μm to about 10 μm and 1 μm to about 5 μm. Also, embodiments and examples herein and embodiments having wavelengths of blue, 440 nm, about 440 nm, 460 nm, green, 515 nm, about 515 nm, 532 nm, about 532 nm, 550 nm, and about 550 nm, and herein Embodiments of the system and method, including embodiments and examples of from about 10 μm to about 0.5 μm, less than 10 μm, less than 5 μm, less than 2 μm, from about 3 μm to about 0.9 μm, about 1 μm, less, and Other values in this paragraph have resolution.

FIG. 5 is a comparison of how quickly blue laser light is absorbed into the copper powder layer to an IR laser. Since the IR laser is diffused into the powder layer outside the pattern to be fused, requiring higher power levels of the laser and resolution is limited in IR by the high diffusion factor, the high absorption of blue laser light is This process is a factor in obtaining the desired resolution, build speed, or both. Therefore, the assumption that 100% of the light is absorbed can be used. If the powder bed is 75% dense, the energy required to heat the powder bed from 600° C. to the melting point of copper of 1085° C. can be calculated based on the heat capacity formula. Since phase transitions are involved, the heat of fusion is included in the calculation of the energy required. Based on the sum of the two components, the energy required to melt a volume of copper of 10 mm x 5.5 mm x 100 µm is approximately 14 Joules. Based on this calculation, the base temperature of the powder is preferably adjusted to compensate for the energy required to melt the metal, or if an auxiliary laser is used to preheat the image area, currently available A possible exemplary DMD array is suitable for use in metal-based additive manufacturing systems.

An embodiment using a 500 Watt blue laser source to heat a copper powder layer through a DMD provides a pulse width of up to 78 ms when pulsed at a repetition rate of 1.5 Hz. be able to. Under these conditions, a 500 Watt blue laser source delivers 39 Joules to the copper powder layer, sufficient energy to melt the copper from a background layer temperature of 400°C.

In some embodiments, the laser-spatial light modulator combination can provide enough energy to melt a 50 μm thick powder layer, but not enough to fuse to the underlying layer. It may not be energy. Because conduction mode welding proceeds spherically through layers of material, the weld is as wide as it is deep. For example, a 50 μm deep bead would be at least 50 μm wide. The minimum feature size should be at least 1.5-2 times the depth of the powder layer to ensure that the powder layer is fused with the layer below it. This means that 75-100 μm wide beads are used to fuse the powder layer to the underlying layer. Taking into account the energy required to fuse to the solidified layer below, the energy required to melt and fuse the powder increases from 36 Joules to 86 Joules when going from 400°C to the melting point of copper. . In embodiments, since this is not achievable with the laser-spatial filter combination alone, the bed temperature is increased or another heat source is added. By adding a second laser, preferably without a spatial light modulator, additional heat is added to raise the temperature without melting the powder. Thus, this second laser preheats the powder to maintain the temperature of the powder layer and the built object above the ambient temperature, e.g. temperature, temperature above 300°C, temperature above 400°C, temperature from about 300°C to about 600°C, temperature within 300°C of the melting point of the powder, temperature within 200°C of the melting point of the powder, melting point of the powder , up to and slightly below the melting temperature of the powder, as well as higher and lower temperatures.

As used herein, unless otherwise specified, the terms spatial light modulator, laser/spatial light modulator, DMD system, laser-spatial, and like terms are used to powder laser patterns and images for shaping laser beams. Similar general types of systems or subsystems using micromirrors, microreflective assemblies, or similar reflective components with micro-level or sub-microlevel resolution to produce on layers, and liquid crystals and others. see crystal-based spatial light modulators of the type

A second laser (eg, the second beam path of FIG. 2 above) illuminates the same area that the laser-spatial light modulator illuminates, as shown in FIG. FIG. 6 shows a layer 600 of metal powder. The preheating laser beam forms a preheating laser pattern 601 that heats an area 605 of layer 600 . A shaped laser pattern 602 , 603 is shown on a layer of metal powder 600 . Thus, the material within area 605 is heated by a second laser beam, eg, a preheating laser beam, and the heated material within laser patterns 602, 603 is fused into the object. In the above case, 86 Joules of heat is required to melt and fuse the powders. If a 500 Watt laser-spatial filter combination provides 39 Joules to the pattern, the second laser provides the remaining 47 Joules. The preheat laser pulse width can be 10% of the duty cycle, or 66 milliseconds, to provide time to move, coat, and perform other functions. This corresponds to a preheating laser power of 750 Watts. Assuming that the second laser heats the powder layer region to within 200° C. of the melting point, the temperature of the powder layer and the underlying layer in the patterned area when the laser-spatial light modulator irradiates the part is rises to the melting point of copper. FIG. 7 shows the timing of the system. This procedure results in melting of the 50 μm powder layer and complete coalescence into the fully packed underlying layer.

