RU2793043C2 - Additive manufacturing system with addressable laser array and real-time feedback control for each source - Google Patents

Abstract

FIELD: array assemblies for combining laser beams.

SUBSTANCE: one embodiment is a system that includes a light source and is configured to provide a multi-spot 1-D image, a multi-spot 2-D image, or both on a powder pad. Moreover, the system contains a light source, which is in optical communication with an array of optical fibres for transmitting a multi-spot image. In addition, the optical fibre array is in optical communication with the imaging optics. At the same time, the image re-forming optics is configured to re-form a multi-spot image on the powder pad, and the light source provides power density for fusion and build-up of the part from the powder.

EFFECT: development of additive manufacturing systems that allow precise control of the print quality, in particular, parts that are built up will have lower porosity, lower defectiveness and better surface roughness.

82 cl, 33 dwg, 1 tbl, 45 ex

Description

[0001] This application: (i) claims under 35 U.S.C. §119(e)(1) filing date benefit, and claims priority, of U.S. Provisional Application No. 62/726,234 filed September 1, 2018, the full disclosure of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

[0002] The present invention relates to array assemblies for combining laser beams; and in particular to array assemblies that can provide high brightness laser beams for use in manufacturing, fabrication, entertainment, graphics, imaging, analysis, tracking, assembly, dental and medical systems and applications.

[0003] Many lasers, and in particular semiconductor lasers such as laser diodes, provide laser beams having desired wavelengths and beam quality, including brightness. These lasers can have wavelengths in the visible range, UV range, IR range, and combinations thereof, as well as higher and lower wavelengths. The field of semiconductor lasers, as well as other laser sources such as fiber lasers, is rapidly evolving as new laser sources are continuously developed and new and existing laser wavelengths are provided. While having the desired beam quality, many of these lasers have lower laser powers than desired or needed for particular applications. Thus, lower powers reduce the usefulness and commercial applicability of these laser sources.

[0004] Additionally, previous efforts to combine these types of lasers have generally been inadequate, among other things, for reasons of difficulty in beam alignment, difficulty in maintaining beam alignment during operation, loss of beam quality, difficulty in spatial placement of laser sources, due to size considerations, power adjustment , etc.

[0005] Infrared (IR) (e.g., having wavelengths greater than 700 nm and in particular greater than 1000 nm) additive manufacturing systems that use a galvanometric scanner suffer, among other things, from two disadvantages that both limit build volume and build speed . In these IR laser systems, the amount of buildup is limited by the final size of the scan system, and the spot that can be created for a given focal length collimator and f-theta lens. For example, when using a 140 mm collimator and a 500 mm F-theta lens, the spot size for a 1 µm laser is approximately 40 µm for a near-field single-mode diffraction-limited beam laser. This gives an addressable powder pad print of approximately 175 mm x 175 mm, which is a limit on the size of the part that can be built up. The second limitation on the growth rate for an IR laser system is the absorption of the laser beam by the powder material. Most untreated materials are moderate to high reflective for infrared wavelengths. As a result, the delivery of infrared laser energy to the powder pad is limited in that a significant portion of the energy is reflected back or deeper into the powder pad. These limitations are in a sense additionally related to each other, exacerbating the problems and disadvantages of IR additive systems. Thus, the final penetration depth of infrared light determines the optimum layer thickness and, as a result, limits the resolution and speed of the process. These and other shortcomings of IR production and system and process build-up have not yet been adequately addressed. Thus, the long-felt need to improve AM systems and processes is not being met.

[0006] As used herein, unless explicitly stated otherwise, the terms "blue laser beams", "blue lasers" and "blue" should be understood in the broadest sense, and generally refer to systems that provide laser beams, laser beams, laser sources such as lasers and laser diodes which provide, for example, propagate, a laser beam or light having a wavelength of 400 nm to 500 nm and about 400 nm to about 500 nm. Blue lasers include wavelengths of 450nm, about 450nm, 460nm, about 460nm. Blue lasers can have bands from about 10 pkm to about 10 nm, about 5 nm, about 10 nm, and about 20 nm, and more and less.

[0007] As used herein, unless explicitly stated otherwise, “UV”, ultraviolet”, “UV spectrum” and “UV region of the spectrum” and similar terms, should be understood in the broadest sense, and will include light with lengths wavelengths from about 10 nm to about 400 nm and from 10 nm to 400 nm.

[0008] As used herein, unless explicitly stated otherwise, the terms "visible", "visible spectrum" and "visible spectrum" and similar terms should be understood in the broadest sense, and will include light with wavelengths from about 380 nm to about 750 nm and 400 nm to 700 nm.

[0009] As used herein, unless explicitly stated otherwise, the terms "green laser beams", "green lasers" and "green" should be understood in the broadest sense and generally refer to systems that provide laser beams, laser beams , laser sources, such as lasers and laser diodes, which provide, for example, propagate, a laser beam or light having a wavelength range from 500 nm to 700 nm and from about 500 nm to about 700 nm. Green lasers include wavelengths of 515 nm, about 515 nm, 550 nm, and about 550 nm. Green lasers can have bands from about 10 pkm to 10 nm, about 5 nm, about 10 nm and about 20 nm, as well as greater and lesser values.

[0010] In general, the term “about” and the symbol “~” as used herein, unless otherwise indicated, are intended to cover the spread or range of ±10%, experimental or instrumental error associated with obtaining the specified value and, preferably, exceeding them.

[0011] Used here, unless otherwise indicated, room temperature is 25°C. And the standard external temperature and pressure is 25°C and 1 atmosphere. Unless explicitly stated otherwise, all tests, test results, physical properties, and values dependent on temperature, dependent on pressure, or both, provided at standard ambient temperature and pressure, will include viscosities.

[0012] Used here, unless otherwise indicated, the reference to ranges of values is intended only to act as a method of notation that indicates individually each individual value that falls within the range. Unless otherwise stated here, each individual value in the range is included in the description of the invention, as if it were individually mentioned here.

[0013] A typically previous method used in additive manufacturing is to use an infrared laser and a galvanometer to scan the surface of the powder bed with a laser beam in a welding process that melts and fuses the fluidized powder to the underlying layer or substrate. This approach has several limitations that determine the speed of the process and other disadvantages in the process. For example, a single laser beam is used to scan the surface, and the buildup rate is limited by the maximum scanning speed of the galvanometers (7 m/s). Manufacturers make extensive use of IR technology and generally assume that this is the only usable wavelength they operate at, with limited success, to overcome this limitation by limiting two or more IR lasers/galvanometers to a system where both can work together to build a single parts or they can work independently to build parts in parallel. These efforts aim to increase the throughput of AM systems, but focus only on IR and have met with limited success, falling short of the long-felt need for improved AM.

[0014] An example of another limitation in IR processing is the high intensity of the laser spot, which puts the system in keyhole welding mode, which causes sputtering and porosity in the part. For example, thanks to a f-theta lens with a focal length of 500 mm, an IR laser creates a spot size of the order of 40-50 microns for an infrared laser with a diffraction-limited beam. If the laser beam operates at an optical power of 100 W, then the intensity of the beam is greater than the intensity required to initiate the keyhole welding mode. The keyhole welding mode creates a fountain of vaporized material that crosses the jet, otherwise the laser beam will scatter and be absorbed by the vaporized metal. In addition, since the keyhole mode of welding relies on creating a hole in the surface of the liquid metal, which is supported by the vapor pressure of the vaporized metal, the vaporized metal can be ejected from the keyhole. This material is sprayed and results in the deposition of molten materials elsewhere on the build-up plane, which can lead to defects in the final part. Although manufacturers of additive manufacturing systems have had some limited success in developing rapid prototyping machines, they have not been able to meet the long-felt need and requirements needed to form commercial or actual parts in volume. To realize this breakthrough in the method of forming the pattern of parts, which has not been achieved in the prior art.

[0015] In general, a problem with IR processing systems is the requirement or need to fuse the powder in the keyhole welding mode. This can usually be a consequence of using a single beam to process the powder. If the laser beam operates at an optical power of 100 W, then the intensity of the beam is greater than the intensity required to initiate the keyhole welding mode. The keyhole welding mode creates a fountain of vaporized material that crosses the jet, otherwise the laser beam will scatter and be absorbed by the vaporized metal. In addition, since the keyhole mode of welding relies on creating a hole in the surface of the liquid metal, which is supported by the vapor pressure of the vaporized metal, material such as vaporized metal can be ejected from the keyhole. This material is sprayed and results in the deposition of molten materials elsewhere on the build-up plane, which can lead to defects in the final part.

[0016] To resolve these restrictions, IR last time Livermore National Laboratory. Lawrence attempted to use an optically activated light valve (OALV). OALV is a high power spatial light modulator that is used to create a light pattern using high power lasers. Although the pattern on the OALV is created by a blue LED or laser source from a projector, the output power from the four laser diode arrays is sent through a spatial light modulator and used to heat the image to its melting point, and a Q-switched IR laser is required to initiate keyhole welding. IR lasers are used in keyhole mode to initiate welding, especially when alloying copper or aluminum materials. This keyhole welding process can create sputtering and porosity in the part, as well as high surface roughness, and is generally required for these materials. This keyhole welding process typically creates sputtering, porosity in the part, and high surface roughness. Thus, the OALV system, like typical IR systems, does not eliminate the adverse effects of keyhole initiation of the buildup process. While it would be better to avoid the keyhole welding step entirely, the prior art has not been able to overcome this problem and has not provided this solution. This failure is mainly due to the fact that at IR wavelengths the absorption properties of many metals are so low that a high peak power laser is required to initiate the process. Because OALV is only transparent in the IR region of the spectrum, it is not possible to build or use this type of system using a visible laser light source as the high energy light source. The cost of the components in this system is very high especially OALV which is a custom component.

[0017] Previous metal-based additive manufacturing apparatuses are very limited in that they either rely on the use of a binder sprayed onto a powder bed followed by a high temperature curing step, or a high power single-mode laser beam is scanned over the powder bed by a galvanometer system at high speeds. Both of these systems have significant drawbacks that cannot be overcome in the prior art. The first system is capable of producing high volume parts with large tolerances due to compression of the parts during the curing process. The second process is limited in buildup speed by the scan rates of the galvanometer, which limits the maximum laser power level that can be used and hence the buildup speed. Additive manufacturing scan-based system builders have worked to overcome this limitation with builders with multiple scan heads and laser systems that do not provide an adequate solution to these problems. This does increase throughput, but the scaling law is linear, in other words, a system with two laser scanners can grow twice as many parts as a system with a single scanner, or grow one part twice as fast. Thus, a high throughput laser metal additive manufacturing system is required that does not suffer from the limitations of the systems currently available.

[0018] This "prior art" section is intended to describe various aspects of the prior art that may be related to embodiments of the present invention. Thus, the foregoing discussion in this section provides a basis for a better understanding of the present invention, and should not be construed as an admission of the conventional art.

SUMMARY OF THE INVENTION

[0019] There has been a longstanding and unmet need for, among other things, assemblies and systems for combining multiple laser beam sources into one or more laser beams while maintaining and improving desired beam quality, such as brightness and power. The present invention, among other things, satisfies these needs by providing proposed and disclosed here, the products of production, devices and processes.

[0020] An embodiment of the present invention provides an additive manufacturing system based on a 1-D or 2-D array of laser beams capable of directly fusing powder in parallel with the possibility of sequential stepping using a precise portal system (Fig. 1, 2, 3). The speed can be increased by adding a 1-D or 2-D secondary laser beam for preheating and controlled cooling (FIG. 4). This secondary laser may also be an addressable array of laser beams to provide a preheat pattern consistent with the buildup pattern.

[0021] Another element of the embodiment of the invention involves the use of a camera for monitoring temperature in real time, for example, a thermal imaging camera. The camera can be used to monitor the real-time temperature of the powder layer as it changes from solid to liquid, and the image on the camera can be correlated with the applied laser pattern, and the power level of individual laser beams can be adjusted according to a predetermined requirement to ensure proper fusion and cooling of the printed details. This feedback temperature control provided additional benefits, such as minimizing the porosity of the manufactured part, as well as optimizing surface roughness and minimizing residual stresses in the part.

