Patent Publication Number: US-11660823-B2

Title: Unfused thermal support area in 3D fabrication systems

Description:
BACKGROUND 
     In three-dimensional (3D) printing, an additive printing process is often used to make three-dimensional solid parts from a digital model. Some 3D printing techniques are considered additive processes because they involve the application of successive layers or volumes of a build material, such as a powder or powder-like build material, to an existing surface (or previous layer). 3D printing often includes solidification of the build material, which for some materials may be accomplished through use of heat and/or a chemical binder. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features of the present disclosure are illustrated by way of example and not limited in the following figure(s), in which like numerals indicate like elements, in which: 
         FIG.  1 A  shows a diagram of an example 3D fabrication system that may form an example unfused thermal support area to reduce a rate at which particles forming a portion of a 3D object thermally bleeds; 
         FIG.  1 B  shows an isometric view of a layer of particles on which a fusing area and an example unfused thermal support area have been formed; 
         FIGS.  1 C- 1 E , respectively, show cross-sectional side views of layers of particles on which a fusing area and an example unfused thermal support area have been formed; 
         FIG.  2    shows a diagram of another example 3D fabrication system that may form an unfused thermal support area to reduce a rate at which particles forming a portion of a 3D object thermally bleeds; 
         FIG.  3    shows a block diagram of an example apparatus that may cause an unfused thermal support area to be formed adjacent to a selected area during formation of a portion of a 3D object; and 
         FIG.  4    shows a flow diagram of an example method for forming an unfused thermal support area. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are 3D fabrication systems, apparatuses, and methods that may be implemented to deposit a fusing agent onto a fusing area of a layer of particles of build material and to deposit an energy absorbing agent to form an unfused thermal support area adjacent to the fusing area. In addition, the 3D fabrication systems and apparatuses disclosed herein may be implemented to supply energy onto the particles, such that the fusing agent deposited on the particles absorbs the energy and causes the temperature of those particles to rise to a level above a melting point temperature of the particles. The particles in the fusing area may thus melt and subsequently fuse together as the melted particles cool and solidify. In addition, the particles on which the fusing agent has not been deposited may not absorb sufficient energy to reach the melting point temperature. 
     However, the energy absorbing agent may be deposited in the unfused thermal support area at a sufficiently low contone level to cause the temperature of the particles in the unfused thermal support area to increase without reaching the melting point temperature. The energy absorbing agent may, in other examples, be deposited at a relatively higher contone level, but with a cooling agent or a defusing agent to keep the temperature of the particles in the unfused thermal support area below the melting point temperature. In one regard, through application of energy onto the energy absorbing agent, the temperature of the particles in the unfused thermal support area may rise without reaching a level that causes those particles to melt and subsequently fuse together. In another regard, because the particles in the unfused thermal support area may not fuse together, those particles may also not fuse with the particles in the fusing area. The particles in the unfused thermal support area may thus increase a temperature around the unfused thermal support area, including the fusing area. 
     As the particles in the fusing area may be at a higher temperature than the particles outside of the fusing agent, thermal bleed may occur from the particles in the fusing area to the particles outside of the fusing area. That is, heat from the particles in the fusing area may be transferred to the particles in the areas surrounding the fusing area. When the fusing area is at or above a certain size, the particles in the fusing area may be heated and may remain heated at a sufficiently high temperature such that the thermal bleed that occurs may be insufficient to prevent the particles from melting and fusing together as intended, e.g., to have an intended strength, rigidity, hardness, color, translucency, surface roughness, combinations thereof, or the like. However, when the size of the fusing area is below the certain size, the rate at which thermal bleed occurs may result in the particles in the fusing area from failing to reach and/or remain at or above the melting point temperature for sufficient melting to occur such that the particles fuse together as intended. The certain size may pertain to a thickness, a width, a length, an area, a volume, or combinations thereof, of the fusing area, which may extend across multiple layers of particles. 
