Three-dimensional object production

Abstract

A three-dimensional object production is provided. An example apparatus for producing a three-dimensional object includes a controller, a build area configured to receive a layer of particulate material, a printhead, and an ultraviolet light emitting diode energy source. The controller causes the printhead to deposit a liquid that absorbs ultraviolet radiation onto the layer of particulate material. The controller also causes the ultraviolet light emitting diode energy source to irradiate the liquid after the liquid has deposited onto the layer of particulate material, thereby heating the liquid and curing a portion of the particulate material.

Description

[0001] This application is a divisional application of the invention patent application filed on January 24, 2018, with application number 201880077697.9 and title "Three-Dimensional Object Production". Background Technology

[0002] Devices that generate three-dimensional objects, including those commonly referred to as "3D printers," provide a convenient way to produce 3D objects. These devices typically receive a definition of a 3D object in the form of an object model. The object model is processed to instruct the device to use one or more particulate materials to produce the object. This can be done on a layer-by-layer basis. Generating objects in 3D presents many challenges that are not present with 2D printing devices. Attached Figure Description

[0003] The various features of this disclosure will become clear from the following detailed description taken in conjunction with the accompanying drawings. Figure 1 This illustrates the features of the present disclosure, and wherein:

[0004] Figure 1 It is a diagram based on the example 3D printing apparatus;

[0005] Figure 2 It is a diagram of the 3D printing apparatus based on the second example;

[0006] Figure 3 It is a diagram based on the 3D printing apparatus of the third example;

[0007] Figure 4 It is a diagram of the 3D printing apparatus based on the fourth example;

[0008] Figure 5 It is a diagram of the 3D printing apparatus based on the fifth example;

[0009] Figure 6 The absorption spectra of particulate materials and liquids according to the example are shown;

[0010] Figure 7 The absorption spectrum of the ink, based on an example, is shown;

[0011] Figure 8 This illustrates a method for producing 3D objects based on an example;

[0012] Figure 9 A graphical representation of an example set of computer-readable instructions within a non-transitory computer-readable storage medium is shown. Detailed Implementation

[0013] In the following description, for illustrative purposes, many specific details of certain examples are set forth. References to "example" or similar language in the specification mean that a particular feature, structure, or characteristic described in connection with that example is included in at least one example, but not necessarily in others.

[0014] As described herein, an example apparatus for producing three-dimensional (3D) objects includes a printhead configured to deposit a liquid that absorbs ultraviolet radiation onto a layer of particulate material, and an ultraviolet light-emitting diode (UV-LED) energy source that emits electromagnetic energy with maximum intensity at wavelengths between about 200 nm and about 405 nm. In some examples, the apparatus also includes a controller to cause the printhead and the UV-LED energy source to perform their functions. The UV-LED energy source irradiates the layer of particulate material with a substantially uniform intensity across the layer after the liquid has been deposited onto the layer of particulate material, thereby heating the liquid and solidifying a portion of the particulate material. Irradiating the layer means that the liquid is also irradiated. When the liquid or one or more components of the liquid absorb the ultraviolet (UV) electromagnetic energy / radiation emitted by the UV-LED energy source, the temperature of the liquid increases. Heat from the liquid is transferred, for example by conduction, to the particulate material near the liquid. The temperature of the particulate material near the liquid also increases. If the temperature of the particulate material near the liquid reaches a threshold temperature, such as a temperature sufficient for melting or sintering for the particulate material, the particulate material will fuse and solidify upon cooling. Therefore, three-dimensional objects can be constructed on a layer-by-layer basis. In some examples, a UV-LED energy source is a UV-LED energy source that includes one or more UV-LEDs, such as an array of UV-LEDs.

[0015] UV-LEDs can emit ultraviolet electromagnetic energy with a narrow spectral width. The spectral width is defined as the range of wavelengths surrounding the peak wavelength at a power level greater than or equal to half the maximum power level. Therefore, most of the power emitted by the energy source will be within the spectral width. In some examples, more than 50%, 60%, 70%, 80%, or 90% of the power can be emitted within this range. The peak wavelength has the maximum intensity and can, for example, have a wavelength located at the center of the spectral width. Therefore, an emitter with a narrow spectral width can emit electromagnetic radiation within a narrow range of the central peak wavelength. Such an emitter can be called a narrowband emitter and can have a spectral width of approximately 5 nm to approximately 50 nm. In contrast, lamp energy sources such as halogen or incandescent type lamps typically emit electromagnetic radiation with a wide spectral width and can have a spectral width greater than approximately 100 nm. In some examples, the lamp energy source has a spectral width of approximately 1000 nm and can have many peaks within the emission spectrum. Therefore, emission with a wide spectral width includes electromagnetic energy spread across a wide wavelength range. The lamp can therefore be called a broadband emitter. Lasers, for example, include extremely narrow spectral widths and can have spectral widths of less than about 5 nm.

[0016] Using UV-LEDs during the fabrication of 3D objects can offer benefits relative to the use of broadband energy sources currently used in 3D printing. For example, certain components, such as the liquids used in 3D printing, can be selected or designed to absorb electromagnetic energy with specific UV wavelengths more effectively than other electromagnetic energy with a different wavelength, such as infrared (IR). Therefore, by using a UV-LED with maximum intensity at wavelengths between approximately 200 nm and approximately 405 nm, combined with a liquid that absorbs this UV radiation, the energy efficiency of the heating process can be improved because the wavelength and / or spectral width of the LED can be selected to match the absorption characteristics of the liquid. This maximizes the amount of energy absorbed by the liquid. This contrasts with conventional systems that use broadband energy sources, which can be energy-inefficient due to the poor absorption of certain wavelengths within the broadband energy range.

