3D printing using carboxamide-containing compounds

Abstract

A three-dimensional printing kit may include a polymeric building material and a fusing agent. The polymeric building material may include polymer particles having a D50 particle size of about 2 μm to about 150 μm. The fusing agent may include an aqueous liquid carrier containing water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and about 2 wt % to about 15 wt % of a carbonamide-containing compound.

Description

[0001] background

[0002] Three-dimensional (3D) printing can be an additive printing method used to manufacture three-dimensional solid parts from digital models. 3D printing is often used for rapid product prototyping, mold generation, master pattern generation, and low-volume manufacturing. Some 3D printing techniques can be considered additive methods because they involve applying successive layers of material. This can be distinguished from other mechanical processes that typically rely on removing material to create the final part. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1A and Figure 1B Together, schematic diagrams of exemplary three-dimensional printing kits according to the present disclosure are provided;

[0005] Figure 2 is a flowchart illustrating an exemplary method of printing a three-dimensional object according to the present disclosure; and

[0006] Figure 3 is a schematic diagram of an exemplary three-dimensional printing system according to the present disclosure.

[0007] Details

[0008] Three-dimensional printing can be an additive process that involves applying successive layers of polymer building materials on which a fusing agent is printed to bind the successive layers of polymer building materials together. More specifically, a fusing agent comprising a carbonamide-containing compound can be selectively applied to a support bed, such as a polymer building material layer on a building platform supporting a polymer building material, to pattern selected areas of the polymer building material layer. The polymer building material layer can be exposed to electromagnetic radiation, and due to the presence of a radiation absorber on the printed portion, the light energy absorbed in those portions of the layer on which the fusing agent is printed can be converted into thermal energy to melt or coalesce the portion, while other portions of the polymer building material do not reach a temperature suitable for melting or coalescing. This can then be repeated on a layer-by-layer basis until a three-dimensional object is formed. The presence of the carbonamide compound in the fusing agent can provide a certain softening of the three-dimensional object formed therefrom.

[0009] Accordingly, a three-dimensional printing kit (or "kit") may include a polymer building material including polymer particles having a D50 particle size of about 2 μm to about 150 μm, and a fusing agent. The fusing agent may include an aqueous liquid carrier containing water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and about 2% by weight to about 15% by weight of a carbonamide-containing compound. In one example, the carbonamide-containing compound may include urea or biurea and be present in the fusing agent at about 4% by weight to about 12% by weight. In another example, the radiation absorber may include carbon black, a metal dithiolene complex, a near-infrared absorbing dye, a near-infrared absorbing pigment, a metal nanoparticle, a conjugated polymer, or a combination thereof. The radiation absorber may be present in the fusing agent, for example, at about 0.1% by weight to about 10% by weight. The aqueous liquid carrier may further include about 0.01% by weight to about 2% by weight of a surfactant in some examples. The polymeric building material may include polyamide, thermoplastic polyamide, polyethylene, polyethylene terephthalate (PET), polystyrene, polyacrylate, polyacetal, polypropylene, polycarbonate, polyester, acrylonitrile butadiene styrene, thermoplastic polyurethane, engineering plastics, polyether ether ketone (PEEK), polymer blends thereof, amorphous polymers thereof, core-shell polymers thereof, or copolymers thereof. In a more specific example, the radiation absorber may be carbon black, and the polymer particles may include thermoplastic polyurethane or thermoplastic polyamide. In another example, a detailing agent may be included as part of the kit. The detailing agent may include a detailing compound to reduce the temperature of the polymeric building material to which the detailing agent is applied.

[0010] In another example, a method for printing a three-dimensional object may include iteratively applying each polymer building material layer containing polymer particles having a D50 particle size of about 2 μm to about 150 μm, and iteratively and selectively distributing a fusing agent to each building material layer based on a three-dimensional object model. The fusing agent may include an aqueous liquid carrier containing water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and about 2% by weight to about 15% by weight of a carbon amide-containing compound. The method may further include iteratively exposing each polymer building material layer in which the fusing agent is distributed to electromagnetic radiation to selectively fuse the polymer particles of the polymer building material in contact with the radiation absorber and form a fused three-dimensional object. In one example, the radiation absorber may include carbon black, and the polymer particles may include thermoplastic polyurethane or thermoplastic polyamide. In another example, the carbon amide-containing compound may include urea or biurea and may be applied to the particulate building material layer at a weight ratio of the carbon amide-containing compound / polymer particles of about 1:50 to about 1:500. In more detail, the method may include selectively spraying a detailing agent including a detailing compound onto various layers of build material, wherein the detailing compound reduces the temperature of the build material onto which the detailing agent is applied.

[0011] In another example, a three-dimensional printing system may include a polymer building material comprising polymer particles having a D50 particle size of about 2 μm to about 150 μm, and may further include a fluid applicator that is fluidly connected to or can be fluidly connected to a fusing agent. The fluid applicator may be guidable to iteratively apply the fusing agent to the polymer building material layer. The fusing agent may include an aqueous liquid carrier containing water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and about 2% by weight to about 15% by weight of a carbonamide-containing compound. In one example, an electromagnetic radiation source may be included, and the electromagnetic radiation source may be positioned to provide electromagnetic radiation to the polymer building material layer having the fusing agent applied thereto. The radiation absorber may selectively absorb infrared energy and may be an infrared electromagnetic radiation source that emits a peak wavelength corresponding to the infrared energy.

[0012] When a three-dimensional printing kit, a method of printing a three-dimensional object, and / or a three-dimensional printing system are discussed herein, such discussions may be considered applicable to each other, regardless of whether they are explicitly discussed in the context of that instance. Thus, for example, when a polymeric building material is discussed in relation to a three-dimensional printing kit, such disclosure is also related to and directly supported in the context of a method of printing a three-dimensional object, a three-dimensional printing system, and vice versa.

[0013] Unless otherwise specified, the terms used herein have their ordinary meanings in the technical field. In some cases, some terms are more specifically defined throughout the specification or included at the end of this specification, so these terms may have the meanings as described herein.

