GB2550343A

GB2550343A - Additive manufacturing system

Info

Publication number: GB2550343A
Application number: GB1608379.2A
Authority: GB
Inventors: Alejandre Ignacio; Comas Esteve; Carlos Cano Emilio
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2016-05-12
Filing date: 2016-05-12
Publication date: 2017-11-22
Also published as: GB201608379D0

Abstract

A fusing assembly 108 of a system for generating a three-dimensional (3D) object, e.g additive manufacture, comprises an enclosure 114 of a fusing lamp 112 having an open end. A first space 122 which encloses the fusing lamp is formed by the enclosure and a first transparent substrate 118; a second space 124, or channel, is formed between the first substrate and a second transparent substrate 120. A cooling fluid 208, such as air flow, is circulated through the enclosure wherein the volume of fluid flowing through the second space 216 is greater than that through the first 214, such that the temperature within the first space is greater than the second space. Openings may be provided to allow ingress and egress of cooling fluid through the first and second spaces wherein the dimensions of the openings are different to limit the amount of cooling fluid to be introduced to the first space. As a result, high temperature conditions as required by the fusing lamps may be maintained in the first space without excessively heating the second layer. A further embodiment is disclosed wherein the ends of the fusing lamp extend beyond the first and second space and are accessible by the cooling fluid.

Description

ADDITIVE MANUFACTURING SYSTEM

Background [0001] Additive manufacturing, also referred to as ‘3D printing’ may involve generating three dimensional (3D) objects by selective solidification of successive layers of a build material. Solidification may occur, for example, by subjecting the build material to heat energy. The heat energy may be generated by sources such as a fusing lamp included within the additive manufacturing system.

Brief Description of the Drawings [0002] The following detailed description references the drawings, wherein: [0003] FIG. 1 is a block diagram of an example additive manufacturing system; [0004] FIG. 2 is block diagram depicting a cross-sectional lateral view of an example fusing lamp assembly of an additive manufacturing system; and [0005] FIG. 3 is a block diagram depicting a cross-sectional longitudinal view of an example fusing lamp assembly of an additive manufacturing system.

Detailed Description [0006] Additive manufacturing allows the generation of three dimensional (3D) objects based on digital information. The 3D objects may be generated using an additive manufacturing system, which are also colloquially referred to as 3D printers. Some systems implementing additive manufacturing generate objects by adding a layer of build material onto a build platform or work area. Thereafter, one or more portions of the layer of build material may be solidified. In some cases, the solidification of layers may be carried out using a laser. In other example a fusing agent may be applied to portions of the build material and a fusing energy applied to the whole surface of the build material, causing those portions of the build material on which fusing agent was deposited to heat up and fuse to generate (or ‘print’) a layer of a 3D object.

[0007] The fusing energy enables fusing of the build material to form a desired shape which is in conformance with the shape and configuration of the 3D object to be generated. The fusing energy is generally provided by way of a fusing lamp assembly, which forms a part of the additive manufacturing system. The fusing lamp assembly may have an array of fusing lamps which generate the fusing energy. The fusing lamp assembly may be enclosed in an enclosure having an open end, which may be covered by any suitable transparent substrate which allows the fusing energy to pass through and at the same time, also provides a shielding or a cover for the internal components of the fusing lamp assembly. Examples of materials for such substrates include, but are not limited to, potassium bromide (KBr) and silicium. It should be noted that the material of the substrate may be any material which allows the fusing energy to pass through, without deviating from the scope of the present subject matter.

[0008] Fusing lamps may be implemented, for example, as longitudinally extending glass tubes with filaments. The ends of such fusing lamps may also be provided with connectors for electrically connecting the fusing lamps to the internal electrical circuitry of the fusing lamp assembly. When in operation, the section of the fusing lamp having the filament reaches high temperatures. In order to ensure that the fusing lamps function in the desired manner, the fusing lamps themselves have to be maintained in an environment having high ambient temperatures. Even though the fusing lamps may be maintained in an environment having high ambient temperature, the ends of the fusing lamps have to be maintained at lower temperatures to ensure the integrity of the lamp itself.

