Patent Publication Number: US-2021178406-A1

Title: 3d printing system with cylone separator

Description:
BACKGROUND 
     In three-dimensional (3D) printing, an additive printing process is often used to make three-dimensional solid parts from a digital model. 3D printing is often used in rapid product prototyping, mold generation, mold master generation, and short-run manufacturing. Some 3D printing techniques are considered additive processes because they involve the application of successive layers of material to an existing surface (template or previous layer). This is unlike traditional machining processes, which often rely upon the removal of material to create the final part. 3D printing often requires curing or fusing of the building material, which for some materials may be accomplished using heat-assisted extrusion, melting, or sintering, and for other materials may be performed through curing of polymer-based build materials. 
    
    
     
       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. 1A  shows a diagram of an example 3D printing system that may include an example cyclone separator to separate build material particles from airflow; 
         FIG. 1B  shows a diagram of the example cyclone separator depicted in  FIG. 1A ; 
         FIG. 2  shows a block diagram of an example 3D printing system; and 
         FIGS. 3 and 4 , respectively, show flow diagrams of example methods for moving build material particles in a 3D printing system. 
     
    
    
     DETAILED DESCRIPTION 
     Disclosed herein are 3D printing systems that may implement feed lines through which build material particles mixed with airflow may be moved from material bins to other locations in the 3D printing systems. A location in a 3D printing system may include, for instance, a hopper from which build material particles may be supplied to a spreader that is to spread the build material particles over a build platform. Another location may be a hopper from which build material particles may be supplied into a storage bin, e.g., reclaimed build material particles may be stored in a reclaimed material storage bin for reuse and/or storage. In any regard, the 3D printing systems disclosed herein may include a cyclone separator that may separate the build material particles from the mixture such that the separated build material particles may be stored in a hopper. 
     As discussed herein, the cyclone separator may receive the mixture of airflow and build material particles from the feed line and may separate the build material particles from the airflow. The cyclone separator may include a chamber wall, a build material particle discharge opening, and a tapered wall connecting the chamber wall and the build material particle discharge opening. A ratio between a diameter of the chamber and a diameter of the discharge opening may be between about 1.5 and about 4.0. The cyclone separator disclosed herein may have a relatively short height while also having a relatively large discharge opening to enable the build material particles to be separated and exhausted from the cyclone separator at a relatively fast rate. In one regard, therefore, the cyclone separator disclosed herein may fit within relatively tight spaces as may be available in 3D printing systems. 
     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.” 
     Reference is first made to  FIGS. 1A and 1B .  FIG. 1A  shows a diagram of an example 3D printing system  100  that may include an example cyclone separator  102  to separate build material particles from airflow.  FIG. 1B  shows a diagram of the example cyclone separator  102  depicted in  FIG. 1A . It should be understood that the 3D printing system  100  depicted in  FIGS. 1A and 1B  and the cyclone separator  102  depicted in  FIG. 1B  may include additional components and that some of the components described herein may be removed and/or modified without departing from scopes of the 3D printing system  100  and the cyclone separator  102  disclosed herein. 
     As shown in  FIGS. 1A and 1B , the 3D printing system  100  may include a feed line  104  through which build material particles, as represented by the arrow  106 , may be fed from a material bin (not shown) into the cyclone separator  102 . Particularly, the feed line  104 , which may be a conduit, a pipe, etc., may be attached to a feed member  108  that is attached to the cyclone separator  102 . The feed member  108  may terminate at an inlet  110  of the cyclone separator  102 . Generally speaking, the build material particles  106  may be delivered from the material bin to the cyclone separator  102  through mixing of the build material particles  106  with airflow and the cyclone separator  102  may separate the build material particles  106  from the airflow. 
     As also shown in  FIG. 1A , the 3D printing system  100  may include an air pressure generator  112  to generate the airflow through the feed line  104 . The air pressure generator  112  may be a fan, a blower, etc., and may pressurize the feed line  104  to generate airflow through the feed line  104 . As the air flows through the feed line  104 , build material particles  106  may be supplied into the airflow from the material bin. The supplied build material particles  106  may be mixed with the airflow in the feed line  104  such that the build material particles  106  may be delivered from the material bin to the cyclone separator  102 . 