[0014] 3D Printing Kit

[0015] exist Figure 1A and 1B A three-dimensional printing kit is shown as an example. The three-dimensional printing kit may include, for example, Figure 1A The polymer building material 110 shown in FIG. Figure 1B The polymer building material may include polymer particles 112, which may have a D50 particle size of, for example, about 2 μm to about 150 μm. The fusing agent may include an aqueous liquid carrier 122 containing water and an organic cosolvent, a radiation absorber 124 that generates heat from absorbed electromagnetic radiation, and about 2 wt % to about 15 wt % of a carbonamide-containing compound 126.

[0016] In some examples, the 3D printing kit may further include other fluids, such as colorants, thinning agents, and the like. The thinning agent may, for example, include a thinning compound, which may be a compound that can reduce the temperature of the polymeric building material when applied to the polymeric building material. In some examples, the thinning agent may be applied around the edge of the application area of ​​the fusing agent. This can prevent agglomeration around the edge caused by heat from the fusing agent application area. The thinning agent may also be applied in the same area where the fusing agent is applied to control the temperature and prevent excessive temperatures when the polymeric building material is fused.

[0017] The polymer building material can be packaged or co-packaged with a fusing agent, a coloring agent, a refinement agent, etc. in a separate container, and / or can be combined with a fusing agent during printing, for example, loaded together in a three-dimensional printing system. Exemplary polymer building materials that can be used include polyamides, thermoplastic polyamides, polyethylene, polyethylene terephthalate (PET), polystyrene, polyacrylates, polyacetals, polypropylene, polycarbonates, polyesters, acrylonitrile butadiene styrene, thermoplastic polyurethanes, engineering plastics, polyetheretherketones (PEEK), polymer blends thereof, amorphous polymers thereof, core-shell polymers thereof, or copolymers thereof. In some more specific examples, the polymer building material can be a thermoplastic polymer material, such as a thermoplastic polyamide or a polyurethane, such as a thermoplastic polyurethane.

[0018] Method for printing three-dimensional objects

[0019] A flowchart of an exemplary three-dimensional (3D) printing method 200 is shown in Figure 2In. The method may include 210 iteratively applying each polymer building material layer containing polymer particles having a D50 particle size of about 2 μm to about 150 μm, and 220 iteratively and selectively distributing a fusing agent to each building material layer based on the three-dimensional object model. The fusing agent may include an aqueous liquid carrier containing water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and about 2% by weight to about 15% by weight of a carbon amide-containing compound. The method may further include 230 iteratively exposing each polymer building material layer in which the fusing agent is distributed to electromagnetic radiation to selectively fuse the polymer particles of the polymer building material in contact with the radiation absorber and form a fused three-dimensional object. In one example, the radiation absorber may include carbon black, and the polymer particles may include thermoplastic polyurethane or thermoplastic polyamide. In another example, the carbon amide-containing compound may include urea or biurea and may be applied to the particulate building material layer at a weight ratio of the carbon amide-containing compound / polymer particles of about 1:50 to about 1:500. In more detail, the method may include selectively spraying a detailing agent including a detailing compound onto various layers of build material, wherein the detailing compound reduces the temperature of the build material onto which the detailing agent is applied.

[0020] In printing in a layer-by-layer manner, a polymer building material may be spread, a fusing agent may be applied, a layer of polymer building material may be exposed to energy, and then the building platform between the polymer bed material and the fusing agent application may be adjusted to be suitable for printing another layer, for example, about 5 μm to about 1 mm, which may correspond to the thickness of a printed layer of a three-dimensional object. Thus, another layer of polymer building material may be added thereon to receive another application of fusing agent, and so on. During the building process, a radiation absorber in the fusing agent may be used to convert energy into thermal energy and promote heat transfer to polymer particles of the polymer building material in contact with the fusing agent containing the radiation absorber. In one example, the fusing agent may increase the temperature of the polymer particles of the polymer building material to above the melting point or softening point of the polymer particles, thereby allowing the polymer building material (or its polymer particles) to fuse (e.g., sinter, bond, solidify, etc.) and form the layers of the three-dimensional object. The method may be repeated until all the layers of the polymer building material have been created and the three-dimensional object has been formed. In some examples, the method may further include heating the polymer building material before dispensing.

[0021] In one example, the method may further include iteratively and selectively dispensing a thinning agent laterally onto each polymeric building material layer at a boundary between a first region where each polymeric building material layer is in contact with the fusing agent and a second region where each polymeric building material layer is not in contact with the fusing agent. This may prevent agglomeration around the edges caused by heat from the region where the fusing agent is applied. The thinning agent may also be applied in the same region where the fusing agent is applied to control the temperature and prevent excessive temperatures when the polymeric building materials are fused.

[0022] In another example, the three-dimensional object formed by the method can be softened (compared to a three-dimensional object printed with the same fusing agent but without the polymer softening fusing compound), or the tensile strength, for example, can be adjusted. Specifically, the three-dimensional object may have problems with tensile strength and elongation at break, which can lead to brittle failure. The use of the fusing agent described herein can provide a way to reduce the hardness of the three-dimensional object and also increase the tensile strength in some cases, especially for different types of thermoplastic polymer building materials, such as thermoplastic polyurethane and / or thermoplastic polyamide. In some examples, the three-dimensional printed object made using the method described herein may have a tensile strength of about 50 MPa to about 100 MPa, about 55 MPa to about 90 MPa, or about 60 MPa to about 85 MPa. In a further example, the three-dimensional printed object may exhibit, for example, a Shore hardness (Shore A or SHA) of about 60 SHA to about 95 SHA, about 70 SHA to about 90 SHA, or about 75 SHA to about 90 SHA, which is a measure of the material's resistance to indentation. These tensile strength and Shore hardness values ​​can depend on the polymeric build material. However, a reduction in Shore hardness compared to using a fusing agent that does not contain a carbonamide-containing compound but is otherwise identical and applied in the same manner can be achieved with many materials, with a reduction in Shore hardness values ​​greater than about 1% to about 25%, about 5% to about 25%, or about 10% to about 20%. In some specific examples, these properties can be achieved for three-dimensional printed objects prepared with any of a number of polymeric build materials, such as those previously described with respect to three-dimensional printing kits.

[0023] 3D Printing System

[0024] exist Figure 3 Schematically illustrates a three-dimensional printing system 300 according to the present disclosure. The three-dimensional printing system may include a polymeric building material 110 and a fluid applicator 310. The polymeric building material may include polymer particles having a D50 particle size of about 2 μm to about 150 μm and may be any of a number of polymeric building materials, such as those previously described with respect to the three-dimensional printing kit. The fluid applicator is connected or connectable to a fusing agent 120. The fusing agent may include an aqueous liquid carrier containing water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and about 2 wt % to about 15 wt % of a carbonamide-containing compound.

