Patent ID: 12194682

DETAILED DESCRIPTION OF THE INVENTION

At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention.

Furthermore, it is understood that this invention is not limited to the particular methodology, materials, or modifications described and, as such, the invention may vary from that which is disclosed herein. It is also understood that the terminology used herein is for the purpose of describing particular aspects, and this invention is not limited to the disclosed aspects.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention pertains. It should be understood that methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the method and apparatus.

Furthermore, as used herein, “and/or” is intended to mean a grammatical conjunction used to indicate that one or more of the elements or conditions recited may be included or occur. For example, a device comprising a first element, a second element and/or a third element, is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or, a device comprising a second element and a third element.

Adverting now to the figures, with specific reference inFIGS.1-2, the present invention may be embodied as a method or an apparatus8for SF/SR. In such a method or apparatus8, one or more additive manufactured parts10needing SF/SR are placed on a platform or tray13in a chamber16of an apparatus8for carrying out SF/SR. An SF/SR fluid22for dissolving and/or eroding the support material28may be sprayed at the part(s)10through nozzles25situated underneath the part(s)10or above the part(s)10or both. The nozzles25below the part(s)10and the nozzles25above the part(s)10may be referred herein as bottom nozzles25B and top nozzles25A, respectively. The fluid22may be supplied from a tank31, open at its upper side. The tank31may be situated below the bottom nozzles25. Located above the tank31below the nozzles25is an umbrella61. The umbrella61is aligned with the spray of fluid22from the nozzles25, and in particular with the spray of fluid22from the nozzles25from above the part10. The umbrella61has a shallow conical shape so that fluid22impacting the umbrella61from the nozzles25flows toward the periphery of the umbrella61. The periphery of the umbrella61has dimensions that are smaller than the open upper side of the tank31so that fluid22flowing down the umbrella61flows over the peripheral edge of the umbrella61into the tank31. A pump33may be used to draw fluid22from the tank31and then force the fluid22through a series of pipes50connected to the nozzles25, which causes the fluid22to spray out of the nozzles25at the part(s)10. Each nozzle25may comprise a pipe or tube section having multiple apertures or nozzles through which the fluid22sprays, and these arrangements are sometimes referenced herein, as a “spray-header”. The fluid22then collects back into the tank31where the fluid22is recycled back through the apparatus, i.e., drawn from the tank31, forced to the nozzles25, sprayed at the parts10, impacted upon the umbrella61, and collected in the tank31. In this mode of operation the apparatus8may be a closed-loop system.

Additive manufactured parts10may be made using numerous different methods, classes of materials (e.g., plastics, metals), specific build materials (e.g., nylon within the plastics class, aluminum within the metals class) and support materials. Each method, class of material, and specific build material can have its own unique qualities and characteristics and thus may require different parameters for effective and efficient removal of support material28. Additionally, for a given type, parts10made by such an additive manufacturing process and/or materials may have very different geometries, including designs having more delicate features than others, which thus may require adjustments for effective and efficient removal of support material28. As explained in more detail herein, the amount of fluid22sprayed, the direction of spray (from top and/or bottom), the location of spray (e.g., left versus right side of part or top versus bottom side of part), the pressure at which fluid22is pumped to the nozzles25, and the degree of atomization, as well as other parameters such as the make-up, temperature and pH of the fluid, can be adjusted to create different combinations or “recipes” of these parameters in order to efficiently and effectively remove a given type of support material28for a given type of build material35and geometric design of additive manufactured part(s)10. In some embodiments of the present invention, an operator can set or change these parameters using a human-machine interface (“HMI”)38, such as a touch screen108connected to a general-purpose computer having a central processing unit (“CPU”)102. The general-purpose computer may have wired or wireless communications links105for sending and receiving communications signals to/from components of the apparatus8.

The fluid22is capable of dissolving and/or degrading support material28, and may be aqueous-based chemical formulations made with a single chemical or a variety of chemicals. The fluid22may, in some embodiments, be referred to as a detergent. Preferably, the fluid22, either naturally or aided by the parameter settings, degrades or dissolves support material28and the rough surface of the part10without also degrading, dissolving or causing damage to the build material35of the part10that is intended to be preserved. Such fluids22can include but are not limited to those fluids that are optimized for SF/SR for parts10made by MJ, SLA and FDM, respectively. In one embodiment, the fluid22is a chemistry line product, such as PG2C support removal solution, available from PostProcess Technologies, Inc. Embodiments are disclosed in PCT/US2018/028685, filed Apr. 20, 2018 and PCT/US/201939398, filed Jun. 26, 2019, the entire disclosures of which are incorporated by reference herein. The fluid22can also include an anti-foaming agent to help minimize foaming of the fluid during the SF/SR process.