     According to examples, by forming the unfused thermal support area adjacent to the fusing area, the rate of thermal bleed from the particles in the fusing area may be reduced. In this regard, the unfused thermal support area may facilitate the melting and fusing together of the particles in the fusing area. In other words, because the particles in the unfused thermal support area are at a higher temperature than the particles outside of the unfused thermal support area and the fusing area, a thermal gradient between the particles in the fusing area and the particles in the unfused thermal support area may be smaller than a thermal gradient between the particles in the fusing area and the particles outside of the unfused thermal support area. As such, the rate at which heat is transferred from the particles in the fusing area to the particles in the unfused thermal support area may be lower than the rate at which heat is transferred from the particles in the fusing area to the particles outside of the unfused thermal support area. 
     As discussed herein, the unfused thermal support area may include unfused particles and thus, the unfused thermal support area may facilitate the melting and fusing of the particles in the fusing area, particularly, when the fusing area is relatively small. According to examples, the energy absorbing agent may be a degradable fluid that may degrade within a certain period of time following receipt of the energy or in the presence of another agent. In these examples, the particles upon which the energy absorbing agent has been deposited may be recycled. 
     Through implementation of the 3D fabrication systems, apparatuses, and methods disclosed herein, 3D objects and/or sections of 3D objects having relatively small sizes, e.g., fine features, may be fabricated to have substantially increased mechanical strength, more accurate colors, improved surface quality, more accurate translucency, or the like. In addition, these results may be achieved without fusing particles outside of the particles that form the 3D objects, which may reduce overall costs associated with fabricating objects with build material particles as those particles may be reused. 
     Before continuing, it is noted that as used herein, the terms “includes” and “including” mean, but is not limited to, “includes” or “including” and “includes at least” or “including at least.” The term “based on” means “based on” and “based at least in part on.” 
     With reference first to  FIG.  1 A , there is shown a diagram of an example 3D fabrication system  100  that may form an unfused thermal support area to reduce a rate at which particles forming a portion of a 3D object thermally bleeds. It should be understood that the 3D fabrication system  100  depicted in  FIG.  1 A  may include additional components and that some of the components described herein may be removed and/or modified without departing from a scope of the 3D fabrication system  100  disclosed herein. 
     The 3D fabrication system  100  may also be termed a 3D printer, a 3D fabricator, or the like. Generally speaking, the 3D fabrication system  100  may be implemented to fabricate 3D objects from particles  102  of build material, which may also be termed build material particles  102 . The particles  102  of build material may include any suitable material including, but not limited to, a polymer, a plastic, a ceramic, a nylon, a metal, combinations thereof, or the like, and may be in the form of a powder or a powder-like material. Additionally, the particles  102  may be formed to have dimensions, e.g., widths, diameters, or the like, that are generally between about 5 μm and about 100 μm. In other examples, the particles  102  may have dimensions that are generally between about 30 μm and about 60 μm. The particles  102  may have any of multiple shapes, for instance, as a result of larger particles being ground into smaller particles. In some examples, the powder may be formed from, or may include, short fibers that may, for example, have been cut into short lengths from long strands or threads of material. The particles  102  have been shown as being partially transparent to enable a fusing area  104  and a thermal support area  106  to be visible. It should thus be understood that the particles  102  may not be transparent, but instead, may be opaque. 
     As shown in  FIG.  1 A , the 3D fabrication system  100  may include a controller  110 , an agent delivery system  120 , and an energy supply system  130 . The controller  110  may control the agent delivery system  120  to deposit a fusing agent, which is represented by the arrow  122 , onto a fusing area  104  of a layer of particles  102 . The controller  110  may also control the agent delivery system  120  to deposit an energy absorbing agent, which is represented by the arrow  124 , onto an unfused thermal support area  106 . The unfused thermal support area  106  may be formed adjacent to the fusing area  104  and may not form part of a 3D object to be fabricated. The controller  110  may further control the energy supply system  130  to supply energy, which is represented by the arrow  132 , onto the layer of particles  102 , the fusing area  104 , and the unfused thermal support area  106 . 