[0025] In more detail, fluid applicator 310 can be a digital fluid ejector, such as a thermal or piezoelectric jet architecture. The fluid applicator can be a flux applicator in one example, which is fluidically connected or fluidically connectable to the flux 120 to iteratively apply the flux to the polymer building material 110 to form the individually patterned object layers 340. The fluid applicator can be any type of device capable of selectively dispensing or applying the flux. For example, the fluid applicator can be a fluid ejector or a digital fluid ejector, such as an inkjet printhead, such as a piezoelectric printhead, a thermal printhead, a continuous printhead, etc. The fluid applicator can also be a sprayer, a dropper, or other similar structure for applying the flux to the polymer building material. Therefore, in some examples, the application can be by spraying or ejecting the flux from a digital fluid jet applicator similar to an inkjet pen.

[0026] In one example, the fluid applicator may be Figure 3 315, but may be supported by any of a number of structures. In another example, the fluid applicator may include a motor (not shown) and may be operable to move back and forth, and the fluid applicator may also move back and forth to provide x-axis and y-axis motion over the polymeric build material when positioned over or adjacent to the polymeric build material on the powder bed of the build platform.

[0027] In one example, the three-dimensional printing system may further include a building platform 320 to support the polymer building material. The polymer building material 110 may be spread from the building material supplier 360 onto the building platform or onto a powder bed of previously applied polymer building material, and then flattened in some cases to make the applied layer more uniform in nature. The building platform may be positioned so that a fusant can be applied from a fluid applicator to the polymer building material layer. The building platform may be configured to drop in height so that subsequent layers of polymer building materials are applied by a supplier and / or a spreader. The polymer building material may be layered in the building platform at a thickness of about 5 μm to about 1 mm. In some examples, each layer may have a relatively uniform thickness. In one example, the thickness of the polymer building material layer may be about 10 μm to about 500 μm or about 30 μm to about 200 μm. In addition, heat may be applied to the building platform or heat may be applied from any other direction or time to make the polymer building material reach a temperature close to its fusion temperature, so that it is easier to raise the temperature to a temperature sufficient to fuse the polymer building material. For example, heat can be applied from the build platform, from above, to the polymer build material in the powder bed, or to the polymer build material before spreading on the powder bed, to preheat the polymer build material to within about 10°C to about 70°C of the fusion temperature of the polymer particles so that less energy can be applied to bring the polymer particles to their fusion temperature.

[0028] After the fusing agent is selectively applied to the polymeric building material, the polymeric building material can be exposed to energy (e) from an electromagnetic radiation source 330. The electromagnetic radiation source can be positioned so that each layer of the polymeric building material is exposed to the radiation energy to selectively fuse the polymer particles of the polymeric building material in contact with the radiation absorber (forming a fused layer 350), thereby iteratively forming a three-dimensional object. The radiation source can be an infrared (IR) or near-IR light source, such as an infrared or near-IR curing lamp, an infrared or near-IR light emitting diode (LED), or a laser having a desired infrared or near-IR electromagnetic wavelength, and can emit electromagnetic radiation having a wavelength of about 400 nm to about 1 mm. In one example, the emitted electromagnetic radiation can have a wavelength of about 400 nm to about 2 µm. In some examples, the radiation source can be operably connected to a lamp / laser driver, an input / output temperature controller, and / or a temperature sensor.

[0029] Polymer building materials

[0030] The polymer building material can be used as a bulk material for a three-dimensionally printed object. As mentioned, the polymer building material can include about 80% to 100% by weight of polymer particles. In another example, the polymer building material can include about 85% to about 95% by weight, about 90% to 100% by weight, or 100% by weight of polymer particles.

[0031] In the examples herein, as mentioned, the polymer building material may include polyamide, thermoplastic polyamide, polyethylene, polyethylene terephthalate (PET), polystyrene, polyacrylate, polyacetal, polypropylene, polycarbonate, polyester, acrylonitrile butadiene styrene, thermoplastic polyurethane, engineering plastics, polyetheretherketone (PEEK), polymer blends thereof, amorphous polymers thereof, core-shell polymers thereof, or copolymers thereof. In another example, the polymer building material may include a thermoplastic polymer building material, such as thermoplastic polyamide and / or thermoplastic polyurethane. The various polymers may have various structures, including various weight average molecular weights, D50 particle sizes, polydispersities of side chain branching, etc.

[0032] The polymer building material may comprise polymer particles of similar size or polymer particles of different sizes. The term "size" or "particle size" as used herein refers to the diameter of a substantially spherical particle, or the effective diameter of a non-spherical particle, such as the diameter of a sphere having the same mass and density (as determined by weight) as the non-spherical particle. Substantially spherical particles (e.g., spherical or nearly spherical) may have a sphericity of >0.84. Thus, any individual polymer particle having a sphericity of <0.84 may be considered as non-spherical (irregularly shaped). For example, the polymer particles may have a D50 particle size of about 2 µm to about 150 µm, about 25 µm to about 125 µm, about 50 µm to about 150 µm, or about 20 µm to about 80 µm. The D50 particle size is based on the equivalent spherical volume of the polymer particle. The D50 particle size may be measured by laser diffraction, microscopic imaging, or other suitable methods, but in some instances, the particle size (or particle size distribution) may be measured using the Malvern TM Mastersizer TM Measurement and / or Characterization. When the polymer particles are not spherical, for example having an aspect ratio of about 1:1, this tool considers the particle size based on the diameter of the equivalent spherical volume of the polymer particles.

[0033] The polymer construction material may further include flow additives, antioxidants, inorganic fillers or any combination thereof in some instances. Typically, the amount of any of these or other similar components may be about 5% by weight or less. Exemplary flow additives may include fumed silica and / or the like. Exemplary antioxidants may include hindered phenols, phosphites, thioethers, hindered amines and / or the like. Exemplary inorganic fillers may include particles such as alumina, silica, glass beads, glass fibers, carbon nanotubes, cellulose and / or the like. Some additives may be present in a variety of additive categories, for example, fumed silica may be both a flow additive and a filler. In some instances, fillers or other types of additives may be embedded in polymer particles or compounded with polymer particles.