     The cyclone separator  102  may include features that are to cause the build material particles  106  to separate from the airflow. As shown, the chamber  114  may be formed of a chamber wall  201 , which may have a circular cross-section at an upper section of the chamber  114  and a tapered wall  118  along a bottom section of the chamber  114 . In addition, a discharge opening  120  may be formed at the bottom of the tapered wall  118 . The cyclone separator  102  may also include an airflow exhaust member  122  having a plurality of openings  124  through which airflow may be exhausted from the chamber  114 . In addition or in other examples, the cyclone separator  102  may be formed of a material that is at least one of anti-static, electrically conductive, triboelectrically similar to the materials, e.g., build material particles  106 , being transported, etc., to reduce adhesion of the build material particles onto the walls of the cyclone separator  102 . 
     In operation, the air pressure generator  112  pressurizes the feed line  104 , which may cause the mixture of airflow and the build material particles  106  to be fed into the chamber  114  of the cyclone separator  102 . In some examples, the velocity of the airflow may be between around 10 m/sec and about 20 m/sec. In any regard, the shape of the cyclone separator  102 , e.g., the chamber  114  and the tapered wall  118 , may cause the mixture of airflow and build material particles  106  to swirl around inside the chamber  114 . That is, the mixture of airflow and build material particles  106  may swirl around in the form of a cyclone, e.g., in a helical pattern, such that rotational effects inside the chamber  114  and gravity separate the build material particles  106  from the mixture. As the build material particles  106  separate from the mixture, the build material particles  106  may fall through the discharge opening  120 . In addition, the airflow may flow out of the chamber through the openings  124  and through an airflow exhaust tube  126 . The airflow may also be exhausted from the 3D printing system  100  as indicated by the arrow  128 . 
     According to examples, the diameter  130  of the chamber  114  may be about 1.5 to about 4.0 times larger than the diameter  132  of the discharge opening  120 . In other words, a ratio between the diameter  130  of the chamber  114  and the diameter  132  of the discharge opening  120  may be between about 1.5 and about 4.0. In some examples, the diameter  130  of the chamber  114  may be between 1.4 to 4.1 times larger than the diameter  132  of the discharge opening  120 . By way of particular example, the diameter  130  of the chamber  114  may be about 3.6 times larger than the diameter  132  of the discharge opening  120 . 
     As also shown in  FIG. 1B , the airflow exhaust member  122  may include a first end  140  that extends into the chamber  114 . The first end  140  may include an end cap  142  and the plurality of openings  124  (which are also referenced herein as apertures  124 ) that extend along the airflow exhaust member  122 . The end cap  142  may have a conical shape that extends away from the discharge opening  120  and toward the airflow exhaust tube  126 . The conical shape of the end cap  142  may facilitate the flow of airflow through the openings  124  through a hole  144  of the airflow exhaust member  122  while minimizing the flow of build material particles through the airflow exhaust member  122 . 
     The hole  144  in the airflow exhaust member  122  may have a diameter  146 . A ratio between the diameter  130  of the chamber  114  and the diameter  146  of the hole  144  in the airflow exhaust member  122  may be between about 2 and about 4. That is, for instance, the diameter  130  of the chamber  114  may be about 2 to about 4 times larger than the diameter  146  of the hole  144 . By way of particular example, the diameter  130  of the chamber  114  may be 2.5 times larger than the diameter  146  of the hole  144 . In addition, a ratio between a height  148  of the chamber  114  and a height  150  of the tapered wall  118  may be between about 0.7 and about 1.5. By way of particular example, the ratio between the height  148  of the chamber  114  and the height  150  of the tapered wall  118  may be about 0.8. 
     In terms of other dimensions, the diameter  130  of the chamber  114  may be about 7.9 times larger than a diameter of the inlet  110 . The diameter  130  of the chamber  114  may be about 2.7 times larger than the height  148  of the chamber  114 . In addition, the diameter  130  of the chamber  114  may be about 2.3 times larger than the height  150  of the tapered wall  118 . 
     As also shown in  FIG. 1B , a material output tube  152  may be attached to the cyclone separator  102  such that material, as represented by the arrows  154 , expelled through the discharge opening  120  of the cyclone separator  102  may be directed to a desired location, e.g., a hopper. According to examples, the discharge opening  120  may have a diameter  132  that is between about 20 mm to about 40 mm. In a particular example, the discharge opening  120  may have a diameter  132  that is about 20 mm. 