[0017] In some examples, UV-LED energy sources emit electromagnetic energy with maximum intensity at wavelengths between approximately 285 nm and approximately 405 nm. UV-LED energy sources emitting energy in this range are relatively inexpensive compared to LEDs of other wavelengths. These UV-LED energy sources also do not have UVC regulation issues because they do not emit energy in the UVC wavelength range of 100–280 nm.

[0018] Compared to more conventional energy sources such as lamps, UV-LED energy sources can also have a long lifespan. Furthermore, UV-LED energy sources allow for simple DC operation, easy drive control, and / or low-voltage operation, and are free from electromagnetic compatibility (EMC), radio frequency interference (RFI), and / or high-voltage operation regulatory issues.

[0019] UV-LED energy sources can also offer benefits in color 3D printing systems. For example, IR tends to be poorly absorbed by white and yellow colored printing agent liquids such as inks used in the color 3D printing process. It has been found that using a UV-LED energy source allows the printing agent temperature to rise much faster than when using a broadband IR energy source. If the printing agent is heated at a faster rate, the melting temperature can be reached in a shorter time, which reduces the total time required to manufacture the 3D object.

[0020] It has been discovered that colored printing liquids, such as inks, currently used in color 3D printing have absorption bands within the UV spectrum. Therefore, inks already possess the ability to absorb energy emitted by a UV-LED energy source with high efficiency. This could mean that when colored liquids are applied, particulate materials can be melted without the addition of additional absorbing liquids, such as dedicated "melting" agents. This effect can be achieved using a UV-LED energy source that emits electromagnetic energy with maximum intensity at wavelengths between approximately 200 nm and approximately 405 nm. Specific wavelengths of the UV-LED energy source within this range can be selected to ensure that the various liquids used in the printing process absorb energy more effectively. For example, each of the individual color liquids in a CMYK ink can have a different absorption spectrum for UV energy, thus allowing selection of wavelengths that are effectively absorbed across all liquids.

[0021] Particulate materials used in 3D printing may poorly absorb some UV wavelengths. For example, the build material polyamide 12 (PA-12) absorbs short-wavelength UV radiation but poorly absorbs longer-wavelength UV radiation. Poor absorption can be defined as absorbing about 20% or 10% of the incident radiation at a wavelength less than the one in question. By depositing a liquid that absorbs longer-wavelength UV radiation onto particulate materials and then irradiating the layer of particulate materials with longer-wavelength UV radiation, the liquid absorbs a higher proportion of the UV radiation than the particulate materials. Therefore, LEDs with UV emission wavelengths that the particulate materials absorb less effectively than the liquid can be selected. Consequently, any particulate material with the liquid applied is heated more than particulate material without the liquid applied. This reduces the likelihood of the particulate material curing in areas where the liquid has not yet been applied when exposed to UV radiation.

[0022] Therefore, in some examples, UV-LED energy sources emit electromagnetic energy with maximum intensity at wavelengths between approximately 385 nm and approximately 405 nm. Certain particulate materials, such as PA-12, may poorly absorb this wavelength, and this wavelength may also be absorbed by certain liquids used in 3D printing. Therefore, the wavelength can be selected based on one or more types of materials and liquids used in 3D printing. For example, in some examples, the liquid can be dye or ink, and common dyes and inks readily absorb such wavelengths. If multiple liquids are being used, the wavelength most effectively absorbed by the liquid can be selected.

[0023] In one example, the UV-LED energy source wavelength is selected to have maximum intensity at a wavelength between approximately 200 nm and approximately 405 nm, and the UV-LED energy source wavelength is greater than 100 nm from the absorption peak of the particulate material. In some examples, when the UV-LED energy wavelength is offset from the absorption peak of the particulate material by at least this amount, the absorption rate of the dried particulate material can be reduced to a level that prevents the material from melting.

[0024] In some examples, UV-LED energy sources emit electromagnetic energy between approximately 385 and 395 nm, with the maximum intensity occurring at a wavelength of approximately 390 nm. This wavelength offers a good balance between the cost of the LED and the good absorption of the liquid used in the printing process.

[0025] In some examples, UV-LED energy sources emit ultraviolet electromagnetic energy with a spectral width of approximately 5 nm to approximately 50 nm. Therefore, UV-LED energy sources possess a narrow spectral width suitable for absorption by a wide variety of liquids used in 3D printing systems. This spectral width within this range can improve absorption efficiency and thus energy efficiency.

[0026] In some examples, the printhead is a first printhead, and the liquid is a first liquid, and the apparatus also includes a second printhead, wherein the controller causes the second printhead to deposit a second liquid that absorbs ultraviolet radiation onto a layer of particulate material after the first printhead has deposited the first liquid. In some examples, the first liquid is a dye, and the second liquid is a pigment-based ink. A dye-based ink may include a colorant dissolved in the liquid, and a pigment-based ink may include powder of a solid colorant suspended in a liquid carrier. In some examples, one or both of the first and second liquids include a pigment or colorant that imparts color to the liquid. The pigment or colorant may be an absorber that causes the liquid to absorb UV radiation.

[0027] In some examples, the first liquid deposited by the first printhead is white; however, in other examples, the first liquid is colorless. A white liquid can be useful when the particulate material is not white, or when the material changes color from white during curing. The white liquid can be deposited on a layer of particulate material to provide a white "base." A colored liquid can be deposited directly on top of this white base, or deposited on a new layer of particulate material. Therefore, the second liquid can be differently colored and can thus be a deposited liquid to impart color to the object. Other colored liquids can also be deposited.