[0034] The polymer building material can be printed into a three-dimensional object with a resolution of about 10 μm to about 150 μm, about 20 μm to about 100 μm, or about 25 μm to about 80 μm. "Resolution" as used herein refers to the size of the smallest feature that can be formed on a three-dimensional object. Depending on the size of the polymer particles present in the polymer building material, the polymer building material can form a layer of about 10 μm to about 150 μm thick, so that the fused layer of the printed object can have approximately the same thickness or, for example, several to multiple times (e.g., 2 to 20 times) thicker than the D50 particle size of the polymer particles. This can provide a resolution in the z-axis direction (e.g., the building direction of the layer) of about 10 μm to about 150 μm. However, in some instances, the polymer building material can also have a sufficiently small particle size and a sufficiently consistent particle shape to provide an x-axis and y-axis resolution (e.g., an axis parallel to the support surface of the building platform) of about the size of the polymer particles, such as about 2 μm to about 150 μm.

[0035] Fusing agent

[0036] In more detail, regarding the fusing agent 120 usable in the 3D printing kit, the method of printing a 3D object, or the 3D printing system as described herein, the fusing agent may include an aqueous liquid carrier, a radiation absorber that generates heat by absorbing electromagnetic radiation, and about 1 wt % to about 15 wt % of a carbonamide-containing compound. The aqueous liquid carrier may include water and an organic co-solvent.

[0037] In more detail, the flux may contain a radiation absorber. The amount of the radiation absorber in the flux may vary depending on the type of radiation absorber. In some examples, the amount of the radiation absorber in the flux may be from about 0.1 wt % to about 10 wt %. In another example, the amount may be from about 0.5 wt % to about 7.5 wt %. In another example, the amount may be from about 1 wt % to about 10 wt %. In a specific example, the amount may be from about 0.5 wt % to about 5 wt %.

[0038] Exemplary radiation absorbers can include carbon black, metal dithiol ene complexes, near infrared absorbing dyes, near infrared absorbing pigments, metal nanoparticles, conjugated polymers, or combinations thereof. In one example, the radiation absorber can be carbon black. In some examples, the radiation absorber can be colored or colorless.

[0039] Examples of near infrared absorbing dyes may include ammonium dyes, tetraaryl diamine dyes, cyanine dyes, phthalocyanine dyes, dithiol ene dyes, and the like. Various near infrared absorbing pigments may also be used. Non-limiting examples may include phosphates having various counter ions such as copper, zinc, iron, magnesium, calcium, strontium, and the like and combinations thereof. Non-limiting specific examples of phosphates may include M2P2O7, M4P2O9, M5P2O 10 、M3(PO4)2、M(PO3)2、M2P4O 12 And combinations thereof, wherein M represents a counterion with an oxidation state of +2. For example, M2P2O7 may include compounds such as Cu2P2O7, Cu / MgP2O7, Cu / ZnP2O7 or any other suitable combination of counterions. The phosphates described herein are not limited to counterions with an oxidation state of +2. Other phosphate counterions may also be used to prepare other suitable near-infrared pigments. Additional near-infrared absorbing pigments may include silicates. Silicates may have counterions identical or similar to phosphates. A non-limiting example may include M2SiO4, M2Si2O6 and other silicates in which M is a counterion with an oxidation state of +2. For example, the silicate M2Si2O6 may include Mg2Si2O6, Mg / CaSi2O6, MgCuSi2O6, Cu2Si2O6, Cu / ZnSi2O6 or other suitable combinations of counterions. The silicates described herein are not limited to counterions with an oxidation state of +2. Other silicate counterions may also be used to prepare other suitable near-infrared pigments.

[0040] In more detail, the carbon amide-containing compound may be present in the flux at about 2% to about 15% by weight. In other examples, the carbon amide-containing compound may be present at about 4% to about 12% by weight, or about 5% to about 10% by weight. In various examples consistent with the three-dimensional printing kit, the carbon amide-containing compound may be defined as shown in Formula I as follows:

[0041]

[0042] wherein R is independently H, NHC(O)NH2, C(O)NH2, C1-C4 lower alkyl, etc. When all four (4) R groups are H, the structure is a urea. When one (1) R group is NHC(O)NH2 and the other three (3) R groups are H, the structure is a biuret. When one (1) R group is C(O)NH2 and the other three (3) R groups are H, the structure is a biuret. Other carbonamide-containing compounds conforming to Formula I may also be used, such as other organically substituted carbonamides.

[0043] According to the disclosed fusing agent formulation, it is modified with a carbonamide-containing compound as a "drop-in" solution for fusing to provide a "softer" (or reduced Shore hardness) three-dimensional object, and in some cases can provide an object with higher tensile strength or elasticity, especially when used with a thermoplastic polymer build material. Thermoplastic polyurethane (TPU) provides an example of a thermoplastic material that can benefit from the hardness / softness modulation that can be obtained using a carbonamide-containing compound as described herein (e.g., by adding the carbonamide-containing compound to the fusing agent), which can bring additional softness and / or elasticity to the material when fused to form a three-dimensional object. Thermoplastic polyamides provide another exemplary class of materials that can be softened by adding a carbonamide-containing compound to the fusing agent. As a more specific example of a useful carbonamide-containing compound, urea and other similar compounds can be effectively used for this purpose. Urea is highly water-soluble, so it can be added to the fusing agent formulation at relatively high concentrations, and therefore can be added at a concentration suitable for promoting changes in the hardness of the printed object when used in the fusing agent. In this and other examples, urea can generate gas at temperatures typically used to fuse TPU and other thermoplastic polymer build materials, and this gas generation can promote bubbles within the part, thereby softening the part and, in some cases, also changing the tensile strength. Taking urea as an example, the generation of gas from urea at the melting temperature of TPU generally does not leave residual byproducts, and the gas generated by the decomposition of urea can be a substantially safe gas to release during the construction of the three-dimensional object. For example, the decomposition of urea can include the generation of CO2 gas, which is substantially safe to the surrounding environment at the amount released.