     The fusing agent  122  may be a liquid, such as an ink, a pigment, a dye, or the like, that may enhance absorption of energy  132  emitted from the energy supply system  130 . The agent delivery system  120  may deliver the fusing agent  122  in the form of droplets onto the layer of particles  102  such that the droplets of fusing agent  122  may be dispersed on the particles  102  and within interstitial spaces between the particles  102  in the fusing area  104 . In the fusing area  104 , the droplets of fusing agent  122  may be supplied at a sufficient density, e.g., contone level, to enhance absorption of sufficient energy  132  to cause the temperature of the particles  102  on which the fusing agent  122  has been deposited to increase to a level that is above a melting point temperature of the particles  102 . In addition, the energy supply system  130  may supply energy  132  at a level that is insufficient to cause the particles  102  upon which the fusing agent  122  has not been supplied to remain below the melting point temperature of the particles  102 . 
     The energy absorbing agent  124  may also be a liquid, such as an ink, a pigment, a dye, or the like, that may enhance absorption of energy  132  emitted from the energy supply system  130 . The agent delivery system  120  may deliver the energy absorbing agent  124  in the form of droplets onto the layer of particles  102  such that the droplets of energy absorbing agent  124  may be dispersed on the particles  102  and within interstitial spaces between the particles  102  in the unfused thermal support area  106 . In the unfused thermal support area  106 , the droplets of energy absorbing agent  124  may be supplied at a sufficiently low density, e.g., contone level, to absorb sufficient energy  132  to cause the temperature of the particles  102  on which the energy absorbing agent  124  has been deposited to increase, but to a level that is below the melting point temperature of the particles  102 . In other words, the droplets of energy absorbing agent  124  may be supplied at a sufficiently low density to increase the temperature of the particles  102  in the unfused thermal support area  106  without causing those particles  102  to fuse together. In addition or in other examples, a cooling agent and/or a defusing agent may be combined with the energy absorbing agent  124 , such that the combination of agents may increase the temperature of the particles  102  upon which the combination has been deposited without causing those particles  102  to fuse together. 
     According to examples, the energy absorbing agent  124  may be a same agent as the fusing agent  122 . In other examples, the energy absorbing agent  124  may be a different agent than the fusing agent  122 . By way of particular example, the energy absorbing agent  124  may be a degradable agent that is to degrade within a predetermined time period following receipt of the supplied energy  132  or when placed into the presence of another agent. For instance, the degradable agent may be a liquid that is to degrade, e.g., evaporate, disintegrate, or the like, for instance, after a few minutes, a few hours, etc., after receiving the energy  132 . In some examples, the degradable agent may be degradable through receipt of a chemical agent, for instance, that degrades the degradable agent without degrading or harming the particles  102 . The degradable agent may degrade during fabrication of an object or following fabrication of the object. In any of these examples, the particles  102  upon which the energy absorbing agent  124  has been deposited may be reused, e.g., recycled, following degradation of the energy absorbing agent  124 . In any of these examples, the density level, e.g., the contone level, at which the droplets of the energy absorbing agent  124  are deposited onto the unfused thermal support area  106  may substantially be lower than the density level at which the droplets of the fusing agent  122  are deposited onto the fusing area  104 . In addition or in other examples, the energy absorbing agent  124  may be mixed with a cooling agent and/or a defusing agent. 
     As the particles  102  in the fusing area  104  may be at a higher temperature than the particles  102  on which the fusing agent  122  has not be been deposited, thermal bleed may occur from the particles  102  in the fusing area  104  to the particles  102  outside of the fusing area  104 . That is, heat from the particles  102  in the fusing area  104  may be transferred to the particles  102  in the areas surrounding the fusing area  104 . When the fusing area  104  is at or above a certain size, the particles  102  in the fusing area  104  may be heated and may remain heated at a sufficiently high temperature such that the thermal bleed that occurs may be insufficient to prevent the particles  102  from melting and fusing together as intended, e.g., to have an intended strength, rigidity, hardness, color, translucency, surface roughness, combinations thereof, or the like. However, when the size of the fusing area  104  is below the certain size, the rate at which thermal bleed occurs may result in the particles  102  in the fusing area  104  from failing to reach and/or remain at or above the melting point temperature for sufficient melting to occur such that the particles  102  fuse together as intended. The certain size may pertain to a thickness, a width, a length, an area, a volume, or combinations thereof, of the fusing area  104 , which may extend across multiple layers of particles  102 . The certain size may also be referenced herein as a predefined size. 