[0028] In some examples, each liquid has a different absorption spectrum in the UV wavelength range. Therefore, the UV radiation wavelength can be selected from the range of 200 nm to 405 nm to optimize, increase, and / or balance the absorption of UV radiation by multiple liquids.

[0029] As described, particulate materials with low UV radiation absorption levels are selected. Therefore, the material is heated most effectively in areas where the liquid absorbs UV radiation. In the example where the second liquid is colored, the application of the first liquid ensures that the particulate material is melted even in areas with low color density. For examples where the application of the second liquid is performed with less than 100% coverage, areas without the second liquid may not be sufficiently heated to melt or solidify; therefore, the application of the first liquid can assist in heating such areas.

[0030] In some examples, the controller causes a UV-LED energy source to irradiate the layer of particulate material before the second liquid is deposited on the second printhead, and thus irradiates the first liquid. Therefore, the portion of particulate material including the first liquid can be preheated to a near-melting temperature without solidifying. In other examples, the portion of particulate material including the first liquid can be fully or partially solidified. This can occur, in addition to or as an alternative to the process of applying energy to the layer of particulate material before applying any liquid.

[0031] In some examples, the apparatus also includes a third printhead, wherein the controller causes the third printhead to deposit a third liquid that absorbs ultraviolet radiation onto a layer of particulate material after the second printhead has deposited the second liquid. For example, the third liquid can be a liquid of a different color than the second liquid. For instance, the second liquid could be cyan, and the third liquid could be magenta. Additional printheads can deposit other colors, such as yellow and black, allowing multiple colors to be assigned to the object as it is built layer by layer. In some examples, the second and third liquids are deposited from different nozzles in the same printhead.

[0032] However, in other examples, the third printhead can be similar to the first printhead, and the third liquid can be the same as the first liquid. In some examples, the first and third printheads are arranged at opposite ends of the printer carriage. For example, the first and third printheads may be at opposite ends of the carriage relative to the direction of travel of the printer cartridge during printing. Thus, the first liquid can be deposited by both the first and third printheads, allowing the print carriage to be used in both directions. A CMYK printhead or nozzle can be located between the first and third printheads. Therefore, in examples where the first and third liquids are the same, the third printhead can be configured to deposit the third liquid after a portion of the particulate material has been fully cured by the UV-LED energy source.

[0033] In some examples, the UV-LED energy source is a first UV-LED energy source, and the device includes a second UV-LED energy source, wherein the controller causes the second UV-LED energy source to irradiate the layer and thus the first liquid before the second printhead deposits the second liquid. Therefore, the second UV-LED energy source can be used to preheat the first liquid, instead of using a single UV-LED energy source to preheat and cure the particulate material. The second UV-LED energy source can be located within the device in a position more suitable for preheating the liquid after it has already been deposited. In some examples, the second UV-LED energy source includes one or more UV-LEDs, such as a UV-LED array.

[0034] In some examples, a first UV-LED energy source has a first peak wavelength and a second UV-LED energy source has a second peak wavelength, and the first and second wavelengths are different from each other. This allows different wavelengths to be used depending on the function. For example, the first wavelength may be more suitable for curing particulate materials, and the second wavelength may be more suitable for preheating.

[0035] In one example, a second peak wavelength for preheating is selected based on a first liquid, and a first peak wavelength is selected based on a second liquid. In some examples, the first peak wavelength is selected based on both the first and second liquids.

[0036] Figure 1 An example 3D printing apparatus 100 is shown. The 3D printing apparatus 100 includes a print head 102. The print head 102 is arranged such that a liquid 104, such as a liquid, is deposited on a platform 108 onto a layer of particulate building material 106 received within a build region. In some examples, the build region and platform 108 are separate from the printing apparatus 100. In this example, the build region and platform 108 are separate but present in use. The particulate material can be, for example... Figure 1The example uses a powdered substrate. The printhead 102 can be movable relative to the material 106. In one case, the printhead 102 can be located in a movable bracket situated above the material 106. The printhead 102 can move over the material 106 in one, two, or three directions, for example along... Figure 1 The x-axis direction is indicated in the middle, along the y-axis, for example, entering and leaving. Figure 1 The page is positioned vertically along the z-axis in some examples. In another case, the platform 108 and material 106 can be movable below the static printhead. Various combinations of methods are possible.

[0037] exist Figure 1 In the example, the printhead includes one or more nozzles configured to deposit liquid onto a portion 112 of a layer of particulate material 106. The jetting mechanism may be based on piezoelectric or thermal elements. The 3D printing apparatus 100 may have a resolution similar to that of a 2D printing apparatus, such as 600 or 1200 dots per inch (DPI).

[0038] Particulate material 106 can be deposited in the build area via matrix supply mechanism 110. Supply mechanism 110 can be configured to supply at least one layer of particulate material 106 onto which liquid 104 can be deposited. In some examples, supply mechanism 110 is detachable from and removable from device 100, and can be present in use.

[0039] exist Figure 1 In the 3D printing apparatus 100, objects can be built up layer by layer. Each layer of material 106 can have a thickness on the z-axis. In one case, this thickness can be between 70 and 120 micrometers, although thicker or thinner layers can be formed in other examples. The 3D printing apparatus 100 is arranged to solidify portions 112 of the material in each successive layer.

[0040] In one example, liquid can be deposited within an addressable region of a layer that forms the building material. Therefore, a three-dimensional object can be constructed by depositing multiple droplets on top of consecutive layers.