[0022] According to an embodiment of the present invention, means are included for depositing the powder in real time in any direction during the printing process, as well as for compacting the powder pad to minimize the porosity of the powder pad. The main mechanism for melting and fusing the powder will be conduction welding as opposed to a galvanometric scanning system where keyhole welding is used. This approach minimizes sputtering and window and optic protection requirements for fabricated parts.

[0023] According to an embodiment, the present invention includes a sealed enclosure for forming an oxygen-free environment and a gas recirculation system continuously purifying the used gas mixture. Filtration of the gas mixture is necessary because volatile powders and welding fumes that are not removed from the environment can affect the image quality and, consequently, the quality of the built-up part.

[0024] According to an embodiment, the present invention includes a micromachining system that performs pre-growth analysis, slicing the part, and determining the optimal build-up strategy. As each portion of the part pattern is printed, the gantry system may move to the next adjacent pattern detail, or may be commanded to move to any arbitrary position if the build-up strategy requires random printing of a partial pattern to minimize residual stresses on the part.

[0025] According to an embodiment, the present invention also does not require a welding monitor other than a simple visible camera to observe the weld pool as it spreads. Since there is a keyholeless welding mode, the weld pool is very stable, even when welding copper and aluminum, which is not possible with an IR laser source. The IR laser source must be supported by a welding monitor, such as an optical coherence tomography (OCT) scanner, to obtain an accurate representation of the keyhole, and how the build-up of the part develops with keyhole mode instabilities. Since the conduction mode of powder-to-base material welding is a very stable welding mode, there is no sputtering, the welded powder is very uniform in thickness and shape, and the part density is 100% due to no material evaporation during the welding process.

[0026] Thus, an additive manufacturing system is provided, the process and the laser system having one or more of the above features. Additionally, a laser system, an additive manufacturing system, a process, and a laser system having one or more of the above features in conjunction with the following laser systems and methods are provided.

[0027] Thus, a laser system for performing laser operations is provided, the system having: a plurality of laser diode assemblies; wherein each laser diode assembly has a plurality of laser diodes capable of producing a single blue laser beam along the path of the laser beam; means for spatially combining the individual blue laser beams to create a combined laser beam having a single far-field spot that is capable of being incorporated into an optical fiber for delivery to a target material; and means for spatially combining the individual blue laser beams in the path of the laser beam and in optical communication with each laser diode.

[0028] Additionally, methods and systems are provided having one or more of the following features: having at least three laser diode assemblies; and the presence in each assembly of laser diodes at least 1 laser diode; wherein the laser diode assemblies are capable of propagating laser beams having a total power of at least about 2 W and a beam parameter property of less than 20 mm mrad; where the beam parameter property is less than 15 mm mrad; where the beam parameter property is less than 10 mm mrad; moreover, the means for spatial combining creates a combined laser beam, N times greater than the power density of the individual laser beams; where N is the number of laser diodes in the assembly of laser diodes; moreover, the means for spatial combining increases the power of the laser beam, while maintaining the brightness of the combined laser beam; whereby the combined laser beam has a power that is at least 50 times the power of the individual laser beam, and whereby the beam parameter product of the combined laser beam does not exceed N times the beam parameter product of the individual laser beam; due to which, the product of the beam parameter of the combined laser beam does not exceed 1.5 * N times the product of the beam parameter of the individual laser beam; due to which, the product of the beam parameter of the combined laser beam does not exceed 1*N times the product of the beam parameter of the individual laser beam; moreover, the means for spatial combining increases the power density of the composite laser beam, while maintaining the brightness of the individual laser beams; whereby the combined laser beam has a power density that is at least 100 times greater than the power of the individual laser beam, and whereby the beam parameter product of the combined laser beam does not exceed 2*N times the beam parameter product of the individual laser beam; due to which, the product of the beam parameter of the combined laser beam does not exceed 1.5 * N times the product of the beam parameter of the individual laser beam; due to which, the product of the beam parameter of the combined laser beam does not exceed 1*N times the product of the beam parameter of the individual laser beam; moreover, the optical fiber is resistant to solarization; moreover, the means for spatial combining has optical nodes selected from the group consisting of plates and wedges parallel to the plane of alignment, to correct at least one of the position errors and pointing errors of the laser diode; wherein the spatial combining means has a polarization beam combiner capable of increasing the effective brightness of the combined laser beams over the individual laser beams; moreover, the laser diode assemblies define separate paths of laser beams with a space between each of the paths, due to which the individual laser beams have a space between each beam; and wherein the means for spatial combining has a collimator for collimating individual laser beams on the axis of the highest light velocity of the laser diodes, a periodic mirror for combining the collimated laser beams, and the periodic mirror is configured to reflect the first laser beam from the first diode in the laser diode assembly and transmits a second laser beam from the second diode in the laser diode assembly, whereby the space between the individual laser beams in the direction of the highest light velocity is filled; moreover, the means for spatial association has a patterned mirror on a glass substrate; moreover, the glass substrate has a sufficient thickness to shift the vertical position of the laser beam from the laser diode to fill the empty space between the laser diodes; and having a stepped heat sink.

[0029] In addition, a laser system is provided for providing a high brightness, high power laser beam, the system having: a plurality of laser diode assemblies; wherein each laser diode assembly has a plurality of laser diodes capable of producing a blue laser beam having an initial brightness; means for spatially combining the blue laser beams to create a combined laser beam having final brightness and forming a single spot in the far field, which is capable of being included in the optical fiber; each laser diode is fixed by an external resonator at a separate wavelength to significantly increase the brightness of the combined laser beam, so that the final brightness of the combined laser beam is close to the initial brightness of the laser beam from a single laser diode.

[0030] Methods and systems are further provided having one or more of the following features: each laser diode is fixed at a single wavelength using an external grating-based resonator, and all laser diode assemblies are combined into a combined beam using a combining means selected from a group consisting of a narrowly spaced optical filter and a diffraction grating; the Raman converter is an optical fiber having a pure fused silica core to provide a higher brightness source and an outer core surrounded by either air or a low refractive index polymer to channel the blue pump light; a Raman converter is used for pumping a Raman converter, for example, an optical fiber having a GeO ₂ doped center core with an outer core to create a source of higher brightness, and an outer core that is larger than the center core to channel blue pump light; the Raman converter is an optical fiber having a core doped with P ₂ O ₅ to create a source of higher brightness, and an outer core that is larger than the central core to channel blue pump light; the Raman converter is an optical fiber having a core with a smooth refractive index profile to create a source of higher brightness, and an outer core that is larger than the central core to channel blue pump light; a Raman transducer having a GeO ₂ doped core with a smooth refractive index profile and an outer core with a stepped refractive index profile; a Raman transducer is used to pump a Raman transducer fiber having a P ₂ O ₅ doped soft index core and an outer stepped refractive index profile; a Raman converter is used to pump a Raman converter fiber having a GeO ₂ doped core with a smooth refractive index profile; the Raman transducer has a core with a smooth refractive index profile doped with P ₂ O ₅ and an outer core with a stepped refractive index profile; the Raman transducer is a diamond to create a higher brightness laser source; the Raman transducer is made of KGW to create a higher brightness laser source; the Raman transducer is made of YVO ₄ to create a higher brightness laser source; the Raman converter is made of Ba(NO ₃ ) ₂ to create a laser source of higher brightness; and the Raman transducer is a high pressure gas to create a higher brightness laser source.

[0031] In addition, a laser system for performing laser operations is provided, the system having: a plurality of laser diode assemblies; wherein each laser diode assembly has a plurality of laser diodes capable of producing a blue laser beam along the path of the laser beam; means for spatially combining the blue laser beams to create a combined laser beam having a single spot in the far field, which is capable of optically connecting to the Raman converter, for pumping the Raman converter, to increase the brightness of the combined laser beam.

[0032] Additionally, a method is provided for providing a combined laser beam, the method having an array of Raman-transformed lasers for generating blue laser beams at different wavelengths and combining the laser beams to create a source of higher power, while maintaining the spatial brightness of the original source.

[0033] In addition, a laser system for performing laser operations is provided, the system having: a plurality of laser diode assemblies; wherein each laser diode assembly has a plurality of laser diodes capable of producing a blue laser beam along the path of the laser beam; optics for collimating and combining beams along the path of the laser beam, which is capable of providing a combined laser beam; and an optical fiber for receiving the combined laser beam.

[0034] In addition, methods and systems are provided having one or more of the following features: an optical fiber is in optical communication with a rare earth doped fiber, whereby the combined laser beam is capable of pumping the rare earth doped fiber to create a laser source higher brightness; and the optical fiber is in optical communication with the outer luminance converter core, whereby the combined laser beam is able to pump the outer luminance core to create a higher brightness enhancement ratio.

[0035] Further, a Raman fiber is provided having: two cores, where one of the two cores is a high brightness central core; and means for suppressing a second-order Raman signal in a central high-brightness core selected from the group consisting of a filter, a fiber Bragg grating, a difference in the V number for the first-order and second-order Raman signals, a two-pass gain difference for the first-order Raman signals, order and second order due to the length of the fiber or resonator mirrors and differences in microbending losses.

[0036] In addition, a second harmonic generation system is provided, the system having: a Raman converter at a first wavelength for generating light in a nonlinear crystal at half a wavelength of the first wavelength; and an externally resonant frequency doubling crystal configured to prevent half wavelength light from propagating through the optical fiber.

[0037] In addition, there are methods and systems having one or more of the following features: the first wavelength is about 460 nm; and the externally resonant frequency doubling crystal is KTP; and the Raman transformer has a non-circular outer core structured to improve the efficiency of the Raman transform.

[0038] Additionally, a third harmonic generation system is provided, the system having: a Raman converter at a first wavelength to generate light at a second wavelength lower than the first wavelength; and an externally resonant frequency doubling crystal configured to prevent lower wavelength light from propagating through the optical fiber.

[0039] A fourth harmonic generation system is further provided, the system having: a Raman converter for generating light at 57.5 nm using an externally resonant frequency doubling crystal configured to prevent the propagation of light with a wavelength of 57.5 nm through the optical fiber.

[0040] A second harmonic generation system is further provided, the system having a rare earth doped luminance converter, such as thulium, that generates coherent radiation at 473 nm when pumped by an array of 450 nm blue laser diodes, to generate light at half the wavelength of the original laser, or 236.5 nm using an externally resonant frequency doubling crystal, but does not allow short wavelength light to propagate through the optical fiber.

[0041] A third harmonic generation system is further provided, the system having a luminance converter doped with a rare earth element, such as thulium, which generates coherent radiation at 473 nm when pumped by an array of 450 nm blue laser diodes to generate light at 118.25 nm using an externally resonant frequency doubling crystal, but does not allow small wavelength light to propagate through the optical fiber.

[0042] A fourth harmonic generation system is further provided, the system having a rare earth doped luminance converter, such as thulium, which generates coherent radiation at 473 nm when pumped by an array of 450 nm blue laser diodes to generate light at 59.1 nm using an externally resonant frequency doubling crystal, but does not allow small wavelength light to propagate through the optical fiber.

[0043] In addition, a laser system for performing laser operations is provided, the system having: at least three laser diode assemblies; each of the at least three laser diode assemblies has at least ten laser diodes, wherein each of the at least ten laser diodes is capable of producing a blue laser beam having a power of at least about 2 watts and a beam parameter product of less than 8 mm-mrad, along the path of the laser beam, where all the paths of the laser beam are essentially parallel, whereby between the laser beams propagating along the paths of the laser beams, the space is set; means for spatially combining and maintaining the brightness of blue laser beams located on all of at least thirty laser beam paths, wherein the means for spatially combining and maintaining brightness has collimating optics for the first axis of the laser beam, an array of vertical prisms for the second axis of the laser beam, and a telescope ; whereby the spatial combining and storing means fills the space between the laser beams with laser energy, thereby providing a combined laser beam at a power of at least about 600 W, and a beam parameter product of less than 44 mm-mrad.