An embodiment of the present invention may be an apparatus8having a housing41comprising a first section44, a second section47arranged adjacent to said first section44, as illustrated inFIGS.1,3A,3B, and3C. The first section44may include a chamber16where the SF/SR of an additive manufactured part10occurs. The second section47may house many of the plumbing components for the apparatus8, such as a pump33, valves59, and hoses62. The second section47can be arranged either below or to the side of the first section44.

The first section44may include a door68for an operator to access the chamber, and place parts10into and remove them from the chamber16. The door68can be a counter-weighted balanced door to allow for easy access. As discussed further below, the chamber16may heat up during the apparatus' operation. The chamber16can include a ventilation or exhaust system to provide a heated equalized chamber16to aid both in the removal of support material28as well as enhancing the evaporation of residual fluid22off of the part10upon completion of the SF/SR process. A ventilation system may be of any type suitable for venting heat and vapors that can build up in the chamber16. As one example, the ventilation system may comprise one or more blowers75pulling air from the chamber16, such as blowers rated, for example, at 0.5 to 1000 cubic feet per minute (CFM). In this approach the ventilation system may create a negative pressure in the chamber16so that when the door68is opened, air is pulled inward through the door68. In another example, the ventilation system may comprise one or more fans or blowers75pushing air into the chamber16, combined with a chimney or other exhaust mechanism78in the roof of the chamber16. The fan or blower75may create a positive pressure in the chamber16and the chimney78allows excess heat and vapors to escape. Additionally, windows81may be placed in the sides of the chamber16to allow for in-process monitoring by humans and sensors of the SF/SR process.

A tray or platform13on which the parts10can be set while an SF/SR process occurs may be situated in the chamber16. A first plurality of nozzles25(such as the top nozzles25A) may be arranged in the chamber16, allowing for fluid22to be sprayed downward toward the parts10situated on the tray13. A second plurality of nozzles25(such as the bottom nozzles25B) may be arranged in the chamber16, directly below the tray13, allowing for fluid22to be sprayed upward toward the parts10situated on the tray13. The bottom nozzles25B and top nozzles25A are thus arranged opposite from each other, spraying in directions toward each other, with the parts10situated therebetween. The first section44also may include a tank31for holding the fluid22. The tank31may be situated below the bottom nozzles25B.

The tray13may have openings of suitable size, quantity and distribution, such as a mesh screen, so that the tray13can support the parts10, yet allow fluid22to be sprayed at the parts10from the bottom nozzles25B, allow fluid22sprayed from both the bottom and top nozzles25B,25A to flow down onto the umbrella61and then into the tank31, and help to prevent support material28that detaches from the part10from falling down into the tank31. A mesh screen53may be arranged beneath the umbrella61between the tank31and the bottom nozzles25B to further prevent pieces of detached support material28from entering the tank31. In this embodiment, the umbrella61is mounted on and attached to the mesh screen53. The mesh screen53has a size that corresponds to or is larger than the upper open side of the tank31. The size of the mesh screen53is greater than the periphery of the umbrella61so that the mesh screen53extends beyond the periphery of the umbrella61. Thus, fluid flowing off the edges of the umbrella61flows through the mesh screen53, but pieces of detached support material are captured on the mesh screen53. Although the mesh screen53is shown extending beneath the umbrella61, in alternative embodiments the mesh screen53may not extend beneath the umbrella, but may extend only beyond the peripheral edges of the umbrella61.

In one embodiment of the invention, a first plurality of nozzles25comprises a single spray-header of nozzles25, and in another embodiment of the invention the first plurality of nozzles25comprises more than a single spray-header of nozzles25, such as three spray-headers of top nozzles25A. The size of the apertures or nozzles in one spray-header of nozzles25can be different from the size of the apertures or nozzles in another spray-header, thereby resulting in different fluid velocities spraying from the two different sets of nozzles25, with one velocity being higher than the other. For example, in the embodiment with three sets of top nozzle spray-headers25A, the first and third sets can each comprise five apertures/nozzles of the same or similar size (or degree of spray angle), while the second set can comprise three apertures/nozzles of a larger size (or degree of spray angle). The top nozzles25A can be either mounted to the housing41itself, or mounted on a movable track42connected to an actuator43that allows the nozzles25to oscillate in the horizontal direction. The second plurality of nozzles25can be identical to the first plurality of nozzles25mounted on a movable track42that is connected to an actuator43, or can be stationary nozzles25that cannot move independently on a track. In one embodiment, the second plurality of nozzles25comprises a spray-header having thirteen nozzles25each of the same or similar size (or degree of spray angle).

