High-speed laser method for 3D forming of parts

Abstract

A part (27) 3D printed by a pulsed laser device (200). The part has a predetermined feature that includes a plurality of 3D prints (29) and voids in a mesh pattern. The mesh pattern has a plurality of locations disposed along a series of substantially parallel rows, and each location includes a 3D print or a void. A pulse from the pulsed laser device forms the 3D prints, and an absence of the pulse forms the voids. The pulsed laser device is controlled by a computing device that sends a packet of instructions to the pulsed laser device, the packet of instructions comprising at least two instructions, each single instruction notifying the laser (20) to pulse or not pulse, thereby creating a 3D print or void at each location on the mesh pattern, respectively.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method for forming 3D products using high speed pulsed lasers. BACKGROUND

[0002] Short pulse laser decoration utilizes energy from nanosecond, picosecond, and femtosecond short pulse lasers across a variety of wavelengths and energies to 3D print parts, such as products, parts, and / or packaging. Importantly, the laser technology used in short pulse laser 3D printing is a high throughput technology that uses a fixed laser source with an electronically / mechanically controlled mirror (i.e., a “galvanometer” set) and lenses (i.e., F-theta and similar lenses) to direct the laser beam from the fixed laser source to the 3D printed product, part, or packaging.

[0003] There is a great deal of interest in the possibilities of presenting parts by laser 3D printing, such as by short pulse laser 3D printing. While lasers are improving, and newer lasers have a variety of energies and wavelengths, these 3D printing processes can still be slow and expensive.

[0004] The current state of the art for technology for laser 3D printing processes includes “raster” 3D printing processes and “vector” 3D printing processes that are either fast but poor in precision and resolution, or slow but higher in precision and resolution. There is no combination of high speed and high precision in the prior art. This problem is particularly pronounced when 3D printing large parts. Raster laser 3D printing processes print in a grid, and the part is 3D printed by the laser row-by-row, point-by-point. Each pulse is “gated” so that the pulse is fired only for dark pixels of the image, and no pulse is fired for bright pixels of the image (or vice versa). Each of the pulses in the pulse is individually gated, and the pulse energy of each pulse can be changed to produce gray scale. When signaling the on / off function of the laser (i.e., “gating”), the raster 3D printing processes of the prior art are effectively limited to lasers with about 100 kHz repetition rate, given the practical limit of about 10 ps update rate, and can only go faster by increasing the pulse spacing, which can sacrifice fine detail, such as necessary for 3D printing small font text and graphics.

[0005] Prior art vector 3D printing processes can operate above 100 kHz, as the pulses are typically gated on while the laser beam is "steered" (by mirrors) in the shape of the vector line being 3D printed. Vector 3D printed parts including text can typically be recognized, as the 3D printed line is typically one pulse wide (unless filled in) and the pulses get closer together near corners, where the surface speed of the laser beam slows down as it turns a corner. It has been found, however, that the placement accuracy of 3D printed pieces with vector 3D printing is compromised at very high surface speeds of the laser beam.

[0006] There are various manufacturing methods for generating 3D structures, in which a laser device plays a central role in the 3D building process. The generic terms for these are laser 3D printing (or 3D laser printing) and stereolithography. Terms such as selective laser melting (SLM) or selective laser sintering (SLS) refer to processes in which solid materials are formed. Another technique is known as laser metal deposition (LMD). In this case, a powder is supplied coaxially through a nozzle into a focused laser spot, and fully dense functional metal parts can be produced. Another laser technique, known as stereolithography (SLA), uses a shorter wavelength laser to locally photopolymerize a liquid.

[0007] The two main attractions of 3D laser printing are: a large number of different parts can be made without having to make any special tools; and, a wide variety of different parts can be made. Only the laser firing instructions need to be changed, without having to make any special tools and methods. In other words, only the software needs to be customized, not the hardware and the general manufacturing strategy.

[0008] Another advantage of 3D printing is that objects with complex geometries can be made flexibly without first having to make special production tools, such as molds. A 3D printer is a very versatile production machine that directly converts a software structure into a real object. This printing process has been developed for a range of materials including metals, ceramics and polymers. Constant wave (CW) and pulsed lasers with a wavelength that is activated, absorbed or otherwise compatible with the material being printed are used for these applications. For example, a 1064 nm wavelength can be used for metal melting / sintering, while a UV 355 nm can be used for photopolymerization.

[0009] Structures can be made that are virtually impossible to make with other methods. The freedom of design is much greater, with far fewer restrictions than the freedom of design that is usually provided by the capabilities of the production method. For example, parts can be made that contain open channels with quite complex shapes, which cannot be made, for example, with drilling. Sometimes, a large number of such openings can be used to effectively cool machine parts, with some fluid flowing through the cooling channels.

[0010] SLA processes come in three main categories: laser-based stereolithography (laser SLA), digital light processing stereolithography (DLP-SLA), and mask SLA (MSLA). For all of these processes, a vat of photoreactive liquid resin is selectively exposed to light in order to form very thin solid layers that stack to create a solid object.

[0011] Laser-based SLA is the original means of stereolithography developed by Charles Hull (co-founder of 3D Systems) in 1986. The technology works by using a UV laser to draw each layer of an object and using two mirrors driven by motors (called galvanometers or "galvos" (one on the X-axis and one on the Y-axis)) to quickly aim the laser beam across the printing area as the laser beam moves, solidifying the resin. To create a solid object, the design must be broken down into a series of points and lines, layer by layer, which are given as a set of coordinates to the "galvos" and the laser draws them out.

[0012] DLP-SLA uses a digital projector to flash a single image of each layer across the entire platform at once. Because the image of each layer is displayed digitally, it is composed of many square pixels, resulting in layers formed of small rectangular bricks called voxels, stacked along the Z-axis. Examples of DLP-SLA orthodontic 3D printers: Park Dental Research / Orchestrate Juell Flash OC, Envisiontec Vida, etc.

[0013] An example of an extreme application of 3D printing is the fabrication of basic parts of rocket engines. The opportunity to create a complex structure designed by computer, optimized for gas flow and stability, although minimal in weight, is important, while constraints such as material cost and processing time are less relevant.

[0014] Rapid manufacturing can also be used conveniently to replace parts. It is often not very economical to produce and store a sufficient number of replacement parts for various machines, especially in cases where the model cycle is relatively short and new types of parts are always needed. Using 3D laser printing, it is possible to store the recipe only in computerized form and produce such replacement parts as needed.

[0015] Therefore, there is still a need for faster, more economical and more precise laser 3D printing. Both the hardware and software that control the laser device and the methods of using these improved laser devices can be improved. Furthermore, the setting of the laser 3D printed piece on the part can be improved to provide both precision and speed.

[0016] Accordingly, it is desirable to provide improved laser devices along with software for operating the laser devices and processes for 3D printing parts at high speed and high precision (such as directly replicating label information, aesthetic and functional features). These improvements should make the process fast, simple, cost effective and scalable to mass production, and allow the resulting parts to have consumer and machine readable features that can replace labels and adhesives, among other benefits. SUMMARY

[0017] The present invention provides a method that addresses one or more of the deficiencies of the prior art and other benefits. The specification, claims, and drawings describe various features and embodiments of the invention, including a 3D part printed by a pulsed laser device. The part has a series of superimposed layers, and each layer has a plurality of 3D printed pieces. Pulses from the pulsed laser device form the 3D printed pieces, and an absence of pulses forms the voids.

[0018] In an embodiment of the invention, a pulsed laser device is controlled by a computing device that sends a package of instructions to the pulsed laser device, the package of instructions including at least 2 individual instructions. Each individual instruction instructs the laser to pulse or not to pulse, where the superimposed layer includes 3D printed pieces and voids in a grid pattern. The grid pattern has a plurality of locations disposed along a series of substantially parallel rows, and each location has one 3D printed piece. Further, pulses from the pulsed laser device form the 3D printed pieces, and an absence of pulses forms the voids. Each individual instruction instructs the laser to pulse or not to pulse, thereby creating a 3D printed piece or a void, respectively, at each location on the grid pattern. The grid pattern has locations disposed along rows, where each pair of adjacent locations is separated by an X-distance, and there are two or more substantially parallel rows, and each pair of adjacent substantially parallel rows is separated by a Y-distance.

[0019] In another embodiment, the Y-distance is greater than the X-distance, and the locations between adjacent parallel rows are stacked, alternatively, the locations between adjacent parallel rows can be offset. Likewise, the locations in a two-dimensional layer can be stacked or offset in the Z direction. The individual instructions within the package can be any combination of 3D printed pieces and voids, including all 3D printed pieces or all voids.

[0020] In yet another embodiment of the invention, there is a method of 3D printing a part by a pulsed laser device, the method including the steps of: defining a series of superimposed layers, the series of superimposed layers including a plurality of 3D printed pieces and voids in a grid pattern, the grid pattern including a plurality of locations disposed along a series of substantially parallel rows, where each location includes one 3D printed piece or one void.

[0021] The method further has the steps of forming the 3D printed piece by pulsing the pulsed laser device and creating voids by not pulsing the pulsed laser device, and controlling the pulsed laser device with a computing device that sends instruction packets to the pulsed laser device. The instruction packets comprise at least 2 individual instructions, where the individual instructions instruct the pulsed laser device to pulse or not pulse, thereby creating a 3D printed piece or a void, respectively, at each location on the grid pattern. At least one of the rows is 3D printed by 2 different packets. Alternatively, at least one of the rows can be 3D printed by 3 different packets. The instruction packets further contain two or less, preferably only one, individual instruction related to the positioning of the locations in the grid pattern.

[0022] The present invention provides many benefits over the prior art, including that 3D printing of objects or parts can be accomplished at much higher precision and at much higher speed than past pulsed laser 3D printing. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a schematic of a laser device according to the present disclosure.

[0024] Figure 2 is a grid according to the present disclosure, where the locations in adjacent parallel rows are offset.

[0025] Figure 3 is a grid according to the present disclosure, where the locations in adjacent parallel rows are offset.

[0026] Figure 4A is an alphanumeric character in a grid pattern 3D printed according to the present invention.

[0027] Figure 4B is an alphanumeric character in a grid pattern 3D printed according to a prior art process.