[0044] In addition, an addressable array laser processing system is provided, wherein the addressable array laser processing system has: at least three laser systems of the type described herein; each of the at least three laser systems is configured to insert each of their combined laser beams into a single optical fiber; whereby each of the at least three combined laser beams is able to be transmitted along the optical fiber connected to it; at least three optical fibers are optically coupled to the laser head; and control system; where the control system has a program having a predetermined sequence for delivering each of the combined laser beams at a predetermined position on the target material.

[0045] In addition, methods and systems are provided for an addressable array having one or more of the following features: a predetermined sequence for individually turning on and off the laser beams from the laser head, thereby forming an image on the powder pad to melt and fuse the target material having powder, into detail; the fibers in the laser head are configured in an arrangement selected from the group consisting of linear, non-linear, circular, rhombic, square, triangular, and hexagonal; the fibers in the laser head are configured in an arrangement selected from the group consisting of 2×5, 5×2, 4×5, at least 5×at least 5, 10×5, 5×10 and 3×4; the target material has a powder pad; and having: an x-y movement system capable of moving the laser head over the powder pad, thereby melting and fusing the powder pad; and a powder delivery system that can move behind the laser source to provide a fresh powder layer behind the fused layer; having: a z-axis movement system capable of moving the laser head to increase and decrease the height of the laser head above the surface of the powder pad; having: a bi-directional powder placement device capable of placing the powder directly behind the delivered laser beam when it propagates in the positive x-axis direction or the negative x-axis direction; having a powder supply system that is coaxial to a plurality of laser beam paths; having a gravity-flowing powder supply system; having a powder supply system in which the powder is entrained in an inert gas flow; having a powder supply system that is transverse to the N laser beams, where N > 1, and the powder is positioned by gravity in front of the laser beams; and having a powder supply system that is transverse to the N laser beams, where N > 1, and the powder is entrained by an inert gas flow that crosses the laser beams.

[0046] In addition, a method is provided for providing a combined blue laser beam having a high brightness, the method having: using a plurality of Raman-transformed lasers to provide a plurality of individual blue laser beams, and combining the individual blue laser beams to create a higher power source while maintaining spatial brightness of the original source; wherein the individual laser beams of the set have different wavelengths.

[0047] In addition, a method for laser processing a target material is provided, the method having an addressable array laser processing system having at least three laser systems, like systems described herein, for generating three separate combined laser beams into three separate optical fibers; passing each of the combined laser beams along the respective optical fiber to the laser head; and directing three separate combined laser beams from the laser head in a predetermined sequence at a predetermined position on the target material.

In one embodiment, the light source comprises an array of fibers that deliver light from an array of fiber Raman lasers operating in the wavelength range from 300 nm to 500 nm.

In one embodiment, the light source contains an array of optical fibers having diameters selected from the group consisting of 10 µm - 50 µm, 50 µm - 100 µm and 100 µm - 500 µm.

In one embodiment, the light source contains a single bundle of separate optical fibers connected to separate light sources, which is re-imaged by optics, which can be 1:0.5, 1:1, 1:2 up to and including 1:10.

In one embodiment, the light source is independently mounted individual fibers.

In one embodiment, the system includes a high resolution thermal imaging camera for directly monitoring the temperature in each spot during operation and providing feedback to a microprocessor that controls the power of each spot and thus the build quality of the part from spot to spot.

In one embodiment, the system includes an array of pyrometers to directly monitor the temperature in each spot during operation and provide feedback to a microprocessor that controls the power of each spot and thus the build quality of the part from spot to spot.

In one embodiment, the light source is a blue laser light source for fusing copper powders.

In one embodiment, the light source is a blue laser light source for fusing gold powders.

In one embodiment, the light source is a blue laser light source for optimal fusion of aluminum powders.

In one embodiment, the light source is a laser blue light source for fusing all metals and metal alloys.

In one embodiment, the print head contains an optical system containing a collimator, which can be a plano-convex lens, a plano-convex aspherical lens, a pair of doublet or triplet lenses, and a focusing optics consisting of a plano-convex lens, a plano-convex aspherical lens , here the source is 1f from the collimating lens and 1f from the focusing lens.

In one embodiment, the printhead optics are reimaging optics with the source at least 2f from the lens and the image at least 2f from the lens in the opposite direction.

In one embodiment, the system further comprises a piston for delivering the powder to the printer pad for redistribution.

In one embodiment, the array of light sources is an array of Raman lasers operating in the wavelength range from 300 nm to 500 nm.

In one embodiment, the light source array is an array of optical fibers with diameters ranging from 10 µm to 50 µm, 50 µm to 100 µm, or 100 µm to 500 µm.

In one embodiment, the array of light sources is a single bundle of separate optical fibers connected to separate light sources, which is re-imaged by optics, which can be 1:0.5, 1:1, 1:2 up to and including 1:10.

In one embodiment, the light source array is independently mounted individual fibers.

In one embodiment, the secondary light source is a Raman laser operating in the wavelength range from 300 nm to 500 nm.

In one embodiment, the secondary light source is a laser diode system operating in the wavelength range of 400 nm - 500 nm.

In one embodiment, the temperature of the powder irradiated by the secondary light source is measured by a thermal imaging camera, and the signal from the camera is used to adjust the average temperature of the illuminated area.

In one embodiment, the temperature of the powder irradiated by the secondary light source is measured by a pyrometer, and the signal from the pyrometer is used to adjust the average temperature of the illuminated area.

In one embodiment, the camera is a high resolution thermal imaging camera for directly monitoring the temperature in each spot during operation and providing feedback to a microprocessor that controls the power of each spot and thus the build quality of the detail from spot to spot.

In one embodiment, the system further comprises a gravity-fed powder delivery system that operates in both directions.

In one embodiment, the system further comprises a piston for delivering the powder to the printer pad for redistribution.

In one embodiment, the system further comprises a rotating wheel moving opposite to the direction of movement of the hopper to compress and compact the powder to reduce the porosity of the powder bed.

In one embodiment, the control signal may be a signal proportional to the temperature of the powder bed.

In one embodiment, the control signal may be a signal proportional to the temperature of the melt pool generated at each point of the 1-D or 2-D image on the powder pad.

One embodiment uses a laser blue light source to fuse copper powders.

One embodiment uses a laser blue light source to fuse gold powders.

One embodiment uses a laser blue light source to optimally fuse aluminum powders.

One embodiment uses a laser blue light source to optimally fuse all other metals and metal alloys.

In one embodiment, the system further comprises a print head, the print head comprising an optical system comprising a collimator, which may be a plano-convex lens, a plano-convex aspherical lens, a pair of doublet or triplet lenses, and a focusing optics consisting of a plano-convex lens, plano-convex aspherical lens, here the source is 1f from the collimating lens and 1f from the focusing lens.

In one embodiment, the optical system in the print head is a reimaging optic where the source is at least 2f from the lens and the image is at least 2f from the lens in the opposite direction.

In one embodiment, the light source array is an array of fibers supplying light from an array of fiber Raman lasers operating in the wavelength range from 300 nm to 500 nm.

In one embodiment, the light source array is an array of optical fibers with diameters ranging from 10 µm to 50 µm, 50 µm to 100 µm, or 100 µm to 500 µm,

In one embodiment, the array of light sources is a single bundle of separate optical fibers connected to separate light sources, which is re-imaged by optics, which can be 1:0.5, 1:1, 1:2 up to and including 1:10.

In one embodiment, the light source array is independently mounted individual fibers.

In one embodiment, the array of secondary light sources is a fiber Raman laser operating in the wavelength range from 300 nm to 500 nm.

In one embodiment, the temperature of the powder irradiated by the array of secondary light sources is measured by a thermal imaging camera, and the signal from the camera is used to adjust the average temperature of the illuminated area.

In one embodiment, the temperature of the powder irradiated by an array of secondary light sources is measured by a pyrometer, and the signal from the pyrometer is used to adjust the average temperature of the illuminated area.

In one embodiment, the camera is a high resolution thermal imaging camera for directly monitoring the temperature in each spot during operation and providing feedback to a microprocessor that controls the power of each spot and thus the build quality of the detail from spot to spot.

In one embodiment, the system further comprises a gravity-fed powder delivery system that operates in both directions.

In one embodiment, the system further comprises a piston for delivering the powder to the printer pad for redistribution.

In one embodiment, the system further comprises a rotating wheel moving opposite to the direction of movement of the hopper to compress and compact the powder to reduce the porosity of the powder bed.

In one embodiment, the control signal may be a signal proportional to the temperature of the powder bed.

In one embodiment, the control signal may be a signal proportional to the temperature of the melt pool generated at each point of the 1-D or 2-D image on the powder pad.

In one embodiment, the system further comprises a print head, the print head comprising an optical system comprising a collimator, which may be a plano-convex lens, a plano-convex aspherical lens, a pair of doublet or triplet lenses, and a focusing optics consisting of a plano-convex lens, plano-convex aspherical lens, here the source is 1f from the collimating lens and 1f from the focusing lens.

In one embodiment, the optical system in the print head is a reimaging optic where the source is at least 2f from the lens and the image is at least 2f from the lens in the opposite direction.

In one embodiment, the system uses a laser blue light source to fuse copper powders.

In one embodiment, the system uses a laser blue light source to fuse gold powders.

In one embodiment, the system uses a blue laser light source to optimally fuse aluminum powders.

In one embodiment, the system uses a laser blue light source to optimally fuse all other metals and metal alloys.

In one embodiment, the printhead is mounted with similar printheads on one or more portals to print images in parallel.

In one embodiment, the printhead is mounted with similar printheads on one or more portals to print an image that is a portion of the part.

In one embodiment, the printhead is mounted with similar printheads on one or more portals and the printhead optical system is used to combine images from multiple sources to create a larger continuous image.

In one embodiment, the print head is installed with similar print heads on one or more portals for printing an image in a checkerboard pattern, which are combined with each other by successive step transfer of intermediate patterns.

In one embodiment, the control signal contains a signal proportional to the temperature of the powder bed.

In one embodiment, the control signal comprises a signal proportional to the temperature of the melt pool generated at each point of the 1-D or 2-D image on the powder pad.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG. 1 is a perspective view of an embodiment of a fiber array 3-D printer in accordance with the present invention.

[0049] FIG. 2A is a perspective view of an embodiment of a fiber-based printhead in accordance with the present invention.

[0050] FIG. 2B is a perspective view of the fiber-based printhead shown in FIG. 2A from a different perspective.

[0051] FIG. 3 is a schematic graphical description of an embodiment of an optical bundle and beam paths, in accordance with the present invention.

[0052] FIG. 4A is a perspective view of an embodiment of a 1-D tow connector outlet for a tow of fibers for a 1-D patterning system in accordance with the present invention.

[0053] FIG. 4B is a perspective view of an embodiment of a fiber combiner in accordance with the present invention.

[0054] FIG. 5A is a diagram of an embodiment of a 3-D printhead with a secondary laser heat source and a primary 1-D patterning system in accordance with the present invention.

[0055] FIG. 5B is a perspective view of an embodiment of an overlapping image of a secondary laser pattern and a multi-spot primary image in accordance with the present invention.

[0056] FIG. 6A is a diagram of an embodiment of a 3-D print head with a secondary laser heat source and a primary 1-D patterning system in accordance with the present invention.

[0057] FIG. 6B is a perspective view of an embodiment of an overlapping image of a secondary laser pattern and a multi-spot primary image in accordance with the present invention.

[0058] FIG. 7A is a diagram of an embodiment of a printhead having a 1-D primary multispot image and a primary image laser diode array heating secondary image in accordance with the present invention.

[0059] FIG. 7B is a perspective view of an embodiment of an overlapping image of a secondary laser pattern and a multi-spot primary image in accordance with the present invention.

[0060] FIG. 8A-8F are plan views of various embodiments of fiber tow image configurations (e.g., laser beams forming a laser beam pattern or laser pattern) on a powder pad in accordance with the present invention, with arrows indicating the direction of movement of the pattern on the pad.