[0041] The apparatus 100 also includes a UV-LED energy source 114. The UV-LED energy source may include one or more UV-LEDs, such as an array of UV-LEDs. After the liquid 104 is applied, the UV-LED energy source 114 emits ultraviolet electromagnetic radiation over the layer 106. The liquid is also configured to absorb the ultraviolet radiation emitted by the UV-LED energy source 114. This radiation melts or sinters the material and then, upon cooling, fixes or solidifies it in the area where the liquid 104 was deposited. For example, the UV-LED energy source can irradiate the layer of material 106 with electromagnetic radiation in a wavelength range, and because the liquid is an absorber of the specific UV wavelength emitted by the UV-LED energy source 114, the liquid absorbs at least some of the energy and transfers at least some of the absorbed energy to the material in the vicinity of the liquid. Areas that do not receive the liquid 104 may not be sufficiently heated to melt and subsequently solidify. To reduce the effect of adjacent material solidifying in other non-target areas, the UV wavelength can be selected such that it is effectively absorbed by the liquid but poorly absorbed by the dry material 106. In one example, the peak intensity is at a wavelength between approximately 385 nm and approximately 405 nm; however, other wavelengths may be appropriate depending on the absorption rate of the liquid and particulate materials.

[0042] The apparatus may also include a controller 116. The controller 116 can control various components of the apparatus 100. The controller 116 may include, for example, one or more processors. The controller 116 may also include memory to store instructions that, when executed, cause the processor(s) to perform one or more methods. For example, the controller may control the movement of the printhead 102, the supply mechanism 110, the carriage, the UV-LED energy source 114, and the platform 108. In some examples, the memory may be a non-transitory computer-readable storage medium. The controller 116 may be directly or indirectly connected to various components of the printing system 100 via one or more communication paths 118, shown as dashed lines. In some examples, each of the various components has its own controller, which may operate independently or collaboratively with each other.

[0043] In one example, liquid 104 is colored. For example, the liquid can be a colorant, such as a dye or a pigment-based ink. Therefore, the liquid can include colorants and / or pigments. The colorant or pigment itself can be an element that enables the liquid to absorb ultraviolet radiation; however, in some examples, other properties of the liquid enable it to absorb radiation.

[0044] Figure 2Another example of a 3D printing apparatus 200, substantially the same as apparatus 100, is shown, but also includes a second printhead 220 configured to deposit a second liquid 222. In this example, the second printhead 220 is arranged adjacent to the first printhead 202, although other arrangements are possible.

[0045] The 3D printing apparatus 200 includes a first printhead 202. The first printhead 202 is arranged to deposit a first liquid 204 onto a layer of particulate building material 206 received within a build region, such as on a platform 208. Similarly, a second printhead 220 is arranged to deposit a second liquid 222 onto the layer of material 206. In one case, the first and second printheads 202, 220 are located in a movable carriage 224 situated above the platform 208. The carriage 324 can move over the material 206 in one, two, or three directions. In another case, the platform 208 and the material 206 may be movable below the stationary carriage 224. In some examples, the first and second printheads 202, 220 are not located in the carriage 224. Various combinations of methods are possible in different examples.

[0046] exist Figure 2 In one example, the first printhead 202 includes one or more nozzles configured to deposit a first liquid 204 onto a portion 212 of the particulate material 206. Similarly, the second printhead 220 includes one or more nozzles configured to deposit a second liquid 222 onto a portion 212 of the particulate material 206. In this example, both liquids are deposited within the same portion 212 and at least partially overlap; however, in some examples, one liquid may be deposited in a region. In one example, each portion receives the first liquid, while in other examples, some portions receive the second liquid.

[0047] The device 200 also includes a UV-LED energy source 214.

[0048] In one specific implementation, apparatus 200 can be used to print colored three-dimensional objects. To achieve good printing quality, a white liquid can first be applied to particulate material 206, upon which one or more other colored liquids, such as cyan, magenta, yellow, and / or black (CMYK) or other spot colors, can be applied. The first liquid can be colorless; however, in one example, the first liquid is a white colored liquid, such as a dye. Therefore, the white colored liquid has no absorption rate of visible light or has a low absorption rate of visible light. The second liquid can be a liquid colorant, which is applied after the first liquid has been deposited. In any case, both the first liquid 204 and the second liquid 222 absorb ultraviolet radiation. In a particular example, the first liquid is Contone-O.

[0049] In the first example, a first printhead 202 deposits a first liquid 204, followed by a second printhead 220 depositing a second liquid 222. Electromagnetic energy is applied to layer 206 by a UV-LED energy source, and one or both liquids absorb the radiation, causing the material to melt or sinter and then solidify or cure in the areas where liquid 204 was deposited upon cooling. For example, the UV-LED energy source can irradiate the layer of material 206 with electromagnetic radiation in the wavelength range, and since the liquid is an absorber of UV, it absorbs the energy and transfers that energy to the material near the liquid. Regions with low color density, i.e., regions with little or no second liquid 222, remain cured due to the presence of the first liquid 204.

[0050] The device may also include a controller 216. The controller 216 can control various components of the device 200 via one or more communication paths 218, such as those related to... Figure 1 The example device 100 is described. The controller 216 can control the order and timing of the first and second printheads 202, 220 depositing their respective liquids onto the layer of particulate material 206.

[0051] Figure 3 Another example of a 3D printing apparatus 300, substantially identical to apparatus 200, is shown, but also includes a third print head 320 configured to deposit a third liquid 328 onto a layer of material 306. The third print head 326 is arranged adjacent to the second print head 320, such that the first print head 302 and the third print head 326 are positioned at opposite ends of the print carriage 324. Other arrangements are possible.