In one embodiment, the laser-spatial light modulator pair is based on a 6,000 Watt blue laser operating at a repetition rate of 1.5 Hz. The preheat laser is a 750 Watt laser. The preheating laser operates for the same duration (66 msec) as described above, bringing the temperature of the powder layer to within 200°C of the melting temperature of the material being melted (e.g. the powder in the powder layer) in the case of copper. up to A pyrometer or FLIR camera monitors the temperature of the powder layer during this preheating process and the laser-spatial light modulator image illuminates an area of the powder layer until the powder fuses to the underlying layer. Control the output to maintain its temperature. A 6,000 Watt laser can be on for 6.5 milliseconds and a 750 Watt laser can be on for 66 milliseconds or more. In this embodiment, the chamber temperature is assumed to be at or near room temperature.

In one embodiment, the laser-spatial light modulator pair is based on a 500 Watt blue laser operating at a maximum repetition rate of 1.5 Hz. The preheat is a 1,000 Watt laser. The preheat laser operates for the same duration of about 78 milliseconds as described above. However, the high power level preheating laser operates for only 25 milliseconds to allow additional time for pattern repositioning. In this embodiment, the chamber temperature was at or near room temperature. .

The disclosed laser print engine is mounted on a precision gantry system such as the embodiment of FIG. 1 within an airtight enclosure. The hermetic enclosure is filled with inert gas, which is continuously circulated to remove fumes as the process progresses. The inert gas environment ensures that there is no surface oxidation during fabrication that would result in porosity in the part. The gantry system causes the head to be positioned in the xy direction, and an elevator is used to move the part down as each new layer is printed. In principle, this approach to step-and-repeat 2-D energy patterns works for any size volume, e.g., 0.5 m ³ , 1 m ³ , 2 m ³ , 3 m Applicable for volumes of ³ , 10 m ³ , 1 m ³ to 10 m ³ and higher and lower values.

Building begins with a computer-aided design file, typically a step file. The software first slices and divides the object into 50 μm or larger or smaller slices depending on the resolution and shape. The surface that appears after slicing is then divided into sections of the same image size as the spatial light modulator. The build plan is then determined by the software as to which part of the pattern should be exposed first, what level of exposure should be, and what support structure should be used, if necessary. The software also determines the optimal on-time for the preheating laser and laser-spatial modulation system. The preheating time varies depending on the density of the base material, the melting temperature of the base material, the amount of material in the layer below the layer to be fused, and the density of the material in the layer below the layer to be fused. Based on part size, part complexity, and part orientation, to maintain the layers and walls or ceiling of the build chamber at optimal temperatures to prevent heat loss at an inappropriate rate to the build environment Alternatively, radiant heaters may be used. A summary of this process sequence is provided in FIG.

The following examples are provided to illustrate various embodiments of laser systems and components of the present invention. These examples are for illustrative purposes, may be prophetic, and should not be viewed as limiting and do not limit the scope of the invention.

Example 1

An embodiment of an additive manufacturing system is shown generally in FIG. System 100 consists of an xy gantry system 101 mounted on a vibration isolation platform. The x-axis 102 of the gantry system consists of a pair of air bearings and a linear motor capable of positioning to sub-micron absolute positions. The motor for the x-axis of the gantry system also bi-directionally moves the powder spreader 105 to spread the powder. The powder is fed either by a second elevator section filled with powder or by a powder hopper that drops the powder onto the powder bed. Powder hoppers, not shown in this view, are attached to the forward and aft portions of the gantry system. The entire system is enclosed within an airtight enclosure, not shown in this figure. The DMD laser printhead 103 is mounted on the y-axis of the gantry system and can traverse the layers and can be repeatedly positioned anywhere along the axis to within 1 micron. The powder bed 104 is on a precision elevator that allows the layer to be lowered by a minimum of 10 μm after each process step. This allows the powder diffuser 105 to place a uniform layer of powder over the previously fused image. A roller 106 rotating in the opposite direction to the direction of travel is used to flatten and compact the powder bed. The powder layer is built in the heater so that elevated temperatures can be used in the build cycle. A laminar flow air knife 109 is positioned directly under the DMD laser printhead to prevent debris and smoke from reaching the window through which the DMD image and auxiliary preheat laser are emitted. The DMD image 107 is positioned over the powder layer according to the slicing software and the pattern changes as the image moves across the width of the image to complete adjacent portions of the part. The images may be moved farther apart as desired to manage heat build-up within the part and to minimize warpage and stress within the part.