[0028] Figure 5 shows a standardized rectangular pattern laser printed by a prior art vector laser process compared to the same pattern laser printed according to the present invention.

[0029] Figure 6 is an exemplary grid of standardized rectangles according to the present invention.

[0030] Figure 7 shows error flag calculation.

[0031] Figure 8 is an illustration of 3D printing made as a result of information packets sent to a laser controller according to the present invention.

[0032] Figure 9is an illustration of a 3D print made as a result of an information package sent to a laser controller according to the present invention.

[0033] Figure 10 is an illustration of a 3D print made as a result of an information package sent to a laser controller according to the present invention.

[0034] Figure 11 is an illustration of a 3D print made as a result of an information package sent to a laser controller according to the present invention.

[0035] Figure 12 A "staged" approach to 3D printing with a laser is shown.

[0036] Figure 13 An inverted approach to 3D printing with a laser is shown. DETAILED DESCRIPTION

[0037] 3D printing operation

[0038] 3D laser printing methods typically work with a liquid or powder bath that has a smooth surface. Then, a laser beam is moved over the top surface, illuminating some portions of the top surface, causing solidification, while missing other portions. Typically, the laser beam is moved only along lines in arbitrary directions, which is called the vector method. In other cases, the entire area is scanned systematically, and the laser beam is turned on only for those portions that are to be processed, which is called the raster method. It is also possible to combine these methods, for example, vector scanning for the outline, and raster scanning for the interior portions.

[0039] The flat structure is lowered slightly into the bath so that the surface of the flat structure is covered with a thin layer of liquid or powder. Sliding a solid object over the surface can help to obtain a smooth surface of the bath. A layer of solid material can then be created on the flat structure using a laser. This process is repeated until the full height of the desired solid workpiece is created.

[0040] Figure 13A "stage" approach to 3D laser printing is shown. The laser device 301 and the platform 303 are both controlled by a computing system 305. The computing system 305 raises and lowers the platform 303 in the Z direction 307. The platform 303 initially starts near the top of the liquid 306 contained in the vat 302. The laser device 301 begins by selectively laser curing a portion of the liquid 306 on the platform 303 to form a first layer of the part 304. When the first layer is complete, the platform 303 is lowered slightly into the vat 302 to allow a fresh layer of liquid to cover the part 304. The laser device 301 then repeats the selective laser curing of the liquid 306 to form a second layer of the part 304. Those skilled in the art will understand that the thickness of each individual layer will be determined by the type and power of the laser used and the complexity of the part being printed. Likewise, each successive layer may be the same as or different from the layer below it, again depending on the design of the desired part. Although in Figure 13 Although "liquid" is used in the description, those skilled in the art will appreciate that the liquid may also be fine-grained metal particles.

[0041] The created workpiece is then removed from the bath, the remaining liquid or powder is removed, and some additional processes (such as polishing) may be applied to improve the surface quality. The remaining unprocessed powder or liquid can be used for the next part to be made.

[0042] Another possibility is to irradiate from the bottom, for example through a glass sheet below the bath. The finished workpiece is then pulled upwards step by step to allow fresh powder or liquid to reach the bottom of the finished workpiece.

[0043] FIG14 shows 3D printing of an inverted head (part 321) using a glass plate 326. The base 322 begins adjacent to the glass plate 326 so that a thin layer of liquid 323 exists between them. The liquid 323 is contained in a vat 325. The laser device 320 selectively cures a portion of the liquid 323 onto the base 322 to form a first layer of the part 321. The base 322 then moves in the Z direction 324 to allow a new layer of liquid 323 to flow between the glass plate 326 and the part 321. The laser device 320 then cures the new layer of liquid 323 to form the next layer on the part 321. Both the laser device 320 and the base 322 are controlled by a computing device (not shown). Figure 13 As is the case with 3D printing, those skilled in the art will understand that the thickness of each individual layer will be determined by the type and power of the laser used and the complexity of the part being printed. Similarly, each successive layer can be the same or different from the layer below it, again depending on the design of the desired part. Although "liquid" is used in the description of FIG. 14 , those skilled in the art will understand that the liquid can also be fine-grained metal particles.

[0044] There are other methods in which solidification of the liquid is done below the top of the liquid. Such methods can involve sub-surface solidification of the liquid by a confocal laser device. In such methods, the focal point of the laser is below the top of the liquid, such that the flux of the laser spot required to solidify the liquid is achieved below the top surface of the liquid.

[0045] There are yet other methods in which the source material is continuously supplied with some kind of feeding mechanism during the method. Such processes are typically largely automated, performed by some kind of 3D laser printer device. However, some amount of manual work is typically required, for example for filling the bath, removing and cleaning the workpiece, etc.

[0046] Suitable lasers for SLA include pulsed fiber lasers and other solid state lasers. When 3D printing metal, an inert gas such as nitrogen or argon is often required to protect the metal from oxidation.

[0047] For melting polymer materials, a CO2 laser at 10.6 pm wavelength is often used; this light is typically well absorbed by polymers. The entire bath is typically heated with a separate infrared source, so relatively small laser power is required, and the resulting temperature gradient is weak. This helps to obtain better quality results.

[0048] Another possibility is to use laser-induced polymerization. Here, the raw material is a liquid containing some monomers, and short wavelength light (e.g. a 355 nm pulsed laser) is used to trigger some kind of activator to start the polymerization.

[0049] 3D fabrication processes for ceramics have not developed as much as for metals and polymers, but different processes are possible. For example, a suspension or paste can be used as a raw material, which can exhibit a sufficiently uniform distribution of ceramic particles (e.g. aluminum oxide or zirconium oxide). Such a suspension can contain a light-curable organic binder material; the binding of the ceramic particles by radical polymerization of the binder material can be initiated, for example, with a blue laser.

[0050] Parts

[0051] As used herein, “part” refers to a single object that is fabricated. The part can be a container, non-limiting examples of which include a bottle, a bag, a package, a cartridge, a can, a cup, a cap, and the like. The part can be made from any kind of commonly used material, including: polymers (i.e. PET, PETG, HDPE, PP, PVOH, LDPE, LLDPE, engineering resins), metals (i.e. aluminum, steel or other alloys), ceramics, glass.

[0052] It should be understood that the parts produced by the 3D printing method of the present application are intended to be three-dimensional, they are produced from a series of 2-dimensional layers. Accordingly, the present specification discusses two-dimensional grids and printing, it should be understood that this applies to the 2D layers from which the 3D parts are printed. For example, the 3D part can be composed of a series of superimposed layers produced by two-dimensional laser printing; that is, 2D layers laser printed in a two-dimensional grid are superimposed to form the 3D part.

[0053] The parts according to the present application can be formed from a single thermoplastic material or resin, or from two or more materials that differ from one another in one or more respects. For example, the part can include one or more thermoplastic resins selected from the group consisting of polyethylene terephthalate (PET), ethylene glycol modified-polyethylene terephthalate (PETG), polystyrene (PS), polycarbonate (PC), polyvinyl chloride (PVC), polyethylene naphthalate (PEN), poly(cyclohexylene dimethylene terephthalate) (PCT), ethylene glycol modified PCT copolymer (PCTG), copolyester of cyclohexanedimethanol and terephthalic acid (PCTA), polybutylene terephthalate (PBCT), acrylonitrile-styrene (AS), styrene-butadiene copolymer (SBC), or a polyolefin such as low density polyethylene (LDPE), linear low density polyethylene (LLPDE), high density polyethylene (HDPE), polypropylene (PP), and combinations thereof. Similarly, the part can include an engineering resin or a ceramic or a metal.

[0054] There are a variety of polymer resins that can be used for SLA (stereolithography) 3D laser printing. The materials used in SLA are light-sensitive thermoset polymers in liquid form, including but not limited to PLA, ABS, nylon, resin, PETG, TPU, ASA, PEI (engineering plastic).

[0055] Metallic structures can be made with various steels or with alloys of nickel, titanium or aluminum. A powder of particles with only one type of metal, or a mixture of different materials, can be used, where only one of these materials is melted and helps to hold the other metal particles together. This technique is also known as selective laser melting.

[0056] Instead of laser melting, laser sintering can be employed. Here, the laser does not completely melt the material, but only bakes the powder particles together. In the case of metal powder, this method is also known as direct metal laser sintering. With this method, a wide range of materials can be used. However, sintered materials often still exhibit a certain significant porosity, i.e. a lower density and weaker mechanical strength.

[0057] An improved method is indirect sintering or two-step sintering, where the laser treatment creates only a preliminary porous structure, which is then sintered again with a heat treatment. In this method, another metal with a lower melting point (e.g. copper) can be introduced, which fills the microscopic voids in the porous structure of the other metal (e.g. steel). In this way, a significant shrinkage of the structure is avoided.

[0058] The thermoplastic material can include monomers derived from renewable resources and / or monomers derived from non-renewable (e.g., petroleum) resources or combinations thereof. For example, the thermoplastic resin can include a polymer made entirely from biologically derived monomers, or a polymer made partially from biologically derived monomers and partially from petroleum derived monomers.

[0059] In some cases, the parts produced with 3D printing are not made for direct use, but only to produce a casting form, using which more parts, replicas, can be made from another material by some kind of casting. The replicas can then be composed of very stable materials that would not be easily used for 3D printing directly. However, this method strongly limits the possible range of geometries, because the internal structure cannot be replicated in this way.

[0060] Tooling is also a preferred use of 3D laser printing. Tooling means the making of tools, such as casting forms or workpiece holding tools. While standard tools can be used for many processes, some processes require very specialized tools, but often not in large quantities, for example, because one tool can be used to make many elements of the final product.

[0061] Laser and laser device

[0062] According to the present invention, a pulsed laser, such as a short pulsed laser, can be used to 3D print a part. Lasers for use in the present invention are commercially available and include nanosecond, picosecond, and femtosecond lasers. These short pulsed lasers can emit pulses applied at high energy density and high repetition rate, which are important to allow high speed laser 3D printing of parts. Laser 3D printing itself includes 3D printed pieces made by melting, photopolymerizing, or photocuring a material to form an object, such as a product, part, or packaging.