[0044] The decomposition of the carbon amide-containing compound to release gas may depend on which carbon amide-containing compound is selected to be used. The decomposition temperature may be matched with the melting temperature of the polymer building material, for example. For example, the melting temperature of the polymer building material may be about 80°C to about 300°C, about 100°C to about 250°C, or about 110°C to about 210°C. In view of these melting temperatures, a polymer building material having a melting temperature overlapping the temperature range of the carbon amide-containing compound generating gas may be selected. For example, urea decomposes at about 132.7°C, and depending on the time frame, it may decompose at a temperature much higher than 132.7°C, as long as it has not yet decomposed at a lower temperature. It is worth noting that the polymer particles of the polymer building material described herein may be selected to have a melting temperature within about 50°C of the decomposition temperature of the carbon amide-containing compound. For example, the "melting temperature" of the polymer building material may be about 10°C to about 70°C lower than the melting temperature of the polymer particles of the polymer building material. Thus, if urea is used in the flux, a thermoplastic polyurethane having a fusing temperature of, for example, about 110°C to about 160°C, or about 120°C to about 150°C may be used. These ranges are exemplary only and may vary depending on the speed of application, the temperature reached during the fusing process, the dwell time and / or intensity of the energy application, the radiation absorber selected for use, the contone level of the applied flux, etc. In addition, in addition to urea, other exemplary carbonamide-containing compounds that may be used that have a higher decomposition temperature include materials such as biuret, biuret, which tend to decompose at longer heating times and / or temperatures than urea, such as about 150°C to about 210°C. In some cases, these and other materials may first decompose into urea and then release CO2 gas during the decomposition of the urea, and these factors may be considered, for example, when selecting carbonamide-containing compounds, formulating the flux, selecting polymeric building materials containing polymer particles, etc.

[0045] In more detail, depending on how much fusing agent is used, for example, various building layers or various portions of each building layer can be made to have a different softness than other layers or other portions of each layer. Thus, customized layer stacks within a component can be prepared to have modulated or different degrees of Shore hardness, tensile strength, and / or other mechanical properties. As an example, by reducing the Shore hardness of a three-dimensional object or a portion of a three-dimensional object, the object may be tougher in tension and / or shear fracture, even if they have a lower hardness.

[0046] When applying the fusing agent to the polymeric building material, the concentration of the carbonamide-containing compound can be considered together with the concentration of the radiation absorber in the fusing agent. These concentrations can be used to determine how much fusing agent is applied to achieve a weight ratio of the fusing agent to the polymeric building material and a weight ratio of the carbonamide-containing compound to the polymeric building material that provide acceptable layer-by-layer fusion and softening, respectively. For example, the fusing agent, as mentioned, can contain about 0.1% by weight to about 10% by weight of the radiation absorber in some examples, and can also contain about 2% by weight to about 15% by weight of the carbonamide-containing compound. Thus, for example, if the fusing agent (10% by weight) is applied to the polymeric building material (90% by weight) at a weight ratio of about 1:9, the radiation absorber / polymer building material weight ratio (as applied) can be about 1:10000 to about 1:100, and the carbonamide-containing compound / polymer building material weight ratio (as applied) can be about 1:500 to about 1:50. If more (up to 20 wt%) or less (as low as 5 wt%) fusing agent is applied to the polymeric build material, these ratios may be expanded accordingly. For reference, for example, the weight ratio of radiation absorber to polymeric build material (as applied) may more typically be from about 1:1000 to about 1:80, and the weight ratio of carbonamide-containing compound to polymeric build material (as applied) may more typically be from about 1:500 to about 1:60.

[0047] In some examples, in addition to the radiation absorber and the carbonamide-containing compound, the aqueous liquid carrier may carry other components or dispersed additives. In some examples, the aqueous liquid carrier may further contain about 0.01% by weight to about 2% by weight or about 0.01% by weight to about 0.5% by weight of a surfactant. In other examples, the fusing agent may further contain a dispersant. The dispersant can help disperse the radiation absorber, the carbonamide-containing compound (if not completely dissolved), other dispersed additives or a combination thereof. In some examples, the dispersant itself can also absorb radiation. Non-limiting examples of dispersants that can be included as radiation absorbers alone or with pigments can include polyoxyethylene glycol octylphenol ether, ethoxylated aliphatic alcohols, carboxylates, polyethylene glycol esters, dehydrated sorbitan esters, carboxamides, polyoxyethylene fatty acid amides, poly (ethylene glycol) p-isooctylphenyl ether, sodium polyacrylate and combinations thereof. As described more fully below, other additives may be present as part of the aqueous liquid carrier.

[0048] Refining agent

[0049] In some examples, the three-dimensional printing kit, the method of printing a three-dimensional object, and / or the three-dimensional printing system may further include a thinning agent and / or its application. The thinning agent may include a thinning compound capable of cooling the polymeric build material when applied. In some examples, the thinning agent may be printed around the edges of the portion of the polymeric build material that is printed by the fusing agent or can be printed by the fusing agent. The thinning agent can increase the selectivity between the fused and unfused portions of the polymeric build material by reducing the temperature of the polymeric build material around the edges of the portion to be fused. In other examples, the thinning agent may be printed in the fusing agent printing area to provide additional cooling when printing the three-dimensional object.

[0050] In some examples, the refiner can be a solvent that can evaporate at the temperature of the particulate building material carried on the powder bed or the building platform. As mentioned above, in some cases, the polymer building material in the powder bed can be preheated to a preheating temperature within about 10°C to about 70°C of the fusion temperature of the polymer building material. Therefore, the refiner can be a solvent that evaporates when in contact with the polymer building material at the preheating temperature, thereby cooling the printed part by evaporative cooling. In some examples, the refiner can include water, a co-solvent, or a combination thereof. In a further example, the refiner can be substantially free of radiation absorbers. That is, in some examples, the refiner can be substantially free of ingredients that absorb enough energy from the energy source to fuse the polymer building material. In some examples, the refiner can include a colorant, such as a dye or a pigment, but the amount is small enough that the colorant does not cause the polymer building material printed with the refiner to fuse when exposed to the energy source.