Example 2

An embodiment of a DMD printhead is shown generally in FIG. The modulated main laser output is sent to the printhead 200 through an industry standard QBH fiber cable 201 . A second laser used for preheating is also sent through industry standard QBH fiber cable 212 . These cables are robust and designed to provide a seal against the external environment during operation. Both cables are 400 μm or smaller diameter fibers inside a protective sheath. A pair of 40 mm collimating lenses 205, 210 are used to collimate the output of each optical fiber. Depending on the shape and uniformity of the beam from the optical fiber, homogenizer and beam shaping optics are inserted immediately after the collimating optics. Both the main laser source (the shaping laser) and the auxiliary laser source (the preheating laser) use homogenizers to provide sufficient intensity for uniform, fused prints. A reflecting mirror 206 is used to direct the collimated beam from the main laser optical fiber 201 onto the DMD at the required angle of 24 degrees from the DMD surface normal. When the laser is on, the mirrors of DMD 202 tilt toward the incoming beam to redirect the beam normal to the DMD surface. When the laser is off, the mirrors of DMD 202 tilt away from the incident beam, redirecting the incident beam away from the incident beam and 48 degrees from the normal vector of the surface of the DMD. Beam dump 204 is placed here because it must capture the beam energy that is off in the image. The beam from DMD 202 is reimaged with a 100 mm FL lens to a spot 200 mm below the laser printhead. This is a 1:1 imaging arrangement, but other ratios can be used depending on the part size and accuracy required. The optical fiber output 212 of the auxiliary laser is collimated by lens 205 and passed through a beam homogenizer to achieve the desired uniformity of fusion. The auxiliary beam is directed or re-imaged to the same spot as the image of the DMD using mirror 207 after beam conditioning. This system does not pass through the same imaging lens as the DMD's beam. However, two beams, both the DMD beam and the auxiliary beam, exit the printhead through a common window 209 . However, depending on the geometry of the system, a second window through which the preheating laser is emitted can also be used. Ultimately, the DMD image 210 overlaps the auxiliary laser beam on the powder bead, as shown in FIG.

Example 3

Embodiments of the present invention relate to using multiple DMDs within the same imaging aperture or parallel imaging apertures. A schematic diagram of a multi-DMD laser printing system 200 is shown in FIG. The system has two laser sculpting subsystems 941,942. Subsystem 941 includes laser source 901, collimator/homogenizer 903, DMD 905, mirror 905a, 2:1 image size reduction optical assembly comprising lens 907 and lens 909, mirror 911, and imaging lens 920. , which are arranged along the laser beam path 913 . In this manner, a laser beam for fusing the powder, eg, a shaping laser beam, propagates through these various components along laser beam path 913 to provide an image as image tile 950a. Image tiles 950a, 950b, 950c, 950d form a tiled image with many tiles. Subsystem 942 includes laser source 902, collimator/homogenizer 904, DMD 906, mirror 906a, a 2:1 image size reduction optical assembly comprising lenses 908 and 910, mirror 912, and imaging lens 920. , which are arranged along the laser beam path 914 . In this manner, a laser beam for fusing the powder, eg, a shaping laser beam, propagates through these various components along laser beam path 914 to provide an image as image tile 950b.

Two additional laser sculpting subsystems similar in configuration to systems 941, 942 may be used in this system, but are not shown in the figure. These additional two systems will provide images for image tiles 950c, 950d. In this embodiment, the tile images are preferably contiguous.

Four additional laser sculpting subsystems similar in configuration to systems 941, 942 may be used in this system, but are not shown in the figure. These additional four systems will provide images for image tiles adjacent to 950a, 950b, 950c, and 950d in the depth direction of the page to produce a 2-D tiled image.

The system can have a lens configuration that provides either an inverted or erect image.

Each DMD has its own laser source, and each DMD's image space is tiled using shearing mirrors, contiguous over an area much larger than can be achieved with a single DMD system. image space can be generated. There is dead space between each DMD image space, which can be minimized by proper placement of shearing mirrors. The image space can be effectively stitched together by adjusting the tilt and position of each shearing mirror. FIG. 9 shows that the image spaces of the two DMDs are uniaxially tiled to create a large composite image on the powder bed surface. This is accomplished by compressing each DMD image using reduction optics, shearing each reduced image together, and reimaging or remagnifying the image to the desired size using a single lens. , N×M DMD image space.

Example 4

Embodiments of the present invention relate to using multiple DMDs in different imaging apertures to provide parallel imaging capability. FIG. 10 shows a multi-DMD system 1000 having a first DMD subsystem 1040 and a second DMD subsystem 1041 for providing two parallel shaping laser beams to build separate images on the powder layer. It is shown. Subsystem 1040 has DMD 1005 positioned along laser beam path 1013 . Subsystem 1040 provides image 1050a. Subsystem 1041 has DMD 1006 positioned along laser beam path 1014 . Subsystem 1041 provides image 1050b.