[0009] Such high temperatures, in some cases, may unwantedly heat the enclosure of the fusing lamp assembly. Furthermore, the heat generated as a result of such high temperatures may be transmitted to a work area where the build material is placed. As would be understood, fusing energy in the form of heat processes the build material placed in the work area such that the build material fuses into a desired shape and configuration. In cases where the fusing lamps operate for long durations, high temperatures may thus be maintained for longer periods. As a result, the temperature of the build material present in the work area may also increase, and in some cases, beyond the temperature at which the build material fuses. A potentially hazardous situation may arise if the heat generated results in the build material being heated to temperatures which exceeds its ignition temperature. In such circumstances, additional cooling mechanisms may have to be implemented which also maintain the temperature within reasonable limits. Furthermore, heating of the enclosures may also pose burn related risks to users using the additive manufacturing system.

[0010] Aspects for effective cooling of the fusing lamp assembly are described. As discussed, the fusing lamp assembly is implemented within an additive manufacturing system for generating 3D objects. The additive manufacturing system includes an enclosure which in turn houses the fusing lamp assembly. The fusing lamp assembly further includes a fusing lamp which may extend longitudinally along the length of the enclosure. In one example, the fusing lamp generates fusing energy in the form of infrared radiation. The enclosure has an open end which allows the fusing energy to be incident on build materials. Such build materials are processed as part of the additive manufacturing process, for generating one or more 3D objects.

[0011] In one example, a first layer and second layer of a transparent substrate is positioned at the open end of the enclosure. The first layer and the second layer are spaced apart and are so positioned such that one of the planar surfaces of the first and the second layer face each other. Each of the first layer and the second layer define spaces which are accessible by a cooling fluid. For example, when positioned the first layer and the inner cavity of the enclosure define a first space which in turn includes the fusing lamp. The first layer and the second layerfurther define another space in the form of a channel fora volume of cooling fluid which may be circulated. It should be noted that the cooling fluid circulated through the first layer and the second layer may originate from a common stream of cooling fluid. In one example, the additive manufacturing system may further include baffles or any other directing plates for directing portion of the common stream of cooling fluid into the first space and another portion of the cooling fluid into the channel.

[0012] As mentioned above, portions of the cooling fluid are circulated through the first space and the space defining the channel, respectively. The first space and the channel may further include openings which control the extent of cooling fluid which may be circulated within the first space, when considered with respect to the channel. For example, the first space and the channel may include one or more openings or holes which restrict the volume of cooling fluid, referred to as a first volume, which may be circulated therein. As a result, the volume of cooling fluid circulating through the first space is less than the volume of the cooling fluid (referred to as second volume) which is circulated through the channel. In one example, the number of holes or their dimensions of the first space and the channel may be such that the internal temperatures within the first space are within an appropriate range for the operation of the fusing lamps. Furthermore, since the second volume, i.e., volume of cooling fluid circulated in the channel is greater, the cooling effect caused within the channel would be also more when considering the first space. Consequently, the second layer of the transparent substrate would also be at a lower temperature when compared with the first layer. The second volume may also be controlled such that fusing energy radiating from the second layer may such that it significantly contributes for fusing the build material, say the build material placed in the work area. In this manner, as the temperature of the build material is controlled allowing fusing of the build material but without the temperatures reaching to an extent where it may ignite the build material placed in the work area.

[0013] As also explained previously, owing to the operation of the fusing lamp, the ends of the fusing lamps may also reach high temperatures. In one example, prior to directing the cooling fluid into the first space and the channel, the common stream of cooling fluid may be passed over the ends of the fusing lamps. As should be noted, the volume of cooling fluid which is directed upon the ends of the fusing lamps is more than the volume which enters the first space or the channel. In this manner, the ends of the fusing lamps are maintained at a lower temperature when considered with respect to the portion of the fusing lamps operating at higher temperatures.