In another embodiment of the invention, nozzles25could be arranged to surround the chamber16so that the nozzles25are on all six sides surrounding the part10in the chamber16. Each nozzle25can be independently controlled by a separate motor or be connected as a nozzle assembly. In this embodiment there are nozzles25mounted both horizontally and vertically.

FIG.4depicts a further embodiment of the invention in which the bottom nozzles25B are arranged as a U-shaped spray-header. As with the embodiment mentioned directly above, the nozzles25may spray the AM part10from different directions and thereby spray additional sides of the AM part10more directly. In a similar manner, the top spray-header of nozzles25A may be U-shaped. Or, both the top spray-header of nozzles25A and the bottom spray-header of nozzles25B may be U-shaped.

Servomotors or other actuators may be used to oscillate a spray-header of nozzles25through a range of distance about a center point. Interface and control buttons may enable an operator to adjust the location of the center point (by causing the spray-header of nozzles25to move forward or backward) and/or the speed at which the nozzles25oscillate. For example, the center point could be set anywhere between a range of 0-275 millimeters and the speed could be set anywhere between a range of 0-50 mm/sec. Or, these parameters may be pre-stored in connection with an operating recipe that the operator has the option to select. In one embodiment of the invention the operator can also adjust the distance that the nozzles25oscillate. The movement of each nozzle25may be tracked by a position sensor. The first plurality of nozzles25could be made to oscillate only if at least one of the valves59to a nozzle contained in the first plurality of nozzle25is open. In such an embodiment, if only the second plurality of nozzles25is activated, then the first plurality of nozzles25does not oscillate.

The nozzles25can be individual nozzles25, or can be tubes/piping having a plurality of apertures therein, e.g. a manifold (each such aperture is also referred to as a “nozzle”), or could include nozzles25secured to the tubes/piping. Additionally, the individual nozzles25, including individual nozzles secured to the tubes/piping, may be constructed to rotate independently, using motors, in order to spray parts10within the chamber16at a variety of angles. Each nozzle25may be independently controlled by a separate motor or be connected to each other so as to form a nozzle assembly. Additionally, each nozzle25could be controlled by a multi-axis robot. The nozzles25may be made to move in horizontal and/or vertical directions. It should be appreciated that each nozzle25may be connected to its own pump and plumbing system.

Both the first and second plurality of nozzles25(e.g., top and bottom nozzles25A,25B) may be connected to a pump33, which may be located within the second section47of the housing41. After drawing fluid22from the tank31, the pump33can force the fluid22through pipes50(which may be a flexible hose) to the nozzles25. A manifold may be used to separate the fluid22output from the pump33into separate supplies for each spray-header of nozzles25. The individual pipe50to each spray-header of nozzles25may include a valve59to control the flow of fluid22to the nozzles25. This arrangement allows nozzles25to be used selectively (on/off), thereby increasing efficiency where all of the nozzles25are not required for SF/SR and/or where it is preferred to have some nozzles25at higher or lower pressures than others.

For example, an embodiment of the invention may have one bottom spray-header of nozzles25and three top spray-headers of nozzles25, where at least one of the top spray-headers has narrow-angle nozzles25(producing comparatively higher velocity spray) and at least one of the other top spray-headers has wide-angle nozzles25(producing comparatively lower velocity spray). In each of the following examples, the valve59controlling flow to the bottom spray-header of nozzles25may always be open. In one mode of operation, all of the valves59controlling flow to the top nozzles25can be closed so that fluid22sprays only from the bottom spray-header25B. This mode can produce the lowest degree of agitation of the additively manufactured parts10being SF/SR processed in the chamber16, and may be referred to as “ultra-low agitation.” In another mode of operation the valve(s)59controlling flow to the top spray-header(s)25A having wide-angle nozzles25may be open, but the valve(s)59controlling flow to the top spray-header(s)25A having narrow-angle nozzles25may be closed. This mode can produce a higher degree of agitation than where only the bottom nozzles25B are used, and may be referred to as “low agitation.” In yet another mode of operation, the valve(s)59controlling flow to the top spray-header(s)25A having wide-angle nozzles25may be open and the valve59controlling flow to one (but not more than one) top spray-header having narrow-angle nozzles25may be open. This mode can produce a higher degree of agitation than the prior example, and may be referred to as “medium agitation.” In yet a further mode of operation, the valve(s)59controlling flow to the top spray-header(s)25A having narrow-angle nozzles25may be open but the valve(s)59controlling flow to the top spray-header(s)25have wide-angle nozzles25may be closed. This mode can produce the highest level of agitation, and may be referred to as “high agitation.” Other arrangements of spray-headers, varying sizes of nozzles25, and open versus closed valves59may be used to create additional variations in the levels of agitation. Thus, the use of terms such as “low,” “medium” and “high” are not meant to be limited to the precise arrangements described in the foregoing examples, but rather to exemplify that various, relative degrees of agitation can be accomplished as desired to meet specific needs.