Each DMD has its own laser light source, and the image space of each DMD is tiled on the surface of the powder bed to produce an image of a checkerboard pattern and areas of no image. The build plan builds individual parts using a single DMD image space, or builds larger parts by building multiple sections in parallel using each separate DMD image space. can be done.

A second, third, or fourth set of systems extending in the depth direction of the page or adjacent to the illustrated system can be used to increase the addressable image area on the powder layer. can.

The system can have a lens configuration that provides either an inverted or erect image.

example 5

Embodiments of the present invention use visible laser beams, particularly laser beams having wavelengths from 350 nm to 700 nm, in additive laser fabrication processes and systems to fabricate articles (e.g., structures, devices, components, parts, films, solid shapes, etc.), starting powders, nanoparticles, particles, pellets, layers, powder layers, atomized powders, liquids, suspensions, emulsions, and laser additive manufacturing techniques including these and 3-D printing techniques. and other starting material combinations and variations known in or later developed.

Example 6

In embodiments in which the laser lamination process builds articles from raw materials, wavelengths are used that have low reflectivity, high absorption, and preferably both, to the starting raw materials. In particular, in one embodiment, the wavelength of the laser beam is preferably about 10% or greater, about 40% or greater, about 50% or greater, and about 60% or greater absorption, and 10% to It is predetermined to have an absorbency in the range of 85%, 10% to 50%, and about 40% to about 50%. In particular, in one embodiment, the wavelength of the laser beam is preferably about 97% or less, about 60% or less, and about 30% or less, and in the range of 70% to 20%, 80% to It is predetermined to have reflectivity in the range of 30%, and in the range of about 75% to about 25%. In embodiments, there may be a combination of these high absorption and low reflectivity. Preferred embodiments of the system and process use a laser beam or beam having a wavelength of about 400 nm to about 500 nm to irradiate gold, copper, brass, silver, aluminum, nickel, alloys of these metals, as well as other metals. , non-metals, materials, and alloys and combinations and variations thereof.

Example 7

In one embodiment, a blue laser, e.g., about 380 nm, is used to additively manufacture articles from gold, copper, brass, nickel, nickel-plated copper, stainless steel, and other materials, metals, non-metals, and alloys. It is preferred to use wavelengths from about 495 nm. A blue laser beam is well absorbed by these materials at room temperature, eg, having an absorption of greater than about 50%. One of the several advantages of the present invention is the use of a laser beam of a preselected wavelength, such as a blue laser beam, that allows the laser energy to be well coupled into the material during laser operation, e.g., during an additive manufacturing process. Ability. By better coupling the laser energy to the material being shaped into the article, the potential for runaway processes that typically occur with infrared lasers is greatly reduced, and preferably eliminated. Better coupling of laser energy allows the use of lower power lasers, which can save capital costs or make multi-laser systems cost effective. Better bonding also results in greater controllability, greater durability, and thus greater reproducibility of shaped articles. These features, which are not found in IR lasers and IR laser additive manufacturing processes, are especially important for products in the fields of electronic components, micromechanical systems, medical components, engine components, and power storage.

Example 8

In one embodiment, a blue laser operating in CW mode is used. CW operation is the ability to rapidly modulate the laser power to control the build process in a feedback loop for optimal mechanical properties, such as reduced surface roughness, improved porosity, and improved electrical properties. and high reproducibility with other physical and aesthetic properties, it is preferred over short pulse lasers in many additive manufacturing applications.

Example 9

Preferably, in some embodiments, active monitoring of the article being built is used to confirm the quality of the article and the efficiency of the additive manufacturing process and system. For example, a temperature camera may be used to monitor the average temperature of the surface as the laser is processing high resolution areas of the printed part, and the laser power may be decreased or increased to reduce weld porosity and damage to the part. A feedback loop can be used to improve the final surface quality. Similarly, as the laser beam is defocused and passed over a large area of low resolution on the part, a feedback loop commands more laser power to maintain the average temperature at the optimum processing temperature, thereby printing the part. time can be greatly reduced.

example 10

Examples of scanners and optics that can be used with the system include mirrors mounted on high speed motors, rotating polygon mirrors, or high speed galvanometers. A mirror mounted on the shaft of a high speed motor produces a scanning beam as the mirror is rotated through 360 degrees. The faster the motor speed, the faster the scan. The only problem with this approach is that the laser must be turned off as soon as the mirror no longer reflects the beam when the rear side of the mirror passes by the laser beam entry window. The fast mirrors can be used for scanning in either the x-axis or the y-axis, and whichever axis is chosen, mirrors scanning the other axis can be used for one complete scan in the first axis. It must scan at a slow rate proportional to the time to complete. A high speed stepper motor is preferably used in this axis to move the mirror in discrete widths and remain stationary while the first axis scan is completed. Similarly, a multi-faceted or polygonal mirror can be used to perform fast scanning functions allowing high scanning speeds since the scan is reset to the starting position as the beam traverses each facet of the mirror. . These types of mirrors are currently used by supermarket scanners to scan barcodes on items as they pass by. The principal axis is scanned by a high speed galvanometer type mirror which is a resonant type motor and oscillates at a continuous frequency which produces high speed movement of the beam. A system in which the galvanometer mirrors are precisely positioned in place and the first and second axis are galvanometer driven mirrors to quickly specify any position on the working layer by moving both mirrors simultaneously It is possible to be in vector mode. A "flying optic" type design in which the beam is sent through free space to mirrors mounted in a gantry type system and moves very fast in two-dimensional, raster, or vector modes. , it is also feasible to combine a mirror mounted on a moving stage.