[0014] As per various aspects of the present subject matter, at least two distinct and separate spaces are created within the fusing lamp assembly. As a result, high temperature ambient conditions at par with the operating temperature requirements of the fusing lamps may be maintained within the first space. This is achieved without excessively heating the second layer and thereby limiting the radiation emanating from the second layer. As a result, conditions which may inadvertently lead to ignition of build material placed in the work area are also avoided. Furthermore, the second layer of the transparent substrate are also at lower temperatures which further minimizes risks of users suffering burns when coming into contact with the second layer covering the opening of the enclosure. Additionally, the section of the fusing lamp having the filament and the ends of the fusing lamps, being maintained at high temperatures and lower temperatures, respectively, provides appropriate conditions for the operations of the fusing lamps. As a result, the efficiency of the fusing lamps may be further enhanced. Furthermore, since the fusing lamps operate within appropriate operating conditions, the operating life effusing lamps may also be enhanced.

[0015] These and other aspects are described in conjunction with various examples as illustrated in FIGS. 1-3. FIG. 1 illustrates a block diagram of an additive manufacturing system 100 (referred to as the system 100) for generating one or more 3D objects. The block diagram illustrate logical blocks representing functional entities which may be present in the system 100. The block diagram does not indicate any specific arrangement of such functional elements nor does it represent the manner in which such elements may be interconnected with each other. Any arrangement of blocks may be implemented without deviating from the scope of the present subject matter. In the present example, the system 100 includes a print assembly 102 and a work area 104. The print assembly 102 in turn may include a print carriage unit 106, fusing lamp assemblies 108-1, 2 and a material coating unit 110. The print assembly 102, i.e., print carriage unit 106, fusing lamp assemblies 108-1, 2 and a material coating unit 110 operate over the work area 104 deposit build material and any other suitable agents, layer-by-layer, in order to generate a 3D object.

[0016] In the present example, each of the fusing lamp assemblies 108-1,2 are identical to each other. The fusing lamp assemblies 108-1, 2 (collectively referred to as assemblies 108) include a set effusing lamps 112-1, 2 respectively, which are enclosed within their respective enclosure. In one example, the fusing lamps 112-1, 2 may be longitudinally extending tubes positioned along the length of the enclosure of the assemblies 108. The set effusing lamps 112-1, 2 each may be composed of an elongated tube carrying filament which generate fusing energy on application of electrical power.

[0017] The following description for the additive manufacturing system 100 as depicted in FIG. 1 is provided considering one of the fusing lamp assemblies 108-1, 2. It should be noted that the same would also be applicable for the other assembly without deviating from the scope of the present subject matter. Continuing with the present example, the fusing lamp assembly 108-1 is enclosed within an enclosure 114-1. Similarly, the fusing lamp assembly 108-2 is also enclosed within another enclosure 114-2.

[0018] For the fusing lamp assembly 108-1 (interchangeably referred to as the assembly 108-1), the enclosure 114-1 is provided with an open end 116. The open end 116 allows the fusing energy generated by the fusing lamps 112 to pass through the enclosure 114-1 and be directed upon any build material that may be placed within the work area 104. The build material may be any material that may be processed by the system 100 in order to generate a 3D object. As shown in FIG. 1, the open end 116 of the assembly 108-1 is provided with a first layer 118 and second layer 120 of a transparent substrate, positioned at the open end 116 of the assembly 108-1. The first layer 118 and the second layer 120 are so positioned such that they are spaced apart with at least one of their respective surfaces facing each other. Although not visible in the present figures, each of the first layer 118 and the second layer 120 extend longitudinally along the length of the assembly 108-1. In one example, the first layer 118 and the second layer 120 are so positioned such that they are parallel to the set effusing lamps 112-1. It should also be noted that the present examples illustrate the first layer 118 and the second layer 120 as planar surfaces. The profile of the first layer 118 and the second layer 120 may be of any other shape depending on the configuration and end application of the system 100. Examples of other profiles include, but are not limited to, convex or concave shapes for the first layer 118 and the second layer 120.