     The certain size may depend, for instance, upon the type of particle  102 , the type of fusing agent  122 , the type and/or strength of energy  132  emitted by the energy supply system  130 , combinations thereof, and the like. In some examples, the certain size may be determined through testing of different combinations of particle  102  types, fusing agent  122  types, energy  132  types and/or strengths, etc. In addition or in other examples, the certain size may be the same for different combinations of particle  102  types, fusing agent  122  types, energy  132  types and/or strengths, etc. In any of these examples, the controller  110  may form the unfused thermal support area  106  adjacent to the fusing area  104  when the fusing area  104  is below the certain size and may not form the unfused thermal support area  106  when the fusing area  104  is at or above the certain size. 
     According to examples disclosed herein, the unfused thermal support area  106  may reduce the rate at which thermal bleed occurs from the particles  102  in the fusing area  104 . In this regard, the unfused thermal support area  106  may facilitate the melting and fusing together of the particles  102  in the fusing area  104 . In other words, because the particles  102  in the unfused thermal support area  106  are at a higher temperature than the particles  102  outside of the unfused thermal support area  106  and the fusing area  104 , a thermal gradient between the particles  102  in the fusing area  104  and the particles  102  in the unfused thermal support area  106  may be smaller than a thermal gradient between the particles  102  in the fusing area  104  and the particles  102  outside of the unfused thermal support area  106 . As such, the rate at which heat is transferred from the particles  102  in the fusing area  104  to the particles  102  in the unfused thermal support area  106  may be lower than the rate at which heat is transferred from the particles  102  in the fusing area  104  to the particles  102  outside of the unfused thermal support area  106 . This may result in the particles  102  in the fusing area  104  to be at a higher temperature, which may reduce the effects of thermal bleed and the particles  102  may thus reach and/or remain at a sufficiently high temperature for the particles  102  to melt and fuse together as intended. 
     The unfused thermal support area  106  may have a similar shape to the fusing area  104  or may have a different shape from the fusing area  104 . The unfused thermal support area  106  may extend at a same distance from the entire periphery of the fusing area  104  or may extend different distances at different locations around the fusing area  104 . The distance or distances at which the unfused thermal support area  106  extends from the fusing area  104 , e.g., the width or widths of the unfused thermal support area  106 , may be based on the amount of temperature increase for the particles  102  in the fusing area  104  to fuse as intended. The width or widths at which the unfused thermal support area  106  may be determined based on testing, estimations of thermal bleed, correlations between fusing area  104  sizes and thermal bleed, etc. In addition, in various examples, the unfused thermal support area  106  may be formed to increase a local temperature around the unfused thermal support area  106  to, for instance, make the temperature distribution on a particle bed more uniform. 
     According to examples, and as shown in  FIG.  1 A , the entire fusing area  104  may be below the certain size. In these examples, the unfused thermal support  106  may be formed around the entire periphery of the fusing area  104 . In other examples, and as shown with respect to  FIG.  1 B , the fusing area  104  may have an irregular shape. That is, the fusing area  104  may include a first feature  140  that is below the certain size and a second feature  142  that is above the certain size. In these examples, a unfused thermal support area  106  may be formed adjacent to the first feature  140  without a unfused thermal support area  106  being formed adjacent to the second feature  142 . In one regard, the unfused thermal support area  106  may selectively be formed to increase the temperature of the particles  102  in the areas of an object that are below the certain size. In addition, the unfused thermal support area  106  may not be adjacent to the second feature  142 , e.g., immediately next to second feature  142 , as the second feature  142  may reach and/or remain at a temperature above the melting point temperature of the particles  102  due to the sufficiently large size of the second feature  142 . As such, thermal bleed of the particles  102  forming the second feature  142  may not be sufficient to prevent the particles  102  forming the second feature  142  from melting and fusing together as intended. 