Example 11

One embodiment of the laser system and method is shown in FIG. System 1100 has a laser source 1101 for providing a laser beam (indicated by ray trace 1122) along a first laser beam path 1122a. The laser beam exits laser source 1101 and propagates along beam path 1122a through collimating lens 1102 and into digital mirror device 1103, which directs the laser beam into a laser beam pattern (illustrated by ray trace 1123). ) along laser beam path 1123a toward focusing lens 1107, and direct the focused laser beam pattern (indicated by ray trace 1124) along laser beam path 1124a to sample 1108 (e.g., a metal powder layer, starting material, starting powder layer, or build material) to the target location 1109 . Also shown is the flow of process gas (eg, an inert gas such as argon) toward and over the target area 1109 . In this way, the system uses the digital mirror device 1103 to shape an object (e.g., a metal object such as a copper part) with a volumetric shape defined by a laser pattern directed from the digital mirror device to the target. Provide a laser pattern.

The system has a heating laser 1105 that provides a heating laser beam (indicated by ray trace 1133) along laser beam path 1133a. Movement of the stage holding the digital mirror device 1103 is in the direction indicated by arrow 1104 .

Example 12A

In the system embodiment of Example 12, laser source 1101 is a blue laser that provides a laser beam having the laser parameters of one of the lasers in Tables 1 and 2.

The focusing lens has a focal length of 100 mm.

Digital mirror devices are DMDs or MEMS. In one embodiment, the DMD has an array of movable mirrors and supports 1920×1080 pixels.

Heating laser 1105 provides a beam having the properties of AO-150 in Table 2.

Example 12B

The system of Examples 12A or 12B stores images of objects built from a powder base 1108 of metal starting material. These images are stored in order and played back synchronously with stage motion 1104 . Fusing the metal powder base to form the shaped object is by conduction mode welding. The peak power of laser 1101 is 80 W, the stage speed is 5 mm/s, and the powder layer is 100 μm.

Example 13

An embodiment of the system is a device that steers the beam without significant mechanical motion. For example, these embodiments do not include or require a scanner to shape the object. Thus, for example, the embodiments of Examples 1-12B and 14-18 can be non-large mechanical systems.

Example 14

In the systems and methods of Examples 1-13, the shaping laser beam has a wavelength selected from among the following wavelengths: blue wavelength region, 400 nm, about 440 nm, 450 nm, about 450 nm, 460 nm, about 460 nm, green wavelength region; 515 nm, about 515 nm, 532 nm, about 532 nm, and the red wavelength region from 600 nm to 700 nm. The shaping laser beam also has one or more of the beam characteristics described herein, such as power, power density, repetition rate, and the like.

example 15

Referring to the schematic diagram of FIG. 15, an additive manufacturing system (1500) for metal, comprising a laser light source (1504) for providing a laser beam for processing; a digital mirror device (1510) in optical communication with the laser light source; ) a digital mirror device (1510), wherein the laser light source is enabled to propagate the processing laser beam along a first laser beam path (1511) to the digital mirror device; Control communication connection (1530) with the memory device (1503), control communication connection (1531) with the GUI (1502), control communication connection (1533) with the digital mirror device (1510), and the laser light source (1504). a control system (1501) in control communication connection (1532) and in control communication connection (1534) with a stage (1505); said stage (1505) comprising a motor (1506) and said digital mirror device (1510); said digital mirror device targeting said processing laser beam along a second laser beam path (1512); projected in a predetermined pattern onto an area (1550), said target area comprising powder (1551); said predetermined pattern comprising said image segment; said control system comprising instructions, said Instructions are provided to synchronize the movement (1570) of the stage and the projection of the image segment onto the target area; whereby the image segment is projected onto the target area to form an overall image of the object to be built. an additive manufacturing system (1500) for metals, adapted to deliver said working laser beam to build said object from said powder.

In one embodiment, this Example 15 control system and control communication connection is used with the systems of Examples 1-14.