[0061] FIG. 9A-9F are plan views of various embodiments of image configurations of a tow of fibers (e.g., laser beams forming a laser beam pattern or laser pattern) on a powder pad, where the image of the primary laser beams is associated with the image of the secondary laser beam, in accordance with the present invention, where the arrows indicate the direction of movement of both patterns on the pillow. (Primary image patches are shown as solid patches, and secondary image patches are shown as outline patches.)

[0062] FIG. 10A-10F are plan views of various embodiments of image configurations of a tow of fibers (e.g., laser beams forming a laser beam pattern or a laser pattern) on a powder pad, where the image of the primary laser beams is associated with the image of the secondary laser beam, and the secondary laser beams have different temporary features that create secondary images of different shapes, in accordance with the present invention, where the arrows indicate the direction of movement of both patterns on the pillow. (Blots in the primary image are shown as solid patches, and the secondary image of the patch is shown as outline patches.)

[0063] FIG. 11 is a schematic plan view of displaying a powder pad image on a thermal imaging camera in accordance with the present invention.

[0064] FIG. 12 is a diagram of an embodiment of a control system and feedback control process in accordance with the present invention.

[0065] FIG. 13 is an image and spectrum of a blue Raman-transformed laser beam in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] The present invention relates to laser materials processing and, in particular, to laser material growth, including laser additive manufacturing processes using laser beams having wavelengths from about 350 nm to 700 nm.

1-D drawing system

[0067] FIG. 1 shows a perspective view of a 3-D (three-dimensional) additive manufacturing device or a printer 100. The printer 100 has a fiber configuration included in the print head, which has a 1-D (one-dimensional) fiber configuration. This 1-D system may have incoming fibers arranged in a linear manner, such as shown in FIG. 2A and 2B and having beam paths, images, and optics as shown, for example, in FIG. 3.

[0068] Thus, in FIG. 1-3 shows an example of a 3-D printer that uses a 1-D patterning system, where 1-D refers to the configuration for a bundle of fibers that provide and fire laser beams used to grow a 3-D object.

[0069] Referring first to FIG. 1, but in the context of FIG. 2A, 2B, and 3, system 100 consists of a portal system xy 101 that moves print head 200 in the x and y direction. the portal system is mounted on a base 112, which may be made of granite or metal, or preferably other materials that are heavy, stable, and both. The base may be vibrationally isolated from the rest of the system using rubber or air mounts underneath to prevent transmission of vibrations from the base to powder pad 110 and printhead 200. The entire system 100 may be enclosed in an airtight environment (not shown) to provide an inert atmosphere for powder processing. The inert atmosphere may be argon, nitrogen, helium, or any other inert gas other than oxygen. An inert atmosphere can be at reduced pressure, atmospheric pressure, or elevated pressure, and can be flowing (inlet and outlet ports), inflowing (i.e., renewable gas flowing in but not flowing out), or non-flowing (inlet and outlet closed after filling). inert gas). A preferred embodiment is argon as well as argon-CO ₂ mixtures to facilitate the flow of molten powder by lowering their surface tension. The gantry table carries the print head 200, and the fiber array is delivered by a QBH type connector 102 to the print head 200. Just below the print head is a powder pad 110 where the image conveyed by the bundle or fiber array is re-imaged 103 on the powder pad 110. The powder is dispensed. a bi-directional powder distributor 108 that rides on a pair of linear rails 109 for precise movement. The powder dispenser can be moved either by y-movement along the Y parallel transfer rail 106 of the portal system 101, or by a separate motor included in the powder dispenser assembly. The powder is loaded into the powder distributor at the front and rear edges of the base 112, and the powder is delivered to the powder bed by gravity. The powder distributor includes a roller 107 that rotates in the opposite direction to the direction of travel to distribute and compress the powder bed. Compressing the powder pad minimizes the porosity of the final part. Power and sensor signals are supplied through the flexible cable tray 105 on the side of the gantry as the gantry moves in the y direction.

[0070] The portal system 101 has a Y parallel transfer guide 106 for moving the print head 200 in the y direction; and has an X parallel transfer guide 111 for moving the print head 200 in the x direction. The system 100 has a powder pad lifter 104 (to move the part down as it builds up so that the next layer can be deposited on the part).

[0071] In the preferred embodiment, print head 200 is shown in FIG. 2A and 2B. In FIG. 2A and 2B are perspective views of the same embodiment but from different perspectives, it will be appreciated that typically the print head will be closed or have a front plate which is not shown in the figures. The tow of fibers has 2, 3, 4, 5, 6, 2-10, and combinations thereof, as well as large numbers, arranged in a line, preferably a straight line. The bundle of fibers is delivered through a QBH connector 201. The QBH connector 201 is held in place by a collet 202 which is mounted on the housing 203 of the printhead 200. The optical system consists of collimating optics 204 and focusing optics 205. These two optics can be replaced by a single imaging optic . The laser beams are launched from the ends of the fibers 210 and the laser beams propagate along the path of the laser beam to the lens 204, the lens 205 and then the output window 209 to form the image 103. In addition to the optical system, the printhead 200 may also include a thermal imaging camera 207 or a pyrometer for monitoring the temperature of the melt bath, through a hole or window 208 for a multispot image 103, on a powder pad.

[0072] FIG. 3 shows a diagram of an embodiment of a 1-D optical system 300 and the path of its laser beams. This 1-D optical system may, for example, be used in the printhead 200. The fiber bundle 301 has five optical fibers 301a, 301b, 301c, 301d, 301e arranged in a straight line and provides output laser beams along the beam path having paths 305 beams, and the output is collimated by a lens 302, which may be a plano-convex lens, a plano-convex aspherical lens, a lens pair, a lens triplet, or a similar type of optic. The collimated beams from the array bundle, having beam paths 307, are then focused onto an image 304 having a row of spots 304a, 304b, 304c, 304d, 304e by a focusing lens 303, which may be a plano-convex lens, a plano-convex aspherical lens, a lens pair , triplet lenses or similar type of optics. The size of the fibers is indicated by scale 320, and the size of the image and spots is shown by scale 321. The curved surfaces of the plano-convex and plano-aspherical lenses face each other to minimize spherical aberrations of the system. The ray path shown in Fig. 3 corresponds to two plano-aspherical fused silica lenses. The spot is in the focal or Fourier transform plane, and due to the small aberrations in the system, there is a slight expansion of the image obtained in the overlap of the individual fiber images, i.e. spots 304a, 304b, 304c, 304d, 304e that make up the image 304. The system may also use a single imaging lens, where the firing end of the fiber source 301 will be located at least 2f from the imaging optics and the imaging plane will be at least at 2f from the same optics. This approach would require a significantly larger lens than the preferred embodiment using a collimating lens and a focusing lens to reimage the fiber tow. A thermal imaging camera or pyrometer preferably monitors the temperature of the melt bath, for each individual spot in the multi-spot image, on the powder bed.

[0073] In embodiments of the 1-D patterning system, the 1-D line of emitters, eg, fiber ends, may be 2, 3, 4, ..., n, depending on the physical size of the fibers and the QBH connector. In an embodiment, there is a single fiber. According to an embodiment, 2 to 15, 2 to 10, 5 to 50, 2 to 1000, 5 to 500, 100 to 2000, more than 10, more than 20, more than 50, and combinations and variations thereof, and larger and smaller amounts of fibers are located, for example, side by side. Thus, for example, fibers with a diameter of 200 µm (having a core diameter of, for example, from about 10 to about 185 µm) and their bundles and the image of the bundles re-imaged on the powder pad to provide power to melt and fuse the powder with the base can be used. material.

[0074] FIG. 4A is a perspective view of an embodiment of a QBH harness connector outlet 700. This connector outlet 700 has five fibers 701 arranged in a straight line to provide five emitters of laser beams and their images, such as circular spots. Connector outlet 700 has a QBH mechanical inlet 702 that accommodates five fibers. This inlet 702 may be inserted into, for example, a printhead or a connector, such as the type shown in FIG. 4b. Connector outlet 700 has a protective coating 703 that covers the optical fibers and has a disconnect sensor.

[0075] An example embodiment of a tow combiner is shown in FIG. 4b. Combiner 806 in this case is an empty space combiner where input fibers 801, 802, 803, 804, 805 are collimated to combine and refocused into output fiber bundle 807, which is then transmitted by optical fibers to, for example, output connector, print head. The bundle of fibers receives power from each of the individual fibers, 801, 802, 803, 804, 805, and is redrawn onto the powder bed. The power from each fiber can be about 2 watts (W), 10W, 100W, about 150W, about 500W, about 1kW, about 2kW, about 1W to about 2kW, about 2W to about 150 watts, from about 250 watts to about 1 kW, or many kilowatts, and combinations and variations thereof, depending on, for example, how fast the portal system can scan and the image size of the fiber bundle.

[0076] Examples of various embodiments of 1-D laser image patterns (eg, multi-spot images) that can be generated by 1-D fiber tow configurations and printheads are shown in FIG. 8A, 8B, 8C, 8D, 8E, 8F. The direction of movement of the pattern on the powder pad is indicated by arrows. These laser patterns can be used with any of the embodiments of additive manufacturing systems, printheads, and methods in accordance with the present invention.

[0077] The spots in a multi-spot image may be round, elliptical, square, rectangular, and other shapes; they can unite, adjoin, overlap, partially overlap; they can be linear, rectilinear, curvilinear, stepped, in a pattern that forms a larger area, such as a square or rectangular; and combinations and variations of these and other configurations and arrangements. These laser patterns can be used with any of the embodiments of additive manufacturing systems, printheads, and methods in accordance with the present invention.

[0078] The part is printed by scanning a 1-D image of a tow of fibers over a powder pad. The 1-D image of the high power fiber outputs is swept on the y-axis by the gantry system and staggered on the x-axis to repeat the pattern. The step change may be adjacent to a simple printer track, or it may vary arbitrarily depending on the stress patterns desired in the final part. After printing, the powder bed lifter, which is positioned under the powder bed, lowers the powder bed by a predetermined amount, (e.g., about 40 µm, about 50 µm, about 60 µm, about 35 µm to about 65 µm, and combinations thereof, and large and smaller distances), the powder spreader distributes an even layer of powder metal, the roller compresses the powder pad to reduce the porosity of the powder. After preparing the powder pad for the next layer, the following layers are printed with a 1-D image of the fiber tow, scanned across its surface.

[0079] The fiber system can also be replaced by individual laser diodes, however this is not a preferred embodiment due to the size of the printhead and the complex electronics required to drive the individual laser diodes. The individual laser diodes may form part of an addressable line array of laser diodes, in which case the individual laser diodes form part of a continuous line array, with individual current drive capabilities. This is a good alternative to the fiber approach with limited single emitter power.

P1-D patterning system with secondary laser

[0080] According to an embodiment, an additional or second laser beam is added to the printhead to provide a means for preheating, controlling cooling, and adjusting the temperature of the printed image. The secondary laser beam may also be referred to as a heating beam; while the primary laser beams, which are used to melt and fuse the powder to form the object, may be referred to as the build-up laser and build-up laser beam.