     Turning now to  FIGS.  1 C- 1 E , there are respectively shown cross-sectional side views of layers of particles  102  on which a fusing area  104  and an example unfused thermal support area  106  have been formed. With reference first to  FIG.  10   , the unfused thermal support area  106  may be formed beneath the fusing area  104 . That is, for instance, the fusing area  104  may be formed directly on top of the particles  102  forming the unfused thermal support area  106 . As shown in  FIG.  1 D , the unfused thermal support area  106  may be formed above the fusing area  104  and as shown in  FIG.  1 E , a first unfused thermal support area  106  may be formed beneath the fusing area  104  and a second unfused thermal support area  106  may be formed above the fusing area  104 . In addition or in other examples, unfused support areas  106  may be formed in various combinations of locations with respect to the fusing area  104 . It should thus be understood that  FIGS.  1 A- 1 E  may indicate that the unfused thermal support area  106  may be formed on any side or on multiple sides adjacent to the fusing area  104 . As used herein, the term “adjacent” with reference to an unfused thermal area  106  may refer to any side, including laterally, below or above, the fusing area  104 . 
     Turning now to  FIG.  2   , there is shown a diagram of another example 3D fabrication system  200  that may form an unfused thermal support area to reduce a rate at which particles forming a portion of a 3D object thermally bleeds. The 3D fabrication system  200  may be similar to the 3D fabrication system  100  depicted in  FIG.  1 A  and may include many of the same components. However, in the 3D fabrication system  200 , the agent delivery system  120  is depicted as including multiple delivery devices  202 ,  204 . That is, the agent delivery system  120  is depicted as including a first agent delivery device  202  that may deliver the fusing agent  122  and a second agent delivery device  204  that may deliver the energy absorbing agent  124 . As noted above, the energy absorbing agent  124  may be the same as or may differ from the fusing agent  122 . 
     Although not shown, the energy supply system  130  may also include a single energy supply device or multiple energy supply devices. In any regard, the energy supply system  130  may supply any of various types of energy. For instance, the energy supply system  130  may supply energy in the form of light (visible, infrared, or both), in the form of heat, in the form of electromagnetic energy, combinations thereof, or the like. According to examples, the type and/or amount of fusing agent  122  and energy absorbing agent  124  deposited onto the particles  102  may be tuned to the type and strength of the energy that the energy supply system  130  emits such that, for instance, the particles  102  may be heated as intended. By way of example, the tuning may be implemented to maximize the heating of the particles  102  while minimizing the amount of energy applied by the energy supply system  130 . 
     The 3D fabrication system  200  may also include build platform  210 , which may be in a build chamber within which 3D objects may be fabricated from the particles  102  provided in respective layers on the build platform  210 . Particularly, the build platform  210  may be provided in a build chamber and may be moved downward as features of a 3D object are formed in successive layers of the particles  102 . Although not shown, the particles  102  may be supplied between a recoater  212  and the build platform  210  and the recoater  212  may be moved in a direction represented by the arrow  214  across the build platform  210  to spread the particles  102  into a layer. In addition, the agent delivery system  120  and the energy supply system  130  may be moved across the build platform  210  as indicated by the arrow  216  to fuse together particles  102  in selected areas of layers of particles  102 . For instance, the agent delivery system  120  and the energy supply system  130  may be supported on a carriage that is to move in the directions  216 . In some examples, the recoater  212  may be provided on the same carriage. In other examples, the agent delivery system  120  and the energy supply system  130  may be supported on separate carriages such that the agent delivery system  120  and the energy supply system  130  may be moved separately with respect to each other. In any regard, following formation of a layer of particles  102  and a portion of a 3D object on the layer, the recoater  212  may be implemented to form another layer and this process may be repeated to fabricate the 3D object. 