Example 16

An additive manufacturing system (1500) for metals, comprising a laser light source (1504) for providing a laser beam for processing; a digital mirror device (1510) in optical communication with the laser light source, wherein the laser light source a digital mirror device (1510) adapted to allow a processing laser beam to propagate along a first laser beam path (1511) to said digital mirror device; a memory device (1503) and a control communication connection ( 1530), in control communication connection (1533) with the digital mirror device (1510), and in control communication connection (1534) with the stage (1505); said stage (1505) comprising said digital mirror device (1510); said digital mirror device directing said processing laser beam to a second laser beam path (1512); ) to a target area (1550) in a predetermined pattern; said predetermined pattern comprising said image segment; said control system comprising instructions, said instructions for causing movement of said stage (1570); and the projection of said image segment onto said target area; whereby said image segment is projected onto said target area to provide an overall image of said object to be shaped. A modeling system (1500).

In one embodiment, the control system and control communication connections of this Example 16 are used with the systems of Examples 1-14.

Example 17

An additive manufacturing system (1500) for metals, comprising a laser light source (1504) for providing a laser beam for processing; a digital mirror device (1510) in optical communication with the laser light source, wherein the laser light source a digital mirror device (1510) adapted to allow a processing laser beam to propagate along a first laser beam path (1511) to said digital mirror device; a memory device (1503) and a control communication connection ( 1530), in control communication connection (1533) with the digital mirror device (1510), and in control communication connection (1534) with the stage (1505); said stage (1505) comprising said digital mirror device (1510); said digital mirror device combining said processing laser beam with a second laser beam; propagated along a path (1512) to a target area (1550) in a predetermined pattern; said predetermined pattern comprising said image segment; said control system comprising instructions, said instructions for movement of said stage; (1570) and the projection of said image segment onto said target area; whereby said image segment is projected onto said target area to form an overall image of said object to be shaped by said processing laser beam. An additive manufacturing system (1500) for metal that delivers a

In one embodiment, the control system and control communication connections of this Example 17 are used with the systems of Examples 1-14.

Example 18

In the systems and methods of Examples 1-17, the laser light source is one or more of the lasers disclosed herein.

It is not necessary to provide or address the theory underlying new and innovative processes, materials, performance, other advantages and properties that are the subject of or related to embodiments of the present invention Please note. Nonetheless, various theories are provided herein to further advance technology in this area. The theory put forth herein in no way limits, restricts or narrows the scope of protection conferred on the claimed invention unless explicitly stated otherwise. These theories may not be required or practiced to utilize the present invention. The present invention contemplates novel and heretofore unknown theories to explain the functional characteristics of embodiments of the methods, articles, materials, devices, and systems of the present invention, and such later developed theories. It should be understood that theory is not intended to limit the scope of protection given to this invention.

It is to be understood that the use of headings herein is for the purpose of clarity and is not limiting in any way. Accordingly, the processes and disclosures set forth under the heading should be read in the context of the entire specification, including various examples. The use of headings herein should not limit the scope of protection to which this invention is entitled.

The various embodiments of the systems, devices, techniques, methods, activities and operations described herein can be used for various other activities and other fields in addition to those described herein. In particular, embodiments of the present invention can be used with the methods, apparatus, and systems of Patent Publication Nos. WO2014/179345, 2016/0067780, 2016/0067827, 2016/0322777, 2017/0343729, 2017/0341180, and 2017/0341144. and the entire disclosures of each are incorporated herein by reference. Additionally, these embodiments may be used, for example, with other devices or activities that may be developed in the future, and with existing devices or activities that are improved in part based on the techniques herein. Also, the various embodiments described herein may be used in various different combinations with each other. Thus, for example, configurations provided in various embodiments herein may be used with each other. For example, the components of embodiments having A, A′ and B and the components of embodiments having A″, C and D can be combined in various combinations in accordance with the teachings herein, eg, A, C, D, and A , A″C and D, and so on. Therefore, the scope of protection given to the present invention should not be limited to the particular embodiments, configurations, or arrangements described in the particular embodiments, examples, or embodiments in the particular drawings.

The present invention may be embodied in forms other than those specifically disclosed herein without departing from the spirit or essential characteristics thereof. The described embodiments are to be considered in all respects as illustrative and not restrictive.