     With reference now to  FIG. 2 , there is shown a block diagram of another example 3D printing system  200  in which the cyclone separator  102  disclosed herein may be implemented. It should be understood that the 3D printing system  200  depicted in  FIG. 2  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 printing system  200  disclosed herein. The description of  FIG. 2  is made with reference to the elements shown in  FIGS. 1A and 1B . 
     The 3D printing system  200  may include a build chamber  202  within which a 3D object  204  may be fabricated from build material particles  201  provided in respective layers in a build bucket  206 . Particularly, a movable build platform  208  may be provided in the build bucket  206  and may be moved downward as the 3D object  204  is formed in successive layers of the build material particles  201 . An upper hopper  212 , which may include the cyclone separator  102  discussed above with respect to  FIGS. 1A and 1B , may supply a spreader  210  with the build material particles  201  and the spreader  210  may move across the build bucket  206  to form the successive layers of build material particles  201 . That is, the cyclone separator  102  may separate the build material particles  201  from the airflow and may supply the build material particles  201  to the spreader  210 . 
     The build material particles  201  may be formed of any suitable material including, but not limited to, polymers, metals, and ceramics and may be in the form of a powder. Additionally, the build material particles  201  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 build material particles  201  may have dimensions that are generally between about 30 μm and about 60 μm. The build material particles  201  may have any of multiple shapes, for instance, as a result of larger particles being ground into smaller particles. 
     Forming components  214  may be implemented to deliver an agent onto selected locations on the layers of build material particles  201  to form sections of the 3D object  204  in the successive layers. The forming components  214  may include an agent delivery device or multiple agent delivery devices, e.g., printheads, fluid delivery devices, etc. Thus, although the forming components  214  have been depicted as a single element, it should be understood that the forming components  214  may represent multiple elements. A heating mechanism  203  to apply heat onto the layers of build material particles  201  to form the sections of the 3D object  204  may also be provided in the build chamber  202 . 
     According to examples, the agent may be a fusing agent that may enhance absorption of heat from the heating mechanism  203  to heat the build material particles  201  to a temperature that is sufficient to cause the build material particles  201  upon which the agent has been deposited to melt. In addition, the heating mechanism  203  may apply heat, e.g., in the form of heat and/or light, at a level that causes the build material particles  201  upon which the agent has been applied to melt without causing the build material particles  201  upon which the agent has not been applied to melt. 
     The forming components  214  may supply multiple types of agents onto the layers build material particles  201 . The multiple types of agents may include agents having different properties with respect to each other. In this regard, the processor  207  may control the forming components  214  to supply the agent or a combination of agents that results in the object  204  having certain features. By way of particular example, the multiple types of agents may be different colored inks and the processor  207  may control the forming components  214  to deposit an agent or a combination of agents onto build material particles  201  to form an object  204  having a particular color from those build material particles  201 . 
     The 3D printing system  200  may include an apparatus  205 , which may include a processor  207  that may control various operations in the 3D printing system  200 , including the spreader  210 , the hopper  212 , and the forming components  214 . The processor  207  may implement operations to control the forming components  214  to form the 3D object  204  in a volume of build material particles  201  contained in the build bucket  206 . 
     The build material particles  201  used to form the 3D object  204  may be composed of build material particles from a fresh supply  220  of build material particles, build material particles from a recycled supply  222  of build material particles, or a mixture thereof. The fresh supply  220  may represent a removable container that contains build material particles that have not undergone any 3D object formation cycles. The recycled supply  222  may represent a removable container that contains build material particles that have undergone at least one 3D object formation cycle and may contain build material particles that have undergone different numbers of 3D object formation cycles with respect to each other. As shown, the build material particles in the fresh supply  220  may be provided into a fresh material hopper  224  and the build material particles in the recycled supply  222  may be provided into a recycled material hopper  226 . Additionally, the build material particles in either or both of the fresh material hopper  224  and the recycled material hopper  226  may be supplied to the upper hopper  212 , which may include a cyclone separator  102 . The build material particles may be provided into the hoppers  224 ,  226  from the respective supplies  220 ,  222  prior to implementing a print job to ensure that there are sufficient build material particles to complete the print job. 