[0051] Aqueous liquid carrier

[0052] The term "aqueous liquid carrier" as used herein may refer to a liquid in a flux, a refiner, and / or other fluid reagents that may be present, such as a colorant. The aqueous liquid carrier may contain water alone or in combination with various additional components. For example, with respect to a flux, the aqueous liquid carrier contains water and an organic cosolvent, but with respect to a refiner, the aqueous liquid carrier may be water, or may contain water and an organic cosolvent. Examples of components that may be included in addition to water may include organic cosolvents, surfactants, buffers, antimicrobial agents, antifouling agents, chelating agents, buffers, and the like. In one example, the aqueous liquid carrier may contain water and an organic cosolvent. In another example, the aqueous liquid carrier may contain water, an organic cosolvent, and a surfactant. In yet another example, the aqueous liquid carrier may contain water, an organic cosolvent, a surfactant, and a buffer (or a buffer and a chelating agent).

[0053] In the examples herein, the aqueous liquid carrier for any other fluid reagent included in the fuser, refiner, or the set, method, and / or system herein may include about 25% by weight to about 90% by weight or about 30% by weight to about 75% by weight of water, and about 5% by weight to about 60% by weight or about 10% by weight to about 50% by weight of organic cosolvent. These weight percentages are based on the entire fluid reagent, rather than just based on the liquid carrier component. Therefore, the liquid carrier may include, for example, deionized water. In an example, the aqueous liquid carrier may include an organic solvent / water ratio of about 2:1 to about 1:2, about 1:1 to about 1:2, about 1:1 to about 1:1.5, or about 1:1 to about 1:1.25. In some examples, such as with respect to the refiner, the aqueous liquid carrier may not carry solids, may be just water, or may include a combination of water and an organic cosolvent as a major component.

[0054] The liquid carrier in any of these fluid agents may include one or more organic co-solvents. Some examples of co-solvents that can be added to the carrier include 1-(2-hydroxyethyl)-2-pyrrolidone, 2-pyrrolidone, 2-methyl-1,3-propanediol, 1,5-pentanediol, triethylene glycol, tetraethylene glycol, 1,6-hexanediol, tripropylene glycol methyl ether, ethoxylated glycerol-1 (LEG-1), or a combination thereof. In one example, the co-solvent may include 2-pyrrolidone. Whether a single co-solvent or a combination of co-solvents is used, the total amount of one or more co-solvents in the flux, refiner, or other fluid agent may be about 5 wt % to about 60 wt %, about 10 wt % to about 50 wt %, about 15 wt % to about 45 wt %, or about 30 wt % to about 50 wt %, based on the total weight percentage of the flux or the total weight percentage of the refiner.

[0055] The aqueous liquid carrier may also include a surfactant. The surfactant may include a nonionic surfactant, a cationic surfactant and / or an anionic surfactant. In one example, the fusing agent includes an anionic surfactant. In another example, the fusing agent includes a nonionic surfactant. In yet another example, the fusing agent includes a blend of an anionic surfactant and a nonionic surfactant. Exemplary nonionic surfactants that can be used include self-emulsifiable nonionic wetting agents based on acetylenic diol chemistry (e.g., SURFYNOL from Air Products and Chemicals, Inc., USA). ® SEF), fluorinated surfactants (e.g. CAPSTONE from DuPont, USA ®In other examples, the surfactant can be an ethoxylated low foam wetting agent (e.g., SURFYNOL from Air Products and Chemicals, Inc., USA). ® 440, SURFYNOL® 465 or SURFYNOL ® CT-111) or ethoxylated wetting agents and molecular defoamers (e.g. Surfynol ® 420). Still other surfactants may include wetting agents and molecular defoamers (e.g., SURFYNOL from Air Products and Chemicals, Inc., USA). ® 104E), alkylphenyl ethoxylates, solvent-free surfactant blends (e.g., SURFYNOL® CT-211 from Air Products and Chemicals, Inc., USA), water-soluble surfactants (e.g., TERGITOL ® TMN-6, TERGITOL ® 15S7 and TERGITOL ® 15S9) or a combination thereof. In other examples, the surfactant may include a nonionic organic surfactant (e.g., TEGO® Wet 510 from Evonik Industries AG, Germany), a nonionic secondary alcohol ethoxylate (e.g., TERGITOL® 15-S-5, TERGITOL® 15-S-7, TERGITOL® 15-S-9, and TERGITOL® 15-S-30, all from The Dow Chemical Company, USA), or a combination thereof. Exemplary anionic surfactants may include alkyl diphenyl oxide disulfonates (e.g., DOWFAX ® 8390 and DOWFAX ®2A1), oleyl polyoxyethylene (3) ether phosphate surfactant (e.g., CRODAFOS™ N3Acid from Croda, UK). Exemplary cationic surfactants that can be used include dodecyl trimethyl ammonium chloride, hexadecyl dimethyl ammonium chloride, or a combination thereof. In some examples, the surfactant (which may be a blend of multiple surfactants) can be present in the flux, refiner, or other fluid agent in an amount of about 0.01 wt % to about 2 wt %, about 0.05 wt % to about 1.5 wt %, or about 0.01 wt % to about 1 wt %.

[0056] In some instances, the liquid carrier may also include a chelating agent, an antimicrobial agent, a buffer, or a combination thereof. Although the amounts of these may vary, if present, these may be present in the fluxing agent, thinning agent, or other fluid agent in an amount of about 0.001% to about 20%, about 0.05% to about 10%, or about 0.1% to about 5% by weight.

[0057] The liquid carrier may contain a chelating agent. One or more chelating agents may be used to minimize or eliminate the harmful effects of heavy metal impurities. Examples of suitable chelating agents may include disodium ethylenediaminetetraacetate (EDTA-Na), ethylenediaminetetraacetic acid (EDTA), and methylglycine diacetic acid (e.g., TRILON from BASF Corp., Germany). ® M). If included, the total amount of one or more chelating agents in the fusing agent, thinning agent or other fluid agent, whether a single chelating agent or a combination of chelating agents is used, may be from 0.01 wt % to about 2 wt % or from about 0.01 wt % to about 0.5 wt %.

[0058] The liquid carrier may also contain an antimicrobial agent. Antimicrobial agents may include biocides and fungicides. Exemplary antimicrobial agents may include NUOSEPT ® (Ashland Inc. (USA)), VANCIDE ® (RT VanderbiltCo., USA), ACTICIDE ® B20 and ACTICIDE ®M20 (Thor Chemicals, UK), PROXEL® GXL (Arch Chemicals, Inc.. USA), BARDAC® 2250, 2280, BARQUAT® 50-65B and CARBOQUAT® 250-T (Lonza Ltd. Corp., Switzerland), KORDEK® MLX (The Dow Chemical Co., USA) and combinations thereof. In one example, if included, the total amount of antimicrobial agent in the fusing agent, thinning agent or other fluid agent can be from about 0.01 wt % to about 1 wt %.