[0019] Owing to the positioning of the first layer 118 and the second layer 120, two portions or spaces within the enclosure 114-1 are formed. For example, the space within the enclosure 114-1 and the first layer 118 forms a first space 122 which encloses the set of fusing lamp 112-1. The first layer 118 and the second layer 120 form a second space which defines a channel 124. In the present example, both the first space 122 and the channel 124 are accessible by a cooling fluid. As would be noted, cooling fluid is utilized for controlling and managing the internal temperatures within the first space 122 and the channel 124. In another example, a first volume of the cooling fluid which is to be circulated through the first space 122 and a second volume of cooling fluid to be circulated through the channel 124. The first volume and the second volume may be controlled using one or more openings which may allow the cooling fluid to enter the first space 122 and the channel 124. For example, the volume of cooling fluid to be circulated in first space 122, i.e., the first volume, may be less than the volume of cooling fluid to be circulated in the channel 124, i.e., the second volume. Once the cooling fluid has circulated within the space of the first space 122 and the channel 124, the cooling fluid may proceed and exit the enclosure 114-1 by one or more vents (not shown FIG. 1) which may be provided in the walls of enclosure 114-1.

[0020] The difference in the volumes of cooling fluid being circulated will have an effect on the degree of cooling of the first space 122 and the channel 124. Therefore, ambient temperatures within the enclosure 114-1 housing the fusing lamps 112, and hence the first layer 118, would be maintained at a temperature which is greater than the temperature of the second layer 120. For example, the temperature within the first space 122 may be between about 300°C to about 350°C. In another example, the temperature within channel 124 may be about 150°C to about 190°C. It is to be noted that the present temperature ranges are examples. The temperatures may differ under varying circumstances, such as based on the type of fusing lamps 112 or the build material used. Other examples resulting in different temperature ranges would also fall within the scope of the present subject matter. In this manner, separate zone having different temperatures may be defined and maintained - with the first space 122 providing a surrounding temperature which is optimal for the working of the fusing lamps 112-1, and the second space within the channel 124 having lower temperature. Consequently, the second layer 120 would be heated less as compared to the first layer 118.

[0021] The extent of cooling within the channel 124 may controlled so that the temperature of the second layer 120 may increase to a value lying within a specific range. Consequently, the extent of fusing energy in the forms of heat radiation would also be less. Since the second layer 120 is maintained at a lower temperature, radiations from the second layer 120 may also be such that it affects the fusing of build material placed in the work area 104 without raising the temperature of the build material to its ignition temperatures.

[0022] In one example, the flow direction cooling fluid may be longitudinal as well as about the inner surface of the enclosure 114-1. Furthermore, the enclosure 114-1 may also include one or more baffles for directing the flow of cooling fluid to one of the first space 122 and the channel 124. The examples as explained in conjunction with FIG. 1 depict a block diagram of an additive manufacturing system 100 with certain components. Additional components or the number of components as represented may also differ without deviating from the scope of the present subject matter. For example, the system 100 may Include a single fusing lamp assembly 108-1, or may include a single fusing lamp 112. Such examples would also be within the scope of the subject matter as described.

[0023] FIGS. 2 and 3 provide, in one example, lateral and longitudinal views of the fusing lamp assembly, respectively. The differing views are provided to depict the lateral flows (shown In FIG. 2) and the longitudinal flows (FIG. 3) of cooling fluid within fusing lamp assembly, such as the assembly 108. Referring to FIG. 2, the assembly 108 includes a set of fusing lamps 112, which as explained previously, generate fusing energy for fusing build material in order to generate one or more 3D objects.

[0024] The assembly 108 is formed as an enclosure 114-1 enclosing the fusing lamps 112. As would be understood, the fusing lamps 112 may generate fusing energy by way of infrared or thermal radiation. Besides the fusing lamps 112, the assembly 108 further includes a reflector 202. In one example, reflector 202 may be parabolic, spherical or cylindrical in shape, with the fusing lamps 112 being positioned at the focal point. In operation, the reflector 202 may reflect the radiation from the fusing lamps 112. The radiation reflected off the reflector 202 may be incident onto a build material for generating 3D objects. Although the reflector 202 is present in the current example, the same should not be construed as a limitation. In other examples, the assembly 108 may not include the reflector 202 without deviating from the scope of the present subject matter.