[0052] The 3D printing apparatus 300 includes a first print head 302. The first print head 302 is arranged to deposit a first liquid 304 onto a layer of particulate building material 306 received within a build region, such as on a platform 308. Similarly, a second print head 320 is arranged to deposit a second liquid 322 onto the layer of material 306. In one case, the first, second, and third print heads 302, 320, and 326 are located in a movable carriage 324 situated above the material 306. The carriage 324 can move over the material 306 in one, two, or three directions. In another case, the platform 308 and the material 306 may be movable below the stationary carriage 324. In some examples, the first, second, and third print heads 302, 320 are not located in the carriage 324. Various combinations of methods are possible.

[0053] exist Figure 3In the example, the first printhead 302 includes one or more nozzles configured to deposit a first liquid 304 onto a portion 312 of a layer of particulate material 306. Similarly, the second printhead 320 includes one or more nozzles configured to deposit a second liquid 322 onto a portion 312 of a layer of particulate material 206.

[0054] The device 300 also includes a UV-LED energy source 314.

[0055] In one implementation, device 300 can be used to print colored three-dimensional objects. (See also: Regarding...) Figure 2 As described, the first liquid 304 can be a white colored liquid, such as a dye, and the second liquid 322 can be another colored liquid, such as a pigment-based ink. Both the first liquid 304 and the second liquid 322 absorb ultraviolet radiation. In one example, the third printhead 326 is substantially similar to the second printhead 320, except that the third liquid is a different color from the second color. Therefore, the third liquid is also an absorber of UV radiation. In one example, the first liquid can be white, the second liquid can be cyan, and the third color can be magenta. Two or more printheads may also be included for yellow and black. After the first, second, and third liquids have been applied, the UV-LED energy source 314 can irradiate the layer of material 306 with electromagnetic radiation to partially cure the material at the site where at least one liquid has been applied. In one example, the second and third printheads are a single entity, and the second and third liquids are different, but deposited from different nozzles within a single printhead.

[0056] However, in another implementation, the third printhead 326 is substantially similar to the first printhead because the third liquid 328 deposited by the third printhead 326 is the same liquid as the first liquid. For example, the third liquid could also be a white liquid. With two printheads dispensing the first liquid, the print carriage is symmetrical and can therefore be used to deposit the first liquid onto the dry material 306 before applying a colored liquid from one or more other printheads. Thus, as the print carriage 324 moves along the X-axis over the layer of material 306, the carriage is able to deposit the white liquid first, regardless of which direction the carriage is moving along the X-axis. Therefore, in the example where the liquid deposited by the third printhead 302 is the first liquid, the UV-LED energy source 314 can irradiate the layer of material 306 with electromagnetic radiation after the first and second printheads 302, 320 have deposited their liquids and before the third printhead 326 deposits the first liquid again. Alternatively, the carriage 324 moves in the y-direction, over a drier material, before the third printhead deposits the first liquid.

[0057] The device may also include a controller 316. The controller 316 can control various components of the device 300 via one or more communication paths 318, such as those related to... Figure 1 The example device 100 is described. The controller 316 can control the order and timing of the first, second, and third printheads 302, 320, 326 depositing their respective liquids onto the layer of particulate material 206.

[0058] Figure 4 Another example of a 3D printing apparatus 400, substantially identical to apparatus 200, is shown, but also includes a second UV-LED energy source 430. In some examples, Figure 1 and 3 The device described may also include a second UV-LED energy source.

[0059] For example, regarding Figure 2 As previously described, the 3D printing apparatus 400 includes a first print head 402. The first print head 402 is arranged to deposit a first liquid 404 onto a layer of particulate building material 406 received within a build region, such as on a platform 408. Similarly, a second print head 420 is arranged to deposit a second liquid 422 onto the material 406 layer. Both the first liquid 404 and the second liquid 422 are absorbers of ultraviolet radiation. In one case, the first and second print heads 402, 420 are located in a movable carriage 424 situated above the material 406. The carriage 424 can move over the material 406 in one, two, or three directions. In another case, the platform 408 and the material 406 may be movable below the stationary carriage 424. In some examples, the first and second print heads 402, 420 are not located in the carriage 424. Various combinations of methods are possible.

[0060] The device may also include a controller 416. The controller 416 can control various components of the device 400 via one or more communication paths 418, such as those related to... Figure 1 The example device 100 is described. The controller 416 can control the sequencing and timing of the first and second printheads 402, 420 depositing their respective liquids onto the layer of particulate material 406, and the sequencing and timing of the first and second UV-LED energy sources 414, 430 irradiating the particulate material 406.

[0061] In one example, the first printhead 402 deposits the first liquid 404 before the second printhead 420 deposits the second liquid 422. However, with Figure 2In the example apparatus 200, prior to the deposition of the second liquid 422 by the second printhead 420, a second UV-LED energy source 430 irradiates a layer of particulate material 406, and thus irradiates the first liquid. Therefore, the second UV-LED energy source 430 preheats the material. After preheating, the second liquid is deposited, and finally, the first UV-LED energy source 414 irradiates the layer of particulate material 406, and thus irradiates both the first and second liquids, to cure a portion of the material.

[0062] In some examples, the first and second UV-LED energy sources are identical and therefore emit electromagnetic radiation with substantially the same physical properties, such as peak wavelength and spectral width. In other examples, however, the first UV-LED energy source has a first peak wavelength, and the second UV-LED energy source has a second peak wavelength, with the first and second wavelengths being different from each other. The wavelengths and / or spectral widths can be selected depending on their intended use. For example, certain wavelengths and / or spectral widths may be more suitable for preheating, while others may be more suitable for the final melting and curing of the material.

