Preheat build materials with preheating sources

An example of an additive manufacturing system is disclosed. The example disclosed herein comprises a build material distributor, a preheating source, and a controller. The build material distributor is to form build material layers from an intended build material having a color. The preheating source is to emit energy at a wavelength related to the intended build material color so that at least a 40% of the energy is absorbed by the build material. The controller is to receive printing instructions to print a 3D object, wherein the printing instructions define an area to be fused in a build material layer. The controller is also to instruct the build material distributor to form the build material layer. The controller is further to control the preheating source to emit energy to preheat a zone comprising the area to be fused.

BACKGROUND

Some three-dimensional printing systems apply a fusing agent over areas of successive layers of un-solidified build material, such as powdered or particulate-type build material, followed by exposure to fusing energy to selectively melt layers of a part of a three-dimensional object that is to be generated. The un-solidified powder may be preheated before the application of fusing agent.

DETAILED DESCRIPTION

The following description is directed to various examples of the disclosure. In the foregoing description, numerous details are set forth to provide an understanding of the examples disclosed herein. However, it will be understood by those skilled in the art that the examples may be practiced without these details. While a limited number of examples have been disclosed, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover such modifications and variations as fall within the scope of the examples. Throughout the present disclosure, the terms “a” and “an” are intended to denote at least one of a particular element. In addition, as used herein, the term “includes” means includes but not limited to, the term “including” means including but not limited to. The term “based on” means based at least in part on.

Three-dimensional printing may depend on application, for example by printing or jetting, of an energy absorbing fusing agent over areas of successive layers of un-solidified build material. According to one example, a suitable build material may be PA12 build material commercially known as V1R10A “HP PA12” available from HP Inc, Each layer may then be exposed to fusing energy to selectively melt layers of a part of a three-dimensional object that is to be generated.

One example of the present disclosure provides an additive manufacturing system that comprises a build material distributor to form build material layers from an intended build material having a color. The additive manufacturing system also comprises a preheating source to emit energy at a wavelength related to the intended build material color, so that at least 40% of the energy is absorbed by the build material The system further comprises a controller to receive printing instructions to print a three-dimensional (3D) object, wherein the printing instructions define an area to be fused in a build material layer; to instruct the build material distributor to form the build material layer; and to control the preheating source to emit energy to preheat a zone comprising the area to be fused. The purpose of preheating the build material zone comprising the area to be fused is to raise the temperature of said area of build material close to but below its melting point. The area from the build material layer other than the zone comprising the area to be fused may not absorb as much energy, and may therefore not heat up significantly.

Another example of the present disclosure provides a method comprising a plurality of operations to be performed. The method comprises receiving printing instructions to print a 3D object by using a build material layer, wherein the printing instructions define an area to be fused in the build material layer. The method also comprises forming the build material layer, by a build material distributor, wherein the build material has a color. The method further comprises preheating a zone comprising the area to be fused by a preheating source, by emitting energy at a wavelength related to the build material color, so that at least 40% of the energy is absorbed by the build material. The purpose of preheating the build material zone comprising the area to be fused is to raise the temperature of said area of build material close to but below its melting point. The method also comprises ejecting, by a fusing agent distributor, fusing agent to the build material layer based on the printing instructions. The method further comprises applying energy, for example by a fusing lamp, to the build material layer to fuse those portions of the layer on which fusing agent was deposited by raising the temperature of the dyed build material above its melting point. In the present disclosure, the fusing lamp and the preheating source are different and separate entities.

Another example of the present disclosure provides a non-transitory machine readable medium storing instructions executable by a processor. The non-transitory machine-readable medium comprises instructions to receive printing instructions to print a 3D object by using a build material layer, wherein the printing instructions define an area to be fused in the build material layer. The non-transitory machine readable medium also comprises instructions to form the build material layer, by a build material distributor, wherein the build material has a color. The non-transitory machine readable medium further comprises instructions to preheat a zone comprising the area to be fused by a preheating source, by emitting energy at a wavelength related to the build material color so that at least 40% of the energy is absorbed by the build material. The purpose of preheating the build material zone comprising the area to be fused is to raise the temperature of said area of build material a close to but below but near its melting point. The non-transitory machine readable medium also comprises instructions to eject, by a fusing distributor, fusing agent to the build material layer based on the printing instructions. The non-transitory machine readable medium further comprises instructions to heat, by a fusing lamp, the build material layer to fuse those portions of the layer on which fusing agent was deposited by raising the temperature of the dyed build material above its melting point. In the present disclosure, the fusing lamp and the preheating source are different and separate entities. Referring now to the figures,FIG.1is a block diagram illustrating an example of an additive manufacturing system100to preheat build materials with preheating sources. The system100comprises a build material distributor110and a preheating source. The build material distributor110may be understood as any mechanism (e.g., printing roller, printing wiper, etc.) to form build material layers from a build material having a color. In an example, the build material distributor110may form a build material layer on a printing bed150. The printing bed150may be internal or removable from the additive manufacturing system100(e.g., the printing bed may not be present when the printer is shipped). The printing bed150may be a surface to receive build material from the build material distributor110in the form of, for example, build material layers having a generally uniform thickness. The generally uniform thickness may range from about 80 microns to about 120 microns, or bigger or smaller. The preheating source120is to emit energy at a wavelength so that at least 40% of the energy is absorbed by the build material. In the present disclosure, the term “a wavelength” may be understood as a single wavelength, or as a narrow band of wavelengths. In an example, the preheating source120is an array comprising one or more LED lights to emit energy at a wavelength, wherein each LED light may be individually controllable to emit energy at a wavelength. Other examples of preheating source120may be laser, laser diodes, laser arrays, and the like. More examples of the preheating source120are disclosed inFIG.2A, andFIG.2B. The system100further comprises a controller130in connection with the build material distributor110and the preheating source120. The controller connection may be by means of a physical wire and/or wireless. The term “controller as used herein may include a series of” instructions encoded on a machine-readable storage medium and executable by a single processor or a plurality of processors. Additionally, or alternatively, a controller may include one or more hardware devices including electronic circuitry, for example a digital and/or analog application-specific integrated circuit (ASIC), for implementing the functionality described herein.