[0025] The enclosure 114 may further include an open end 116 from which radiation reflected off the reflector 202 may be allowed to pass through. In one example, first layer 118 and the second layer 120 of a transparent substrate material are positioned at the open end 116 of the enclosure 114. The first layer 118 and the second layer 120 are so positioned such that the both the layers 118, 120 extend longitudinally along the length of the enclosure 114. In one example, the first layer 118 and the second layer 120 may be parallel to the fusing lamps 112. Furthermore, the first layer 118 and the second layer 120 are so located such that they are spaced apart with respect to each other.

[0026] Owing to the positioning of the first layer 118 and the second layer 120, two spaces within the enclosure 114 of the assembly 108 are defined. For example, the inner portion of the enclosure 114 and the first layer 118 define a first space 122, as shown in FIG.2. The first space 122, amongst other things encloses the fusing lamps 112 and the reflector 202. It should also be noted that the first space 122 may include other components (not shown in FIG. 2) without deviating from the scope of the present subject matter. A second space in the form of a channel 124 is formed by the first layer 118 and the second layer 120. The channel 124 as such may not include any components and provides a passage for circulation of cooling fluid.

[0027] The enclosure 114 of the assembly 108 further includes an entry port 204 on an upper side, and an exit port 206 on a side wall of the enclosure 114. The positioning of the entry port 204 and the exit port 206 may also be different limiting the scope of the present subject matter. The entry port 204 provides an entry for a common stream 208 of cooling fluid. In one example, the cooling fluid is air. The cooling fluid may be provided through a common chamber (discussed in FIG. 3) and may be circulated by an air circulating fan. As is illustrated, the common stream 208 on entering the enclosure 114 is split into two streams 210,212. The stream 210 may proceed further downwards as shown towards the first space 122 and the channel 124. The stream 212 in turn may flow in a manner such that it is directed over the ends of the fusing lamps 112. In one example, the common stream 208 may be split using one or more baffles (not shown in FIG. 2).

[0028] Stream 210 moves laterally downwards towards the first space 122 and the channel 124. As the stream 210 passes the reflector 202, the stream 210 splits further into further streams 214, 216. Stream 214 (as illustrated) flows into the first space 122 and the stream 216 flows into the second space defining the channel 124. The openings of the first space 122 and the channel 124 may be such that the volume of cooling fluid flowing into the first space 122 is less than the volume of cooling fluid flowing through the channel 124. For the present description, the difference in the volume of cooling fluid circulating through first space 122 and the channel 124 is depicted by the difference in the number of arrows illustrating streams 214 and 216. As would be appreciated For example, stream 214 being depicted by a single arrow is meant to exemplify that the volume of cooling fluid passing through the first space 122 is less than the volume of cooling fluid in the channel 124 (which is depicted by multiple arrows representing stream 214). As the streams 214 and 216 flow through the first space 122 and the channel 124, they may converge as indicated and finally the converged stream 218 may be ejected out of the exit port 206. In one example, the exit port 206 may include a plurality of vents or air holes provides on the side of the walls of the enclosure 114 through which the converged stream may exit.

[0029] While traversing the spaces of the first space 122 and the channel 124, the streams 214 and 216 besides following a circular path also travel longitudinally along the lengths of the first space 122 and the channel 124. The longitudinal flow paths of the streams 214 and 216 are also discussed in conjunction with FIG. 3. As discussed, the volume of the cooling fluid being circulated through the first space 122 and the channel 124 differ, with more cooling fluid circulated through the space defining the channel 124 as compared to the first space 122. It should be noted that the when operating, the fusing lamps 112 may reach specific temperatures. Consequently, owing to heat generated by the fusing lamps, the ambient temperatures within the first space 122 may reach to levels which correspond to the specific temperatures which the fusing lamps 112 may reach while operating. In the absence of cooling fluid, the heat generated may also be transferred to the channel 124 by way of convention or conduction. In one example, the temperature within the first space 122 may be between about 300°C to about 350°C. In another example, the temperature within channel 124 may be about 150°C to about 190°C.