[0059] In some examples, the liquid carrier may further comprise one or more buffer solutions. In some examples, the one or more buffer solutions may withstand small pH changes (e.g., less than 1) when a small amount of a water-soluble acid or a water-soluble base is added to a composition comprising the one or more buffer solutions. The one or more buffer solutions may have a pH range of about 5 to about 9.5, or about 7 to about 9, or about 7.5 to about 8.5. In some examples, the one or more buffer solutions may comprise a polyhydroxy-functional amine. In other examples, the one or more buffer solutions may include potassium hydroxide, 2-[4-(2-hydroxyethyl)piperazin-1-yl]ethanesulfonic acid, 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIZMA® sold by Sigma-Aldrich, USA), 3-morpholinopropanesulfonic acid, triethanolamine, 2-[bis-(2-hydroxyethyl)-amino]-2-hydroxymethylpropane-1,3-diol (bis trismethane), N-methyl-D-glucamine, N,N,N'N'-tetrakis-(2-hydroxyethyl)-ethylenediamine and N,N,N'N'-tetrakis-(2-hydroxypropyl)-ethylenediamine, β-alanine, betaine, or a mixture thereof. In other examples, the one or more buffer solutions may include 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIZMA® sold by Sigma-Aldrich, USA), β-alanine, betaine, or a mixture thereof. If included, the buffer solution may be added to the fusing agent, thinning agent or other fluid reagent in an amount of about 0.01 wt % to about 10 wt %, about 0.1 wt % to about 7.5 wt %, about 0.05 wt % to about 5 wt %.

[0060] definition

[0061] It is noted that as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0062] As used herein, the term "about", when referring to a value or range, allows for a certain degree of variability in the value or range, such as within 10% of the specified value or specified range limit, or within 5% in one aspect. The term "about" when modifying a numerical range is also understood to include the range bounded by the exact numerical value indicated as a numerical subrange, such as a range of about 1% to about 5% by weight includes 1% to 5% by weight as an expressly supported subrange.

[0063] As used herein, "kit" may be synonymous with and understood to include a plurality of components, wherein the different components may be separately contained prior to use (although in some cases packaged together in separate containers), but these components may be combined together during use, such as during the three-dimensional object construction method described herein. The container may be any type of vessel, box, or receptacle made of any material.

[0064] As used herein, "dispensing", when referring to a possible fusing agent, refers to any technique that can be used to place or arrange a fluid, such as a fusing agent, on or in a layer of a polymeric building material to form a green body object. For example, "applying" can refer to "spraying", "jetting", "dripping", "spraying", etc.

[0065] As used herein, "jetting" or "ejection" refers to a fluid reagent or other composition discharged by an ejection or ejection architecture, such as an inkjet architecture. The inkjet architecture may include a thermal or piezoelectric architecture. In addition, such an architecture may be configured to print different droplet sizes, such as up to about 20 picoliters (pL), up to about 30 pL, or up to about 50 pL, etc. Exemplary ranges may include about 2 pL to about 50 pL, or about 3 pL to about 12 pL.

[0066] As used herein, for convenience, multiple items, structural elements, compositional elements, and / or materials may be set forth in general lists. However, these lists should be interpreted as if each member of the list were provided as a separate and unique member. Therefore, unless otherwise indicated, any member of such a list should not be construed as a de facto equivalent of any other member of the same list based on appearance in the same group.

[0067] Concentration, size, amount and other numerical data may be presented in range format in this article.It is to be understood that such range format is used only for convenience and brevity, and should be flexibly interpreted as including the numerical value clearly listed as the limit of the range, and also including all single numerical values ​​or sub-ranges contained in the range, just as clearly listing each numerical value and sub-range.For example, the weight ratio range of about 1 wt % to about 20 wt % should be interpreted as including the clearly listed limit of 1 wt % and 20 wt %, and also including each weight, such as about 2 wt %, about 11 wt %, about 14 wt %, and sub-range, such as about 10 wt % to about 20 wt %, about 5 wt % to about 15 wt %, etc. Example

[0068] The following examples illustrate embodiments of the present disclosure. Many modifications and alternative compositions, methods and systems may be devised without departing from the present disclosure. The appended claims are intended to cover such modifications and arrangements.

[0069] Example 1 – Preparation of flux

[0070] Two exemplary fusing agents (FA-1 and FA-2) and one "control" fusing agent (FA-C) were prepared by mixing together the components in Table 1. Both FA-1 and FA-2 contained urea, which is a carbonamide-containing compound. The "control" fusing agent did not contain a carbonamide-containing compound.

[0071] Table 1: Fusing Agents

[0072] .

[0073] Example 2 – Preparation of three-dimensional objects

[0074] Several dog bone (or barbell) shaped three-dimensional printed objects were prepared using two different polymer building materials from two different manufacturers and three different fusing agents given in Table 1 of Example 1. The polymer building materials in this evaluation were both thermoplastic polyurethane particles (TPU-1 and TPU-2). The two different thermoplastic polyurethanes had different weight average molecular weights, D50 particle sizes, and polydispersities of side chain branching, but both can be used in polymer building materials within the scope disclosed herein and according to embodiments of the present disclosure.

[0075] More specifically, for each combination of fusing agent (FA-1, FA-2, or FA-C) and polymer build material (TPU-1 or TPU-2), a total of five "Type 5" (ASTMD638) dogbones were printed using a multi-jet fusion (MJF) printer under common printing conditions, with a print bed temperature of approximately 130°C, heat fusing using a common infrared lamp that controls the heating by turning it on and off, a printer speed (15 inches per second) and allowing multiple passes per layer. The dog-bone-shaped objects formed from the various material combinations were shaped to have an elongated midsection and two enlarged ends located on either side. After printing, all of the formed dog-bone-shaped objects were sandblasted.