[0063] Any suitable laser can be used to 3D print the part 10. Figure 1One example of a laser device 200 according to the present application is shown, which includes a laser 20 that can be used for 3D printing parts. The laser device 200 includes a laser 20, which can be any laser capable of generating sufficient energy to 3D print parts, such as a UV laser with a power in the range of 1 W to 60 W and a laser wavelength of 355 nanometers, or an IR 3D printing laser with a power in the range of 1 W to 300 W or even 500 W and a laser wavelength of 1064 nanometers. Such lasers can be obtained from various vendors, including the IPG ULPN-355-10-1-3-M 3D printer or YLPN-1-1x350-50-3M MOPA module available from IPG Photonics of Oxford, MA, United States. Other brands and types of lasers are possible, and different power ranges and settings can be used. The laser device can include optics that can be used to direct the laser beam as needed, and / or modify the laser beam, such as by changing the energy density and / or spot size of the laser beam 28.

[0064] The frequency or repetition rate, measured in Hz, is the number of laser pulses that a single laser can deliver in one second. For example, a 1 MHz laser delivers 1,000,000 pulses per second, while a 100 kHz repetition rate laser delivers 100,000 pulses per second. Repetition rate can be important for processing a particular laser emission job in a short amount of time (i.e., high speed laser 3D printing). More pulses available per unit time are nearly linearly related to the time needed by the 3D printer for a given row of a particular job (and vice versa).

[0065] The pulse energy is the amount of energy contained in a single laser pulse, and is typically measured in µJ or mJ. Generally, the pulse energy is in the range of 0.001 J to 3000 J, more preferably 0.1 J to 2000 J, more preferably 0.1 J to 1000 J, more preferably 5 uJ to 1000 uJ (2 mJ), more preferably in the range of 7 µJ - 1000 µJ, and more preferably 10 uJ - 300 µJ. The average power of the laser is then given as the pulse energy multiplied by the repetition rate.

[0066] Average Power = Pulse Energy (J) Repetition Rate (Hz or 1 / second).

[0067] The peak power is equal to the pulse energy divided by the pulse duration, and the pulse duration can be less than 100 nanoseconds, less than 50 nanoseconds, less than 20 nanoseconds, less than 10 nanoseconds, or less than 1 nanosecond. Thus, the pulse energy and the pulse duration are linearly related to the peak power. The shorter pulse durations that are achievable using nanosecond, picosecond, and femtosecond lasers allow for very high peak powers, which contribute to the ability to 3D print parts.

[0068] In Figure 1 In the depicted laser apparatus 200, a laser 20 projects a laser beam 28 onto an X-mirror 22 that is rotated by an X-galvanometer 21. The X-mirror 22 and the X-galvanometer 21 together form an X-galvanometer set. The laser beam 28 is then projected onto a Y-mirror 24 that is rotated by a Y-galvanometer 23. The Y-mirror 24 and the Y-galvanometer 23 together form a Y-galvanometer set. The X-mirror 22 and the Y-mirror 24 work together, respectively, to direct the laser beam 28 to a location of a desired 3D printed part 29 on a part 27 to be 3D printed. The laser beam 28 will typically pass through a lens 26 before reaching the part 27. The distance from the lens 26 to the part 27 is a focal length 25.

[0069] The combined optics of the laser apparatus can function to cause the laser beam to be swept over the surface of the part in successive passes. The laser beam can be directed by the X-mirror to be swept over the part in the X-direction along a first row in the grid while pulses are emitted (or omitted). The combination of the speed of the sweep of the laser beam over the surface of the part (also referred to as the surface speed of the laser beam) and the repetition rate of the laser pulses then determines the pitch of the 3D printed part along the X-direction.

[0070] X-pitch Repetition rate = surface speed

[0071] The laser can emit one or more pulses while being swept over the part at a given location, thereby creating a location (or locations) that is 3D printed, or the laser can omit pulses while being swept over the part at a given location, thereby creating a location (i.e., a void) that is not marked. The laser beam can be swept over the part at a constant surface speed while pulses are emitted and / or omitted. The surface speed or sweep speed is as defined above. The laser beam can be subsequently swept over the part along a second row in the grid (such as a row adjacent to the first row) while pulses are emitted (or omitted). The laser beam can be swept over the first and second rows in the same direction or in opposite directions. For example, the laser beam can be swept over the first row from “left to right” and over the subsequent / adjacent row from “right to left.”

[0072] Laser 3D printing

[0073] The parts of the present invention are typically 3D printed through processes of foaming, carbonization, ablation, etching, reduction, oxidation, and / or phase change. The term foaming refers to the process whereby a laser beam melts and vaporizes a portion of the material, which process creates a bubble that is trapped within the melted resin and diffusely reflects light upon cooling.

[0074] When carbonizing a material, the laser heats the surface of the material (typically to a minimum of 100°C), releasing a combination of oxygen, hydrogen, or decomposition products. Carbonization typically results in a dark 3D printed part with a higher carbon content than the original material, making it a good choice for lighter colored parts, with relatively little contrast shown on darker materials.

[0075] There are additional methods of 3D printing parts. For example, annealing is a unique laser process that can be used on metals and other materials. Energy from the laser beam creates an oxidation process beneath the surface of the material, which results in a color change on the surface of the material.

[0076] Spot size is an important parameter of the laser 3D printing of the present invention and relates to the focused area of the laser beam that contacts the part. "Spot size" is the diameter of a circular spot. The spot is circular, but an elliptical spot can be obtained by controlling the laser beam optics relative to the part. Spot size can be modified by focusing or defocusing the laser beam, but the "flux" (= energy per unit area) within the spot decreases as the spot is magnified or defocused. Theoretically, the smallest spot size achievable using any laser is the wavelength of the laser itself. In practice, the smallest spot size achievable using a pulsed laser is about 7 pm - 20 pm. The spot size of the laser 3D printing of the present invention can be in the range of about 10 pm to about 150 pm, preferably about 20 pm to about 100 pm, more preferably about 30 pm to about 80 pm, and even more preferably about 40 pm to about 60 pm. As discussed in the background of the present invention, the spot size of conventional laser 3D printing for date codes (e.g., using a CO2 laser) and the like is a minimum of 250 pm and can exceed 800 pm. Another way to consider spot size in the context of 3D printing is the size of a painter's brush that an artist would use to paint. If you want very fine detail, you would utilize a smaller spot size. Larger areas to be covered can prefer a larger spot size. However, the laser 3D printing mechanism requires a minimum flux to achieve the desired 3D printed part, so balancing the pulse energy, pulse duration, pulse overlap, and spot size is critical.

[0077] Additionally, there is a region around the laser contact point that can also be heated during the 3D printing process, although little or no material will be 3D printed. This "heat affected zone" can still create effects such as crystallization that can affect the appearance and / or performance of the target material. Short pulse lasers (e.g. nanosecond lasers) have some heat affected zone, although substantially less than microsecond pulse or CW type lasers (e.g. CO2, longer pulse IR lasers, etc.). Picosecond and femtosecond lasers are often referred to as "ultra-short pulse" and have very little, to no heat affected zone. This ability helps control the thermal effects of 3D printing.

[0078] The geometry of the 3D printing pitch is a key factor in the cycle time and flux (or energy per unit area) provided to the part. For example, the pitch between 3D printed parts can be such that the 3D printed parts do not overlap at all and have 0% overlap. At 0% overlap, each individual laser pulse is responsible for the energy provided for the 3D printed part. If the laser does not have enough pulse energy or peak power to achieve the desired 3D print, the pulse pitch can be reduced to points that overlap in one or both of the X and Y directions; overlapping points include providing more than one laser pulse to the area of the part where the points overlap, which provides a higher flux or energy per unit area to that portion of the part. Additionally, the pulse pitch is a key factor for cycle time. If the laser has a fixed repetition rate or pulse frequency, to achieve the lowest processing time (also known as cycle time), one would want to spread out the pulses as much as possible while still achieving the desired 3D print type and 3D print contrast. In one embodiment of the invention, the pulses are non-overlapping.

[0079] Pulse duration is the length of time that the pulse stays above half of its maximum value. The shorter the pulse, the higher the peak power that can be produced using the average power. This is because average power = pulse energy (J) Repetition rate (Hz or 1 / second). Peak power is equal to pulse energy divided by pulse duration. So when the pulse duration becomes significantly shorter, the resulting peak pulse power is significantly higher. This peak power enables improved melting, photopolymerization, or photocuring at the surface being 3D printed. Short pulse lasers take advantage of this phenomenon to 3D print parts and enable 3D printing mechanisms that are not typically present in longer pulse lasers.

[0080] Packaging

[0081] One way the current CV bitmap process can overcome the 10 ps limitation update rate is to include multiple single instructions in one command packet to the pulsed laser device. That is, the single instruction to either pulse or not pulse in a single update causes the laser to fire a pulse to create a 3D print or omit a pulse to leave a void. In such a process, each row can contain both locations to be 3D printed and locations to be left unmarked according to the command packet.

[0082] The constant speed of the laser sweep speed causes the X spacing within these multiple 3D print (or void) chains to remain consistent. Recall that the laser sweep speed is determined as: X-distance Repetition rate = surface speed Increasing the repetition rate of the laser from 100 kHz to 200 kHz doubles the sweep speed of the laser beam and can help to shorten the cycle time.

[0083] Of course, including multiple single instructions in a single update increases the complexity of the pattern that can be produced. While a laser 3D printing process that includes only one pulse per update (i.e., a laser with a 10 ps update rate and a 100 kHz repetition rate) can produce complexity in a single 3D print or void, such as: 3D print - void - 3D print - void - 3D print - void The same process with a 200 kHz laser would have twice the sweep speed, but can only produce details such as: 3D print - 3D print - void - void - 3D print - 3D print - void - void - 3D print - 3D print - void - void In the current CV bitmap process, the sweep speed of the laser beam across the surface of the part is much faster than can be achieved with currently available laser 3D printing processes, such as raster and vector 3D printing processes.

[0084] The packets of single instructions defined herein can be transmitted to the laser device at regular time intervals, such as every 10 s. The packets of single instructions defined herein contain the 3D print / void information as described above, but can also contain additional instructions in each packet. For example, the information packet can include single instructions related to the positioning of the locations to be 3D printed. Those skilled in the art will appreciate that in order to improve the speed and accuracy of the overall pulsed laser 3D printing process, two things need to be done. First, each information packet should include the maximum number of single instructions that the processor will allow, and second, the number of instructions related to 3D prints / voids should be maximized relative to other instruction information in the same packet.