[0030] Since the volume of cooling fluid circulating through the first space 122 (stream 214) is less than the volume of cooling fluid directed through the channel 124 (steam 216), the extent of cooling which is affected onto the first space 122 will be less in comparison to the extent of cooling which occurs in the space defining the channel 124. The volume of the cooling fluid may be so controlled such that ambient temperatures within the first space 122 are maintained to about a level which conforms to the temperature specification as may be prescribed for operating the fusing lamps 112.

[0031] As the volume of cooling fluid within the channel 124 (depicted by stream 216) is more, the cooling of the space within the channel 124 would also be more when compared with respect to the first space 122. In such a case, any heating of the space within the channel 124 due to the temperature of the first space 122 may also be minimized or less considering that more cooling fluid is circulated through the space defining the channel 124. In this manner, regardless of the temperature of the first space 122, the temperature of the space within the channel 124 may be maintained lower as compared to the ambient temperatures within the first space 122. As a result, the second layer 120 is also susceptible to less heating when compared to the heating of the first layer 118 (which is in direct contact with the first space 122). Consequently, any radiation emanating from the second layer 120 would also be less.

[0032] The temperature of the space within the channel 124 may be such that it conforms to temperature ranges which may be prescribed for efficiently fusing any build material to generate one or more 3D objects. The examples described in conjunction with one assembly 108 would also be applicable for other fusing lamp assemblies, such as fusing lamp assembly 108-2 without any limitations. The aspects which have been described in conjunction with FIG. 2 are examples and should not be construed as limiting the scope of the present subject matter. As discussed in conjunction with FIG. 2, the flow of the cooling fluid follows both a lateral part (as explained in FIG. 2). As the cooling fluid is introduced, it also travels longitudinally along the first space 122 and the channel 124, extending along the length of the enclosure 114. These aspects are further explained in conjunction with FIG. 3. As should be understood, the section of the fusing lamp having the filament and the ends of the fusing lamps, being maintained at high temperatures and lower temperatures, respectively, provide appropriate conditions for the operations of the fusing lamps. This may increase the operational efficiency and further enhance the operating life of the fusing lamps.

[0033] FIG. 3 provides, in one example, a longitudinal cross-sectional view of a fusing lamp assembly, such as assembly 108. In the present example, the assembly 108 includes an upper chamber 302 and a lower chamber 304. The upper chamber 302 provides a passage for cooling fluid (e.g., as indicated by stream 208). The cooling fluid in turn may be introduced within the upper chamber 302 through an entry port 306 present on an upper side of the chamber 302. The cooling fluid may be driven by a cooling unit or a cooling fan.

[0034] The lower chamber 304 houses a fusing lamp, such as fusing lamp 112. The fusing lamp 112 also extends longitudinally along the length of the enclosure 114 of the assembly 108. The fusing lamp 11 may be supported by holders or other supports 308 in order to rigidly retain its position within the lower chamber 304. The fusing lamp 112 further includes a fusing energy portion which releases fusing energy when the system 100 is in operation. The fusing lamp 112 may also include ends 310-a, b. The ends 310-a, b are utilized for connecting the fusing lamp 112 with the internal electrical circuitry of the additive manufacturing system, such as the system 100.

[0035] The enclosure 114 may further include an open end 116 to allow fusing energy from the fusing lamp 112 to pass through for generating one or more 3D objects. The enclosure 114 may further include first layer 118 and second layer 120 placed at the open end 116. The first layer 118 and the second layer 120 define distinct spaces, such as the first space 122 and space defining a channel 124. The first space 122 encloses the fusing lamp 112 and may also enclose any other components, such as a reflector (not shown in FIG. 3). In one example, the support 308 may be positioned just prior to the ends 310-a, b. such that the ends 310-a, b extend beyond the first space 122 and the space defining the channel 124.