     Generally speaking, the processor  207  may control the mixture or ratio of the fresh build material particles and recycled build material particles that are supplied to the upper hopper  212 . The ratio may depend upon the type of 3D object  204  being formed. For instance, a higher fresh build material particle to recycled build material particle ratio, e.g., up to a 100 percent fresh build material particle composition, may be supplied when the 3D object  204  is to have a higher quality, to have thinner sections, have higher tolerance requirements, or the like. Conversely, a lower fresh build material particle to recycled build material particle ratio, e.g., up to a 100 percent recycled build material particle composition, may be supplied when the 3D object  204  is to have a lower quality as may occur when the 3D object  204  is a test piece or a non-production piece, when the 3D object  204  is to have lower tolerance requirements, or the like. The ratio may be user-defined, may be based upon a particular print job, may be based upon a print setting of the 3D printing system  200 , and/or the like. 
     In any regard, the processor  207  may control the ratio of the fresh and the recycled build material particles supplied to the upper hopper  212  through control of respective feeders  228 ,  230 . A first feeder  228  may be positioned along a supply line from the fresh material hopper  224  and a second feeder  230  may be positioned along a supply line  232 , which may be equivalent to the feed line  104  depicted in  FIGS. 1A and 1B , from the recycled material hopper  226 . The first feeder  228  and the second feeder  230  may be rotary airlocks that may regulate the flow of the build material particles from the respective hoppers  224 ,  226  along a feed line  232  toward the upper hopper  212 . The feed line  232  may also be supplied with air from an input device  234  to assist in the flow of build material particles from the hoppers  224 ,  226  to the upper hopper  212  and cyclone separator  102 . 
     A third feeder  236 , which may also be a rotary airlock (which allows forward-flow of powder and restricts back-flow of air), may be positioned along a supply line from the upper hopper  212  to the spreader  210 . The upper hopper  212  may include a level sensor (not shown) that may detect the level of build material particles contained in the upper hopper  212 . The processor  207  may determine the level of the build material particles contained in the upper hopper  212  from the detected level and may control the feeders  228 ,  230  to supply additional build material particles in a particular ratio when the processor  207  determines that the build material particle level in the upper hopper  212  is below a threshold level, e.g., to ensure that there is a sufficient amount of build material particles to form a layer of build material particles having a certain thickness during a next spreader  210  pass. 
     The 3D printing system  200  may also include a collection mechanism  209 , which may include a blow box  240 , a filter  242 , a sieve  244 , and a reclaimed material hopper  246 . Airflow through the collection mechanism  209  may be provided by a collection blower  248 . The collection mechanism  209  may reclaim incidental build material particles  201  from the build bucket  206  as well as from a location adjacent to the build bucket  206  as shown in  FIG. 2 . Particularly, following formation of the 3D object  204 , the build material particles  201  may remain in powder form and the collection mechanism  209  may reclaim the build material particles  201  that were not formed into the 3D object  204 . That is, the incidental build material particles  201  may be separated from the 3D object  204  through application of a vacuum force inside the build bucket  206 . The collection mechanism  209  may also be vibrated to separate the incidental build material particles  201  from the 3D object  204 . 
     The incidental build material particles  201  in the build bucket  206  may be sucked into the blow box  240  and through the filter  242  and the sieve  244  before being collected in the reclaimed material hopper  246 . Additionally, during spreading of the build material particles  201  to form layers on the build bucket  206 , e.g., as the spreader  210  moves across the build bucket  206 , excess build material particles  201  may collect around a perimeter of the build bucket  206 . As shown, a perimeter vacuum  216  may be provided to collect the excess build material particles  201 , such that the collected build material particles  201  may be supplied to the collection mechanism  209 . A valve  250 , such as an electronically controllable three-way valve, may be provided along a feed line  252  from the build bucket  206  and the perimeter vacuum  216 . In examples, the processor  207  may manipulate the valve  250  such that particles flow from the perimeter vacuum  216  during formation of the 3D object  204  and flow from the build bucket  206  following formation of the 3D object  204 . 