An operator can use the HMI38to select a desired level of agitation, or the agitation level may be pre-stored in connection with a given operating recipe that the operator has the option to select. By setting the agitation level, the apparatus8automatically opens and closes the valves59to the nozzles25as appropriate to achieve that selected level of agitation. These parameters can be set individually or by selecting a pre-stored recipe.

The pressure of the fluid22pumped through the system may be a function of a variety of factors including the action of the pump33, the length, sizing and configuration of the plumbing between the pump33and the nozzles25, and the sizes and quantity of nozzles25. The apparatus8may have one or more sensors65C located at or near the inlet to each valve59leading to each spray-header of nozzles25, or at another suitable location, for measuring and monitoring the pressure of the fluid22being forced to the nozzles25. This pressure can be, for example, from 0.01 psi to 100 psi. During operation, the pressure can change for a variety of reasons, and the apparatus8may include sensors65C for measuring the pressure. The apparatus may alert the operator if the pressure begins to decrease or increase from the level expected, or initially achieved, for a given set of SF/SR processing parameters, and also may alert the operator if the pressure drops below or exceeds minimum and maximum levels, respectively. These minimum and maximum levels can be pre-programmed into the apparatus8. Additionally, if these minimum or maximum pressure levels are exceeded, the apparatus8can to automatically shut down.

An embodiment of the invention may simultaneously achieve a high rate of fluid flow through the nozzles25, such as 5 to 150 gallons per minute, and a low pressure at which the fluid22is provided to the nozzles25, such as 15-30 psi. The speed at which support material is removed may be aided by having as much flow of fluid22on the part10as possible, while protecting the build material35of the part10from erosion by maintaining the fluid velocity below a desired level. The nozzle aperture sizes (and/or spray angles), quantities of nozzles25and specifications for the pump33and plumbing may be selected to achieve these multiple goals. Additionally, oscillating the nozzles25changes the direction and speed of the spray exiting the nozzles25, which provides an additional opportunity for modulating both the force of the fluid22impacting the parts10as well as the area covered by that fluid22. For example, oscillating the nozzles25at a higher speed may result in a lower average force at which the fluid22impacts the additive manufactured parts10and a wider coverage area within the chamber16.

In another embodiment of the invention as illustrated inFIG.5, a wider chamber16is used and there are two systems of top and bottom nozzles25, arranged adjacent to each other, effectively defining first processing region87and second processing region90within the chamber16. In this embodiment, fluid22is delivered to the first processing region87by the first top nozzles25A1and first bottom nozzles25B1, and fluid22is delivered to the second processing region90by the second top nozzles25A2and second bottom nozzles25B2. In this embodiment, the tank31situated below the bottom nozzles25B can be a single tank31spanning the two regions87,90. A first pump33A can be connected to the first top and first bottom nozzles25A1,25B1, and a second pump33B can be connected to the second top and second bottom nozzles25A2,25B2. In this embodiment, the pumps33, valves59, spray-headers of nozzles25, and all of the various settings relating thereto can be set and operated in the two regions87,90independently.

This embodiment enables the apparatus8to have different flow rates, pressures and spray velocities (i.e., agitation levels) as between the two regions87,90. This can be useful in several ways. For example, some additive manufactured parts10are long and have more support material28and/or surface areas of build material35toward one end of the part10(“heavy end”) versus the opposite end (“light end”). If the same flow, pressure levels and spray velocities were applied across the entire part10, then either the light end would be at risk for over-processing (which might include degradation or warping of the part10) or the heavy end of the part10would be at risk for under-processing (leaving too much support material28or un-smoothed surfaces of build material35remaining on the part10). By having two independent SF/SR processing regions87,90, the part10can be situated in the chamber16so that the end with more support material28and/or surface areas of build material35lies in the region that has higher flow, pressure and spray velocity, while the other end of the part10with less support material28and/or surfaces areas of build material35lies in the region that has lower flow, pressure and spray velocity. This protects the second end of the part10from over-processing and the first end of the part10from under-processing. Another advantage of having two regions is that a given part10may have more support material near its bottom area than near its top area. A quantity of these parts10could be simultaneously SF/SR processed with a portion of the quantity oriented upright in one region and the other portion oriented upside down in the other region, with each region having flow of fluid22and pressure appropriate for those orientations of the parts.