[0085] To illustrate the packing concept of the present invention, one can think of a vehicle such as a bus. On a given bus there can be, for example, 2, 4, 8, 16, 32, 64 or more seats. It goes without saying that driving a bus with 16 seats and only 4 people on the bus from point A to point B is an inefficient use of the bus. Likewise, filling each information packet with the maximum number of single instructions will increase the efficiency of the overall process. Furthermore, if you have a bus with only 8 seats and you fill 3 of those seats with position or location instructions, you are left with only five seats for 3D-printed piece / void instructions, which is the desired outcome of the process.

[0086] When moving the laser beam across a given position row, the pulsed laser 3D printing process of the present invention operates with a constant laser repetition rate and a constant surface speed, with a short deceleration / reacceleration process at the turning point at the end of each row. During this turning process, the laser does not 3D print. Furthermore, the rows are linear, so the only directional change occurs again at the end of each row. During the short turning period, the instruction packet can include a larger amount of location information.

[0087] Similarly, the constant surface speed and constant repetition rate make it so that at the beginning of the 3D printing notified by any given packet, the position along the given row is largely predetermined (i.e., consistent X-distance). Thus, a packet of single instructions can only need one location instruction in addition to the beginning and end of each row. The location instruction can include an X component, a Y component, and a Z component. It will be appreciated that the Z component of the location information can always be zero when laser 3D printing is performed on a flat surface.

[0088] Because the pulsed laser moves at a constant surface speed, the end point of the 3D printing notified by one packet determines the start point of the next packet. Thus, one single instruction related to location serves a dual purpose for the end position of one packet and the start position of the next packet. Those skilled in the art will appreciate that speed is defined as the distance traveled divided by the time required to travel that distance. Each packet has a set time, and one location instruction tells the laser device how far to travel, which defines the speed. Thus, no additional instructions related to speed are needed, freeing up more computational space (e.g., seats on a bus) for 3D-printed piece / void instruction information. This simplification of speed and location maximizes the number of single instructions related to 3D-printed pieces and voids. This speeds up the overall process and makes it more accurate. This level of packet use efficiency cannot be achieved with prior art processes (i.e., raster, vector) that, for example, draw a boundary and then fill in between the lines. Those prior art processes require additional amounts of speed and location information within each information packet.

[0089] Accordingly, a part can be 3D printed by a pulsed laser device to create a predetermined feature comprising a plurality of 3D printed pieces and voids in a grid pattern. The grid pattern consists of a plurality of positions arranged along a series of substantially parallel rows, where each position comprises either one 3D printed piece or one void. Pulses from the pulsed laser device form the 3D printed pieces, and the absence of pulses forms the voids. The pulsed laser device is controlled by a computing device that sends a packet of instructions to the pulsed laser device, the packet of instructions comprising at least 2, preferably at least 4, more preferably at least 8, and even more preferably at least 16, or even at least 32 or at least 64 or more individual instructions, where each individual instruction informs the laser whether to fire a pulse toward the surface, thereby creating a 3D printed piece or a void, respectively, at each position on the grid pattern. The packet of instructions can be provided to the laser device at an update rate of 10 ps. The update rate at which the packet can be provided to the laser device can be less than 10 ps, preferably 7.5 ps, or 5 ps or even 2.5 ps (ps = microsecond).

[0090] Figure 8 is an example of one row of a grid pattern with packets P1, P2, P3, and P4, each containing 2 individual instructions to the pulsed laser device. P1 instructs the pulsed laser device to fire a pulse twice, thereby making two 3D printed pieces. P2 instructs the pulsed laser device to not fire a pulse twice, thereby leaving two voids. P3 instructs the pulsed laser device to fire a pulse once and then not fire a pulse once, thereby creating one 3D printed piece and leaving one void. P4 instructs the pulsed laser device to do the opposite of P3. Those skilled in the art can use this system of 3D printed pieces and voids in a grid pattern to form any of the various predetermined features as defined herein.

[0091] Figure 9 is an example of one row of a grid pattern with packets P1, P2, P3, and P4, each containing 4 individual instructions to the pulsed laser device. P1 instructs the pulsed laser device to fire a pulse three times and not fire a pulse once, thereby creating three 3D printed pieces and one void. P2 instructs the pulsed laser device to fire a pulse twice and then not fire a pulse twice, thereby creating two 3D printed pieces and leaving two voids. P3 instructs the pulsed laser device to fire a pulse once, not fire a pulse, fire a pulse again, and then not fire a pulse, thereby creating a 3D printed piece-void-3D printed piece-void pattern. P4 instructs the pulsed laser device to not fire a pulse three times and then fire a pulse once, thereby creating three voids and one 3D printed piece.

[0092] Figure 10is an example of one row of a grid pattern with packets P1 and P2, each packet containing 8 individual instructions to the pulsed laser device. P1 instructs the pulsed laser device to pulse twice, not pulse, pulse, not pulse, pulse twice, and not pulse. P2 instructs the pulsed laser device to pulse eight times. It should be understood that prior art polygon scanners can send two or more instructions to the pulsed laser device. But the instructions are all either pulses, or all are not pulses. For example, a polygon scanner can send eight on-pulse instructions, then eight no-pulse instructions. These prior art polygon scanners cannot send the individual instructions according to the present invention. Those skilled in the art will understand that by controlling each and every location with 3D prints or voids as taught by the present invention, an incredible improved versatility is achieved. By utilizing the individual packet instructions of the present invention, predetermined features can be 3D printed on a surface at an incredible speed and accuracy.

[0093] Figure 11 is an example of one row of a grid pattern with packet P1, which contains 16 individual instructions to the pulsed laser device. P1 instructs the pulsed laser device to pulse twice, then not pulse twice. This pattern is repeated three more times for a total of 16 individual instructions in one packet of information.

[0094] Further provided herein is a method of 3D printing a part by a pulsed laser device, the method comprising the following steps. First, a predetermined feature is defined, the predetermined feature comprising a plurality of 3D prints and voids in a grid pattern, the grid pattern comprising a plurality of locations arranged along a series of substantially parallel rows. Each location comprises either a 3D print or a void. The 3D prints are then formed by causing the pulsed laser device to pulse, and the voids are created by causing the pulsed laser device to not pulse. Of course, you are not "creating" the voids, you are simply leaving locations that are not 3D printed, which are defined by this specification as "voids". The pulsed laser device is controlled by a computing device, which sends packets of instructions to the pulsed laser device, the packets of instructions comprising 2, preferably 4, more preferably 8, and even more preferably 16 or more individual instructions. Each individual instruction instructs the pulsed laser device to pulse or not pulse, thereby creating either a 3D print or a void, respectively, at each location on the grid pattern.

[0095] Grid

[0096] As used herein, "grid" or "bitmap grid" refers to a regular periodic array that can include a plurality of locations of laser-induced print. The array of print can be formed in the grid as two-dimensional layers in the X and Y directions, and a series of two-dimensional layers can be overlaid in the Z direction to form a 3D part. The periodicity of the array includes periodicity in both the X and Y directions. The plurality of 3D printed parts within the grid can be present at every location within the grid or can not be present at every location within the grid. That is, a 3D printed part can or can not be present at a location within the grid (i.e., a void). As described above, the laser device sweeps a laser beam across the part when a laser pulse is emitted from the laser or no pulse is emitted. When the laser emits a pulse to a given location, a 3D printed location occurs, while when the laser does not emit a pulse to a given location, an unmarked location is produced. The laser beam can be swept across the part at a constant surface speed, while the repetition rate of the laser is constant, so the periodicity of the locations in the direction that the laser beam is swept across the part (i.e., the X direction) will be regular (i.e., X-distance), even though the spacing of the 3D printed locations can not be equal in view of the possibility of unmarked locations. In the case of unmarked locations, the distance between any 3D printed locations along the same direction (i.e., in the X direction) can be an integer of the minimum distance between 3D printed parts measured in that direction (i.e., 2x, 3x, or greater).

[0097] The laser beam can be swept across the part in subsequent rows. The laser beam can be scanned from left to right or right to left, and can be scanned in the same direction as it moves from one row to another (e.g., like a carriage return on a typewriter, as in a raster process), or can be scanned in alternating directions as it moves from one row to another. Key contributors to reducing cycle time include scanning the laser beam in alternating directions as it moves from one row to another. The rows can be generally parallel to one another. The distance between adjacent rows is the Y-distance. The locations in adjacent rows can be directly above / below one another or can be offset relative to one another. It will be appreciated that an offset equal to the X-distance results in realignment of the locations between rows.

[0098] As previously discussed, laser 3D printed pieces can be non-overlapping to reduce the time required for 3D printing a given pattern (i.e., "3D printing time"). By spacing the 3D printed pieces apart in either or both the X-direction and / or the Y-direction, the 3D printing time can be further reduced, however, this increased spacing can result in poor consistency and fragile and / or highly porous 3D parts. For example, increasing the X-distance allows for faster surface speed of the laser beam across the surface of the part when 3D printing a given row (at a constant repetition rate). Increasing the Y-distance allows for fewer turns during the course of 3D printing a given predetermined pattern. Alternatively, the 3D printing can be touching or even overlapping to increase the strength and / or reduce the porosity of the resulting 3D part.

[0099] The X-distance is preferably in the range of about 0.005 mm to about 0.500 mm; more preferably about 0.010 mm to about 0.100 mm; even more preferably about 0.040 mm to about 0.075 mm. The Y-distance is preferably in the range of about 0.010 mm to about 2.0 mm; more preferably about 0.050 mm to about 0.150 mm; even more preferably about 0.060 mm to about 0.075 mm.