     A fourth feeder  254 , which may also be a rotary airlock, may be provided to feed the reclaimed build material particles  256  contained in the reclaimed material hopper  246  to the upper hopper  212  and/or to a lower hopper  258 . The fourth feeder  254  may feed the reclaimed build material particles  256  through the feed line  232 . A valve  260 , such as an electronic three-way valve, e.g., the valve  260  may be a three-port, two-state valve in which materials may flow in one of two directions), may be provided along the feed line  232  and may direct the reclaimed build material particles  256  to the upper hopper  212  and cyclone separator  102  (which may be positioned in or atop the upper hopper  212 ) or may divert the reclaimed build material particles  256  to the lower hopper  258 , which may also include the cyclone separator  102  discussed with respect to  FIGS. 1A and 1B . The processor  207  may also manipulate the valve  260  to control whether the reclaimed build material particles  256  are supplied to the upper hopper  212  or the lower hopper  258 . As discussed above, the processor  207  may make this determination based upon the ratio of fresh and recycled build material particles that is to be used to form the 3D object  204 . In addition, or in other examples, the cyclone separator  102  in the lower hopper  258  may be implemented to assist in a material changeout in which, for instance, the material in the hoppers  220  and  226  may be emptied into the recycled supply  222  prior to new powder being supplied via the fresh supply  220  and the fresh material hopper  224 . 
     A fifth feeder  262 , which may also be a rotary airlock, may be provided to feed the reclaimed build material particles  256  contained in the lower hopper  258  and cyclone separator  102  to the recycled supply  222  and/or the recycled material hopper  226 . The processor  207  may control the fifth feeder  262  to feed the reclaimed build material particles  256  into the recycled supply  222  in instances in which the reclaimed build material particles  256  are not to be used in a current build. In addition, the processor  207  may control the fifth feeder  262  to feed the reclaimed build material particles  256  into the recycled material hopper  226  in instances in which the reclaimed build material particles  256  are to be used in a current build. 
     The 3D printing system  200  may also include a blower  270 , which may be equivalent to the air pressure generator  112 , that may create suction to enhance airflow through the lines in the 3D printing system  200 . The airflow may flow through a filter box  272  and a filter  274  that may remove particulates from the airflow from the upper hopper  212  and the lower hopper  258  prior to the airflow being exhausted from the 3D printing system  200 . In other words, the blower  270 , filter box  272 , and filter  274  may represent parts of the outlets of the cyclone separators  102  in the upper hopper  212  and the lower hopper  258  and may collect particulates that were not removed from the airflow in the cyclone separators  102  connected to the upper and/or lower hoppers  212  and  258 . 
     Although not shown in  FIG. 2 , the apparatus  205  may also include an interface through which the processor  207  may communicate instructions to a plurality of components contained in the 3D printing system  200 . The interface may be any suitable hardware and/or software through which the processor  207  may communicate the instructions. In any regard, the processor  207  may communicate with the components of the 3D printing system  200  as discussed above. 
     The processor  207  may be a semiconductor-based microprocessor, a central processing unit (CPU), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a graphics processing unit (GPU), a tensor processing unit (TPU), and/or other hardware device. The apparatus  205  may also include a memory  110  that may have stored thereon machine readable instructions (which may also be termed computer readable instructions) that the processor  207  may execute. The memory may be an electronic, magnetic, optical, or other physical storage device that contains or stores executable instructions. The memory 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, 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. 
     Various manners in which the apparatus  205  and the 3D printing system  200  may be implemented are discussed in greater detail with respect to the methods  300  and  400  respectively depicted in  FIGS. 3 and 4 .  FIGS. 3 and 4 , respectively, depict example methods  300  and  400  for moving build material particles within a 3D printing system. Particularly,  FIGS. 3 and 4 , respective depict example methods  300  and  400  for feeding build material particles to a cyclone separator  102  or to multiple cyclone separators  102  and for clearing out build material particles from the cyclone separator(s)  102 . It should be apparent to those of ordinary skill in the art that the methods  300  and  400  may represent a generalized illustration and that other operations may be added or existing operations may be removed, modified, or rearranged without departing from scopes of the methods  300  and  400 . 
     The descriptions of the methods  300  and  400  are made with reference to the apparatus  205 , the cyclone separator  102 , and the 3D printing system  200  illustrated in  FIGS. 1A, 1B, and 2  for purposes of illustration. It should be understood that apparatuses and 3D printing systems having other configurations may be implemented to perform the methods  300  and  400  without departing from scopes of the methods  300  and  400 . In any regard, the processor  207  may execute a set of machine readable instructions to execute the methods  300  and  400 . In addition, the method  400  may be implemented following the method  300  or may be implemented separately from the method  300 . 