When illuminated, colored bodies reflect or absorb some of the illuminating wavelengths. Leveraging the color of a body to be illuminated (e.g., build material) in conjunction with the energy wavelength band from the light source (e.g., preheating source light) may lead to said illuminated body to absorb a bigger amount of the incoming energy. Precisely, bodies with colors that can absorb substantially the totality of a narrow band light source emissions may lead to high energy-efficient systems. This may substantially reduce the energy reflected (wasted) by the colored bodies and therefore enabling the design of energy-efficient heating systems, for example, an energy-efficient build material preheating system. In an example, a yellow body absorbs at least the 40% of a light source that emits energy at a wavelength comprised in the range defined from 450 nanometers (nm) to 495 nm, for example a blue light. Therefore, following this example, a system (e.g., system100) comprising a build material layer having a yellow color, and a preheating source (e.g., preheating source120) emitting blue light may be an energy-efficient system to pre-heat said yellow build material. In another example, an orange body absorbs at least the 40% of a light source that emits energy at a wavelength comprised in the range defined from 450 nanometers (nm) to 495 nm, for example a blue light. Therefore, following this example, a system (e.g., system100) comprising a build material layer having an orange color, and a preheating source (e.g., preheating source120) emitting blue light may be an energy-efficient system to pre-heat said orange build material. In yet another example, a white body (e.g., Titanium Dioxide) absorbs at least the 40% of a light source that emits energy at a wavelength of less than 400 nanometers (nm), for example Ultraviolet (UV) light. Therefore, following this example, a system (e.g., system100) comprising a build material layer having a white color, and a preheating source (e.g., preheating source120) emitting UV light may be a energy-efficient system to pre-heat said white build material. In the present disclosure the term “UV light” may be understood in its broad spectrum as it may comprise Ultraviolet A (UVA) wavelengths, ranging from about 315 nm to about 400 nm; Ultraviolet B (UVB) wavelengths, ranging from about 280 nm to about 315 nm; Ultraviolet C (UVC) wavelengths, ranging from about 100 nm to about 380 nm; and/or any other UV wavelength. Other combinations from build material color and preheating source energy wavelengths may be defined without departing from the scope of the present disclosure.

As an example, the preheating source is to emit energy at a wavelength related to the dyed build material color so that at least 40% of the energy is absorbed by the dyed build material. As an additional example, the preheating source is to emit energy at a wavelength related to the dyed build material color so that at least 50% of the energy is absorbed by the dyed build material. As an additional example, the preheating source is to emit energy at a wavelength related to the dyed build material color so that at least 60% of the energy is absorbed by the dyed build material. As an additional example, the preheating source is to emit energy at a wavelength related to the dyed build material color so that at least 90% of the energy is absorbed by the dyed build material. As an additional example, the preheating source is to emit energy at a wavelength related to the dyed build material color so that at least 98% of the energy is absorbed by the dyed build material.

As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be, for example, an additional 15% more or an additional 15% less than the endpoints of the range. The degree of flexibility of this term can be dictated by the particular variable and would be within the knowledge of those skilled in the art to determine based on experience and the associated description herein.

The controller130is to receive printing instructions140to print a 3D object, wherein the printing instructions140define an area to be fused in a build material layer. The printing instructions140to print a 3D object may be derived from a 3D object model of a 3D object. An example of a 3D object model may be generated using a Computer Aided Design (CAD) application which is a tool that may be used to create precision drawings or technical illustrations. Another example of a 3D model may be a Computer Aided Manufacturing (CAM) application which is a tool that may be used to design products such as electronic circuit boards in computers and other devices. The 3D printing instructions may be instructions that, for example, describe at which locations on a powder bed drops of different print agents should be printed. Some examples of printing agents are fusing agents and detailing agents. A 3D object model may be defined in vector type format, and 2D rasterized images may be generated from this each representing slices of the object model. Each slice may then be processed to determine how printing agents should be printed to generate a layer of an object corresponding to the slice. The 3D printing instructions140define the 3D object to print by, for example, defining the plurality of slices of said object to be generated. Each slice may determine a cross-sectional area and/or a cross-sectional shape of the 3D object to be produced by the additive manufacturing apparatus100and determines the print agents that should be printed thereon. The cross-sectional area and/or the cross-sectional shape, may be the areas to be fused, Therefore, a slice from the plurality of slices may define which sections of the build material layer may need to be fused to print the 3D object.

The controller130is to instruct the build material distributor to form the build material layer. The build material layer may be formed on top of the printing bed150and it is a layer comprised of build material. The build material may be an un-solidified powder that may be, for example, nylon powder. In one example, the build material has a yellow color. In another example, the build material has an orange color. In another example, the build material has white color. In yet another example, the build material powder particles may be of the same or different colors wherein said colors, upon illumination with a narrow band preheating source (e.g., preheating source120), the colored particles absorb over 40% of the energy of the preheating source. These are examples and other build material colors may be used without departing from the scope of the present disclosure.

The controller130is to control the preheating source120to emit energy to preheat a zone comprising the area to be fused. The zone comprising the area to be fused comprises the total surface of the area to be fused and may further comprise an additional surface of the build material layer that is not to be fused. In the present disclosure the preheating stage may be understood as heating the build material layer, by for example preheating source120irradiation, up to the point that the build material temperature is close but below the melting point of the build material. The controller130is to control the preheating source120to irradiate energy at specific zones comprising the areas to be fused previously defined by the printing instructions140of a 3D object. A plurality of examples of the zone comprising the area to be fused are disclosed in further detail inFIG.3A-3D.