[0100] Figure 2 and Figure 3 all show various depictions of a grid according to the present invention. More specifically, Figure 2 is a grid 39 according to the present invention showing the X-direction 30, the Y-direction 32, the X-distance 31, and the Y-distance 33. Potential 3D printing locations 36 are depicted by the hollow circles that make up the grid. Further, in Figure 2 , when the angle 35 between the X-direction 30 and the locations in the adjacent row 34 drawn in the Y-direction between two potential 3D printing locations is about 90 degrees, the locations 36 in the parallel row 38 are "stacked." In other words, if a vector is used to connect adjacent 3D printed pieces from the array to form a parallelogram (i.e., a unit cell), the locations are stacked when the interior angles of the parallelogram are about 90 degrees. The locations are offset when the interior angles of the parallelogram are other than 90 degrees (i.e., 120 degrees and 60 degrees). The X-distance is measured in the X-direction from the center of one location to the center of an adjacent location.

[0101] Those skilled in the art will appreciate that the unit cell of the grid has four axes of symmetry, a horizontal, a vertical, and two diagonal. The laser 3D printing discussed herein can occur along any of these four axes.

[0102] Figure 3is another grid 49 according to the invention, showing an offset 44 having an offset distance 47 between adjacent parallel rows 48. The offset 44 is defined by an angle 45 between a position 46 in a row 48 and a nearest position 46 in an adjacent row 48, where the offset 44 exists when the angle 45 is greater than or less than 90 degrees. Figure 3 Further shown are an X-direction 40, an X-distance 41, a Y-direction 42, and a Y-distance 43.

[0103] The periodicity of the positions comprising the grid includes a periodicity in the X-direction and a periodicity in the Y-direction. The X-direction and the Y-direction can be substantially orthogonal to each other. As Figure 2 and Figure 3 Depicted, the grids 39 and 49 can each take the form of equidistant positions along consecutive parallel rows. A direction parallel to the consecutive parallel rows is taken as the X-direction (30, 40), and a direction substantially perpendicular to the X-direction is taken as the Y-direction (32, 42). The spacing between adjacent positions along any of the parallel rows (e.g. in the X-direction) is taken as the X-distance (31, 41), and the distance between adjacent parallel rows is taken as the Y-distance (33, 43).

[0104] The grid 39 can be a stacked grid as Figure 2 depicted. In a stacked grid, a position along a first row at which a 3D-printed item can be applied is directly above a position along a second row immediately below the first row. In other words, an angle 35 between a row segment connecting a first position along the first row and an adjacent position along the first row and a row segment connecting a first position along the second row and its nearest position is 90°. In a stacked grid, the spacing between adjacent positions along the X-axis is equal to the X-distance 31, and the shortest spacing between adjacent positions between adjacent X-axes is the Y-distance 33.

[0105] The grid can be an offset grid as Figure 3 depicted. In an offset grid 49, a position along a first X-axis at which a 3D-printed item can be applied is not directly above a position along a second X-axis immediately below the first X-axis. In other words, an angle 45 between a row segment connecting a first position along the first X-axis and an adjacent position along the first X-axis and a row segment connecting a first position along the second X-axis and its nearest position is greater than or less than 90°.

[0106] Just as positions within a two-dimensional grid comprising two-dimensional layers (i.e., comprising prints and voids) can be stacked or offset, subsequent overlapping grids can also comprise stacked or offset positions in the Z-direction. Positions in adjacent stacked layers are "stacked" when the angle between adjacent positions in adjacent stacked layers is approximately 90 degrees from both the X-direction and the Y-direction defined by the grid in either of the adjacent layers. Positions in adjacent stacked layers are offset when the angle is different from 90 degrees.

[0107] For example, when the print spacing within a layer comprises non-overlapping or non-touching prints within a single layer grid, an offset configuration of the layer can be desired. For example, where the prints within a given two-dimensional layer are non-overlapping and non-touching, these prints can be bridged by using an offset configuration of the layer, where the prints in adjacent layers overlap or touch multiple non-overlapping and non-touching prints.

[0108] Stacked layers in the Z-direction can be unequally or equally spaced along the Z-direction. Such spacing is Z-spacing. A 3D part can comprise a periodicity in the Z-direction, where the Z-spacing between adjacent layers is similar between stacked layers comprising the 3D part. Z-spacing can range from as small as a few nanometers or as large as a few millimeters, and can depend on the size of the 3D prints and / or the stacking / offset properties of the configuration of the two-dimensional layers. Z-spacing is preferably in the range of about 2 nm to about 2 mm; more preferably about 1 m to about 1 mm; more preferably about 10 m to about 500 m; and more preferably about 20 m to about 200 m.

[0109] Those skilled in the art will appreciate that the X-direction and Y-direction defining any two-dimensional layer is chosen somewhat arbitrarily with respect to a predetermined pattern. For example, Figure 4B An example of a "2" made by laser 3D printing is depicted, where the X-direction is vertical with respect to the "2" 61 3D printed. Those skilled in the art will appreciate that the X-direction can also easily be horizontal with respect to the "2" 61 3D printed.

[0110] Those skilled in the art will appreciate that any conventional laser printing process can be used in conjunction with the CV bitmap laser printing process. For example, a 3D part comprising stacked CV bitmap printed layers can further comprise additional prints formed by a vector process. One example comprises a 3D part in which the internal prints making up the part are formed by the CV bitmap process of the present invention, and the outline or external portion of the 3D part can be formed by a vector process.

[0111] Those skilled in the art will appreciate that the regular spacing between the grid (e.g. 39 and 49) and the adjacent locations assumes a flat surface of the part. In the case where the part surface is curved, the spacing can vary with the curvature of the surface.

[0112] Figure 4A and Figure 4B The difference between laser 3D printing via bit map grid 3D printing using the inventive CV bitmap process 4A and existing vector 3D printing process 4B is shown. In both cases, alphanumeric characters 60 and 61 (i.e. the number "2") are 3D printed with a laser. Alphanumeric character 60 is substantially better defined with clean, crisp edges and very little stray 3D printed material. Figure 4B Instead, alphanumeric character 61 has edges that are largely undefined and a large amount of stray 3D printed material 62 outside the boundaries of the alphanumeric character. Both characters 60 and 61 are 3D printed in approximately the same amount of time.

[0113] Laser 3D printing rate improvement

[0114] As discussed above, the present invention can laser 3D print parts faster and more accurately than existing processes. Existing raster processes are very slow but relatively accurate, while vector laser 3D printing processes are faster at low speeds and accurate, but very sloppy at high speeds, resulting in illegible 3D printed material that is difficult for a consumer or machine to read. Raster and vector are different graphic file types that require different laser processing modes. The main difference between the modes required for each type of laser processing involves the movement of the galvanometer or laser beam guide and the parameters used.

[0115] Vector paths are generally slower for images because the multiple fixed short start and stop points require the galvanometer set to spend time accelerating to the maximum surface speed set by the user (determined by the pulse spacing multiplied by the repetition rate) and the length of the vector distance. Longer vector distances allow the vector laser to reach its maximum surface speed, while shorter vector distances cause the laser to constantly accelerate and decelerate and never reach the maximum surface speed, resulting in longer 3D printing cycle times.

[0116] Vector processing is also less accurate at high speeds due to the acceleration / deceleration of the galvanometer that directs the laser beam. Specifically, the position of each laser 3D-print must be communicated from the computer drive software to the laser 3D-printing device, and this communication must be updated during the 3D-printing of a predetermined pattern, for example, as the laser beam traverses a given row. The typical update frequency for this communication is about 10 ps, so a laser output pulse with a repetition rate of 100 kHz would allow for an update in the communication for each single position in the grid. The same is true for raster laser 3D-printing processes, which can further include a variation in pulse power for each pulse as a means to achieve gray scale (e.g., dithering). As the surface speed of the laser beam increases across the surface of the part, a repetition rate greater than 100 kHz is needed to achieve the X-pitch required within a row, and each update from the software must now convey the position of multiple laser 3D-prints (or voids / non-3D-prints). While the calculations can be performed almost instantaneously, it is believed that the galvanometer cannot respond so quickly in the extremely fast time domain of high-speed laser 3D-printing, and the acceleration / deceleration profile of the vector process results in a large number of mispositioned 3D-prints within a given row compared to the constant surface speed profile of the present invention.

[0117] Figure 4B The effect of running a vector-type process at high speeds and the mispositioning of 3D-prints within a row when 3D-printing involves text of alphanumeric characters is depicted. This figure shows many rows that are shifted from one another, where the 3D-prints are initiated too early or too late so that the outline of the alphanumeric character is jagged and the overall appearance is blurry and potentially illegible (e.g., unable to distinguish between an “8” and a “0”).

[0118] In contrast, the process of the present invention and the resulting pattern can be created by a constant surface velocity (CV) bitmap path. The CV bitmap laser 3D-printing process allows for increased speed and increased accuracy because there are no start points and stop points within a row, but rather a user-defined maximum surface speed (again, pulse pitch multiplied by repetition rate) that is constant as pulses or 3D-prints are applied. Furthermore, the laser device of the present invention can increase speed when 3D-printing is not being performed over a relatively long distance (relative to the X-distance). For example, if there is a distance of 2-3 mm (or greater) between 3D-prints in a row of 3D-prints, the laser device can speed up without losing accuracy; otherwise, the laser beam moves at a constant surface speed simultaneously with the pulses. This is another reason why the 3D-printing system of the present invention is faster and more accurate than existing devices.

[0119] Smaller galvo sets (e.g., including lower mass mirrors) are able to achieve higher accelerations to reach the user-defined maximum surface speed. These galvos can be tuned to high acceleration values that allow the mirrors to reach their desired angular velocity in a shorter amount of time. Interestingly, these values can be specifically tuned for higher value bitmap processing as compared to vector processing. Additionally, in vector laser software, there is a maximum 3D print surface speed limit setting so that the laser 3D print approaches its desired commanded position. When the maximum surface speed threshold is increased, the laser pulses have more error in vector processing relative to their desired position. Note that in CV bitmap Figure 3 D print mode, the maximum surface speed threshold can be significantly increased, achieving overall lower 3D print cycle times relative to vector, and still keeping the pulses in their predetermined positions, since the surface speed (e.g., both the angular velocity of the mirror and the surface speed of the laser beam) is constant during the 3D print process.

[0120] The angular velocity of the galvo set is important for job cycle time because it is directly related to the surface speed of the laser beam across the part. The surface speed of the laser beam is set by the angular velocity of the galvo / mirror pair and the focal length of the laser device.