     Although not shown, the 3D fabrication system  200  may include a heater to maintain an ambient temperature of the build envelope or chamber at a relatively high temperature. In addition or in other examples, the build platform  210  may be heated to heat the particles  102  to a relatively high temperature. The relatively high temperature may be a temperature near the melting temperature of the particles  102  such that a relatively low level of energy  132  may be applied to selectively fuse the particles  102 . 
     With reference now to  FIG.  3   , there is shown a block diagram of an example apparatus  300  that may cause an unfused thermal support area to be formed adjacent to a selected area during formation of a portion of a 3D object. It should be understood that the example apparatus  300  depicted in  FIG.  3    may include additional features and that some of the features described herein may be removed and/or modified without departing from the scope of the apparatus  300 . In addition, the features of the apparatus  300  are described with respect to the components of the 3D fabrication systems  100 ,  200  discussed above with respect to  FIGS.  1 A and  2   . 
     Generally speaking, the apparatus  300  may be a computing device, a control device of a 3D fabrication system  100 ,  200 , or the like. As shown in  FIG.  3   , the apparatus  300  may include a controller  302  that may control operations of the apparatus  300 . The controller  302  may be equivalent to the controller  110  discussed above. The controller  302  may be a semiconductor-based microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and/or other suitable hardware device. 
     The apparatus  300  may also include a memory  310  that may have stored thereon machine readable instructions  312 - 316  (which may also be termed computer readable instructions) that the controller  302  may execute. The memory  310  may be an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. The memory  310  may be, for example, Random Access memory (RAM), an Electrically Erasable Programmable Read-Only Memory (EEPROM), a storage device, an optical disc, and the like. The memory  310 , which may also be referred to as a computer readable storage medium, may be a non-transitory machine-readable storage medium, where the term “non-transitory” does not encompass transitory propagating signals. 
     The controller  302  may fetch, decode, and execute the instructions  312  to cause fusing agent  122  to be deposited onto a selected area, e.g., a fusing area  104 , of a layer of particles  102  of build material. For instance, the controller  302  may control the agent delivery system  120  to deposit the fusing agent  122  onto the selected area of the layer of particles  102 . The controller  302  may fetch, decode, and execute the instructions  314  to cause an energy absorbing agent  124  to be deposited onto an unfused thermal support area  106  of the layer of particles  102  that is adjacent to the selected area  104 . For instance, the controller  302  may control the agent delivery system  120  to deposit the energy absorbing agent  124  onto the unfused thermal support area  106  of the layer of particles  102 . The controller  302  may fetch, decode, and execute the instructions  316  to cause energy to be applied. For instance, the controller  302  may control the energy supply system  130  to supply energy  132  onto the layer of particles  102 , the deposited fusing agent  122 , and the deposited energy absorbing agent  124 . As discussed herein, application of the energy  132  may cause the particles  102  on which the fusing agent  122  has been deposited to be heated to a temperature above a melting point temperature of the particles  102  and the particles  102  on which the energy absorbing agent  124  has been deposited to be heated to a higher temperature that is below the melting point temperature of the particles  102 . 
     In other examples, instead of the memory  310 , the apparatus  300  may include hardware logic blocks that may perform functions similar to the instructions  312 - 316 . In yet other examples, the apparats  300  may include a combination of instructions and hardware logic blocks to implement or execute functions corresponding to the instructions  312 - 316 . In any of these examples, the controller  302  may implement the hardware logic blocks and/or execute the instructions  312 - 316 . 