In an embodiment where nozzles are configured to oscillate during a SF/SR process, a motion-monitoring sensor can be used to detect which of the nozzles25are moving during the SF/SR process. The apparatus8may frequently monitor the position of the nozzles25and if no motion is detected, the apparatus8may attempt to reset the motor controlling movement of the nozzles25. If a reset of the motor is unsuccessful, then the HMI38may alert a user and pause the SF/SR process since the apparatus8may not be operating properly. The detection of nozzle movement may be done via an encoder arranged on each motor or by other suitable means.

The tank31may be filled automatically with fluid22based on parameters set by the operator or as may be pre-stored in connection with a given operating recipe that the operator has the option to select. To this end, the apparatus8may include devices for supplying each of water, support material solvent (also referred to as detergent), and anti-foaming agent supplies. Water may be supplied from a facility's water supply19or from a reservoir or other storage tank. Solvent and anti-foaming agent may be supplied each from their own reservoir or storage tank, such as a 5-gallon bucket56connected to the apparatus by a hose62or other conduit. The hose62for each of the solvent and anti-foaming agent may be connected to a mechanism, such as a water-powered pump, for automatically dispensing such fluids into the tank.

A liquid level sensor65D may be situated in the tank31to detect the level of the fluid22in the tank31, thereby enabling a determination of when the fluid22filling the tank31reaches the maximum level, at which point the sensor65D sends a signal that is interpreted and results in the filling to automatically stop. The sensor65D also may be employed to enable detection of when the fluid22drops below a desired level during operation, which can happen for example as fluids evaporate, and may send a signal that is interpreted and may result in alerting the operator to use the interface to cause more fluids to be dosed into the tank (which dosing again stops automatically if the maximum fill level is reached). Alternatively, programming could be provided to cause this dosing to occur automatically.

Use of this auto-dose feature ensures that enough fluid22is arranged in the apparatus8for the SF/SR process to run properly. When an apparatus8runs for an extended period of time at high temperatures, the fluid22used in the SF/SR process evaporates. Also, amounts of fluid22may adhere to interior surfaces of chamber16and to surfaces of components within chamber16. In order to ensure that enough fluid22remains in the system, a configurable desired fluid level may be set in the software of the apparatus8, and the fluid level in the tank31may be detected using a liquid level sensor65D such as a floating sensor to detect the liquid level. If the liquid level falls below the desired level, the apparatus8could react by supplying additional amounts of one or more components of the fluid22(e.g., water, solvent, anti-foaming agent) into the tank31. Additionally, a configurable time interval could be set by a user for checking the liquid level during the SF/SR process. At the end of a configurable time interval, the SF/SR process may pause for an amount of time (for example, 30 seconds) in order to let foam that may have formed in the tank31to settle. Once the settling time has elapsed, a liquid level measurement may be taken. If the liquid level has not attained the desired level, the apparatus8may automatically add fluid to the tank31and in order to fill the tank31up to the desired liquid level.

A heater96, such as an immersion heater, and a sensor65B for measuring temperature, may be situated in or in connection with the tank31. Additionally, a pH sensor65A may be situated in or in connection with the tank31. The heater96may be used to heat the fluid22to a desired temperature and, based on feedback from the temperature sensor65B, to maintain the fluid22at that temperature. The heater96may be used to heat the fluid22to a desired temperature within an allowable range, such as for example, 85.degree. F. to 160.degree. F., or another process-suitable range. The fluid22in the tank31may be heated to the desired temperature prior to starting the SF/SR process to spray the parts10, or the fluid22can be used before it is heated at all or when it is only partially heated to the desired temperature. In this latter approach, the SF/SR process begins with the fluid22at a low temperature and, as time elapses during the SF/SR process, the heater96operates to increase the temperature of the fluid22to the desired level. The approach of gradually increasing the temperature of the fluid22can aid in the removal of support material28. This is because the fluid22can usually remove support material28over a range of temperatures. Thus, by engaging in SF/SR as the fluid temperature rises, the fluid22can begin to remove support material28as the fluid22reaches the lowest temperature suitable for removing support material28and then remove the support material28more rapidly as the fluid approaches the final desired temperature. In this manner, the build material35of the part10will not heat up as much as compared to the case where the fluid22is at the highest temperature from the start of the SF/SR process. This helps to protect the build material35of the part10from degradation, such as warping.