[0076] Example 3 – Evaluation of mechanical properties

[0077] The mechanical properties of the dogbones prepared according to Example 2 were evaluated and averaged from 5 dogbones for each combination of flux and polymer build material. Specifically, as provided in Table 2 below, the tensile strength or UTS (MPa) and Shore hardness (Shore A or SHA) were determined for each material combination.

[0078] Table 2 - Mechanical Properties

[0079] .

[0080] With regard to Table 2 above, a desirable result is to reduce the Shore hardness while increasing the tensile strength or not significantly affecting the tensile strength. Since the carboxamide-containing compound can act as a softening compound, the increased tensile strength, in some achievable examples, can mean greater elongation at break and other properties related to stretchability, while if the softening of the three-dimensional object is the goal of mechanical property modification, the reduction in Shore hardness is acceptable. With this in mind, as can be seen in Table 2, in this particular embodiment, the addition of 4 wt% of the carboxamide-containing compound (urea) (FA-1) provides a slight increase in tensile strength with TPU-2 and a slight decrease in tensile strength with TPU-1, indicating a slight change in tensile strength. However, in terms of Shore hardness, it was found that FA-1 was slightly softer when combined with TPU-1 and TPU-2. Therefore, even at 4 wt%, the Shore hardness is slightly reduced, while the tensile strength changes slightly. When the urea concentration in the fusing agent is made above 4 wt% to 8 wt% (FA-2), the reduction in hardness is significantly changed to provide a softer three-dimensional object, and the tensile strength is significantly enhanced for TPU-1. For FA-2 and TPU-2, the reduction in tensile strength is slight compared to the significantly changed Shore hardness (or enhanced softness) provided by the same combination.

Claims

1. A three-dimensional printing kit, comprising: a polymeric building material comprising polymer particles having a D50 particle size of 2 µm to 150 µm; and A flux comprising an aqueous liquid carrier containing water and an organic cosolvent, a radiation absorber that generates heat by absorbing electromagnetic radiation, and 2 to 15 weight percent of a carbonamide-containing compound, wherein the carbonamide-containing compound comprises urea or biurea and is present in the flux at 4 to 12 weight percent, and wherein the radiation absorber comprises carbon black, a metal dithiol-ene complex, a near-infrared absorbing dye, a near-infrared absorbing pigment, metal nanoparticles, a conjugated polymer, or a combination thereof.

2. The 3D printing kit of claim 1, wherein the radiation absorber comprises carbon black, metal dithiol-ene complexes, near-infrared absorbing dyes, near-infrared absorbing pigments, metal nanoparticles, conjugated polymers, or combinations thereof.

3. The 3D printing kit of claim 1, wherein the radiation absorber is present in the fusing agent at 0.1 wt % to 10 wt %.

4. The 3D printing kit according to claim 1, wherein the aqueous liquid carrier further comprises 0.01 wt% to 2 wt% of a surfactant.

5. The 3D printing kit of claim 1 , wherein the polymer building material comprises polyamide, thermoplastic polyamide, polyethylene, polyethylene terephthalate (PET), polystyrene, polyacrylate, polyacetal, polypropylene, polycarbonate, polyester, acrylonitrile butadiene styrene, thermoplastic polyurethane, engineering plastic, polyether ether ketone (PEEK), polymer blends thereof, amorphous polymers thereof, core-shell polymers thereof, or copolymers thereof.

6. The 3D printing kit of claim 1, wherein the radiation absorber is carbon black and the polymer particles comprise thermoplastic polyurethane or thermoplastic polyamide.

7. The 3D printing kit of claim 1, further comprising a detailing agent, wherein the detailing agent comprises a detailing compound to reduce the temperature of a polymeric build material to which the detailing agent is applied.

8. A method for printing a three-dimensional object, comprising: iteratively applying individual layers of a polymeric building material comprising polymer particles having a D50 particle size of 2 µm to 150 µm; Iteratively and selectively dispensing a fusing agent onto each building material layer based on the three-dimensional object model, wherein the fusing agent comprises an aqueous liquid carrier comprising water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and 2 wt % to 15 wt % of a carbonamide-containing compound, wherein the carbonamide-containing compound comprises urea or biurea and is present in the fusing agent at 4 wt % to 12 wt %, and wherein the radiation absorber comprises carbon black, a metal dithiol-ene complex, a near infrared absorbing dye, a near infrared absorbing pigment, metal nanoparticles, a conjugated polymer, or a combination thereof; and Individual layers of polymeric building material having the fusing agent dispensed therein are iteratively exposed to electromagnetic radiation to selectively fuse polymer particles of the polymeric building material in contact with the radiation absorber and form a fused three-dimensional object.

9. The method of claim 8, wherein the radiation absorber is carbon black and the polymer particles comprise thermoplastic polyurethane or thermoplastic polyamide.

10. The method of claim 8, wherein the carbonamide-containing compound comprises urea or biurea and is applied to the particulate building material layer at a carbonamide-containing compound / polymer particle weight ratio of 1:50 to 1:

500.

11. The method of claim 8, further comprising selectively spraying a detailing agent comprising a detailing compound onto each build material layer, wherein the detailing compound reduces the temperature of the build material onto which the detailing agent is applied.

12. A three-dimensional printing system, comprising: a polymeric building material comprising polymer particles having a D50 particle size of 2 µm to 150 µm; and A fluid applicator fluidly connected or fluidly connectable to a fusing agent, wherein the fluid applicator is directable to iteratively apply the fusing agent to the layers of polymeric building material, the fusing agent comprising an aqueous liquid carrier comprising water and an organic cosolvent, a radiation absorber that generates heat from absorbed electromagnetic radiation, and 2 wt % to 15 wt % of a carbonamide-containing compound, wherein the carbonamide-containing compound comprises urea or biurea and is present in the fusing agent at 4 wt % to 12 wt %, and wherein the radiation absorber comprises carbon black, a metal dithiol-ene complex, a near infrared absorbing dye, a near infrared absorbing pigment, metal nanoparticles, a conjugated polymer, or a combination thereof.

13. The three-dimensional printing system of claim 12, further comprising an electromagnetic radiation source positioned to provide electromagnetic radiation to the layer of polymeric build material having the fusing agent applied thereto.

14. The three-dimensional printing system of claim 13, wherein the radiation absorber selectively absorbs infrared energy and wherein the electromagnetic radiation source is an infrared electromagnetic radiation source that emits a peak wavelength corresponding to the infrared energy.

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