[0121] Surface Speed = Galvo Angular Velocity (rad / sec) Focal Length (mm)

[0122] When producing a laser 3D print within a given row, the surface speed is primarily controlled by the X galvo / mirror set. The job cycle time is more dependent on the laser surface speed in the X direction than in the Y direction, and the X galvo / mirror set can be more responsive than the Y galvo / mirror set. For example, the mirror on the X galvo / mirror set can be smaller (i.e., lower mass, smaller mirror size, lower inertia, higher acceleration motor capability)

[0123] In current CV bitmap processes, the surface speed of the laser beam across the surface of the part is much faster than what is achievable with currently available laser 3D print processes, such as raster and vector 3D print processes. Current processes typically demonstrate surface speeds of about 1 m / s - 2 m / s or less. The CV bitmap process of the present invention provides surface speeds higher than 8 m / s, and further provides surface speeds equal to or greater than 10 m / s, 15 m / s, 18 m / s, 22.5 m / s, 32.5 m / s, 45 m / s, 60 m / s, and even up to 90 m / s or more.

[0124] The scan path of the laser beam across the part surface can also help reduce cycle time. Conventional raster laser 3D printing processes scan the laser beam across a row in either a right-to-left or left-to-right direction (also referred to as unidirectional) and "hop" the laser beam back after 3D printing each row to start the subsequent row (like a carriage return on a typewriter). In this way, the subsequent row can be easily registered (i.e., stacked) and the grid position can be aligned based on this consistent starting point. To eliminate the hop distance and reduce the time between each 3D printed row, the current CV bitmap process uses a "bidirectional" process where 3D printing can occur in both directions in an alternating fashion (i.e., 3D printing occurs from left to right in the first row and from right to left in the subsequent row).

[0125] To maintain the pulse row alignment, the laser device can be programmed to incorporate a laser at rest, which is a delay function for each alternating row to maintain the pulse alignment. For example, at a 3D printing surface speed of about 22.5 m / sec, an 8 microsecond delay is used for alternating rows. Typical bitmap laser software settings allow for the selection of a single pulse spacing or pitch that is common in both the X direction and the Y direction. By creating different X and Y distances, similar contrast can be created for both human readable (e.g., text) and machine readable (e.g., UPC code, QR code) objects.

[0126] The laser at rest is an element of the turn profile of the laser beam scan path. The turn profile refers to the path followed by the laser beam as it turns between rows (i.e., after a left-to-right 3D printed row, turning to right-to-left 3D print the subsequent row) guided by the galvanometer set. The laser is typically off (i.e., not emitting a pulse) during the turn. The laser at rest helps to align the 3D printed pieces within adjacent rows. For example, when the grid is a stacked grid, the laser at rest ensures that the 3D printed pieces in adjacent rows remain stacked. If an offset grid is used, the laser at rest will ensure that the grid remains offset and the amount of offset remains relatively constant. The laser at rest can be determined experimentally and typically varies with the angular velocity of the galvanometer set.

[0127] The turning profile of the laser beam after completing a row can also contribute to reducing cycle time. As previously discussed, the laser beam is guided by a galvanometer set and the ability of the galvanometer set to accelerate and decelerate is a known limitation to the speed and accuracy of laser 3D printing in other (e.g., vector) 3D printing processes. The current CV bitmap process overcomes these limitations. For example, the current CV bitmap process does not accelerate or decelerate the laser beam when the laser emits a pulse (i.e., makes a laser 3D printed piece). Rather, the laser beam is only accelerated / decelerated when the laser is not 3D printing a piece, such as when the laser beam skips over multiple voids (or even entire rows) or when the laser beam turns at the end of a row and before 3D printing a subsequent row. The turning profile can be symmetrical or asymmetrical. Given the high speed at which the laser beam sweeps over the surface of the piece, an asymmetrical turning profile can be preferred.

[0128] As previously discussed, the geometry of the 3D printed piece spacing is a key factor in cycle time. As discussed, expanding the locations within the grid (i.e., increasing the X-distance and Y-distance) can result in reduced cycle time. Within a row, the X-distance contributes to cycle time because the laser surface speed is determined by the laser repetition rate and the X-distance. Increasing the Y-distance improves cycle time by reducing the number of turns (i.e., the number of rows that include a predetermined feature) that the galvanometer set must make, which at high speeds can account for 30-70% of the total cycle time. For example, the X distance can be made smaller and the Y distance made larger to obtain a similar appearance image with a reduced total cycle time. It has further been found that reducing the X-distance while increasing the Y-distance provides a faster cycle time and improved legibility of the features that are 3D printed.

[0129] The choice of orientation of the 3D printing direction can also affect the job cycle time at very high surface speeds. At very high surface speeds, the turn time can increase to the extent that it dominates the job cycle time. Selecting the 3D printing direction to be approximately parallel to the longer dimension of the feature minimizes the turns and can reduce the job cycle time. As previously discussed, the X-distance and Y-distance can be different, and this difference can contribute to reducing the work period and can compensate for any loss of strength or increase in porosity of the 3D piece by reducing the spacing in any other direction.

[0130] In the laser 3D printing process of the present invention, the laser source is fixed and the laser beam is guided by a laser device that includes a series of lenses and mirrors controlled by an algorithm. The algorithm is able to read a digital image of the desired 3D printed pattern (e.g., from a PDF file of the desired image) and convert the image to the 3D printed pattern on the target.

[0131] Microscopy

[0132] A number of parts were 3D printed according to the process of the present application, as well as comparative parts 3D printed with existing processes. The results of these comparisons are given in Tables 1, 2 and 3, and Figure 5 In order to obtain these comparison data, samples were cut from laser 3D printed HDPE blow molded bottles containing Ti02 using a utility knife and scissors. If the cut sample was not properly flat, the sample was leveled to the microscope stage by using tape or a frame. A stereomicroscope equipped with a color camera, such as an Axiocam 305 (5 megapixel CMOS, Carl Zeiss Microscopy, LLC, Thornwood, NY), was used to image the characters, numbers and images of interest of the sample using reflected light illumination, such as implemented with an LED ring light and a light source such as a Cold-light source CL 6000 LED light (Carl Zeiss Microscopy, LLC, Thornwood, NY). A typical light intensity of 80-100% of maximum light intensity was used. Individual laser 3D printed pieces that make up the character, number or image of interest were resolved using an appropriate magnification that combined with a zoom factor using an objective such as an Achromat S 1.5x FWD 28mm (Carl Zeiss Microscopy, LLC, Thornwood, NY) such that the total magnification was between 10x and 345x. For example, a character, number or image with a font size of 10pt, the total magnification was about 40x magnification. After the number of interest entered the field of view of the camera, the character, number or image was brought into focus using manual skills or, preferably, via a user interface platform using an autofocus module such as the Zen Autofocus module with Zen V2.6 Blue Edition or higher, Carl Zeiss Microscopy, LLC, Thornwood, NY. Prior to collecting the image of the character, number or image, the imaging settings were optimized by using the auto exposure option from the user interface platform along with the light intensity. The image was collected in the highest resolution format possible, such as ZVI, and then exported as a Tiff file with a resolution of about 2464 x 2056 pixels. Furthermore, the 3D printed rows of characters, numbers or illustrations should be nearly parallel to the horizontal boundaries of the image. If needed, multiple images taken at higher magnification can be precisely stitched together to encompass the entire area of the character, number or image.

[0133] Image analysis

[0134] Images from the microscope appear in gray, but were captured in color. The images are converted to grayscale using the NTSC protocol. Suitable image analysis software is required to perform this step and several other image processing steps. Analysis functions implemented in MATLAB, available from The Mathworks, Inc., Natick, MA, are referenced in this method description.

[0135] Microscopy and subsequent image analysis can be performed on one or more predetermined patterns, a portion of a predetermined pattern, or individual images within a predetermined pattern, such as graphics or alphanumeric characters. In the case of image analysis of a portion of a predetermined pattern, the portion, such as an individual graphic or alphanumeric character, must be separated from any surrounding image, character, or artwork prior to analysis. A mask can be drawn around the character or image of interest in the predetermined pattern. The mask separates the character or image from other portion characters, numbers, barcodes, artwork, dirt, or other imperfections that can be present in the image.

[0136] Image analysis first relies on identifying the laser 3D printed piece that comprises the image. The laser 3D printed piece can be identified by any reasonable means. For example, by repeatedly performing thresholding on the grayscale image from the microscope. The starting threshold is set to capture only a few pixels that fall within some of the 3D printed pieces. Then, the threshold is gradually changed, capturing increasing areas of the 3D printed pieces. The progressive thresholding continues from the starting threshold to a stopping threshold. The stopping threshold can be determined automatically, such as by using the “multithresh” function of MATLAB (i.e., Otsu’s method). Progressive thresholding can be advantageous in the analysis because the areas of the 3D printed pieces can overlap and / or merge, and the background can not be perfectly uniform. The direction of the threshold progression (i.e., light to dark or dark to light) can be used to identify dark 3D printed pieces relative to a relatively light background or light 3D printed pieces relative to a relatively dark background. In the presented example, dark 3D printed pieces are identified relative to a relatively light background.

[0137] Once a region reaches a certain size, connected components can then be used to identify individual 3D prints. A connected components algorithm is executed using each new threshold to group touching pixels into blobs. When a blob reaches 50% of the 3D print area, it is identified as a 3D print. The centroid method implemented in MATLAB's "regionprops" function is used to find the center coordinates of the 3D print. These centers are then used (see below) to determine the spacing between adjacent 3D prints in a row (e.g., X-distance) and the spacing between adjacent rows of 3D prints (e.g., Y-distance).

[0138] Determining observed X- and Y-distances and standard deviation

[0139] An exemplary means of determining the X-distance and Y-distance and their standard deviations can also be accomplished using image analysis, but one skilled in the art will recognize that any means of determining these distances and standard deviations can be used. One means of determining these values through image analysis includes using "Delaunay Triangulation." For the Delaunay Triangulation method, the center coordinates of the 3D prints are passed to MATLAB's "Delaunay Triangulation" function, which creates a triangulation based on the center points. The edges of the Delaunay Triangulation never cross, and the center points are connected in a nearest neighbor fashion.