The pH sensor65A can detect the pH of the fluid22, which at the outset can be a reflection of the combination of liquids forming the fluid22(e.g., solvent, water and, if used, anti-foaming agent) and may be used while filling the tank31to achieve the desired pH. The pH can change during the apparatus'8operation, for example due to dissolved support material28contaminating the fluid22or due to evaporation of portions of the fluid22. The pH sensor65A may be used to detect such changes and to alert the operator when the pH drops below or exceeds a desired level, whereupon the operator may use the HMI38to cause dosing of fluids as needed to adjust the pH to the desired level. For example, if the pH is too high (i.e., too basic), then more solvent can be added. But if the pH is too low (i.e., too acidic), then more water can be added. Alternatively, the apparatus8may be configured to automatically dose fluids as needed to adjust the pH. The desired temperature and pH may be set by the operator using the HMI38, or may be pre-stored in connection with a given operating recipe that the operator has the option to select.

As the fluid22flows through the apparatus8, its temperature can change, which may be undesirable. In particular, it is important to maintain the fluid22at the desired temperature as it travels from the tank31to the nozzles25. Yet, many pumps33heat up while they are operating and transfer that heat to the fluid22as it moves through the pump33. In embodiments of the present invention, it is preferable to use a pump33that adds minimal heat to the fluid22, such as a magnetically coupled pump33.

Atomization of the fluid22by spraying it through appropriately sized nozzles25, where the fluid22separates into small droplets while also spreading out in a flat fan, hollow cone, or full cone spray pattern helps to control the force at which fluid22impacts the part10while maximizing flow of the fluid22. The top nozzles25A may be further away from the parts10being SF/SR processed than the bottom nozzles25B, and in such a configuration, the force of the spray from the top nozzles25A as it impacts the parts10can sometimes fall below a desired amount. The design of the bottom nozzles25B can help with this. The spray from the bottom nozzles25B may have enough force to hit the bottom of the parts10and then continue to travel upwards to heights above the parts10. There, the droplets combine with each other and/or droplets from the top nozzles25A into larger droplets, whereupon these larger droplets fall down onto the parts10. Aided by both gravity and the force of the drops from the top spray nozzles25A, these larger particles may hit the parts10with more flow and kinetic energy than drops coming from the top nozzles25A alone or the bottom nozzles25B alone. Nonetheless, the top nozzles25A may be mounted in a way so as to be adjustable closer to or further away from the parts10. Likewise, the location of the parts10may be adjustable such that parts10are set further away from the bottom nozzles25B and thus closer to the top nozzles25A, or vice-versa.

The fluid22in the tank31may be drained automatically. At the end of each SF/SR process, there may be the option to drain all the fluid22from the tank31and replace it with new fluid22. This option may be pre-set by the operator or selected by the operator upon the completion of an SF/SR process. An auto-drain feature may also be used to drain the tank31after a prescribed number of SF/SR processes, which may be set by the operator.

After the tank31is drained, the tank31may be automatically filled with clean water, and used for rinsing the part10in order to remove fluid22remaining on the part10. The water may be heated in the same manner as the fluid22. When selecting the parameters for the SF/SR process, the operator may set the temperature for the rinsing water or select the temperature from a pre-stored recipe. In one embodiment, the fluid22for removing support material28may be automatically drained from the tank31after the designated run time and replaced with clean water (using the same auto-fill mechanisms described above), which is then cycled through the apparatus8to rinse the parts10, at the same agitation level setting as used during the support removal portion of the SF/SR process. During this rinsing process, the water may be pre-heated to the desired temperature or the temperature may be gradually raised while the apparatus is running.

During the SF/SR process, heat from the fluid22in the tank31can heat up air in the chamber16. This heated air in the chamber helps, in turn, to maintain the fluid22at the desired temperature while fluid22is sprayed from the nozzles25and collects back into the tank31. At the end of a SF/SR and/or rinse cycle, the heater96in the tank31may be kept operating to maintain the heat in the chamber16, which, in turn, may be useful for drying the parts10prior to removing them from the chamber16. When carried out in this manner, an SF/SR process may be said to be a “dry-to-dry” process: that is the parts10placed in the chamber16are dry and do not require preparation work to be done on them prior to the SF/SR process, and the parts10come out of the chamber16dry after the SF/SR process is complete.