[0081] An embodiment of a printhead having primary and secondary laser beams is shown in FIG. 5A, the bundle of fibers that provides the primary laser beams and produces the primary image 409 (which may be a multi-spot image) on the powder pad is delivered by a QBH connector 401 and attached to the print head 400 by a collet 402. An optical system for the beam path and beam delivery for the primary image 409 consists of a lens 405 for collimating the exit of the bundle of fibers. The collimated output is then focused onto the powder pad as the primary image 409 by the focusing lens 406. This optical system is similar to the previous description where the lenses can be plano-convex, plano-convex aspherical, doublets or triplets. The second laser beam is introduced into the print head 400 through an optical fiber delivered by a QBH connector 403 which is attached to the print head by a collet 404. A lens 407 is used to collimate the output of the fiber. Lens 407 may be plano-convex, plano-convex aspherical, doublet, or triplet. At high power levels, the doublet or triplet must have an air separation since most cements cannot withstand high power levels. The collimated beam is then converted and focused into a powder pad by a lens or microlens system 408 which shapes the beam into a secondary image and redirects it to overlap with the primary image 409. An embodiment of these overlapping images is shown in FIG. 5b. The overlapping images 450 may be a primary multi-spot image 451 having primary spots 411, 412, 413, 414, 415 that propagate from the primary fibers in the primary fiber tow. The primary spots are combined with the secondary image 410 of the secondary converted laser beam. Preferably, the secondary image heats the volume of powder 420. In this embodiment, the secondary laser beam is designed to deliver most of its energy just ahead of the 1-D pattern 451 carried in the “y” direction indicated by arrow 416. Both the primary 451 and secondary 410 patterns move at the same speed and in the same direction 416. This secondary beam pattern preheats the powder, helps the tow image to melt the powder and fuse it to the substrate, and provides some post-fusion heat to anneal the material, thus reducing internal stresses in the printed part. . The rest of the system functions as described in the previous section, where a thermal imaging camera or array of pyrometers is built into the system to provide feedback to the laser systems to support the powder just before imaging the primary fiber tow 451 at a predetermined temperature, preferably just below the melting point of the powder. During the fusion process, feedback from the thermal imaging camera or pyrometer array is used to adjust the power of the secondary laser, the individual lasers in the fiber bundle that produce the image 451, and both to create a predetermined temperature of the powder in the fiber bundle image. The predetermined powder temperatures used in the system will initially be empirically determined with the system and used as a guide for all build-ups to minimize surface roughness, part porosity and part size. The secondary laser source can be 50 W, 100 W, 150 W, 500 W, 1000 W, about 50 W to about 2 kW, about 250 W to about 1 kW, and many kilowatts, and all values in these ranges, depending on, for example, the scanning speed of the printhead and the area of the fiber array pattern used.

[0082] FIG. 6A and 6B show a perspective view of a laser head 500 that provides a combined image 509 of secondary image 552 and primary image 551, where both the secondary fiber tow and the laser source provide an addressable thermal pattern on the powder pad. Fig. 6 illustrates the use of a recycled fiber bundle where the fiber bundle is connected by a connector 503 to printhead 500 by collet 504. The primary fiber bundle is connected by connector 501 and collet 502 to printhead 500 and has a collimating lens 505 and a Fourier transform focusing lens 506. The lens 507 collimates the bundle of fibers and the transformation system 508 creates n bundle images of the bundle of recycled fibers which can be individually manipulated to form an image 552 which in this embodiment has images 516, 517, 518, 519, 520 which correspond to the volume of powder in the powder. pillow that is heated. By controlling the on and off times of each secondary laser source, the preheating and cooling characteristics of each respective image volume 516-520 can be varied. According to the embodiment of FIG. 5B, the two outer fibers that provide the outer secondary images 516, 520 are switched on and off simultaneously to preheat the outer edge of the pattern. Then the two inner fibers that provide the images 517, 519 turn on a little later so that the heat generated from the outer fibers is absorbed into the inner regions since less energy is required in the inner regions due to the heating of the two outer regions. The image 518 of the central secondary fiber requires even less power, so the source turns on later at a lower power level and turns off later to provide heat to anneal either one area corresponding to laser spot 513 or the entire area corresponding to laser spots 511-515, which form primary multi-spot image 551, depending on the thermal conductivity of the material and the design of the part. Each secondary fiber can deliver 30 watts, 100 watts, 150 watts, about 50 watts to about 2 kW, about 250 watts to about 1 kW, and many kilowatts of power, and all values in these ranges, depending on, for example, scan speed print head and heated pattern size.

[0083] FIGS. 7A and 7B show perspective views of a laser printhead 600 that provides a multi-spot primary laser beam image 608 having spots 610, 611, 612, 613, 614 and a secondary laser beam image 609 that overlaps image 608 and heats a volume of 651 powder. The primary laser source is a diode array 601 (which may provide a 1-D pattern or a 2-D pattern) the primary laser beam path exits the array 601 and enters the first beam conversion optics 604 and then the second beam conversion optics 605 to form an image 608 which is a 1-D pattern, on the surface of the powder pad. The secondary laser has a fiber or bundle of fibers connected to the printhead 600 by a connector 603 and a collet 603. The secondary laser beam path extends from the fiber or bundle of fibers to a collimating lens 606 and then to a beam conversion optics 607 to form and overlay an image 609 of the secondary laser beam with image 608 of the primary laser beam. The direction of movement of the laser beams and their respective images relative to the powder pad is indicated by arrow 615.

[0084] According to the embodiment of FIG. 7A and 7B, an addressable array of laser diodes creates an addressable thermal pattern on the powder pad. Each emitter of the addressable laser diode array 601 may have a power of 3W, 10W, or higher, which is limited by the diode array technology. On their own, the power levels of individual laser diodes are insufficient to melt many metallic materials, so a secondary heat source or laser source, which is provided by the fiber or bundle of fibers in connector 602, is necessary for any design that uses an addressable array of laser diodes. Either a heated powder pad or a secondary laser source can be used. Here, a secondary laser source is used to provide an image 609 to preheat the powder volume 651 to just below the melting point, and a laser diode array image 608 is used to melt and fuse the powder with the material underneath. The secondary laser source may be a single fiber, bundle of fibers that is connected to print head 600 by connector 602 and collet 603, or the secondary laser source may be another array of laser diodes that is collimated and reimaged to form a single image 609 or series of images, for example, shown according to the embodiment of FIG. 6A. The preferred embodiment for the laser diode array is a blue laser diode due to its higher absorption compared to an IR laser diode. 1-D patterns that can be used in a direct array of laser diodes are most likely the embodiment of FIG. 8B and 8D where diode spacing is to be considered in any design, however the optics that transform the image can be used to produce any of the images of the embodiments in FIG. 8A-8A.

[0085] One or more or all of the primary laser beams forming the primary laser beam pattern may be entirely within the secondary laser pattern, partially within the secondary laser pattern, entirely outside the second laser beam pattern, and combinations and variations thereof. According to embodiments, the patterns of the primary and secondary laser beams can move at the same speed in the same direction, at different speeds in the same direction (for example, the primary is faster, or the secondary is faster) and in different directions, with the same or different speeds) and their combinations and varieties. The primary and secondary laser beams can also be moved in independent predetermined patterns to build up specific types of objects or impart specific types of features to the growing object.

[0086] The primary laser beam pattern may have one, two, three, four or more, and dozens or more laser beams. The secondary laser beam pattern may be a single beam, or may be multiple laser beams or multiple overlapping laser beams, and combinations and variations thereof.

[0087] The cross section of the primary laser beam may be round, elliptical, or square, or other shapes. Patterns of the primary laser beam can be arranged linearly, in a square configuration, in a rectangular configuration, in a circular configuration, in an elliptical configuration, in a parabolic configuration (convex or concave with respect to the movement of the pattern), in the form of an arc (convex or concave with respect to the movement of the pattern), arrow configuration or “V”, rhombic configuration, as well as in the form of other geometric shapes and configurations and their combinations and varieties.

[0088] According to an embodiment, the secondary pattern can be obtained with a high intensity visible, UV or IR light lamp whose light passes through a spatial light modulator, or a high power laser whose light passes through a spatial light modulator, or a laser array containing 1 to N sources forming a 1-D or 2-D pattern. The secondary laser array may be an array of laser diodes or an array of fibers connected to separate laser systems.

[0089] 2-D Patterning System

[0090] A preferred embodiment involves the use of two-dimensional (2-D) fiber bundles or laser arrays as a source of heat, or energy, when printing a metal part. An example of some 2-D fiber tows and the laser patterns or multispot images they produce are shown in the embodiments of FIG. 8D-8F. In FIG. 8F shows an image of square spots formed from an array of square or rectangular optical fibers or other optics that form beams to provide these spots. According to an embodiment, the transition from a 1-D patterning system to an embodiment of a 2-D patterning system is to add one or more rows of fibers in the print head (compare Fig. 8C with 8E) and the ability to print faster due to the increased addressable area. These 2-D sources can have individual laser power levels of 3W, 10W, 20W, 100W, 150W, about 50W to about 2kW, about 250W to about 1kW, and many kilowatts depending on speed. scanning of the printing system and the size of the printed pattern.

[0091] The 2-D patterning system may also be combined with a single secondary laser source, an array of secondary laser sources, or a bundle of secondary laser sources, and combinations and variations thereof, to provide energy for preheating or controlled cooling of the printed pattern. In embodiments, a single secondary laser can be superimposed on high power powder-pad images. In FIG. 9A-9F are plan views of embodiments of composite images from primary images and secondary images. The direction of movement of the patterns of both the primary and secondary beams is indicated by an arrow in each figure.

[0092] FIG. 9A shows an embodiment of a rectilinear multispot 1-D primary image at an angle to direction movement and fully in a circular secondary image.

[0093] FIG. 9B shows an embodiment of the primary image, which is a slanted 1-D image array with a dead zone between each spot, compensated for the angle of the spots, and a single secondary image provided by a secondary laser source to preheat the powder to fuse. In this embodiment, the secondary image is adjacent to, but without overlapping, the pattern of the primary beam.

[0094] FIG. 9C shows an embodiment of a simple line array primary image overlaid with a rectangular secondary laser image to provide both preheat and post-fusion energy for temperature control through a build-up sequence.

[0095] FIG. 9D shows an embodiment of a spaced 2-D pattern array overlaid by a single elliptical secondary laser spot, again to provide the energy needed for a given scan speed to bring the powder to just below melting temperature and to provide a means to anneal the material after welding.

[0096] FIG. 9E shows a 2-D embodiment of a dense fiber array primary image, again with a single preheat beam image from a secondary laser source adjacent to and in front of the primary image.

[0097] FIG. 9F shows an embodiment of a 2-D primary image from a dense array of square fibers that are adjacent. In an embodiment, the squares overlap to minimize processing intervals. This dense array pattern is overlaid with a secondary laser source with the intent of preheating the powder, providing additional energy during the melting and bonding process and finally providing the same temperature control after the melting and fusion step.

[0098] These secondary laser sources for the secondary image patterns of the embodiments of FIGS. 9A-9F, and in other secondary laser pattern and image embodiments, may have a power of about 2W, about 3W, about 10W, about 20W, about 50W, about 100W, about 150W, about 50W to about 2kW, about 10W to about 200W, about 50W to about 500W, about 250W to about 1kW and many kilowatts, depending on, for example, the scanning speed of the printhead, the power of the primary laser beam and the size of the heated area.

[0099] Combining a primary bundled fiber laser source with a secondary bundled fiber source allows the preheating and cooling temperature cycles to be varied during object growth. Thus, the preheating and cooling processing cycles can change, for example, adapt to the conditions of the growth of the object as it builds up. Thus, information about the property of the object to be built up, such as temperature, roughness, density, spectrum of emitted or reflected light, is used to change and adjust the properties of the laser beam of the secondary fiber, such as time and power, and thus adjust the secondary image on the fly. ” in relation to the primary image, the build-up of the subject, and both. In FIG. 10A-10F show the various timing patterns and effects that are possible when an addressable laser image pattern is overlapped with an addressable secondary preheat pattern. An additional benefit of laser preheating is the elimination of the need to heat the entire pad or chamber, which requires significantly more energy.