FIG.2A-2Billustrate examples of preheating sources.FIG.2Ais a block diagram illustrating an example of a preheating source according to an implementation. The preheating source may be a LED array220A. The LED array220A may be the same as or similar to the preheating source120fromFIG.1. The LED array220A is a two-dimensional (2D) static array and comprises a plurality of LEDs therein. In the example, the LED array220A comprises a first LED222A-1, a second LED222A-2, a third LED222A-3, a fourth LED222A-4, a fifth LED222A-5, a sixth LED222A-6, a seventh LED222A-7, and an eighth LED222A-8. The eight LEDs from the LED array220A may be referred hereinafter as the plurality of LEDs (222A-1-222A-8). This is an example, and arrays comprising more or less LEDs can be derived therefrom without departing from the scope of the present disclosure. The plurality of LEDs from the LED array220A are to emit energy that spans substantially the full width and length of the build material layer and are controllable to emit energy to the one or more areas to be fused. In the example, the plurality of LEDs are installed on the surface of the LED array220A, however other layouts can be derived therefrom. In an example, the LED array220A may be located in a substantially parallel position at a distance from about 15 millimeters to about 300 millimeters from the printing bed (e.g., printing bed150fromFIG.1). Precisely, the distance may depend on the light optics and the place in the system where the lights are located.

In an example, one LED from the plurality of LEDs (222A-1-222A-8) may be a blue LED, wherein the blue LED has a wavelength comprised in the range defined from about 450 nm to about 495 nm. In another example, each LED from the plurality of LEDs may be a blue LED, wherein the blue LED has a wavelength comprised in the range defined from about 450 nm to about 495 nm. In another example, one LED from the plurality of LEDs (222A-1-222A-8) may be a UV LED, wherein the UV LED has a wavelength of less than 400 nm. In yet another example, each LED from the plurality of LEDs may be a UV LED, wherein the UV LED has a wavelength of less than about 400 nm. These are examples and other LED colors, and/or LED color combinations, may be used without departing from the scope of the present disclosure.

A controller (e.g., controller130fromFIG.1) may control the plurality of LEDs (222A-1-222A-8) to emit energy to preheat a zone comprising the area to be fused. In one example, the area to be fused may be the area below the top right quadrant of the LED array220A, then the controller may activate the LEDs that can irradiate said area, for example the second LED222A-2, the third LED222A-3, and the fifth LED222A-5. In another example, the area to be fused may be the area below the central area of the LED array220A, then the controller may activate the LEDs that can irradiate said area to be fused, for example the second LED222A-2, the fourth LED222A-4, the fifth LED222A-5, and the seventh LED222A-7. In an example, the controller may also select a certain LED beam angle from an LED from the plurality of LEDs (222A-1-222A-8), to cause said LED to illuminate a specific portion of the powder bed (e.g., powder bed150fromFIG.1). These are examples, and more examples can be derived therefrom.

FIG.2Bis a block diagram illustrating another example of a preheating source. The preheating source may be a LED array220B. The LED array220B may be the same as, or similar to, the preheating source120fromFIG.1. In an example, the LED array220B is a one-dimensional (1D) array and comprises a plurality of offset LEDs therein. In another example, the LED array220B is a 2D array and comprises a plurality of offset LEDs therein. In the example, the LED array220B comprises a first LED222B-1, a second LED222B-2, and a third LED222B-3. The three LEDs from the LED array220B may be referred hereinafter as the plurality of LEDs (222B-1-222B-3). This is an example, and arrays comprising more or less LEDs can be derived therefrom without departing from the scope of the present disclosure. The plurality of LEDs from the LED array220B are to emit energy that spans substantially the full width of the build material layer on the printing bed250B and are controllable to emit energy to the one or more areas to be fused. The LED array220B may be movable along the length of the build material layer on the printing bed250B by moving means224B. The moving means224B may be any mechanism that allows the LED array220B to move along the length of the build material layer on the printing bed250B in a controlled manner. In an example, the moving means224B may comprise a guide and an engine, wherein the LED array220B is movable through the guide and the engine controls said movement based on the instructions of a controller (e.g., controller130fromFIG.1). Other examples of moving mean, such as a movable carriage, may be used without departing from the scope of the disclosure. In the example, the plurality of LEDs (222B-1-222B-3) are placed throughout the length of the LED array220B, however other layouts can be derived therefrom. In an example, the LED array220B may be located in a substantially parallel position at a distance from about 15 millimeters to about 300 millimeters from the printing bed (e.g., printing bed150fromFIG.1). Precisely, the distance may depend on the light optics and the place in the system where the lights are located.

In one example, one LED from the plurality of LEDs (222B-1-222B-3) may be a blue LED light, wherein the blue LED has a wavelength comprised in the range defined from about 450 nm to about 495 nm. In another example, each LED from the plurality of LEDs may be a blue LED light, wherein the blue LED has a wavelength comprised in the range defined from about 450 nm to about 495 nm. In another example, one LED from the plurality of LEDs (222B-1-222B-3) may be a UV LED, wherein the UV LED has a wavelength of less than 400 nm. In yet another example, each LED from the plurality of LEDs may be a UV LED, wherein the UV LED has a wavelength of less than about 400 nm. These are examples and other LED colors, and/or LED color combinations, may be used without departing from the scope of the present disclosure.

A controller (e.g., controller130fromFIG.1) may control the plurality of LEDs (222B-1-222B-3) to emit energy to preheat a zone comprising the area to be fused. The controller may also control the LED array220B movement along the length of the build material layer on the printing bed250B. The controller may activate the LEDs that can irradiate the zone comprising the area to be fused in a given time, leaving the other LEDs inactivated. In an example, the area to be fused may be the area below the top right quadrant of the LED array220B and the LED array220B may be in the starting position as drawn inFIG.2B, then the controller may activate the first LED222B-1at the starting point and when the LED array220B moves along the length of the printing bed250B, the controller may deactivate the first LED222B-1when said LED does not irradiate the area to be fused anymore. In an example, the controller may also select a certain LED beam angle from an LED from the plurality of LEDs (222B-1-222B-3), to cause said LED to illuminate a specific portion of the powder bed (e.g., powder bed150fromFIG.1). This is an example, and more examples can be derived therefrom.