Operation. A method according to the present invention, illustrated inFIG.6, may comprise the following of steps to remove support material28and/or finish a surface of build material35of a part10and rinse residual material from a part10made using additive manufacturing. The operator may use200the HMI38to cause the tank31to fill with fluid22. The operator also may use the HMI38to set other SF/SR processing parameters for the additive manufactured parts10to be SF/SR processed, including temperature (of both the support removal and rinsing fluids), pH of the fluid22, the length of run time (in hours and minutes), agitation level (e.g., ultra-low, low, medium or high agitation), center-point position of the top spray-header(s) of nozzles25, the range of distance through which the top nozzles25A oscillate, and the speed of oscillation of the top nozzles25A. Additionally, the operator may place203one or more additive manufactured parts10on the tray13within the chamber16. The heater96in the tank31may operate to heat the fluid22, which in turn helps to heat the air in the chamber16. The fluid22can be brought to full temperature prior to starting the SF/SR process, or gradually after the SF/SR process begins.

Next, the pump(s)33may activate, drawing fluid22from the tank31, through the pump(s)33, and then forcing206the fluid22through the manifold (if used) and those of the open valves59toward and through the nozzles25associated with the open valves59in order to spray the fluid22. The upper nozzles25A may oscillate when the associated valves59are open and allow fluid22to flow to the nozzles25A, and those nozzles25A may rotate or otherwise move in accordance with the selected settings. The fluid22then exits the nozzles25as atomized and/or semi-atomized fluid22and collides with the part10, including the support material28, whereupon the support material28begins to dissolve or otherwise separate from the part10and/or rough surfaces of build material35of the part begin to smooth. The fluid22then passes through the openings in the tray13, impacts on the umbrella61, flows off the umbrella61, and collects209in the tank31located under the bottom nozzles25B, whereupon the fluid22cycles206through the nozzles25again as the pump33continues to draw fluid22from tank31. This cycling212of the fluid22continues for the duration of the run time set by the operator or until the operator manually stops the SF/SR process.

During the SF/SR process, the apparatus8may measure the fluid level in the tank31to ensure enough fluid22is contained in the tank31. If there is not enough fluid22in the tank31(e.g., due to evaporation) the apparatus8may add fluid22components, such as the water, solvent and/or anti-foaming agent as appropriate. The apparatus8also may measure the pH of the fluid22and dose the tank31with water and/or solvent as needed to maintain the desired pH level.

After the prescribed amount of time, the spraying stops, the fluid22may automatically drain215from the tank31, the tank31may automatically fill215with clean water, and then the spraying may re-start to rinse the parts10. The water may be cycled218through the system until a prescribed amount of time has elapsed, the rinsing process stops, and the parts10may remain in the chamber16for drying by the heated air in the chamber16.

The ventilation system may operate during the SF/SR process to safely exhaust excess vapors and thus prevent them from escaping out of the chamber16to areas that could pose a threat to users standing around the apparatus8while the SF/SR process is occurring. The ventilation system may be kept running for a time interval (for example, 5 minutes) after an SF/SR process is completed.

The method may be carried out so as to determine the agitation level in concert with optimal temperature in order to maximize the speed and efficiency of SF/SR processing. When the fluid22is too cool, the support material28may not be removed as efficiently, but when the fluid is too hot, the part can experience damage such as shape degradation, including warpage. Additionally, as will be appreciated by the disclosure herein, the hardware, electronics, software and fluid22may work together to provide desired levels of efficacy and efficiency, from delicate support removal to more robust removal with higher throughput.

Settable parameters can be different and/or customized for particular build and support materials35,28out of which the additive manufactured parts10are made, the part geometries including the geometries of support structures, and the degree and speed of support material removal desired. Balancing and varying these parameters increases the efficacy and efficiency at which support material28can be removed. The apparatus8can be pre-programmed at a factory with “recipes” of the parameter settings known to be suitable for various support and build materials28,35, part geometries, etc. Thus, by a single activation operation, e.g. pressing one button or a short sequence of buttons, the operator may be able to set all of the parameters for a given SF/SR process. Additionally, the operator can set parameters and save them as a recipe, which the operator can then select in the future rather than re-inputting each of the settings.

The present invention may further include a logic controller99to monitor communication between a central processing unit (“CPU”)102and the HMI38. In such an embodiment of the invention, a signal may be sent from the HMI38to the CPU102, and vice-versa. The logic controller99may monitor this signal to make sure the signal changes during the SF/SR process. If the signal stops, the logic controller99may react by either shutting down the apparatus8, or the HMI38will inform the operator to restart the apparatus8. The HMI38and CPU102may be connected to the Internet in order to be operated and evaluated remotely. Additionally, this Internet connection could enable the use of a database that contains a plurality of test parameters and additional recipes that may be used to optimize the SF/SR and rinse processes. The database may alternatively be contained on a hard drive that may be associated with the apparatus8itself and be uploaded periodically to a remotely located storage device.

The apparatus8may collect and store data about settings and about how the apparatus8should or does operate, which can be used to service the apparatus8and as feedback for improving SF/SR settings for various types of support and build materials28,35and part geometries.