     Various manners in which the controller  110 ,  302  may operate are discussed in greater detail with respect to the method  400  depicted in  FIG.  4   . Particularly,  FIG.  4    depicts a flow diagram of an example method  400  for forming an unfused thermal support area  106 . It should be understood that the method  400  depicted in  FIG.  4    may include additional operations and that some of the operations described therein may be removed and/or modified without departing from scope of the method  400 . The description of the method  400  is made with reference to the features depicted in  FIGS.  1 A- 3    for purposes of illustration. 
     At block  402 , the controller  110 ,  302  may control an agent delivery system  120  to deposit a fusing agent  122  onto a fusing area  104  of a layer of particles  102  of build material corresponding to an object being fabricated. 
     At block  404 , the controller  110 ,  302  may control the agent delivery system  120  to deposit an energy absorbing agent  124  onto an unfused thermal support area  106  of the layer of particles  102 . 
     At block  406 , the controller  110 ,  302  may control an energy supply system  130  to supply energy  132  onto the layer of particles  102 , including the deposited fusing agent  122  and the deposited energy absorbing agent  124 . As discussed herein, application of the energy  134  may cause the particles  102  on which the fusing agent  122  has been deposited to be heated to a temperature above a melting point temperature of the particles  102  and the particles  102  on which the energy absorbing agent  124  has been deposited to be heated to a higher temperature that is below the melting point temperature of the particles  102 . As also discussed herein, by increasing the temperature of the particles  102  in an area adjacent to the fusing area  104 , the rate at which thermal bleed occurs among the particles  102  in the fusing area  104  may be reduced. This may also result in the particles  102  in the fusing area  104  reaching and remaining at a temperature above a melting point temperature of the particles  102  to cause the particles  102  to melt and properly fuse together. 
     According to examples, at block  404 , the controller  110 ,  302  may control the agent delivery system  120  to deposit the energy absorbing agent  124  at a sufficiently low contone level to cause the particles  102  on which the energy absorbing agent  124  is deposited to remain unfused responsive to receipt of energy from the energy supply system  130 . In addition or in other examples, the controller  110 ,  302  may control the agent delivery system  120  to deposit a mixture of the energy absorbing agent  124  and a cooling agent and/or a defusing agent to cause the particles  102  on which the energy absorbing agent  124  is deposited to remain unfused responsive to receipt of energy from the energy supply system  130 . 
     In other examples, the controller  110 ,  302  may determine whether the fusing area  104  corresponds to a portion of the object to be fabricated that has a size below a predefined size. In these examples, the controller  110 ,  302  may control the agent delivery system  120  to deposit the energy absorbing agent  124  in the unfused thermal support area  106  based on the size of the fusing area  104  falling below the predefined size. In addition, the controller  110 ,  302  may not control the agent delivery system  120  to deposit the energy absorbing agent  124  in an unfused thermal support area  106  based on the size of the fusing area  104  meeting or exceeding the predefined size. In other words, the controller  110 ,  302  may control the agent delivery system  120  to form an unfused thermal support area  106  based on a determination that the particles  102  in the fusing area  104  may not reach the melting point temperature without the unfused thermal support area  106 . 
     Some or all of the operations set forth in the method  400  may be included as utilities, programs, or subprograms, in any desired computer accessible medium. In addition, the method  400  may be embodied by computer programs, which may exist in a variety of forms both active and inactive. For example, they may exist as machine readable instructions, including source code, object code, executable code or other formats. Any of the above may be embodied on a non-transitory computer readable storage medium. 
     Examples of non-transitory computer readable storage media include computer system RAM, ROM, EPROM, EEPROM, and magnetic or optical disks or tapes. It is therefore to be understood that any electronic device capable of executing the above-described functions may perform those functions enumerated above. 
     Although described specifically throughout the entirety of the instant disclosure, representative examples of the present disclosure have utility over a wide range of applications, and the above discussion is not intended and should not be construed to be limiting, but is offered as an illustrative discussion of aspects of the disclosure. 
     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 only and are not meant as limitations. Many variations are possible within the spirit and scope of the disclosure, which is intended to be defined by the following claims—and their equivalents—in which all terms are meant in their broadest reasonable sense unless otherwise indicated.