[0140] The X-distance is taken as the distance between adjacent 3D printed locations along a given row within the grid. Adjacent 3D printed locations along a given row results in horizontal edges within the Delaunay Triangulation data structure. These horizontal edges can be separated from other edges in the triangulation by calculating the angle of the edge. The horizontal edges in a row of the grid will be within + / - 10 degrees of the horizontal edge of the image. The grid is composed of periodic spacing of locations along the row, so the X-spacing should be relatively consistent (e.g., with a low standard deviation). In this analysis, horizontal edges of length 2 times the programmed distance can be considered as an indication of non-adjacent locations and not considered. The observed X-distance determined when analyzing an image such as an alphanumeric character is then taken as the average length of the horizontal edges between adjacent 3D prints for all 3D prints / rows within a given image or character. The X-distance for multiple characters in a macro image can then be further averaged to provide an average X-distance for a given 3D printing condition and a given image or predetermined pattern. Table 1 depicts the observed X-distance for a series of 3D printing conditions for characters / numbers associated with the depicted UPC code.

[0141] The Y-distance can be determined as the vertical distance between adjacent rows. In the Delaunay Triangulation, a horizontal edge can be the part of 2 adjacent triangles. Each base edge contributes 2 vertices to each of the triangles, and the third vertex is the nearest neighbor 3D print in the adjacent row above or below the base edge.

[0142] For each of the bottom edges, the vertical distance to the nearest 3D printed piece located above and below the bottom edge is determined. Only the minimum of these two distances (i.e., the nearest distance) is recorded. Using only the minimum distance helps ensure that the row is contiguous and helps prevent double counting of rows. The average and standard deviation of these vertical distances on a given image is then taken as the average Y-distance and standard deviation for that image. The topmost and bottommost rows of a character / number are not used as the base of the measured triangle because they only have one adjacent row. The Y-distances for multiple images in a predetermined pattern or portion thereof can then be further averaged to provide an average Y-distance and standard deviation for a given predetermined pattern or portion thereof, such as a given alphanumeric character.

[0143] As Figure 4B shown, the vector laser 3D printing process at high speeds can result in significant displacement or overhang of 3D printed pieces or voids within a row, resulting in a blurred image (such as an alphanumeric character) with a jagged profile. The laser 3D printing process of the present invention, and the parts 3D printed thereby, do not result in such significant displacement and blurring. Any of a variety of means can be used to indicate displacement within a row, including simple visual inspection. For example, such a means can include simply observing a character (or other element of a predetermined pattern) and assessing whether the character is legible given prior knowledge of the intended 3D printed pattern (e.g., alphanumeric character). Displacement can also be quantified. Importantly, human and machine readable patterns typically include "smooth" profiles (relative to Figure 6 the jagged profile shown in B). In other words, for both user readable patterns and machine readable patterns, the leftmost and rightmost 3D printed locations within a given row or 3D printed portion of a row are typically not substantially displaced from the (respectively) leftmost and rightmost 3D printed locations in the adjacent rows (above and below) in the X-direction. Such displacement of the 3D printed locations results in a blurred and ambiguous pattern that produces a larger pattern / character than intended and reduces both user and machine readability.

[0144] In quantifying displacement, for a given character or pattern element, the start point of each 3D printed portion within a line is taken as the leftmost 3D printed piece and the end point of each 3D printed portion within a line is taken as the rightmost 3D printed piece. The start and end points of each 3D printed portion within a line are determined relative to the corresponding start and end points of its above and below adjacent lines, respectively. If the start point of both the above and below lines is to the left of the start point of the measured line, the line under consideration is determined to be "shifted" to the left of the character / pattern element, and if the end point of both the above and below lines is to the right of the end point of the measured line, the line under consideration is determined to be "shifted" to the right. The horizontal distance from the start (and end) point of the line to the start (and end) point of the above and below lines, respectively, is determined, and the displacement is taken as the shorter of the two distances. The left side displacement is the displacement determined from the start point, and the right side displacement is the displacement determined from the end point. A 3D printed portion within a line can not include displacement, i.e. either the left side displacement or the right side displacement or both the left side displacement and the right side displacement. The topmost and bottommost lines comprising the image being analyzed, i.e. the alphanumeric character, are omitted from the analysis as they do not have two adjacent lines. One means of identifying the start and end points of each line uses the Delaunay Triangulation analysis discussed previously for determining the X-distance and Y-distance and standard deviation.

[0145] The "displacement" of a given image such as an alphanumeric character is the sum of the displacements of the lines comprising the character divided by the number of lines making up the character.

[0146] Displacement = (Total displacement in character) / (Number of lines in character) 100

[0147] The "Ave Displacement" or average displacement of a predetermined pattern comprising a plurality of alphanumeric characters as text is simply the sum of the displacements of each character in a sample set divided by the number "n" of characters in the sample.

[0148] Another method of quantifying the precision of high speed laser 3D printing of the present invention is the percentage of incorrectly 3D printed locations, or "error flagging". Referring now to Figure 7 , the illustration shows an alphanumeric character "2" 3D printed in a grid pattern according to the present invention. There are approximately 130 3D printed locations 54. In Figure 7 , there are 8 voids 101 that should have been 3D printed. In addition, there are 4 3D printed locations 100 that should have been voids. Clearly, both the voids that should have been 3D printed and the 3D printed locations that should have been voids are errors of incorrect 3D printing, so they are added together and compared to the number of 3D printed locations. In Figure 7In the example of FIG. 6, there are 12 errors (8+4) out of a total of 130 required 3D printed locations. Error marker% = number of errors divided by the number of required 3D printed locations multiplied by 100, ((12 / 130) 100) = 9.23%. Figure 4B A severely error 3D printed alphanumeric character ("2") is shown in which the error marker% is greater than 20%.

[0149] The "average error marker%" for a predetermined pattern of text including a plurality of alphanumeric characters is simply the sum of the error marker% for each alphanumeric character divided by the number of alphanumeric characters. To achieve the desired readability of text composed of alphanumeric characters, the average error marker% for the alphanumeric characters is less than about 20%, preferably less than about 15%, more preferably less than about 10%, even more preferably less than about 5%. For both the mean value calculation and the standard deviation specification, the following criteria will be used to calculate the average.

[0150] Samples and data

[0151] Table 1 shows data obtained by 3D printing four different parts with the same pattern of laser and then analyzing them using the method described above. The 3D printing in this case is an industry standard UPC code. Those skilled in the art will appreciate that a UPC, which must appear on all consumer purchased goods, must have clearly defined black bars and alphanumeric characters on a lighter, preferably white, background in order for the UPC scanner to quickly and accurately read the code. In other words, the UPC code must be accurately printed or 3D printed to be accurately read by a scanner or a person. By way of example, Figure 7 A laser 3D printed UPC code 70 is shown in accordance with the process of the present application. The UPC code 70 is a mixture of bars 72 and alphanumeric characters 74 of different widths.

[0152] Prior to the present application, vector laser 3D printing was the fastest available laser 3D printing system, but Table 1 clearly shows that as the speed of vector 3D printing increases, the accuracy of the 3D printing decreases significantly. More specifically, the vector 3D printing was tested at maximum current angular velocities of 15.6 rad / sec, 350 rad / sec, and 1000 rad / sec, and compared to the CV bit Figure 3 D printing of the present application at a maximum surface speed of 1000 rad / sec. In the first row, the target Y-distance is provided, and the actual Y-distance in mm is measured for each of n samples, and then averaged. More importantly, the standard deviation sigma The standard deviation is a measure of how far individual samples deviate from the target Y-distance. For example, if only two samples are run at a target Y-distance of 0.150, and one sample is 0.200 and the other is 0.100, their average will be exactly the target value of 0.150. But the precision will be terrible. The standard deviation in this example will be a large number, indicating that the two hypothetical samples lack precision, where their average will appear to be on target.

[0153] Vector 3D printing at a galvanometer angular velocity of 15.6 radians / second (first entry in Table 1) was compared to CV bitmap printing at 1000 radians / second (last entry in Table 1), average X-distance and average Y-distance, and corresponding standard deviations were similar over the four target X-distances and Y-distances tested. When the galvanometer angular velocity of the vector 3D printing was increased to 1000 radians / second, the average X-distance and corresponding standard deviation remained reasonable, but the Y-distance standard deviation became unacceptable, and the UPC code was ultimately unreadable by both the machine reading the barcode and the human reading the numerals. For the UPC code 3D printed by the process of the present invention, even at the maximum galvanometer angular velocity of 1000 radians / second, both the average X-distance and standard deviation, and the average Y-distance and standard deviation were very good. Thus, the CV bitmap laser 3D printing of the present invention provides a significant benefit over the speed and precision of existing vector 3D printing systems. Figure 3 where

[0154] = σ = standard deviation; n = number of samples used; x i = individual deviation from the mean for each sample; and x = mean or simple average of the samples. It should be understood that the units of the standard deviation σ are mm (millimeters). Those skilled in the art will appreciate that a "relative" standard deviation is also often reported. The relative standard deviation is unitless because relative standard deviation = (σmm / σmeanmm). S When determining the average displacement or average misregistration of a series of alphanumeric characters, such as text, the sample size must include at least 6 different alphanumeric characters selected from the group consisting of S, s, R, r, T, t, N, n, A, a, E, e, O, o, U, u, 1, 2, 3, 4, 5, 6, 7, 8, and 9, and the sample size should not exceed 10 alphanumeric characters. Further, the alphanumeric characters should be in the range of 6pt to 16pt font size (approximately 2.1mm to 5.64mm tall).

[0155] Table 1

[0156]

[0157] ​3D printing precision and speed: X-distance, Y-distance (in mm)

[0158] X t , Y t = target X and Y distances

[0159] n = number of samples tested

[0160] X, Y = average X-distance, Y-distance for n samples tested Standard deviation of X-distance, Y-distance for n samples tested A%D = average %D for n samples This list indicates the maximum amperage speed that can be used for the equipment used, not the actual speed. See also Table 3, where the maximum amperage speed appears in row 3.