[00100] Temperature control system

[00101] Previous additive manufacturing systems, prior to the present invention, operate without feedback, which does not allow precise control of print quality. This has been a significant drawback of these previous systems, which the embodiments of the present invention allow to solve and improve. According to an embodiment of the present invention, a feedback loop is used to fine-tune the temperature in each of the 1-D or 2-D patterns as well as the secondary laser pattern and the powder pad where the patterns are delivered. This feedback loop provides numerous benefits including, for example, parts that are built up will have lower porosity, lower imperfections, and better surface roughness than an open-loop system can achieve. Due to the relatively slow travel speed of the portal system compared to galvanometer systems, it is possible to measure the temperature of the powder bed at each point in the print pattern and change the power setting of the laser addressing that area of the print pattern to a more optimal setting in real time, during the printing process, for example, adjusting "on the fly" of the printing process based on the temperature profile of the object as it builds up. In an embodiment, the temperature profile of the pad is monitored and controlled from laser spot to laser spot to then adjust the power, timing, and both laser spots to control the item buildup process. Fig. 11 illustrates how a fiber bundle image 1101 can be re-imaged 1103 onto a camera sensor array 1102. The sensor array reading software can then recognize the heated areas and provide the average temperature of each area. If all laser sources are of the same power, then the center pixels will read a much higher temperature than the outer pixels, and the power to the inner sources may be reduced until a uniform temperature profile is achieved. This keeps the powder melting and fusing within the optimal temperature range. This applies not only to 2-D images of a fiber bundle, but also to 1-D images of a fiber bundle. After measuring the area temperature as shown in FIG. 12, a sequence of command signals 1204-1210 is computed that increase or decrease power to each region until a uniform or predetermined optimal temperature profile is reached. Thus, an image 1201 of an array or tow of fibers on a powder bed is imaged onto an image acquisition and analysis device, such as sensors, a camera, such as a FLIR camera. This provides a matrix 1202 of temperature profiles on a per-pixel basis. A processor, such as a computer, a microprocessor, interpolates and translates the temperature profiles from matrix 1202 in relation to the splice program and adjusts the laser power in accordance with the splice strategy by sending control signals 1204-1210 to the lasers associated with the individual fibers or images produced by those lasers. Thus, on-the-fly spot-to-spot adjustment of the laser beam and build-up profile is provided. Also, by providing a real-time feedback signal to the laser sources, in the event that the powder is not properly melted, it will be done to increase the power to that area to increase the likelihood of it being properly melted. This will occur in areas where there is great variability in the diameter of the powders, with larger diameter powders requiring more energy to melt than smaller diameter powders. It is also critical to keep small-diameter powders from evaporating, so real-time temperature feedback from laser sources can be used to set a region-averaged temperature sufficient to melt large powder particles, but not enough to vaporize smaller powder particles.

[00102] Examples of systems, processing, configurations, and methods of embodiments of the present systems and methods are shown in Table I.

[00103] Table I.

Material Layer thickness (µm) Power of each primary laser (W) Spot diameter of each primary laser (µm) Number of primary spots X Number of primary spots Y Secondary laser beam power (W) Secondary Spot Preheat Temperature (°C) Spot size of the secondary laser beam (µm) (X) Spot size of the secondary laser beam (µm) (Y) Growth rate (cm ³ /h) Cu 100 100 200 1 1 1 21 200 200 54 Cu 100 100 200 1 2 1 21 200 400 108 Cu 100 100 200 1 3 1 21 200 600 162 Cu 100 100 200 1 1 100 200 200 200 61 Cu 100 100 200 1 2 100 200 200 400 122 Cu 100 100 200 1 3 100 200 200 600 183 Cu 100 100 200 1 1 100 600 200 200 85 Cu 100 100 200 1 2 200 600 200 400 170 Cu 100 100 200 1 3 400 600 200 600 226 Cu 100 100 200 1 1 100 600 200 200 85 Cu 100 100 200 1 5 200 600 200 1000 68 Cu 100 100 200 1 10 1000 600 200 2000 170 Cu 100 100 200 1 10 400 600 200 2000 68 Cu 100 100 200 1 10 1000 600 200 2000 170 Cu 100 100 200 1 10 2500 600 200 2000 424 Cu 100 100 200 4 10 4000 600 800 2000 170 Cu 100 100 200 4 10 5000 600 800 2000 212 Cu 100 100 200 4 10 12000 600 800 2000 509 Al 100 100 200 1 1 1 21 200 200 67 Al 100 100 200 1 2 1 21 200 400 133 Al 100 100 200 1 3 1 21 200 600 200 Al 100 100 200 1 1 100 200 200 200 117 Al 100 100 200 1 2 100 200 200 400 234 Al 100 100 200 1 3 100 200 200 600 351 Al 100 100 200 1 1 150 400 200 200 164 Al 100 100 200 1 2 400 400 200 400 218 Al 100 100 200 1 3 800 400 200 600 291 Al 100 100 200 1 1 100 400 200 200 109 Al 100 100 200 1 5 600 400 200 1000 131 Al 100 100 200 1 10 2000 400 200 2000 218 Al 100 100 200 1 10 400 400 200 2000 44 Al 100 100 200 1 10 1000 400 200 2000 109 Al 100 100 200 1 10 2500 400 200 2000 273 Al 100 100 200 4 10 4000 400 800 2000 109 Al 100 100 200 4 10 5000 400 800 2000 136 Al 100 100 200 4 10 12000 400 800 2000 327 SS304 100 100 200 1 1 1 21 200 200 26 SS304 100 100 200 1 2 1 21 200 400 52 SS304 100 100 200 1 3 1 21 200 600 78 SS304 100 100 200 1 1 100 200 200 200 29 SS304 100 100 200 1 2 100 200 200 400 57 SS304 100 100 200 1 3 200 200 200 600 86 SS304 100 100 200 1 1 200 600 200 200 37 SS304 100 100 200 1 2 200 600 200 400 75 SS304 100 100 200 1 3 600 600 200 600 112 SS304 100 100 200 1 1 100 600 200 200 37 SS304 100 100 200 1 5 500 600 200 1000 97 SS304 100 100 200 1 10 3000 600 200 2000 290 SS304 100 100 200 1 10 600 600 200 2000 58 SS304 100 100 200 1 10 2000 600 200 2000 194 SS304 100 100 200 1 10 5000 600 200 2000 373 SS304 100 100 200 4 10 6000 600 800 2000 145 SS304 100 100 200 4 10 10000 600 800 2000 242 SS304 100 100 200 4 10 18000 600 800 2000 435

[00104] Additionally, and generally, embodiments of the present invention relate to combining laser beams, systems for creating these combinations, and processes using combined beams. In particular, the present invention relates to arrays, assemblies and devices for combining laser beams from multiple laser beam sources into one or more combined laser beams. These combined laser beams preferably retain, enhance and both different aspects and properties of laser beams from separate sources.

[00105] Embodiments of the present array assemblies, and the combined laser beams they provide, may find wide application. Embodiments of the present array assemblies are compact and durable. Embodiments of the present array assemblies are applicable to welding, additive manufacturing including 3-D printing; additive manufacturing systems - milling, for example, additive and subtractive manufacturing; astronomy; meteorology; image formation; projections, including entertainment ones; and medicine, including dentistry, etc.

[00106] Although this specification focuses on blue laser diode arrays, it should be understood that this embodiment is only intended to illustrate the types of array assemblies, systems, processes, and combined laser beams contemplated by the present invention. Thus, embodiments of the present invention include array assemblies for combining laser beams from various laser beam sources, such as solid state lasers, fiber lasers, semiconductor lasers, and other types of lasers and combinations and variations thereof. Embodiments of the present invention include combining laser beams over all wavelengths, for example, laser beams having wavelengths from about 380 nm to about 800 nm (for example, visible light), from about 400 nm to about 880 nm, from about 100 nm to about 400 nm, from 700 nm to 1 µm, and combinations, varieties of specific wavelengths in these different ranges. Embodiments of the present arrays may also find use in microwave coherent radiation (eg, wavelengths greater than about 1 mm). Embodiments of the present arrays may combine beams from one, two, three, tens, or hundreds of laser sources. These laser beams can have powers ranging from a few milliwatts to watts to kilowatts.

[00107] An embodiment of the present invention consists of an array of blue laser diodes that are combined in a configuration to advantageously create a high brightness laser source. This high brightness laser source can be used directly for material processing, i.e. marking, cutting, welding, hard soldering, heat treatment, annealing. Materials to be processed, such as raw materials or target materials, may include any material or component or composition, and, for example, may include semiconductor components, such as, but not limited to, TFTs (Thin Film Transistors), raw materials 3 -D printing, metals including gold, silver, platinum, aluminum and copper, plastics, cloth and semiconductor wafers, etc. Direct processing may include, for example, gold ablation from electronics, projection displays, and laser light shows, etc.

[00108] Embodiments of the present high brightness laser sources can also be used to pump a Raman laser or an anti-Stokes laser. The Raman medium can be fiber optics or a crystal such as diamond, KGW (potassium gadolinium tungstate, KGd(WO ₄ ) ₂ ), YVO ₄ and Ba(NO ₃ ) ₂ . In an embodiment, the high brightness laser sources are blue laser diode sources, which are semiconductor devices operating in the 400 nm-500 nm wavelength range. The Raman medium is a brightness converter and is capable of increasing the brightness of sources in the form of blue laser diodes. The increase in brightness can take place completely before the creation of a single-mode source with diffraction-limited beams, i.e. a beam having an M2 of about 1 and 1.5 with a beam product parameter less than 1, less than 0.7, less than 0.5, less than 0.2 and less than 0.13 mm-mrad depending on the wavelength.

[00109] In an embodiment of “n” or “N” (e.g., two, three, four, etc., tens, hundreds, or more), the laser diode sources can be implemented as a bundle of optical fibers, which provides an addressable a light source that can be used for laser operations and procedures for marking, melting, welding, ablation, annealing, heat treatment, cutting of materials and their combinations and varieties, etc.

[00110] An embodiment of a laser system with an addressable laser delivery configuration. The system has an addressable laser diode system. The system provides independently addressable laser beams to a plurality of fibers (considering larger and smaller numbers of fibers and laser beams). The fibers are combined into a bundle of fibers, which is contained in a protective tube or cover. The fibers in the fiber bundle are fused together to form a print head which includes an optical assembly that focuses and guides laser beams, along the beam paths, to the target material. The print head and powder hoppers move together with the positive direction movement of the print head according to. Additional material may be placed on top of the fused material with each pass of the print head or hopper. The printhead is bi-directional and will fuse material in both directions as the printhead moves, so the powder hoppers act behind the printhead to build up the material to be fused on the next pass of the laser printhead.

[00111] By "addressable array" is meant that one or more of: power; duration of ignition; ignition sequences; ignition positions; beam power; beam spot shape as well as focal length, such as z-direction penetration depth, can be independently varied, controlled and predetermined, or each laser beam in each fiber to provide accurate and pre-defined delivery patterns that can be generated from high-precision end products of the target material (e.g., stackable materials) addressable array embodiments may also have the ability for individual beams and laser spots created by that beam to perform modified, predefined, and precise laser operations, such as annealing, ablation, and melting.

[00112] The following examples are provided to illustrate various embodiments of the laser arrays, systems, devices, and methods of the present invention. These examples are given for purposes of illustration and are not to be construed as limiting the scope of the present invention.

[00113] Example 1

[00114] An array of blue laser diodes spatially combined to create a single spot in the far field, which can be connected to a solarization resistant optical fiber for delivery to a preform.

[00115] Example 2

[00116] An array of blue laser diodes as described in Example 1, which is a polarization beam combined to increase the effective brightness of the laser beam.

[00117] Example 3

[00118] An array of blue laser diodes with space between each of the collimated beams on the fast axis of the laser diodes, which are then combined with a periodic plate that reflects the first laser(s) diode(s) and transmits the second laser(s) ) diode(s) to fill the space between the laser diodes in the direction of the highest light velocity of the first array.

[00119] Example 4

[00120] A patterned mirror on a glass substrate that is used to perform space filling in Example 3.

[00121] Example 5

[00122] A patterned mirror on one side of the glass substrate to effect space filling in Example 3, and the glass substrate is thick enough to shift the vertical position of each laser diode to fill the empty space between the individual laser diodes.

[00123] Example 6

[00124] The stepped heat sink that fills the space in Example 3 is a patterned mirror as described in Example 4.

[00125] Example 7

[00126] An array of blue laser diodes as described in Example 1, where each of the individual lasers is externally locked to a different wavelength to substantially increase the brightness of the array to the equivalent brightness of a single laser diode source.