[0063] Preheating of the first liquid can also be achieved in devices in which a single UV-LED energy source is present, such as in... Figure 1-3 In the example, the first UV-LED energy source can be used for both preheating and final melting of the material.

[0064] In some examples, the first UV-LED energy source is located on the print carriage. Similarly, in devices that include a second UV-LED energy source, one or both energy sources can be located on the print carriage. This allows the UV-LED energy source to move along with the print carriage. Figure 5 An example of this is shown.

[0065] Figure 5 Another example of a 3D printing apparatus 500, substantially identical to apparatus 300, is shown, but also includes a second UV-LED energy source 530. Furthermore, the first and second UV-LED energy sources 514, 530 are located on a bracket. Each UV-LED energy source is arranged to heat the entire layer of material 506. In some examples, the first and second UV-LED energy sources are not located on a bracket.

[0066] For example, regarding Figure 3As previously described, the apparatus 500 includes a first printhead 502, a second printhead 520, and a third printhead 526. The first printhead 502 is arranged to deposit a first liquid 504 onto a layer of particulate building material 506 received within a build region, such as on a platform 508. Similarly, the second printhead 520 is arranged to deposit a second liquid 522 onto the layer of material 506. Similarly, the third printhead 526 is arranged to deposit a third liquid 528 onto the layer of material 506. In one case, a carriage 524 is movable over the material 506 in one, two, or three directions. In another case, the platform 508 and the material 506 may be movable below the stationary carriage 524. Various combinations of methods are possible.

[0067] Device 500 also includes first and second UV-LED energy sources 514 and 530. Figure 5 In this configuration, first and third printheads 502 and 526 are arranged at opposite ends of print carriage 524, with one or more second printheads 522 located therebetween. Adjacent to the first printhead 502 is a second UV-LED energy source 530, which itself is adjacent to the second printhead 520. Adjacent to the third printhead 526 is a first UV-LED energy source 514, which itself is adjacent to the second printhead 520. In this example, the first and third printheads 502 and 526 are arranged to deposit the same liquid.

[0068] In one implementation, device 500 can be used to print colored 3D objects. (See also: Regarding...) Figure 2 As described, the first liquid 504, 528 can be a white colored liquid, such as a dye, and the second liquid 522 can be another colored liquid, such as a pigment-based ink. Both the first liquid 504, 528 and the second liquid 522 absorb ultraviolet radiation.

[0069] During use, the print carriage 524 moves at least along the X direction. At a specific time, the carriage is moving towards the positive x direction. Figure 5 The carriage moves to its right. Therefore, as the carriage moves, each element on the carriage operates sequentially. For example, the first printhead 502 first deposits a first liquid onto the particulate material 506. Next, a second UV-LED energy source 530 irradiates the layer of material 506 to preheat the material 506. Next, one or more second printheads 520 deposit a colored liquid to develop color within the layer of material 506. Next, a first UV-LED energy source 514 irradiates the layer 506 to solidify the material in the areas where the liquid has been deposited. At this time, the print carriage moves towards... Figure 5Positioned on the right side. Next, the supply mechanism 510 deposits a subsequent layer of material on top of layer 506. Then, for example, the process can be repeated again as the carriage moves in the opposite direction. Thus, the third printhead first deposits the first liquid onto the new layer of material.

[0070] In one example, each colored layer of particulate material is formed on top of a previously formed white layer. This can be useful if the colored layer has a coverage value of less than 100%. Alternating white and colored layers can thus be created. For example, this can be achieved by initially forming a white layer, where a first white liquid is applied to a first layer of particulate material. Electromagnetic energy from a UV-LED energy source is then applied to the first layer, causing it to melt. Thus, the first layer forms a white reflective layer, on which subsequent fully or partially colored layers can be formed. For example, after forming the first white layer, a second layer of particulate material can be applied on top of the first layer. The first liquid is then deposited in some areas where no color is applied, and the second liquid is deposited in other areas where color is applied. Electromagnetic energy from a UV-LED energy source is then applied to the second layer, causing it to melt. Therefore, Figure 5 Layer 506 shown corresponds to this second layer, and the first layer lies beneath layer 506. As described, this technique can be used to create objects with less than 100% color coverage. For example, a 50% cyan colored layer can be achieved in this way. This can be useful when a colored liquid is deposited on a white surface and the particulate material itself is not pure white when melted. In some examples, preheating the colored layer after one of the liquids is optional.

[0071] The device may also include a controller 516. The controller 516 can control various components of the device 500 via one or more communication paths 518, such as those related to... Figure 1 The example device 100 is described. The controller 516 can control the order and timing of the printheads 502, 520, 526 depositing their respective liquids onto the layer of particulate material 506, and the order and timing of the first and second UV-LED energy sources 514, 530 irradiating the particulate material 506.

[0072] In some examples, the controller causes a first printhead to deposit a first liquid that absorbs ultraviolet radiation onto a first layer of particulate material, and then causes a UV-LED to irradiate the first layer of particulate material after the first liquid has been deposited, thereby heating the first liquid and curing a portion of the particulate material. In some examples, the controller also causes a supply mechanism to form a second layer of particulate material and causes the first printhead to deposit the first liquid onto the second layer, and causes a second printhead to deposit a second liquid onto the second layer. The controller also causes a UV-LED to irradiate the second layer of particulate material, thereby heating the first and second liquids and curing a portion of the particulate material.

[0073] In some examples, such as Figure 1-5 In the system described, each of the UV-LEDs in the UV-LED array irradiates the layer of particulate material substantially simultaneously. However, in other examples, the UV-LEDs in the UV-LED array irradiate the layer sequentially by applying energy in a scanning manner.