FIG.3A-3Dillustrate examples of a zone comprising an area to be fused.FIG.3Ais a block diagram illustrating an example of a zone comprising an area to be fused. The build material layer on the printing bed350A comprises an area to be fused370A and a preheating zone320A comprising the area to be fused. The preheating zone320A may be the same as, or similar to the zone comprising the area to be fused referred inFIG.1, and may be defined by a controller based on 3D printing instructions. A preheating source (e.g., preheating source120fromFIG.1) is to emit energy to preheat the preheating zone320A before the fusing operation. The area to be fused370A may be defined by 3D printing instructions (e.g., printing instructions140fromFIG.1) and may be the area in which droplets of fusing agent may be ejected thereon. The printing bed350A may be similar or the same as the printing bed150fromFIG.1. The preheating zone320A comprises the area to be fused370A and may also comprise part of the build material layer that is not to be fused. In the example, the preheating zone320A has substantially a rectangular shape, wherein the area to be fused370A is substantially placed in the middle. A preheating source (e.g., preheating source120fromFIG.1) may be controlled by a controller (e.g., controller130fromFIG.1) to emit energy to preheat the preheating zone comprising the area to be fused320A.

FIG.3Bis a block diagram illustrating another example of a zone comprising an area to be fused. The build material layer on the printing bed350B comprises an area to be fused370B and a preheating zone320B comprising the area to be fused. The preheating zone320B may be the same as, or similar to the zone comprising the area to be fused referred inFIG.1, and may be defined by a controller based on 3D printing instructions. A preheating source (e.g., preheating source120fromFIG.1) is to emit energy to preheat the preheating zone320B before the fusing operation. The area to be fused370B may be defined by 3D printing instructions (e.g., printing instructions140fromFIG.1) and may be the area in which droplets of fusing agent may be ejected thereon. The printing bed350B may be similar or the same as the printing bed150fromFIG.1. The preheating zone320B comprises the area to be fused370B and may also comprise part of the build material layer that is not to be fused. In the example, the preheating zone320B has a similar shape as the area to be fused370B but extended (covering a greater surface), wherein the area to be fused370A is substantially placed in the middle. In some implementations, the preheating zone320B may have coarsely pixelated shape depending on the heating precision of the preheating source beam. The extension of the preheating zone320B with respect to the area to be fused370B may vary depending on the example. In an example the preheating zone320B extends by a predetermined distance around the perimeter of the area to be fused370B, In another example, the preheating zone320B may not extend the area to be fused370B, therefore the preheating zone320B, and the area to be fused370B being substantially covering the same area, More examples can be derived without departing from the scope of the present disclosure. A preheating source (e.g., preheating source120fromFIG.1) may be controlled by a controller (e.g., controller130fromFIG.1) to emit energy to preheat the preheating zone comprising the area to be fused320B.

FIG.3Cis a block diagram illustrating another example of a zone comprising an area to be fused. The build material layer on the printing bed350C comprises a first area to be fused370C-1and a second area to be fused370C-2and a single preheating zone320C comprising the first area to be fused370C-1and the second area to be fused370C-2. The preheating zone320C may be the same as, or similar to the zone comprising the area to be fused referred inFIG.1, and may be defined by a controller based on 3D printing instructions. A preheating source (e.g., preheating source120fromFIG.1) is to emit energy to preheat the preheating zone320A before the fusing operation. The first area to be fused370C-1and the second area to be fused370C-2may be defined by 3D printing instructions (e.g., printing instructions140fromFIG.1) and may be the area in which droplets of fusing agent may be ejected thereon. The printing bed350C may be similar or the same as the printing bed150fromFIG.1, The preheating zone320C comprises the first area to be fused370C-1and the second area to be fused370C-2; and may also comprise part of the build material layer that is not to be fused. In the example, the preheating zone320C has substantially a rectangular shape, wherein the area to be fused370C-1is substantially placed in the middle of a first half of the preheating zone320C, and the second area to be fused370C-2is substantially placed in the middle of a second half of the preheating zone320C. A preheating source (e.g., preheating source120fromFIG.1) may be controlled by a controller (e.g., controller130fromFIG.1) to emit energy to preheat the preheating zone comprising the area to be fused320A.

FIG.3Dis a block diagram illustrating another example of a zone comprising an area to be fused. The build material layer on the printing bed350D comprises a first area to be fused370D-1, a second area to be fused370D-2, a first preheating zone320D-1comprising the first area to be fused, and a second preheating zone320D-2comprising the second area to be fused. The first preheating zone320D-1and the second preheating zone320D-2may be the same as, or similar to the zone comprising the area to be fused referred inFIG.1, and may be defined by a controller based on 3D printing instructions. A preheating source (e.g., preheating source120fromFIG.1) is to emit energy to preheat the preheating zone320B before the fusing operation. The first area to be fused370D-1and the second area to be fused370D-2may be defined by 3D printing instructions (e.g., printing instructions140fromFIG.1) and may be the area in which droplets of fusing agent may be ejected thereon. The printing bed350D may be similar or the same as the printing bed150fromFIG.1. The first preheating320D-1comprises the first area to be fused370D-1and may also comprise part of the build material layer that is not to be fused. Likewise, the second preheating zone320D-2comprises the second area to be fused370D-2and may also comprise part of the build material layer that is not to be fused. In the example, the first preheating zone320D-1has a similar shape as the area to be fused370D-1but extended (covering a greater surface), wherein the first area to be fused370D-1is substantially placed in the middle. In some implementations, the preheating zone320D-1may have coarsely pixelated shape depending on the heating precision of the preheating source beam. The extension of the first preheating zone320D-1with respect to the first area to be fused370D-1may vary depending on the example. In an example, the first preheating zone320D-1extends by a predetermined distance around the perimeter of the first area to be fused370D-1. In another example, the first preheating320D-1may not extend the first area to be fused370D-1, therefore the first preheating zone320D-1, and the first area to be fused370D-1being substantially covering the same area. Similar description may apply to the second preheating zone320D-2, and the second area to be fused370D-2. More examples can be derived without departing from the scope of the present disclosure. A preheating source (e.g., preheating source120fromFIG.1) may be controlled by a controller (e.g., controller130fromFIG.1) to emit energy to preheat the first preheating zone comprising the first area to be fused320D-1, and the second preheating zone comprising the second area to be fused320D-2as separate entities.