Claims (60)

a. a laser light source (1504) for providing a processing laser beam;
b. A digital mirror device (1510) in optical communication with a laser light source such that the laser light source can propagate the processing laser beam along a first laser beam path (1511) to the digital mirror device. a digital mirror device (1510) configured to
c. Control communication connection (1530) with the memory device (1503), control communication connection (1531) with the GUI (1502), control communication connection (1533) with the digital mirror device (1510), and the laser light source (1504). a control system (1501) in control communication connection (1532) and in control communication connection (1534) with the stage (1505);
d. said memory device having a plurality of image segments of an overall image of the object to be built;
e. said stage (1505) comprising a motor (1506) and said digital mirror device (1510);
f. The digital mirror device is adapted to project the working laser beam along a second laser beam path (1512) to a target area (1550) in a predetermined pattern, the target area containing powder (1551). has
g. said predetermined pattern comprising said image segment;
h. said control system comprising instructions, said instructions being adapted to synchronize movement (1570) of said stage and projection of said image segment onto said target area;
i. for metal, whereby the image segment is projected onto the target area to deliver the working laser beam to an overall image of the object to be shaped to shape the object from the powder; additive manufacturing system (1500). 2. The additive manufacturing system of claim 1, wherein the digital mirror device is selected from the group consisting of a digital micromirror device and a microelectromechanical system. Laser system according to claim 1 or 2, wherein the processing laser beam has a wavelength in the range of 300 nm to 800 nm. Laser system according to claim 1 or 2, wherein the processing laser beam has a wavelength in the range of 300 nm to 600 nm. Laser system according to claim 1 or 2, wherein the processing laser beam has a wavelength in the range of 400 nm to 500 nm. Laser system according to claim 1 or 2, wherein the processing laser beam has a wavelength in the range of 500 nm to 600 nm. 7. The laser system of any one of claims 1-6, wherein the digital mirror device is air cooled. 7. The laser system of any one of claims 1-6, wherein the digital mirror device is cooled by a cooling device selected from the group consisting of the microchannel cooler, water heat exchanger, and Peltier cooler. . 9. The laser system of any one of claims 1-8, further comprising strip radiant heaters for maintaining the temperature of the build chamber. 10. The laser system of any one of claims 1-9, further comprising a heated build plate. 11. A laser system according to any preceding claim, further comprising a separate auxiliary laser for heating the powder layer only where the pattern will impinge. 12. The laser system of any one of claims 1-11, further comprising an inert atmosphere. 13. A laser system according to any preceding claim, wherein the predetermined pattern has a power density of several kW. 14. The laser system of any one of claims 1-13, wherein the system is a system that steers the beam without significant mechanical movement. 15. A method of operating the system of any one of claims 1-14 to build an object from metal powder. 16. The method of claim 15, wherein said metal powder is selected from the group consisting of gold, silver, platinum, copper, aluminum, and alloys thereof. a. a laser light source (1504) for providing a processing laser beam;
b. A digital mirror device (1510) in optical communication with a laser light source such that the laser light source can propagate the processing laser beam along a first laser beam path (1511) to the digital mirror device. a digital mirror device (1510) configured to
c. a control system (1501) connected (1530) for control communication with the memory device (1503), connected (1533) for control communication with the digital mirror device (1510), and connected (1534) for control communication with the stage (1505); , and
d. said memory device having a plurality of image segments of an entire object to be modeled;
e. said stage (1505) comprising said digital mirror device (1510);
f. the digital mirror device is adapted to propagate the working laser beam along a second laser beam path (1512) to a target area (1550) in a predetermined pattern;
g. said predetermined pattern comprising said image segment;
h. said control system comprising instructions, said instructions being adapted to synchronize movement (1570) of said stage and projection of said image segment onto said target area;
i. An additive manufacturing system (1500) for metal whereby said image segment is projected onto said target area to provide an overall image of said object to be shaped. 18. The additive manufacturing system of Claim 17, wherein the digital mirror device is selected from the group consisting of a digital micromirror device and a microelectromechanical system. The additive manufacturing system according to claim 17 or 18, wherein the processing laser beam has a wavelength in the range of 300nm to 800nm. Laser system according to claim 17 or 18, wherein the processing laser beam has a wavelength in the range of 300nm to 600nm. The additive manufacturing system according to claim 17 or 18, wherein the processing laser beam has a wavelength in the range of 400nm to 500nm. The additive manufacturing system according to claim 17 or 18, wherein the processing laser beam has a wavelength in the range of 500nm to 600nm. 23. The additive manufacturing system of any one of claims 17-22, wherein the digital mirror device is air cooled. Additive manufacturing according to any one of claims 17 to 22, wherein said digital mirror device is cooled by a cooling device selected from the group consisting of said microchannel cooler, water heat exchanger and Peltier cooler. system. 25. The additive manufacturing system of any one of claims 17-24, further comprising strip radiant heaters for maintaining the temperature of the build chamber. 26. The additive manufacturing system of any one of claims 17-25, further comprising a heated build plate. 