[0036] In operation, cooling fluid may be introduced into upper chamber 302 through the entry port 306, it moves as common stream 208 along the length of the upper chamber 302. As the cooling fluid is introduced a portion of the cooling fluid may branch off and may pass through a port 310 directly overlaying above the end 310-a. The cooling fluid may pass through the first port 310-a, and is directed upon the end 310-a. Once the cooling fluid passes over the end 310-a, it may further proceed and pass through one or more exit ports 206 provided on the side wall of the enclosure 114. In a similar manner, as the common stream 208 traverses the upper chamber 302 it may pass through another entry port, e.g., entry port 204. In one example, the port 204 may also lay directly above the end 310-b of the fusing lamp 112. As the common stream passes through the port 204, it is directed over the end 310-b of the fusing lamp. In one example, the cooling of the ends 310-a,b is such that the temperature of the ends 310-a,b is maintained at temperatures less than 250°C. It should be noted that the temperature at which the ends 310-a,b is to be maintained may vary depending on the type of the fusing lamps 112. Other temperatures at which the ends 310-a,b are maintained may also be possible without deviating from the scope of the present subject matter.

[0037] The common stream 208 of the cooling fluid proceeds further and may split into streams 214, 216. Furthermore, the lower chamber 304 may include one or more baffles for splitting the common stream 208 to streams 214, 216. The stream 214 (as illustrated) flows into the first space 122 and the stream 216 flows into the space defining the channel 124. The openings of the first space 122 and the channel 124 may determine the volume of cooling fluid which may flow into the first space 122 and the channel 124. For example, the volume of cooling fluid flowing through the first space 122 is less than the volume of cooling fluid flowing through the channel 124. Similar to FIG. 2, the difference in volume of the cooling fluid flowing through the first space 122 and the space defining the channel 124 is depicted by the difference in the number of arrows illustrating streams 214 and 216.

[0038] The stream 214 progresses through the first space 122 along the length of the enclosure 114 as indicated. In a similar manner, the stream 216 moves through the channel 124 along the length of the enclosure 114. In one example, the beginning of the first space 122 and the channel 124 may include one or more openings. The openings may be such that they control the volume of cooling fluid which enters the first space 122 and the space defining the channel 124. In the present example, the volume of the cooling fluid being circulated through the first space 122 is less than the volume of cooling fluid circulated through the space defining the channel 124. Since the volume of cooling fluid circulating through the first space 122 (stream 214) is less, the cooling of the first space 122 will also be less in comparison to the extent of cooling which occurs in the space defining the channel 124. Furthermore, the volume of the cooling fluid may be such that ambient temperatures within the first space 122 are maintained to about a level which conforms to the operating temperature specification of the fusing lamps 112. As one example, the temperature within the first space 122 may be between about 300°C to about 350°C. In another example, the temperature within channel 124 may be about 1 SOX to about 190°C.

[0039] Considering that the volume of cooling fluid within the channel 124 (depicted by stream 216) is more, the cooling of the space within the channel 124 would also be more when compared to the first space 122. As a result, any heating of the space within the channel 124 due to the proximity with the first space 122 may also be minimized or less considering that more cooling fluid is circulated through the space defining the channel 124. In this manner, the temperature of the space within the channel 124 may be maintained lower as compared to the ambient temperatures within the first space 122. As a result, the second layer 120 is also susceptible to less heating when compared to the heating of the first layer 118 (which is in direct contact with the first space 122).

[0040] The temperature of the space within the channel 124 may be such that it conforms to temperature ranges which may be prescribed for efficiently fusing any build material in order to generate one or more 3D objects. Portions of the assembly 108 which are exposed to and facing the build material to be processed, are also at lower temperatures minimizing the chances of igniting the build material, or also risks. In addition, the end portions, i.e., ends 310-a,b of the fusing lamp 112 are also maintained at a lower temperature as per the operating specifications for the fusing lamp 112. As should be understood, the section of the fusing lamp having the filament and the ends of the fusing lamps, being maintained at high temperatures and lower temperatures, respectively, provide appropriate conditions for the operations of the fusing lamps. This may increase the operational efficiency and further enhance the operating life of the fusing lamps.