FIG.4is a block diagram illustrating an additive manufacturing system400to preheat build materials with preheating sources according to an example. The system400comprises a build material distributor410, a preheating source420, and a color module460. The build material distributor410may be the same as, or similar to the build material distributor110fromFIG.1. The preheating source420may be the same as or similar to the preheating source120fromFIG.1. The build material distributor410may be understood as any mechanism (e.g., printing roller, printing wiper, etc.) to form build material layers from a build material having a color that absorbs less than 40% of the wavelength energy emitted by the preheating source420, wherein the preheating source420illuminates the build material color. The build material color may be different from the build material color of the build material layer ofFIG.1. In an example, the build material distributor410may form a build material layer on a printing bed450. The printing bed450may be internal or removable from the additive manufacturing system400(e.g., the printing bed may not be present when the printer is shipped). The printing bed150, may be a surface to receive build material from the build material distributor410in the form of, for example, build material layers having a generally uniform thickness. The generally uniform thickness may range from about 80 microns to about 120 microns, or bigger or smaller. The preheating source420is to emit energy at a wavelength so that at least 40% of the energy is absorbed by the build material. The build material bed450may be the same as or similar to the building printing bed150fromFIG.1. The color module460is to eject a composition that is different from the fusing agent that dyes the build material layer in a color that absorbs at least the 40% if the wavelength energy emitted by the preheating source420, wherein the preheating source420illuminates the build material color. The color of the build material layer after the dyeing operation of the color module460may be similar or the same as the build material layer color ofFIG.1. In an example, the composition ejected by the color module may be printing liquid composition that may comprise, for example, a dye or pigments. In an example, the preheating source420is an array comprising one or more LED lights to emit energy at a wavelength, wherein each LED light may be individually controllable to emit energy at a wavelength. Other examples of preheating source420may be laser, laser diodes, laser arrays, and the like. The system400further comprises a controller430in connection with the build material distributor410, the preheating source420, and the color module460. The controller430may receive printing instructions440and may have the same functionality as the controller130that receives the printing instructions140fromFIG.1. The controller connection may be by means of a physical wire and/or wireless. The term “controller” as used herein may include a series of instructions encoded on a machine-readable storage medium and executable by a single processor or a plurality of processors. Additionally, or alternatively, a controller may include one or more hardware devices including electronic circuitry, for example a digital and/or analog application-specific integrated circuit (ASIC), for implementing the functionality described herein.

In an example, the color module460may dye the build material layer, for example in yellow color. In another example, the color module460may dye the build material layer in orange color. In another example, the color module460may dye the build material layer in white color. In yet another example, the color module460may dye the build material powder particles in different colors wherein said colors, upon illumination with a narrow band preheating source (e.g., preheating source420), the colored particles absorb over 40% of the preheating source. These are examples and other build material color dyes may be used without departing from the scope of the present disclosure.

The additive manufacturing system400enables using non-dyed build material as raw material, and then dye said non-dyed build material in the most appropriate color to be energy-efficient preheated, and therefore being compliant with the teaching of the present disclosure.

The color module460may eject a composition that dyes the build material layer in a color that absorbs at least a 40% of the wavelengths energy, upon preheating source420illumination. For example, the color module460may comprise one or more printheads465to apply the composition to the build material layer.

FIG.5is a block diagram illustrating another example of an additive manufacturing system500to preheat build materials with preheating sources according to an example. The system500comprises a build material distributor510, a preheating source520, a fusing distributor570, and a fusing lamp580. The build material distributor510may be the same as or similar to the build material distributor110fromFIG.1. The preheating source520may be the same as or similar to the preheating source120fromFIG.1. The build material distributor510may be understood as any mechanism (e.g., printing roller, printing wiper, etc.) to form build material layers from a build material having a color. In an example, the build material distributor510may form a build material layer on a printing bed550. The printing bed550may be internal or removable from the additive manufacturing system500(e.g., the printing bed may not be present when the printer is shipped). The printing bed550may be a surface to receive build material from the build material distributor510in the form of, for example, build material layers having a generally uniform thickness. The generally uniform thickness may range from about 80 microns to about 120 microns, or bigger or smaller. The preheating source520is to emit energy at a wavelength related to the build material color so that at least 40% of the energy is absorbed by the build material. The build material bed550may be the same as or similar to the building printing bed150fromFIG.1. The preheating source520may be an array comprising one or more LED lights to emit energy. The fusing distributor570is to eject fusing agent to the build material layer. The fusing lamp580is to heat the build material layer. The fusing lamp580may be a separate entity as the preheating source520. As an example, a fusing lamp may be made of Tungsten and may comprise resistive heaters that may irradiate the printing bed550by a wide band of energy wavelengths. The system500further comprises a controller530in connection with the build material distributor510, the preheating source520, the fusing distributor570, and the fusing lamp580. The controller530may receive printing instructions540and may have the same functionality as the controller130that receives the printing instructions140fromFIG.1. The controller connection may be by means of a physical wire and/or wireless. The term “controller” as used herein may include a series of instructions encoded on a machine-readable storage medium and executable by a single processor or a plurality of processors. Additionally, or alternatively, a controller may include one or more hardware devices including electronic circuitry, for example a digital and/or analog application-specific integrated circuit (ASIC), for implementing the functionality described herein.