27. The additive manufacturing system of any one of claims 17-26, further comprising a separate auxiliary laser for heating the powder layer only where the pattern will impinge. 28. The additive manufacturing system of any one of claims 17-27, further comprising an inert atmosphere. 29. The additive manufacturing system of any one of claims 17-28, wherein the predetermined pattern has a power density of several kW. 30. The additive manufacturing system of any one of claims 17-29, wherein the system is a beam steering system without significant mechanical movement. 31. A method of operating the system of any one of claims 17-30 to build an object from metal powder. 32. The method of claim 31, wherein said metal powder is selected from the group consisting of gold, silver, platinum, copper, aluminum, and alloys thereof. 31. The additive manufacturing system of any of claims 17-30, wherein the control system (1501) is further in control communication connection (1531) with a GUI (1502). 34. The additive manufacturing system of any of claims 17-30 and 33, wherein the control system (1501) is further in control communication connection (1533) with the laser light source (1504). 35. The additive manufacturing system of any one of claims 17-30 and 33-34, wherein the stage (1505) comprises a motor (1506). 36. The additive manufacturing system of any one of claims 17-32 and 33-35, wherein the target area comprises powder (1551). 37. The additive manufacturing system of Claim 36, wherein said metal powder is selected from the group consisting of gold, silver, platinum, copper, aluminum, and alloys thereof. 37. or wherein said image segment is projected onto said target area to deliver said processing laser beam to said image of said entirety of said object to be shaped, thereby shaping said object from said powder; 37. The additive manufacturing system according to 37. a. a laser light source (1504) for providing a processing laser beam;
b. A digital mirror device (1510) in optical communication with a laser light source such that the laser light source can propagate the processing laser beam along a first laser beam path (1511) to the digital mirror device. a digital mirror device (1510) configured to
c. a control system (1501) connected (1530) for control communication with the memory device (1503), connected (1533) for control communication with the digital mirror device (1510), and connected (1534) for control communication with the stage (1505); , and
d. said memory device having a plurality of image segments defining an overall image of the object to be built;
e. said stage (1505) comprising said digital mirror device (1510);
f. the digital mirror device is adapted to propagate the working laser beam along a second laser beam path (1512) to a target area (1550) in a predetermined pattern;
g. said predetermined pattern comprising said image segment;
h. said control system comprising instructions, said instructions being adapted to synchronize movement (1570) of said stage and projection of said image segment onto said target area;
i. An additive manufacturing system (1500) for metal, wherein the image segment is projected onto the target area thereby delivering the processing laser beam to an overall image of the object to be built. 40. The additive manufacturing system of Claim 39, wherein said digital mirror device is selected from the group consisting of a digital micromirror device and a microelectromechanical system. 41. The laser system of claim 39 or 40, wherein the working laser beam has a wavelength in the range of 300nm to 800nm. 41. The laser system of claim 39 or 40, wherein the working laser beam has a wavelength in the range of 300nm to 600nm. 41. A laser system according to claim 39 or 40, wherein said processing laser beam has a wavelength in the range of 400nm to 500nm. 41. A laser system according to claim 39 or 40, wherein said working laser beam has a wavelength in the range of 500nm to 600nm. 41. A laser system according to claim 39 or 40, wherein said digital mirror device is air cooled. 46. The laser system of any one of claims 40-45, wherein said digital mirror device is cooled by a cooling device selected from the group consisting of said microchannel cooler, water heat exchanger and Peltier cooler. . 47. The laser system of any one of claims 40-46, further comprising strip radiant heaters for maintaining the temperature of the build chamber. 48. The laser system of any one of claims 40-47, further comprising a heated build plate. 49. A laser system according to any one of claims 40 to 48, further comprising a separate auxiliary laser for heating the powder layer only where the pattern will impinge. 50. The laser system of any one of claims 40-49, further comprising an inert atmosphere. 51. A laser system according to any one of claims 40 to 50, wherein said predetermined pattern has a power density of several kW. 52. The laser system of any one of claims 40-51, wherein the system is a system that steers the beam without significant mechanical motion. 53. A method of operating the system of any one of claims 40-52 to build an object from metal powder. 54. The method of claim 53, wherein said metal powder is selected from the group consisting of gold, silver, platinum, copper, aluminum, and alloys thereof. 53. The additive manufacturing system of any of claims 40-52, wherein the control system (1501) is further in control communication connection (1531) with a GUI (1502). 56. The additive manufacturing system of any of claims 42-52 and 55, wherein the control system (1501) is further in control communication connection (1533) with the laser light source (1504). 57. The additive manufacturing system of any one of claims 42-52 and 55-56, wherein the stage (1505) comprises a motor (1506). 58. The additive manufacturing system of any one of claims 52-52 and 55-57, wherein the target area comprises powder (1551). 59. The additive manufacturing system of Claim 58, wherein the metal powder is selected from the group consisting of gold, silver, platinum, copper, aluminum, and alloys thereof. 59. or wherein said image segment is projected onto said target area to deliver said processing laser beam to said image of said entirety of said object to be shaped, thereby shaping said object from said powder; 59. The additive manufacturing system according to 59.

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