[00127] Example 8

[00128] A blue laser diode array as described in Example 1, where the individual laser diode arrays are locked to a single wavelength using an external grating-based resonator, and all laser diode arrays are combined into a single beam using either narrowly spaced optical filters, or diffraction gratings.

[00129] Example 9

[00130] An array of blue laser diodes as described in Example 1, which is used to pump a Raman converter, such as an optical fiber having a pure fused silica core to provide a higher brightness source and a fluorinated outer core to channel the blue pump light.

[00131] Example 10

[00132] An array of blue laser diodes, as described in Example 1, which is used to pump a Raman converter, for example, an optical fiber having a GeO ₂ doped central core with an outer core to produce a higher brightness source, and an outer core that is larger than the central core, to channel blue pump light.

[00133] Example 11

[00134] An array of blue laser diodes, as described in Example 1, which is used to pump a Raman converter, for example, an optical fiber having a P ₂ O ₅ doped core to create a source of higher brightness, and an outer core that is larger than central core, for channeling blue pump light.

[00135] Example 12

[00136] An array of blue laser diodes, as described in Example 1, which is used to pump a Raman converter, such as an optical fiber having a core with a smooth refractive index profile to produce a higher brightness source, and an outer core that is larger than the central core , to sewer blue light pumping.

[00137] Example 13

[00138] An array of blue laser diodes as described in Example 1, which is used to pump a Raman transducer fiber having a GeO ₂ doped core with a smooth refractive index profile and an outer core with a stepped refractive index profile.

[00139] Example 14

[00140] An array of blue laser diodes as described in Example 1, which is used to pump a Raman transducer fiber having a P ₂ O ₅ doped smooth index core and a step index outer core.

[00141] Example 15

[00142] An array of blue laser diodes as described in Example 1, which is used to pump a Raman transducer fiber having a GeO ₂ doped core with a smooth refractive index profile.

[00143] Example 16

[00144] An array of blue laser diodes as described in Example 1, which is used to pump a Raman transducer fiber having a P ₂ O ₅ doped smooth index core and a step index outer core.

[00145] Example 17

[00146] Other embodiments and variations of the embodiment of Example 1 are contemplated. An array of blue laser diodes, as described in Example 1, which is used to pump a Raman transducer, such as a diamond, to create a higher brightness laser source. In FIG. 13 shows an image 1301 and a spectrum 1302 of a blue Raman-transformed laser beam from a diamond crystal and a wavelength shift from 450 nm to 478 nm. An array of blue laser diodes, as described in example 1, which is used to pump a Raman converter, such as a KGW, to create a higher brightness laser source. An array of blue laser diodes, as described in Example 1, which is used to pump a Raman transducer such as YVO ₄ to create a higher brightness laser source. An array of blue laser diodes, as described in Example 1, which is used to pump a Raman converter, such as Ba(NO ₃ ) ₂ , to create a higher brightness laser source. An array of blue laser diodes, as described in Example 1, which is used to pump a Raman converter, which is a high pressure gas, to create a higher brightness laser source. An array of blue laser diodes as described in Example 1, which is used to pump a rare earth doped crystal to create a higher brightness laser source. An array of blue laser diodes as described in Example 1, which is used to pump a rare earth doped fiber to create a higher brightness laser source. An array of blue laser diodes, as described in Example 1, which is used to pump the outer core of the luminance converter to create a higher luminance enhancement factor.

[00147] Example 18

[00148] An array of Raman-transformed lasers that operate at separate wavelengths and are combined to create a higher power source while maintaining the spatial brightness of the original source.

[00149] Example 19

[00150] Dual-core Raman fiber and means for suppressing a second-order Raman signal in a high-brightness central core using a filter, a fiber Bragg grating, V-number differences for first-order and second-order Raman signals, or differences in microbending loss.

[00151] Example 20

[00152] N laser diodes, where N > 1, that can be individually turned on and off and can be imaged onto a powder pad to melt and fuse the powder into a unique piece.

[00153] Example 21

[00154] N arrays of laser diodes, where N > 1 in example 1, the output of which can be a connected fiber, and each fiber can be arranged linearly or non-linearly to create an addressable array of high power laser beams that can be imaged or focused on a powder for melting or fusing the powder into a unique shape layer by layer.

[00155] Example 22

[00156] One or more arrays of laser diodes coupled via a Raman converter, the output of which may be a connected fiber, and each fiber may be arranged linearly or non-linearly to create an addressable array N, where N > 1 high power laser beams that can be imaged or focus on the powder to melt or fuse the powder into a unique shape layer by layer.

[00157] Example 23

[00158] An x-y motion system that can transport N, where N > 1, laser blue light sources over the powder pad while melting and fusing the powder pad with the powder delivery system positioned behind the laser source to provide a fresh powder layer behind the fused layer.

[00159] Example 24

[00160] A z-axis movement system that can increase/decrease the height of the part/powder pad in Example 20 after placing a new layer of powder.

[00161] Example 25

[00162] The z-axis movement system can increase/decrease the height of the part/powder in Example 20 after the powder layer is fused by the laser source.

[00163] Example 26

[00164] The bi-directional powder placement capability of Example 20 where the powder is positioned directly behind the laser spot(s) as it propagates in the positive x-axis direction or the negative x-axis direction.

[00165] Example 27

[00166] The bi-directional powder placement capability of Example 20 where the powder is positioned directly behind the laser(s) spot(s) as it propagates in the positive y-axis direction or the negative y-axis direction.

[00167] Example 28

[00168] Powder delivery system, coaxial with N laser beams, where N > 1.

[00169] Example 29

[00170] A powder feeding system where the powder is fed by gravity.

[00171] Example 30

[00172] A powder supply system where the powder is entrained in an inert gas flow.

[00173] Example 31

[00174] The powder supply system is transverse to the N laser beams, where N > 1, and the powder is positioned by gravity directly in front of the laser beams.

[00175] Example 32

[00176] The powder supply system is transverse to N laser beams, where N > 1, and the powder is entrained by an inert gas flow that crosses the laser beams.

[00177] Example 33

[00178] A second harmonic generation system that uses the output of a Raman converter, such as at 460 nm, to generate light at half the wavelength of the original laser, or 230 nm, which consists of an externally resonant frequency doubling crystal, such as KTP, but does not allow low light wavelength to propagate through the optical fiber.

[00179] Example 34

[00180] A third harmonic generation system that uses the output of a Raman converter at, for example, 460 nm to generate light at 115 nm using an externally resonant frequency doubling crystal, but does not allow short wavelength light to propagate through the optical fiber.

[00181] Example 35

[00182] A fourth harmonic generation system that uses the output of a Raman converter at, for example, 460 nm to generate light at 57.5 nm using an externally resonant frequency doubling crystal, but does not allow short wavelength light to propagate through the optical fiber.

[00183] Example 36

[00184] A second harmonic generation system that uses the output of a rare earth-doped luminance converter, such as thulium, that generates coherent radiation at 473 nm when pumped by an array of 450 nm blue laser diodes to generate light at half the wavelength of the original laser, or 236.5 nm using an externally resonant frequency doubling crystal, but does not allow small wavelength light to propagate through the optical fiber.

[00185] Example 37

[00186] A third harmonic generation system that uses the output of a rare earth doped luminance converter such as thulium that generates coherent radiation at 473 nm when pumped by an array of 450 nm blue laser diodes to generate light at 118.25 nm using external resonant frequency doubling crystal, but does not allow small wavelength light to propagate through the optical fiber.

[00187] Example 38

[00188] A fourth harmonic generation system that uses the output of a rare earth-doped luminance converter such as thulium that generates coherent radiation at 473 nm when pumped by an array of 450 nm blue laser diodes to generate light at 59.1 nm using external resonant frequency doubling crystal, but does not allow small wavelength light to propagate through the optical fiber.

[00189] Example 39

[00190] All other rare earth doped fibers and crystals that can be pumped with a 450 nm high power source to generate a visible or near visible output can be used in Examples 34-38.

[00191] Example 40

[00192] Launching high power visible light into a non-circular outer core or cladding to pump the inner core of either a Raman or rare earth doped fiber.

[00193] Example 41

[00194] Using a polarization maintenance fiber to increase the gain of a Raman fiber by aligning the pump polarization with that of the Raman oscillator.

[00195] Example 42

[00196] An array of blue laser diodes, as described in Example 1, which is used to pump a Raman transducer, such as an optical fiber, that is structured to produce a higher brightness source of a particular polarization.

[00197] Example 43

[00198] An array of blue laser diodes, as described in Example 1, which is used to pump a Raman transducer, such as an optical fiber, that is structured to produce a source of higher brightness of a particular polarization and maintain the polarization state of the pump source.

[00199] Example 44

[00200] An array of blue laser diodes, as described in Example 1, which is used to pump a Raman converter, such as an optical fiber, to create a higher brightness source with a non-circular outer core structured to increase the efficiency of the Raman transform.

[00201] Example 45

[00202] Embodiments of Examples 1-44 may also include one or more of the following components or assemblies: devices for leveling the powder at the end of each pass prior to laser scanning of the powder pad; devices for scaling laser output power by combining multiple low power laser modules through a fiber combiner to create a higher power output beam; devices for scaling the output power of the blue laser module by combining multiple low power laser modules through empty space to create a higher power output beam; devices for combining multiple laser modules on a single base plate with built-in cooling.

[00203] Note that there is no requirement to provide or address the theory behind the new and innovative feature or other useful features and properties that are the subject of or associated with the embodiments of the present invention. However, various theories are provided in this specification for further advances in the art in this important area, and in particular in the important area of lasers, laser processing, and laser applications. These theories are proposed in this specification, and unless expressly stated to the contrary, do not in any way limit or limit the scope of protection afforded to the claimed invention. These theories may not be required or practiced in order to use the present invention. It should also be understood that the present invention may lead to new, hitherto unknown theories explaining the operation, function and features of embodiments of the methods, products, materials, devices and systems of the present invention; and such later developed theories should not limit the scope of the protection afforded by the present invention.

[00204] It should be understood that the use of headings in this specification is for illustrative purposes and is in no way limiting. Thus, the processes and disclosures described under the heading are to be read in their entirety in this specification, which includes various examples. The use of headings in this specification is not to limit the scope of the protection afforded by the present invention.

[00205] Various embodiments of the lasers, diodes, arrays, modules, assemblies, acts, and operations set forth in this specification may be used in the above areas and in various other areas. Among others, embodiments of the present invention can be used with the methods, devices, and system presented in Patent Applications Nos. WO 2014/179345, 2016/0067780, 2016/0067827, 2016/0322777, 2017/0343729, 2017/0341180 and 2017/0341144, the disclosure of each of which is hereby incorporated by reference in its entirety. Additionally, these embodiments, for example, can be used with: existing lasers, additive manufacturing systems, operations and activities, and other existing equipment; future lasers, operations and activities of additive manufacturing systems; and such items that can be modified, in part, based on the principles of this specification. Additionally, the various embodiments set forth in this specification may be used in a variety of combinations with each other. Thus, for example, the configurations provided in the various embodiments of this specification can be used with each other. For example, components of an embodiment having A, A' and B and components of an embodiment having A'', C and D can be used with each other in various combinations, for example, A, C, D and A, A'' C and D, etc., in accordance with the principles of this specification. Thus, the scope of protection provided by the present invention is not to be limited to a specific embodiment, configuration or arrangement presented in a specific embodiment, example, or according to an embodiment in a specific figure.

[00206] The invention may be embodied in other forms other than those specifically disclosed herein without departing from its spirit or important characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive.