The fusing agent is a composition that may be applied to the build material layer. In an example, the fusing agent may be a printing liquid composition. When a suitable amount of energy (e.g., energy irradiated by fusing lamp580) is applied to the combination of build material and fusing agent, said energy may cause the combination of build material and fusing agent to heat up above the melting point and to fuse and solidify. The fusing agent may be stored in a fusing agent repository575connected to the fusing distributor570. In the example, the fusing agent repository575is outside the additive manufacturing system500, however other system examples may include the fusing agent repository570.

According to one example, a suitable fusing agent may be an ink-type formulation comprising carbon black, such as, for example, the fusing agent formulation commercially known as V1Q60Q “HP fusing agent” available from HP Inc. In one example such a fusing agent may additionally comprise an infra-red light absorber. In one example such an ink may additionally comprise a near infra-red light absorber. In one example such a fusing agent may additionally comprise a visible light absorber. In one example such an ink may additionally comprise a UV light absorber. Examples of inks comprising visible light enhancers are dye based colored ink and pigment based colored ink, such as inks commercially known as CE039A and CE042A available from HP Inc.

The controller530is to receive printing instructions540and derive the area to be fused in the build material layer therefrom. The controller530may instruct the build material distributor510to form the build material layer, and control the preheating source520to preheat the zone comprising the area to be fused. The controller530may further instruct the fusing distributor to eject fusing agent to the build material layer based on the printing instructions540. The printing instructions540may define the areas to be fused, and the controller may instruct the fusing distributor to eject fusing agent to said areas to be fused on the build material layer. The controller530may also instruct the fusing lamp680to heat the build material layer to heat up above the melting point to fuse the combination of build material and fusing agent and solidify.

An example of fusing operation has been disclosed, however different fusing operations may be applied. For example, some alternative fusing processes may be Selective Laser Sintering (SLS), Selective Laser Melting (SLM) and/or Direct Metal Laser Sintering (DMLS), which are an additive manufacturing technique designed to use a high power-density laser to melt and fuse metallic powders together.

FIG.6is a block diagram illustrating another example of an additive manufacturing system600to preheat build materials with preheating sources according to an example. The system600comprises a build material distributor610, an preheating source620, a fusing distributor670, a detailing engine690, and a fusing lamp680. The build material distributor610may be the same as or similar to the build material distributor110fromFIG.1, The preheating source620may be the same as or similar to the preheating source120fromFIG.1. The build material distributor610may be understood as any mechanism (e.g., printing roller, printing wiper, etc.) to form build material layers from a build material having a color. In an example, the build material distributor610may form a build material layer on a printing bed650. The printing bed650may be internal or removable from the additive manufacturing system600(e.g., the printing bed may not be present when the printer is shipped). The printing bed650may be a surface to receive build material from the build material distributor610in the form of, for example, build material layers having a generally uniform thickness. The generally uniform thickness may range from about 80 microns to about 120 microns, or bigger or smaller. The preheating source620is to emit energy at a wavelength so that at least 40% of the energy is absorbed by the build material. The build material bed650may be the same as or similar to the building printing bed150fromFIG.1. The preheating source620may be an array comprising one or more LED lights to emit energy at a wavelength. The fusing distributor670is to eject fusing agent to the build material layer. The fusing distributor670may have the same functionality as the fusing distributor570fromFIG.5. The detailing engine690is to eject detailing agent to the build material layer. The fusing lamp680is to heat the build material layer to fuse those portions of the layer on which fusing agent was deposited by raising the temperature of the dyed build material above its melting point. The fusing lamp680may be a separate entity as the preheating source620. As an example, a heating lamp may be made of Tungsten and may comprise resistive heaters that may irradiate the printing bed650by a wide band of energy wavelengths. The system600further comprises a controller630in connection with the build material distributor610, the preheating source620, the fusing distributor670, the detailing agent690, and the fusing lamp680. The controller630may receive printing instructions640and may have the same functionality as the controller130that receives the printing instructions140fromFIG.1. The controller connection may be by means of a physical wire and/or wireless. The term “controller” as used herein may include a series of instructions encoded on a machine-readable storage medium and executable by a single processor or a plurality of processors, Additionally, or alternatively, a controller may include one or more hardware devices including electronic circuitry, for example a digital and/or analog application-specific integrated circuit (ASIC), for implementing the functionality described herein.

The fusing agent is a composition that may be applied to the build material layer. In an example, the fusing agent may be a printing liquid composition. When a suitable amount of energy (e.g., energy irradiated by fusing lamp680) is applied to the combination of build material and fusing agent, said energy may cause the combination of build material and fusing agent to heat up above the melting point and to fuse and solidify. The detailing agent is another composition that may be applied to the build material layer before applying energy to fuse the build material and the fusing agent. The detailing agent may provide temperature control, for example, around the boundaries of areas printed with the fusing agent, or may modulate the effect of the fusing agent. If the amount of irradiation and temperature are not properly controlled, too much of the printed areas and surrounding un-solidified build material from the build material layer may melt, or the printed areas may not melt sufficiently. For example, when a printed area is selectively melted, smaller areas may tend to cool faster than larger areas, resulting in potentially weaker mechanical properties in the smaller areas. The detailing agent may include, for example, a clear liquid, or liquid of a single or different colors. According to one example, a suitable detailing agent may be a formulation commercially known as V1Q61A “HP detailing agent” available from HP Inc. The fusing agent may be stored in a fusing agent repository675connected to the fusing distributor670. The detailing agent may be stored in a detailing agent repository695connected to the detailing engine690. In the example, the fusing agent repository675and the detailing agent repository695are outside the additive manufacturing system600, however other system examples may include the fusing agent repository675and/or the detailing agent repository695.