[0041] Although examples for the present disclosure have been described in language specific to structural features and/or methods, it should stood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

Claims

We claim:

1. An assembly of an additive manufacturing system for generating a three-dimensional (3D) object, the assembly comprising: an enclosure of a fusing lamp assembly, wherein the enclosure comprises an open end; a fusing lamp within the enclosure to generate fusing energy for processing a build material; a first layer and a second layer of transparent substrate positioned at the open end of the enclosure and arranged apart, wherein: the first layer and the enclosure define a first space enclosing the fusing lamp, wherein the first space is accessible by a first volume of cooling fluid, and the first layer and the second layer define a channel for a second volume of cooling fluid to be circulated through the enclosure with the second volume being greater than the first volume, such that temperature within the first space is greater than temperature of the channel.

2. The system as claimed in claim 1, wherein the enclosure further comprises openings to allow ingress and egress of cooling fluid within the first space and the channel.

3. The system as claimed in claim 2, wherein the dimensions of the openings for the first space and the channel are different so as to limit the amount of cooling fluid to be introduced into the first space with respect to the volume of the cooling fluid circulated through the channel.

4. The system as claimed in claim 1, wherein the transparent substrate is to allow the fusing energy emanating from the fusing lamps to pass through.

5. The system as claimed in claim 1 further comprising a circulating unit for circulating the cooling fluid through the enclosure.

6. The system as claimed in claim 1 further comprising a baffle positioned at an opening of the first space to direct portion of the cooling fluid circulated through the enclosure into the first space.

7. The system as claimed in claim 1, wherein the first layer and the second layer are each parallel to the fusing lamp.

8. The system as claimed in claim 7, wherein the temperature within the first space is about a rated operating temperature of the fusing lamp.

9. A fusing assembly of a system for generating a three-dimensional (3D) object, the fusing assembly comprising: an enclosure having an open end and a plurality of ports; a fusing lamp within the enclosure to process a build material, with the open end of the enclosure facing the build material to be processed; a first substrate layer and a second substrate layer; a first space enclosing the fusing lamp, with the first space formed by the enclosure and a first substrate layer positioned near the open end of the enclosure; and a second space formed between the first substrate layer and a second substrate layer, with the second substrate layer so positioned such that the first substrate layer lies between the fusing lamp and the second substrate layer, wherein each of the first space and the second space are accessible by different volumes of cooling fluid to be circulated through the enclosure, with the volume of coolant fluid to be circulated through the first space being less than volume of coolant fluid to be circulated through the channel.

10. The assembly as claimed in claim 9, wherein the first substrate layer and the second substrate layer are parallel to each other.

11. The assembly as claimed in claim 9, wherein the first substrate layer and the second substrate layer are to cover the open end of the enclosure.

12. The assembly as claimed in claim 9, wherein the first substrate layer and the second substrate layer is of a material which is to allow fusing energy generated by the fusing lamp to pass through.

13. The assembly as claimed in claim 9, wherein an end of the first space is dimensioned to limit the extent of cooling fluid that is circulated through therein, as compared to the volume of cooling fluid circulated through the second space.

14. A fusing lamp assembly for a system for generating a three-dimensional (3D) object, the assembly comprising: an upper chamber to form a passage for introducing cooling fluid; a lower chamber formed by an enclosure having a plurality of ports and an end open facing the object being generated; a fusing lamp linearly extending within the enclosure, having a filament portion and two ends, wherein the two ends each are to provide an electrical connection; a first space, accessible by a cooling fluid, enclosing the filament portion of the fusing lamp wherein the first space is formed by a first layer of a substrate and the enclosure; and a second space formed between the first layer and a second layer of transparent substrate positioned at the open end of the enclosure, and wherein each of the ends of the fusing lamps extend beyond the first space and the second space and are accessible by the cooling fluid directly through any one of the ports.

15. The fusing lamp assembly as claimed in claim 14, further comprising directing plates to control volume of cooling fluid to be circulated through the first space and the second space, with the volume to be circulated through the second space being greater than the volume to be circulated through the first space, such that temperature within the first space is greater than temperature of the second space.