[0161] For X (target) = 0.045 mm, Surface speed = 22.5 m / s; for X (target) = 0.050 mm, surface speed = 25 m / s; Table 2 is another set of comparative data, where UPC codes were laser 3D printed in legible precision. That is, at each speed and each target Y-distance and X-distance, the time it took to create a machine-readable UPC was measured. As is clear, with each successive increase in Velocity Max, the time it took to laser 3D print the UPC code in precise / legible fashion actually took longer for the vector 3D printing process Table 2 Total time for 3D printing (seconds) All X-distances and Y-distances are in mm

[0162] Table 3 contains data taken from samples laser 3D printed as shown in Figure 5 The top row of Table 3 indicates which of the five samples (81-85) shown in Figure 5 is the data corresponding to, how each sample was laser 3D printed, and how it compares to the other samples. Figure 5 A 5 mm square 88, a sample text 87 (alphanumeric characters "Abg123") and a series of 1 mm by 5 mm rectangles 86 spaced 1 mm apart are shown. The 700,000 rad / sec 2The normal acceleration rate is 500 kHz, with a repetition rate of 500 kHz. The second row of Table 3 shows how each sample was 3D printed, the third row is the maximum galvanometer angular velocity for laser 3D printing, and the fourth and fifth rows are qualitative descriptions of the results. Actual data for 3D printing a 5 mm square 88, text 87, and a 1 mm by 5 mm standardized rectangle 86 are shown in the remaining rows of Table 3. Once again, it is very clear that the speed and accuracy of laser 3D printing of CV bitmaps according to the present invention far outperform existing vector 3D printing systems. An f-theta lens with a focal length of 250 mm was used.

[0163] Table 3

[0164] Standardized rectangular method

[0165] The standardized rectangle method is a standardized test for measuring the speed and accuracy of any laser device. Simply put, any laser device that can be programmed to print 20 identical rectangles (similar to a simplified UPC code) can be tested. The details of the test are given below, but those skilled in the art will recognize that the time taken to print the standardized rectangles is important for demonstrating the benefits of the present invention. The last two rows of Table 3 show examples of the time required to print standardized rectangles using four laser devices / processes available today and one laser device / process according to the present invention. Existing laser devices / processes require 1.5 seconds to 1.0 seconds to print the standardized rectangles. The laser device / process according to the present invention only requires 0.185 seconds, which is 500%-800% faster than existing equipment.

[0166] like Figure 5 As shown, the normalized rectangle 86 is Figure 9 A series of 20 identical rectangles 91 are approximately 1 mm wide 95 by approximately 5 mm high 93, spaced approximately 1 mm apart. Rectangle width 95 must be within the range of 0.94 mm to 1.22 mm. Rectangle height 93 must be within the range of 4.8 mm to 5.00 mm. Each rectangle contains 80-84 parallel rows 97. Each row is in the X direction 92, spanning a 1 mm width 98. Therefore, the distance between rows, the Y distance 96, is within the range of 0.24 mm to 0.26 mm. In each row 97, there are 20-24 3D printed parts 99. Obviously, for the sake of clarity, not all 3D printed parts 99 are shown.

[0167] All percentages are by weight of the composition, unless otherwise designated. All ratios are by weight, unless specifically stated otherwise. All numerical ranges are inclusive of narrower ranges; delineations of ranges are merely intended to charge certain embodiments. The endpoints of all ranges and other specified numerical values are not to be understood as limiting beyond the range itself. Numerical designations of effective significant digits do not limit the indicated amount nor the accuracy of the measurements. All measurements are understood to be made at about 25 °C and at ambient conditions, where "ambient conditions" means conditions under about one atmosphere pressure and about 50% relative humidity.

[0168] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such quantity is meant to encompass lesser and greater ranges as would be appreciated by one skilled in the art. For example, a dimension disclosed as "40 mm" is meant to state "about 40 mm."

[0169] Every document cited herein, including any cross referenced or related patent or application and any patent or application to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any application disclosed or claimed herein or that it alone, or along with any other document, teaches, suggests or discloses any such application. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall control. In addition, the bibliography of patents and publications listed below is provided for informational purposes only and is not admitted as prior art to the present application.

[0170] While particular embodiments of the present application have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the application. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this application.

Claims

1. A 3D part printed by a pulsed laser device, the part comprising: A series of stacked layers, where each layer includes multiple 3D printed parts; wherein pulses from the pulsed laser device form the 3D print, and absence of pulses form gaps, The pulse laser device is controlled by a computing device, which sends an instruction packet to the pulse laser device. The instruction packet includes at least two single instructions, wherein each single instruction notifies the laser to pulse or not pulse.

2. The 3D part of claim 1 , wherein the overlay comprises 3D prints and voids in a grid pattern, the grid pattern comprising a plurality of locations arranged along a series of substantially parallel rows, wherein each location comprises either a 3D print or a void; and wherein pulses from the pulsed laser device form the 3D print, and the absence of pulses forms the voids; and Each individual instruction tells the laser to pulse or not pulse, thereby creating a 3D print or a void, respectively, at each location on the grid pattern.

3. The component according to claim 2, wherein the positions between adjacent parallel rows are offset.

4. The part according to claim 2 or 3, wherein the positions in the two-dimensional layer are offset in the Z direction.

5. A method for 3D printing a part using a pulsed laser device, the method comprising the following steps: defining a series of superimposed layers, the series of superimposed layers comprising a plurality of 3D prints and voids in a grid pattern, the grid pattern comprising a plurality of locations arranged along a series of substantially parallel rows, wherein each location comprises one 3D print or one void; forming the 3D print by pulsing the pulsed laser device, and creating the void by unpulsing the pulsed laser device; as well as The pulsed laser device is controlled by a computing device, which sends an instruction packet to the pulsed laser device, wherein the instruction packet includes at least two individual instructions, wherein the individual instructions instruct the pulsed laser device to pulse or not pulse, thereby creating a 3D print or a void at each location on the grid pattern, respectively.

6. The method of claim 5, wherein at least one of the rows is 3D printed from two different packages.

7. The method of claim 5, wherein the instruction packet further comprises two or fewer, preferably only one single instruction, related to positioning of a position in the grid pattern.

8. A part 3D printed by a pulsed laser, the part comprising a predetermined grid pattern: wherein the grid pattern comprises a plurality of locations positioned in two or more rows, wherein the two or more rows are substantially parallel, each pair of adjacent locations in the plurality of locations along any one of the two or more rows are separated by an X-distance, and each adjacent pair in the two or more rows are separated by a Y-distance; wherein the beam of the pulsed laser moves across the row at a constant surface speed of greater than about 8 m / s, preferably 14 m / s, more preferably 18 m / s, even more preferably 22 m / s while forming the continuous 3D print; and wherein the standard deviation of the Y-distance is less than about 0.040, preferably less than about 0.034, preferably less than about 0.028, more preferably less than about 0.010, and even more preferably less than about 0.

005.

9. The part of claim 8, wherein the beam of the pulsed laser moves in a bidirectional profile such that the laser beam moves in a first direction along a first row and in a second direction along a second row.

10. The part according to claim 8, wherein the beam of the pulsed laser is directed by two galvanometer groups, each galvanometer group comprising a mirror and a galvanometer, wherein the angular velocity of rotation of at least one galvanometer group is greater than about 40 rad / sec, preferably 56 rad / sec, more preferably 72 rad / sec, even more preferably 90 rad / sec.

11. The part of claim 8, wherein the beam of the pulsed laser has a repetition rate greater than about 100 kHz.

12. A part 3D printed by a pulsed laser, the part comprising a series of 3D printed overlapping layers, each overlapping layer comprising a predetermined grid pattern: wherein the grid pattern comprises a plurality of locations positioned in two or more rows, wherein the two or more rows are substantially parallel, each pair of adjacent locations in the plurality of locations along any one of the two or more rows are separated by an X-distance, and each adjacent pair in the two or more rows are separated by a Y-distance; wherein the beam of the pulsed laser moves across the row at a constant surface speed of greater than about 8 m / s, preferably 14 m / s, more preferably 18 m / s, even more preferably 22 m / s while forming the continuous mark; and wherein the grid pattern has an average displacement % of less than about 150%, preferably less than about 120%, preferably less than about 100%, more preferably less than about 70%, even more preferably less than about 50%.

13. The part according to claim 12, wherein the beam of the pulsed laser is directed by two galvanometer groups, each galvanometer group comprising a mirror and a galvanometer, wherein the angular velocity of rotation of at least one galvanometer group is greater than about 40 rad / sec, preferably 56 rad / sec, more preferably 72 rad / sec, even more preferably 90 rad / sec.

14. A part 3D printed by a pulsed laser, the part comprising a series of 3D printed overlapping layers, each overlapping layer comprising a pattern of predetermined locations, each location comprising a 3D print or a void in a grid pattern: wherein the grid pattern comprises a plurality of locations positioned in two or more rows, wherein the two or more rows are substantially parallel, each pair of adjacent locations in the plurality of locations along any one of the two or more rows are separated by an X-distance, and each adjacent pair in the two or more rows are separated by a Y-distance; wherein the beam of the pulsed laser moves across the row at a constant surface speed while pulsing greater than about 8 m / s, preferably 14 m / s, more preferably 18 m / s, even more preferably 22 m / s when forming the continuous 3D print; and, wherein the average % mislabeling is less than about 20%, preferably less than about 15%, more preferably less than about 10%, even more preferably less than about 5%.

15. A part having a surface 3D printed by a pulsed laser, the surface comprising a first pattern of predetermined locations wherein each location comprises a 3D print or a void in a grid pattern and a second pattern of predetermined locations wherein each location comprises a 3D print or a void in a grid pattern: wherein the first grid pattern and the second grid pattern comprise a plurality of locations positioned in two or more rows, wherein the two or more rows are substantially parallel, wherein each pair of adjacent locations in the plurality of locations along any one of the two or more rows are separated by an X-distance, and wherein each adjacent pair in the two or more rows are separated by a Y-distance; and wherein the first grid pattern and the second grid pattern differ in at least one of the X-distance and the Y-distance; and wherein the pulsed laser has a beam that moves across the row at a constant surface speed while pulsing greater than about 8 m / s, preferably 14 m / s, more preferably 18 m / s, even more preferably 22 m / s when forming the continuous 3D print.

Images