The controller630is to receive printing instructions640and derive the area to be fused in the build material layer therefrom. The controller630may instruct the build material distributor610to form the build material layer, and control the preheating source520to preheat the zone comprising the area to be fused. The controller630may further instruct the fusing distributor to eject fusing agent to the build material layer based on the printing instructions640. The printing instructions640may define the areas to be fused, and the controller may instruct the fusing distributor670to eject fusing agent to said areas to be fused on the build material layer. The controller630may further instruct the detailing engine690to eject detailing agent to the build material layer based on the printing instructions640. In an example, the detailing agent may be ejected in the boundaries of the fusing agent. The controller630may also instruct the fusing lamp680to heat the build material layer to heat up above the melting point to fuse the combination of build material and fusing agent and solidify.

An example fusing operation has been disclosed, however different fusing operations may be applied. For example, some alternative fusing processes may be Selective Laser Sintering (SLS), Selective Laser Melting (SLM) and/or Direct Metal Laser Sintering (DMLS), which are an additive manufacturing technique designed to use a high power-density laser to melt and fuse metallic powders together.

FIG.7is a block diagram illustrating another example of an additive manufacturing system700to preheat build materials with preheating sources according to an example. The system700comprises a build material distributor710, a preheating source720, and a build material support750. The build material support750may comprise a printing bed755. In the examples the additive manufacturing system700is in operation, the build material support750may further comprise the previously build material layers758. The build material distributor710may be the same as or similar to the build material distributor110fromFIG.1. The preheating source720may be the same as or similar to the preheating source120fromFIG.1. The build material distributor710may be understood as any mechanism (e.g., printing roller, printing wiper, etc.) to form build material layers from a build material having a color with the. In an example, the build material distributor710may form a build material layer on the printing bed755. The printing bed755may be a surface to receive build material from the build material distributor710in the form of, for example, build material layers having generally uniform thickness. The generally uniform thickness may range from about 80 microns to about 120 microns, or bigger or smaller. The preheating source720is to emit energy at a wavelength so that at least 40% of the energy is absorbed by the build material. The preheating source720may be an array comprising one or more LED lights to emit energy at a wavelength. The system700further comprises a controller730in connection with the build material distributor710, and the preheating source720. In some examples, the controller730may also be connected to the build material support750. The controller530may receive printing instructions740and may have the same functionality as the controller130that receives the printing instructions140fromFIG.1. The controller connection may be by means of a physical wire and/or wireless. The term “controller” as used herein may include a series of instructions encoded on a machine-readable storage medium and executable by a single processor or a plurality of processors. Additionally, or alternatively, a controller may include one or more hardware devices including electronic circuitry, for example a digital and/or analog application-specific integrated circuit (ASIC), for implementing the functionality described herein.

The build material support750may be a modular device that may be installed in the additive manufacturing system700. In one example, the build material support750may be permanently installed in the additive manufacturing system700. In another example, the build material support750may be attached and detached from the additive manufacturing system700by means of a moving mechanism, for example, wheels installed under the bottom surface of the build material support750. The build material support750comprises the printing bed755wherein the build material layer can be formed by the build material distributor710. The build material support750may further comprise previously built material layers758wherein previously printed layers from the 3D object to be printed may be stored.

FIG.8is a flowchart of an example method800for preheating build materials with preheating sources according to an example. Method800may be described below as being executed or performed by an apparatus, such as apparatus100ofFIG.1. Various other suitable systems may be used as well, such as, for example apparatus400ofFIG.4, apparatus500ofFIG.5, apparatus600fromFIG.6, and apparatus700fromFIG.7. Method800may be implemented in the form of executable instructions stored on a machine-readable storage medium and executed by a single processor or a plurality of processors of the apparatus100, and/or in the form of any electronic circuitry, for example digital and/or analog ASIC. In some implementations of the present disclosure, method800may include more or less blocks than are shown inFIG.8. In some implementations, one or more of the blocks of method800may, at certain times, be ongoing and/or may repeat.

The method800may start at block810, and continue to block820, where a controller (e.g., controller130fromFIG.1) may receive printing instructions (e.g., printing instructions140fromFIG.1) to print a 3D object by using a build material layer, wherein the printing instructions define an area to be fused in the build material layer. At block830, a build material distributor (e.g., build material distributor110fromFIG.1) forms the build material layer wherein the build material has a color. At block840, a preheating source (e.g., preheating source120fromFIG.1) preheats a zone comprising the area to be fused by emitting energy at a wavelength related to the build material color so that at least 40% of the energy is absorbed by the build material. At block850, a fusing distributor (e.g., fusing distributor570fromFIG.5) ejects fusing agent to the build material layer based on the printing instructions. At block860, a fusing lamp (e.g., fusing lamp580fromFIG.8) heats the build material layer to fuse those portions of the layer on which fusing agent was deposited by raising the temperature of the dyed build material above its melting point. At block870, the method800may end. Method800may be repeated multiple times to build the 3D object, each time being printed a subsequent layer.

FIG.9is a flowchart of another example method900for preheating build materials with preheating sources according to an example. Method900may be a sub-method from method800ofFIG.8by adding an additional block, for example after block830. In an example, the method900may be used in the event the build material powder is a non-dyed build material powder. Method900may be described below as being executed or performed by an apparatus, such as apparatus100ofFIG.1. Various other suitable systems may be used as well, such as, for example apparatus400ofFIG.4, apparatus500ofFIG.5, apparatus600fromFIG.6, and apparatus700fromFIG.7. Method900may be implemented in the form of executable instructions stored on a machine-readable storage medium and executed by a single processor or a plurality of processors of the apparatus100, and/or in the form of any electronic circuitry, for example digital and/or analog ASIC. In some implementations of the present disclosure, method900may include more or less blocks than are shown inFIG.9. In some implementations, one or more of the blocks of method900may, at certain times, be ongoing and/or may repeat.