[0074] Figure 6 The following are shown: an example dye absorption spectrum 602 for a first liquid, in this case Contone-O; an emission spectrum of a UV-LED with maximum intensity emission at 385 nm; and an absorption spectrum 606 for an example particulate material PA-12. PA-12 has an absorptivity peak at approximately 350 nm. Therefore, in this example, most of the emitted UV energy will be absorbed by the dye, and very little energy will be absorbed by the material in regions where the dye has not yet deposited. For example, approximately 70% of the energy incident on the dye will be absorbed by the dye, and less than 10% of the energy incident on the particulate material will be absorbed by the particulate material in regions without dye. In some cases, the energy absorbed by the particulate material in regions without dye is insufficient to melt and subsequently fused. In this example, similar results can be achieved using Contone-O, PA-12, and a UV-LED with maximum intensity at wavelengths between approximately 385 nm and approximately 405 nm.

[0075] In some examples, the UV-LED energy source emits electromagnetic energy with maximum intensity at wavelengths between approximately 350 nm and approximately 405 nm. A suitable first liquid with a peak absorption rate within this range can be used. Wavelengths within this range can be sufficiently removed from the peak absorption rate of PA-12 to reduce the likelihood that the dry particulate material will reach its melting temperature.

[0076] It should be understood that the chosen UV-LED wavelength depends on the liquid being used and on the particulate material, and therefore other suitable wavelengths can be used to achieve the same or similar results.

[0077] exist Figure 6In one example, the first liquid (dye) has an absorptivity peak at approximately 385 nm; however, in other examples, other liquids with absorptivity peaks in the range of approximately 350 nm to approximately 420 nm can be used. Therefore, a suitable UV LED emitting radiation within this range can be selected. Due to practical limitations such as cost, a UV-LED emitting radiation in the range of 365 nm to 400 nm can be selected.

[0078] Figure 7 Absorption spectra of example yellow (Y), magenta (M), and cyan (C) pigment-based inks are shown. The black colorant has approximately 100% absorption efficiency in this range. Also shown (on an arbitrary vertical scale) is the output intensity of an example UV-LED labeled as a UV LED, which in this example is a 395nm LED in terms of its spectral width. The 395nm LED is an example of an readily available LED. Another such example is a 405nm LED. The spectral width of this example UV-LED is approximately 20nm. Such UV-LED energy sources will be efficiently absorbed by all these colorants. For example, at this wavelength, cyan will have approximately 95% absorption efficiency, magenta will have approximately 75% absorption efficiency, yellow will have approximately 100% absorption efficiency, and black will have approximately 100% absorption efficiency. Similarly, as... Figure 6 As explained in the text, UV-LEDs with maximum intensity at approximately 395 nm will also be effectively absorbed by Contone-O with an absorption efficiency of approximately 70%, and will be poorly absorbed by dried PA-12 with an absorption efficiency of approximately 10%.

[0079] Figure 8 This is a flowchart illustrating method 800. This method can be performed by example devices 100, 200, 300, 400, and 500. At block 802, the method includes forming a layer of particulate material. At block 804, the method includes depositing a liquid that absorbs ultraviolet radiation onto the layer of particulate material. At block 806, the method includes, after the liquid has been deposited onto the layer of particulate material, heating the liquid using an ultraviolet light-emitting diode energy source to solidify a portion of the particulate material.

[0080] In some example methods, heating a liquid using an ultraviolet light-emitting diode energy source involves irradiating a layer of particulate material with ultraviolet electromagnetic energy having a spectral width of about 5 nm to about 50 nm.

[0081] In some example methods, heating a liquid using an ultraviolet light-emitting diode energy source involves irradiating a layer of particulate material with ultraviolet electromagnetic energy having maximum intensity at wavelengths between about 200 nm and about 405 nm.

[0082] In some example methods, heating a liquid using an ultraviolet light-emitting diode energy source involves irradiating a layer of particulate material with ultraviolet electromagnetic energy having maximum intensity at wavelengths between about 385 nm and about 405 nm.

[0083] In some example methods, the liquid is a first liquid, and the method further includes heating the first liquid with an ultraviolet light-emitting diode energy source before depositing the second liquid, wherein the second liquid absorbs ultraviolet radiation.

[0084] Some system components and methods described herein may be implemented using non-transitory computer program code that can be stored on a non-transitory storage medium. In some examples, a controller may include a non-transitory computer-readable storage medium containing a set of computer-readable instructions stored thereon. The controller may also include one or more processors 903. In some examples, control may be partitioned or distributed among two or more controllers implementing all or part of the methods described herein.

[0085] Figure 9 An example of such a non-transitory computer-readable storage medium 900 is shown, comprising a set of computer-readable instructions 901 that, when executed by at least one processor 903, cause one or more processors 903 to implement the methods described herein. The computer-readable instructions 901 can be retrieved from a machine-readable medium, which is, for example, any medium that can contain, store, or maintain programs and data for use by or in conjunction with an instruction execution system. In this case, the machine-readable medium can include any of a number of physical media, such as, for example, electrical, magnetic, optical, electromagnetic, or semiconductor media. More specific examples of suitable machine-readable media include, but are not limited to, hard disk drives, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory, or portable disks.

[0086] In the example, instruction 901 causes processor 903 in the stacking system to form a layer of particulate material at block 902. At block 904, instruction 901 causes processor 903 to deposit a liquid that absorbs ultraviolet radiation onto the layer of particulate material. At block 906, instruction 901 causes processor 903 to heat the liquid using an ultraviolet light-emitting diode (UV) power source after the liquid has been deposited onto the layer of particulate material, thereby heating the liquid and solidifying a portion of the particulate material. In some examples, the UV light-emitting diode power source emits electromagnetic energy with maximum intensity at wavelengths between approximately 200 nm and approximately 405 nm.