Claims (86)

1. An additive manufacturing system comprising a light source configured to provide a multi-spot 1-D image, a multi-spot 2-D image, or both on a powder bed; wherein the system comprises: a light source in optical communication with an array of optical fibers for transmitting a multi-spot image; wherein the array of optical fibers is in optical communication with the imaging optics; the re-imaging optics being configured to re-image the multi-spot image on the powder pad; wherein the light source provides the power density for fusing and building up the powder part. 2. The system of claim. 1, in which the light source contains an array of fibers supplying light from an array of fiber Raman lasers operating in the wavelength range from 300 nm to 500 nm. 3. The system of claim. 1, in which the light source contains an array of laser diodes operating in the wavelength range from about 400 nm to about 500 nm. 4. The system of claim. 1, in which the light source contains an array of optical fibers connected to laser diodes operating in the wavelength range from about 400 nm to about 500 nm. 5. The system according to any one of paragraphs. 1-4, wherein the light source comprises an array of optical fibers having diameters selected from the group consisting of 10-50 µm, 50-100 µm and 100-500 µm. 6. The system of claim. 1, in which the light source is a single bundle of separate optical fibers connected to separate light sources, which is re-imaged by optics, which is one of 1:0.5, 1:1, 1:2 up to up to 1:10 inclusive. 7. The system of claim. 1, in which the light source is a bundle of fibers installed in a single QBH connector. 8. The system of claim. 1, in which the light source is independently installed individual fibers. 9. The system according to claim 1 or 6, further comprising a thermal imaging camera for directly monitoring the temperature in each spot during operation and providing a feedback signal to the microprocessor, which regulates the power of each spot and, thus, the quality of the build-up of the part from spot to stain. 10. The system according to claim 1 or 6, further comprising an array of pyrometers for directly monitoring the temperature in each spot during operation and providing a feedback signal to the microprocessor, which regulates the power of each spot and, thus, the quality of the build-up of the part from spot to spot. 11. The system of claim 1, wherein the light source is a printhead consisting of an array of light sources that is mounted on an x-y gantry to transfer a 1-D or 2-D image across the surface of the powder pad. 12. The system of claim. 1, which uses a gravity powder delivery system that operates in both directions. 13. The system of claim. 1, which includes a rotating wheel, moving opposite to the direction of movement of the hopper, to compress and compact the powder to reduce the porosity of the powder bed. 14. The system of claim. 1, wherein the light source is a laser blue light source for alloying copper powders. 15. The system of claim 1 wherein the light source is a blue laser light source for melting gold powders. 16. The system of claim. 1, in which the light source is a blue laser light source for optimal fusion of aluminum powders. 17. The system of claim 1 wherein the light source is a laser blue light source for fusing all metals and metal alloys. 18. The system of claim 11 further comprising a thermal imaging camera optics system, wherein the printhead combines the optics with the thermal imaging camera system to reimage and adjust the powder temperature in areas exposed to the fiber array or diode array image. 19. The system of claim. 11, in which the print head further comprises an optical system containing a collimator, which is one of a plano-convex lens, a plano-convex aspherical lens, a pair of doublet or triplet lenses, and a focusing optics, consisting of one of plano-convex -convex lens, plano-convex aspherical lens, here the source is 1f from the collimating lens and 1f from the focusing lens. 20. The system of claim 11, wherein the printhead further comprises an optical system comprising a source and a lens, wherein the printhead optical system is a reimaging optic with a source at least 2f from the lens and the image is at least measure 2f away from the lens in the opposite direction. 21. The system of claim 1, further comprising a piston for delivering the powder to the printer pad for redistribution. 22. The system of claim. 1, further including an optical coherence tomography (OCT) system for monitoring the welding process in real time. 23. The system of claim. 1, further comprising a print head, and the print head includes an optical system containing a collimator, which is one of a plano-convex lens, a plano-convex aspherical lens, a pair of doublet or triplet lenses, and a focusing optics consisting of one of the plano-convex lens, plano-convex aspherical lens, here the source is 1f from the collimating lens and 1f from the focusing lens. 24. The system of claim 23 wherein the optical system in the printhead is a reimaging optic where the source is at least 2f from the lens and the image is at least 2f from the lens in the opposite direction. 25. The system of claim 1, further comprising a camera system for tracking each image pixel and feed back a real-time control signal to each laser to control the melting and fusing of the powder to optimize surface roughness, porosity and stress in the resulting part. 26. The system of claim 25, wherein the control signal comprises a signal proportional to the temperature of the powder bed. 27. The system of claim 25, wherein the control signal comprises a signal proportional to the temperature of the melt pool generated at each point of the 1-D or 2-D image on the powder pad. 28. An additive manufacturing system based on an array of light sources and a secondary light source to adjust the temperature of the build-up area, which is a 1-D or 2-D image on a powder pad, while providing power density to fuse and grow the part with a camera system to track each image pixel and feed back a real-time control signal to each laser to control powder melting and fusion to optimize surface roughness, porosity and stress in the resulting part; and wherein the system comprises: a light source in optical communication with an array of optical fibers for transmitting a multi-spot image; wherein the array of optical fibers is in optical communication with the reimaging optics. 29. The system of claim 28 wherein the light source array is an array of Raman lasers operating in the wavelength range of 300 nm to 500 nm. 30. The system of claim 28 wherein the light source array is an array of laser diodes operating in the 400-500 nm wavelength range. 31. The system of claim. 28, in which the array of light sources is an array of optical fibers connected to laser diodes operating in the wavelength range of 400-500 nm. 32. The system of claim 28, wherein the light source array is an array of optical fibers with diameters ranging from 10-50 µm, 50-100 µm, or 100-500 µm. 33. The system of claim 28, wherein the light source array is a single bundle of individual optical fibers connected to individual light sources, which is re-imaged by an optic that is one of 1:0.5, 1:1, 1:2 up to and including 1:10. 34. The system of claim 28, wherein the light source array is a bundle of fibers installed in a single QBH connector. 35. The system of claim 28, wherein the array of light sources are independently mounted individual fibers. 36. The system of claim. 28, in which the secondary light source is a Raman laser operating in the wavelength range from 300 nm to 500 nm. 37. The system of claim 28 wherein the secondary light source is a laser diode system operating in the 400-500 nm wavelength range. 38. The system of claim. 28, in which the secondary light source is displayed on the same area where the 1-D or 2-D pattern is displayed. 39. The system of claim 28, wherein the temperature of the powder irradiated by the secondary light source is measured by a thermal imaging camera, and the signal from the camera is used to adjust the temperature of the illuminated area. 40. The system of claim 28 wherein the temperature of the powder irradiated by the secondary light source is measured by a pyrometer and the signal from the pyrometer is used to adjust the temperature of the illuminated area. 41. The system of claim 28, wherein the camera is a thermal imaging camera for directly monitoring the temperature in each spot during operation and providing feedback to a microprocessor that controls the power of each spot and thus the build quality of the part from spot to spot. stain. 42. The system of claim 28, wherein the chamber is an array of pyrometers for directly monitoring the temperature in each spot during operation and providing feedback to a microprocessor that controls the power of each spot and thus the build quality of the part from spot to spot. 43. The system of claim 28, wherein the array of light sources constitutes a printhead that is mounted on an x-y gantry to transfer a 1-D or 2-D image across the surface of the powder pad. 44. The system of claim 28, further comprising a gravity-fed powder delivery system that operates in both directions. 45. The system of claim 28, further comprising a piston for delivering the powder to the printer pad for redistribution. 46. The system of claim. 28, further including a rotating wheel moving opposite to the direction of travel of the hopper for compressing and compacting the powder to reduce the porosity of the powder bed. 47. The system of claim 28 wherein the control signal is a signal proportional to the temperature of the powder bed. 48. The system of claim 28, wherein the control signal is a signal proportional to the temperature of the melt pool generated at each point of the 1-D or 2-D image on the powder pad. 49. The system of claim 28, which uses a laser blue light source to fuse copper powders. 50. The system of claim 28, which uses a laser blue light source to fuse gold powders. 51. The system of claim 28, which uses a laser blue light source to optimally fuse aluminum powders. 52. The system of claim 28, which uses a laser blue light source to optimally fuse all other metals and metal alloys. 53. The system of claim. 28, further including an optical coherence tomography (OCT) system for tracking the welding process in real time. 54. An additive manufacturing system based on an array of light sources and an array of secondary light sources to adjust the temperature of the build-up area, which is a 1-D or 2-D image on a powder pad, while providing power density to fuse and grow the part with a camera system to track each pixel image and real-time control signal feedback to each laser to control powder melting and fusion to optimize surface roughness, porosity and stress in the resulting part; and wherein the system comprises: a light source in optical communication with an array of optical fibers for transmitting a multi-spot image; wherein the array of optical fibers is in optical communication with the reimaging optics. 55. The system of claim 54, wherein the light source array is an array of fibers supplying light from an array of fiber Raman lasers operating in the wavelength range of 300 nm to 500 nm. 56. The system of claim 54 wherein the light source array is an array of laser diodes operating in the 400-500 nm wavelength range. 57. The system of claim 54, wherein the light source array is an array of optical fibers connected to laser diodes operating in the 400-500 nm wavelength range. 58. The system of claim 54, wherein the light source array is an array of optical fibers with diameters ranging from 10-50 microns, 50-100 microns, or 100-500 microns. 59. The system of claim 54, wherein the light source array is a single bundle of separate optical fibers connected to separate light sources, which is re-imaged by an optic that is one of 1:0.5, 1:1, 1:2 up to and including 1:10. 60. The system of claim 54, wherein the light source array is a bundle of fibers installed in a single QBH connector. 61. The system of claim 54, wherein the array of light sources are independently mounted individual fibers. 62. The system of claim 54, wherein the secondary light source array is a fiber Raman laser operating in the wavelength range of 300 nm to 500 nm. 63. The system of claim 54, wherein the secondary light source array is a laser diode system operating in the 400-500 nm wavelength range. 64. The system of claim 54 wherein the array of secondary light sources is drawn onto the same area where the 1-D or 2-D pattern is drawn. 65. The system of claim 54, further comprising a thermal imaging camera, wherein the temperature of the powder irradiated by the array of secondary light sources is measured by the thermal imaging camera, and the signal from the camera is used to adjust the temperature of the illuminated area. 66. The system of claim 54 wherein the temperature of the powder irradiated by the array of secondary light sources is measured by a pyrometer and the signal from the pyrometer is used to adjust the temperature of the illuminated area. 67. The system of claim 54, wherein the camera is a thermal imaging camera for directly monitoring the temperature in each spot during operation and providing feedback to a microprocessor that controls the power of each spot and thus the build quality of the part from spot to spot. stain. 68. The system of claim 54, wherein the camera is an array of pyrometers for directly monitoring the temperature in each spot during operation and providing feedback to a microprocessor that controls the power of each spot and thus the build quality of the part from spot to spot. 69. The system of claim 54, wherein the array of light sources constitutes a printhead that is mounted on an x-y gantry to transfer a 1-D or 2-D image across the surface of the powder pad. 70. The system of claim 54, further comprising a gravity-fed powder delivery system that operates in both directions. 71. The system of claim 54, further comprising a piston for delivering the powder to the printer pad for redistribution. 72. The system of claim. 54, further comprising a rotating wheel moving opposite to the direction of movement of the hopper for compressing and compacting the powder to reduce the porosity of the powder bed. 73. The system of claim 54, wherein the control signal is a signal proportional to the temperature of the powder bed. 74. The system of claim 54, wherein the control signal is a signal proportional to the temperature of the melt pool generated at each point of the 1-D or 2-D image on the powder pad. 75. The system of claim 54, which uses a laser blue light source to fuse copper powders. 76. The system of claim 54, which uses a laser blue light source to fuse gold powders. 77. The system of claim 54, which uses a laser blue light source to optimally fuse aluminum powders. 78. The system of claim 54, which uses a laser blue light source to optimally fuse all other metals and metal alloys. 79. The system of claim. 54, in which the print head is installed with additional similar print heads on one or more portals for parallel printing of images. 80. The system of claim. 54, in which the print head is installed with additional similar print heads on one or more portals to print an image that is a part of the part. 81. The system of claim. 54, wherein the print head is mounted with additional similar print heads on one or more portals, and the optical system of the print head is used to combine images from multiple sources to create a continuous image. 82. The system of claim. 54, in which the print head is installed with additional similar print heads on one or more portals for printing an image in a checkerboard pattern, which are combined with each other by successive step transfer of intermediate patterns.

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