The method900may start at block932, and continue to block934, where a color module (e.g., color module460fromFIG.4) may eject a composition that dyes the build material layer in a color that absorbs at least the 40% if the wavelength energy emitted by the preheating source420. At block936, the method900may end.

FIG.10is a flowchart of another example method1000for preheating build materials with preheating sources according to an example. Method1000may be a sub-method from method800ofFIG.8by adding an additional block, for example after block850. Method1000may be described below as being executed or performed by an apparatus, such as apparatus100ofFIG.1, Various other suitable systems may be used as well, such as, for example apparatus400ofFIG.4, apparatus500ofFIG.5, apparatus600fromFIG.6, and apparatus700fromFIG.7. Method1000may be implemented in the form of executable instructions stored on a machine-readable storage medium and executed by a single processor or a plurality of processors of the apparatus100, and/or in the form of any electronic circuitry, for example digital and/or analog ASIC. In some implementations of the present disclosure, method1000may include more or less blocks than are shown inFIG.10. In some implementations, one or more of the blocks of method1000may, at certain times, be ongoing and/or may repeat.

The method1000may start at block1052, and continue to block1054, where a detailing engine (e.g., detailing engine690fromFIG.6) ejects detailing agent to the build material layer based on the printing instructions (e.g., printing instructions640fromFIG.6). At block1056, the method900may end.

FIG.11is a block diagram illustrating an example of a processor-based system1100to preheat build materials with a light emitting diode array. In some implementations, the system1100may be or may form part of a printing device, such as an additive manufacturing system. In some implementations, the system1000is a processor-based system and may include a processor1110coupled to a machine-readable medium1120. The processor1110may include a single-core processor, a multi-core processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), and/or any other hardware device suitable for retrieval and/or execution of instructions from the machine-readable medium1120(e.g., instructions1121,1122,1123,1124, and1125) to perform functions related to various examples. Additionally, or alternatively, the processor1110may include electronic circuitry for performing the functionality described herein, including the functionality of instructions1121,1122,1123,1124, and/or1125. With respect of the executable instructions represented as boxes inFIG.11, it should be understood that part or all of the executable instructions and/or electronic circuits included within one box may, in alternative implementations, be included in a different box shown in the figures or in a different box not shown.

The machine-readable medium1120may be any medium suitable for storing executable instructions, such as a random-access memory (RAM), electrically erasable programmable read-only memory (EEPROM), flash memory, hard disk drives, optical disks, and the like. In some example implementations, the machine-readable medium1120may be a tangible, non-transitory medium, where the term “non-transitory” does not encompass transitory propagating signals. The machine-readable medium1120may be disposed within the processor-based system1100, as shown inFIG.11, in which case the executable instructions may be deemed “installed” on the system1100. Alternatively, the machine-readable medium1120may be a portable (e.g., external) storage medium, for example, that allows system1100to remotely execute the instructions or download the instructions from the storage medium. In this case, the executable instructions may be part of an “installation package”. As described further herein below, the machine-readable medium may be encoded with a set of executable instructions1121-1125.

Instructions1121, when executed by the processor1110, may receive printing instructions (e.g., printing instructions140fromFIG.1) to print a 3D object by using a build material layer, wherein the printing instructions define an area to be fused in the build material layer. Instructions1122, when executed by the processor1110, may form the build material layer, by a build material distributor (build material distributor110fromFIG.1), wherein the build material has a color. Instructions1123, when executed by the processor1110, may cause the processor1110to preheat a zone comprising the area to be fused by a preheating source (e.g., preheating source120fromFIG.1), by emitting energy at a wavelength related to the intended build material color, so that at least 40% of the energy is absorbed by the build material. Instructions1124, when executed by the processor1110, may cause the processor1110to eject, by a fusing agent distributor (e.g., fusing agent distributor570fromFIG.5), fusing agent to the build material layer based on the printing instructions. Instructions1125, when executed by the processor1110, may cause the processor1125to heat, by a fusing lamp (e.g., fusing lamp580fromFIG.5), the build material layer to fuse those portions of the layer on which fusing agent was deposited by raising the temperature of the dyed build material above its melting point.

The machine-readable medium1120may include further instructions. For example, instructions that when executed by the processor1110, may cause the processor1110to eject, by a color module (e.g., color module460fromFIG.4), a composition that dyes the build material layer in a color that absorbs at least the 40% if the wavelength energy emitted by the preheating source.

The machine-readable medium1120may include further instructions. For example, instructions that when executed by the processor1110, may cause the processor1110to eject, by a detailing engine (e.g., detailing engine690fromFIG.6), detailing agent to the build material layer based on the printing instructions.

The above examples may be implemented by hardware, or software in combination with hardware. For example, the various methods, processes and functional modules described herein may be implemented by a physical processor (the term processor is to be implemented broadly to include CPU, processing module, ASIC, logic module, or programmable gate array, etc.). The processes, methods and functional modules may all be performed by a single processor or split between several processors; reference in this disclosure or the claims to a “processor” should thus be interpreted to mean “at least one processor”. The processes, method and functional modules are implemented as machine-readable instructions executable by at least one processor, hardware logic circuitry of the at least one processors, or a combination thereof.

The drawings in the examples of the present disclosure are some examples. It should be noted that some units and functions of the procedure are not necessarily essential for implementing the present disclosure. The units may be combined into one unit or further divided into multiple sub-units. What has been described and illustrated herein is an example of the disclosure along with some of its variations. The terms, descriptions and figures used herein are set forth by way of illustration. Many variations are possible within the scope of the disclosure, which is intended to be defined by the following claims and their equivalents.