     At block  302 , an air pressure generator  112  (e.g., blower  270 ) may be operated to generate airflow at a first flow rate within a feed line  104 ,  232  and a cyclone separator  102 . At block  304 , a feeder  228  to supply build material particles  201  into the feed line  104 ,  232  may be turned on to supply build material particles  201  into the feed line  104 ,  232  from a material hopper  224 . Turning on the feeder  228  may cause build material particles  201  to mix with the airflow in the feed line  104 ,  232  and to be delivered into the cyclone separator  102  located in the upper hopper  212  and/or the lower hopper  258 . In addition, as discussed above, the cyclone separator  102  may separate the build material particles  201  from the airflow and the separated build material particles  201  may be stored in the upper hopper  212  and/or the lower hopper  258 . 
     At block  306 , the feeder  228  may be turned off to stop the supply of material particles into the feed line  104 ,  232 . That is, for instance, the processor  207  may control the feeder  228  to move to a closed position following a predetermined length of time after controlling the feeder  228  to be turned on, e.g., moved to an opened position. The predetermined length of time may be based upon any number of factors, for instance, following completion of a print job, at a set interval of time, under a user direction, etc. 
     At block  308 , the air pressure generator  112 ,  270  may be operated to generate airflow at a second flow rate within the feed line  104 ,  232  and the cyclone separator  102 . The second flow rate may be significantly higher than the first flow rate and may remove the material particles  201  that have become attached to the cyclone separator  102 . The air pressure generator  112 ,  270  may be operated to generate airflow at the second (greater) flow rate for a certain period of time. The certain period of time may pertain to a length of time that is sufficient to remove the build material particles  201  from interior walls of the cyclone separator  102  and other conduits through which the build material particles  106  have been fed. 
     At block  310 , following the certain period of time, the air pressure generator  112 ,  270  may be operated to generate airflow at the first flow rate within the feed line  104 ,  232  and the cyclone separator  102 . In addition, at block  312 , the feeder  228  may be turned on, e.g., opened, to supply build material particles  201  into the airflow being fed in the feed line  104 ,  232  and into the cyclone separator  102 . 
     Turning now to  FIG. 4 , at block  402 , the feeder  228  may be turned off. At block  404 , a second feeder  230  to supply reclaimed build material particles  201  into the feed line  104 ,  232  may be turned on to supply reclaimed build material particles  201  into the feed line  104 ,  232  from a reclaimed material bin  226 . Turning on of the second feeder  230  may cause reclaimed build material particles  201  to mix with the airflow in the feed line  104 ,  232 . At block  406 , a valve  260  may be manipulated to direct airflow including the reclaimed build material particles  201  to a second cyclone separator  102 , for instance, the cyclone separator  102  located in the lower hopper  258 . As discussed above, the cyclone separator  102  may separate the build material particles  201  from the airflow and the separated build material particles  201  may be captured in the lower hopper  258 . 
     At block  408 , the feeder  230  may be turned off, e.g., stopped, to stop the transfer of reclaimed build material particles  201  into the feed line  104 ,  232 . That is, for instance, the processor  207  may control the feeder  230  to move to a closed position following a predetermined length of time after controlling the feeder  230  to move to an opened position. The predetermined length of time may be based upon any number of factors, for instance, following completion of a print job, at a set interval of time, under a user direction, etc. 
     At block  410 , the air pressure generator  112 ,  270  may be operated to generate airflow at a second flow rate within the feed line  104 ,  232  and the cyclone separator  102  in the lower hopper  258 . The second flow rate may be significantly higher than the first flow rate and may remove the material particles  201  that have become attached to the cyclone separator  102  and/or other conduits. The air pressure generator  112 ,  270  may be operated to generate airflow at the second flow rate for a certain period of time. The certain period of time may pertain to a length of time that is sufficient to remove the build material particles  201  from interior walls of the cyclone separator  102 . 
     At block  412 , following the certain period of time, the air pressure generator  112 ,  270  may be operated to generate airflow at the first flow rate within the feed line  104 ,  232  and the cyclone separator  102 . In addition, at block  414 , the feeder  230  may be turned on, e.g., opened, to supply build material particles  201  into the airflow being fed in the feed line  104 ,  232  and into the cyclone separator  102 . 
     Some or all of the operations set forth in the methods  300  and  400  may be contained as utilities, programs, or subprograms, in any desired computer accessible medium. In addition, some or all of the operations set forth in the methods  300  and  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.