[0087] The foregoing description has been presented to illustrate and describe examples of the principles described. This description is not intended to be exhaustive or to limit these principles to any precise form disclosed. Many modifications and variations are possible in accordance with the foregoing teachings. It should be understood that any feature described with respect to any example may be used alone, or in combination with other features described, and may also be used in combination with any feature of any other example, or may be any combination of any other example.

Claims

1. An apparatus for producing three-dimensional objects, the apparatus comprising: Controller; First printhead; as well as A second printhead is used to deposit a colorant according to the desired color of the object; and Ultraviolet light-emitting diodes (LEDs) are energy sources used to emit electromagnetic energy. Wherein, the controller: The first printhead deposits a first liquid that absorbs ultraviolet radiation emitted by the ultraviolet light-emitting diode energy source onto a layer of particulate material; and The ultraviolet light-emitting diode energy source irradiates and preheats at least a portion of the particulate material layer after the first liquid has been deposited onto the particulate material layer; and The second printhead deposits the desired colorant onto the preheated portion of the particulate material layer.

2. The apparatus of claim 1, wherein the ultraviolet light-emitting diode energy source is used to emit ultraviolet electromagnetic energy having a spectral width of about 5 nm to about 50 nm.

3. The apparatus of claim 1, wherein the ultraviolet light-emitting diode energy source is used to emit electromagnetic energy with maximum intensity at a wavelength between about 385 nm and about 405 nm.

4. The apparatus of claim 1, wherein the controller: The second printhead deposits a colorant, comprising a second liquid that absorbs ultraviolet radiation emitted by the ultraviolet light-emitting diode energy source, onto a layer of particulate material after the first printhead has deposited the first liquid.

5. The apparatus of claim 4, wherein the first liquid deposited by the first printhead is white.

6. The apparatus of claim 4, further comprising a third printhead, wherein the controller causes: The third printhead, after the second printhead has deposited the second liquid, will deposit a third liquid that absorbs ultraviolet radiation emitted by the ultraviolet light-emitting diode energy source onto the layer of particulate material.

7. The apparatus according to claim 4, wherein the ultraviolet light-emitting diode energy source is a first ultraviolet light-emitting diode energy source, the apparatus comprising: Second ultraviolet light-emitting diode energy source; The controller causes the second ultraviolet light-emitting diode energy source to irradiate at least a portion of the layer of particulate material before the second printhead deposits the second liquid.

8. The apparatus of claim 7, wherein the first ultraviolet light-emitting diode energy source has a first peak wavelength and the second ultraviolet light-emitting diode energy source has a second peak wavelength, the first peak wavelength and the second peak wavelength being different from each other.

9. The apparatus of claim 1, wherein the ultraviolet light-emitting diode energy source is used to emit electromagnetic energy with maximum intensity at a wavelength between about 200 nm and about 405 nm.

10. The apparatus of claim 1, wherein the first liquid comprises a white dye.

11. The apparatus of claim 1, wherein the second printhead is used to deposit cyan, yellow, magenta and black inks to form the desired color.

12. The apparatus of claim 1, further comprising a movable bracket supporting the first printhead, the second printhead and the ultraviolet light-emitting diode energy source, the bracket further supporting the second ultraviolet light-emitting diode energy source and a third printhead for depositing the first liquid.

13. The apparatus of claim 12, wherein the second printhead is disposed between the first printhead and the third printhead such that, when the carriage moves in either direction, the first printhead or the third printhead deposits the first liquid onto the particulate material, the first liquid is preheated by one of the energy sources, and then the second printhead prints the desired color after preheating, and the particulate material and the colored image are then fused together by another energy source.

14. The apparatus of claim 1, further comprising a bracket capable of bidirectional movement above the particulate material, wherein, Along the direction of movement of the bracket, the bracket supports the first printhead, the ultraviolet light-emitting diode energy source, the second printhead, the second ultraviolet light-emitting diode energy source, and the third printhead for depositing the first liquid.

15. A method for producing a three-dimensional object, the method comprising: Forming a layer of particulate material; A liquid that absorbs ultraviolet radiation is deposited onto a layer of particulate material to form a surface for receiving the desired color. After the liquid has been deposited onto the layer of particulate material, the liquid is heated using an ultraviolet light-emitting diode energy source; as well as The desired colorant is printed onto a heated liquid and particle layer.

16. The method of claim 15, wherein heating the liquid using an ultraviolet light-emitting diode energy source comprises irradiating at least a portion of the layer of particulate material with ultraviolet electromagnetic energy having a spectral width of about 5 nm to about 50 nm.

17. The method of claim 15, wherein the ultraviolet light-emitting diode energy source emits electromagnetic energy with maximum intensity at a wavelength between about 385 nm and about 405 nm.

18. The method of claim 15, wherein the colorant comprises a second liquid, wherein the second liquid absorbs ultraviolet radiation.

19. The method of claim 15, further comprising heating the liquid, colorant, and particulate material using a second ultraviolet light-emitting diode energy source to fuse the particulate material into a portion of the object having the desired color.

20. A non-transitory computer-readable storage medium storing instructions, said instructions causing the processor, when executed by a processor, to: Forming a layer of particulate material; A liquid that absorbs ultraviolet radiation is deposited onto a layer of particulate material to form a surface for receiving the desired color. After the liquid has been deposited onto the layer of particulate material, the liquid is heated using an ultraviolet light-emitting diode energy source; as well as The desired colorant is printed onto a heated liquid and particle layer.

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