In the embodiments shown inFIGS.1,4, and5, the umbrella61serves to prevent the fluid22being sprayed at the part10from forcefully impacting the fluid collecting the tank31, thereby shielding the fluid22in the tank31. As described above, the fluid22can be sprayed at the part10from the nozzles25at pressure. Some of the spray flows past the part10and through the platform13. In the absence of the umbrella61, the spray could forcefully impact the fluid collecting in the tank31, possibly leading to undesirable foaming of the fluid collecting in the tank31. The umbrella61is aligned to intercept the spray of fluid22so as to prevent it from forcefully impacting the fluid collecting in the tank31. The umbrella61diverts the fluid22toward the periphery of the umbrella61so that the fluid22gently flows into the tank31. By reducing some or all the spray that forcefully impacts the fluid collecting in the tank31, foaming can be reduced.

The umbrella61can be made of any suitable material, such as stainless steel or a non-reactive plastic. The umbrella may have a shape other than a shallow cone. For example, the umbrella may have an inverted conical shape (with a drain in the middle), a flat planar shape, or a flat slanted planar shape. The umbrella may be formed of a single piece of material or multiple pieces, e.g., a multiple piece baffle. A property of these different umbrella shapes is that they intercept the flow of spray to reduce its force before allowing the fluid to collect in the tank for reuse.

FIG.7shows an alternative embodiment of an apparatus208for surface finishing or support removal of parts made by an additive manufacturing process. The apparatus208inFIG.7has components that are similar to those in the apparatus8shown inFIG.1, and like components inFIG.7are indicated by the same numerals as inFIG.1.

The apparatus inFIG.7includes a diverter shield261. The diverter shield261serves a function similar to the umbrella61shown inFIGS.1,4, and5. The diverter shield261is located below the bottom nozzles25B and is aligned with the direction of the spray of fluid22from the upper nozzles25A located above the platform13. As shown inFIGS.7and8, the diverter shield262has a shield main body portion263that has a shallow profile that tapers toward an opening264at a center of the main body portion263. The diverter shield261can be made of any suitable material, such as stainless steel or a non-reactive plastic. Connected to the diverter shield261at the opening264is a drain member265. The drain member265has an upper portion266, a lower portion268and a middle portion270. The upper portion266of the drain member265connects to the opening264of the diverter shield261. The lower portion268of the drain member265opens to the tank31. The middle portion270connects the upper portion266to the lower portion268and provides for a flow path between the bottom of the diverter shield261to the tank31. In this embodiment, the tank31is located spaced away from the spraying fluid22to reduce or eliminate foaming caused by impact of the fluid spray on the fluid contained in the tank31. In one embodiment, the tank31may be located outside the chamber16.

The apparatus208inFIG.7operates similarly to the apparatus8shown inFIG.1,4, or5. Spray22from the nozzles25impacts or falls on the main body portion263of the diverter shield261. Because the main body portion263is slanted toward the opening264, fluid22does not accumulate on the main body portion263of the diverter shield261. Instead, fluid22impacting or falling on the main body portion263of the diverter shield261flows toward the opening264and drains through the opening264into the drain member265. Fluid22flows through the drain member265into the tank31from which it is then pumped back to the nozzles22as described in connection with the other embodiments. Because fluid does not accumulate on the main body portion263of the diverter shield261, foaming is reduced or eliminated.

FIG.9shows another alternative embodiment of an apparatus308for surface finishing or support removal of parts made by an additive manufacturing process. The apparatus308inFIG.9has components that are similar to those in the apparatus8shown inFIG.1and the apparatus208shown inFIG.7, and like components inFIG.9are indicated by the same numerals as inFIGS.1and7. In the embodiment ofFIG.9, a floor361of the chamber16tapers toward a drainage opening364located in the center of the floor361. Like the embodiment inFIG.7, a drain member265connects to the drainage opening364to allow fluid to drain to the tank31. In the apparatus308inFIG.9, the tank31is located outside the chamber16. In the apparatus308inFIG.9, in addition to the mesh53located in the chamber16below the nozzles25, there may be an additional mesh screen located between the lower portion268of the drain member265and the tank31. Like the embodiment ofFIG.7, the embodiment ofFIG.9prevents or reduces foaming by locating the tank31away from the spray from the nozzles25. Also like the embodiment of the apparatus inFIG.7, the embodiment308inFIG.9does not allow fluid to accumulate where spray from the nozzles25can cause foaming.

A diverter comprised of an umbrella or a diverter shield aligned to intercept a spray used for post-processing of parts made by additive manufacturing techniques can be used in other post processing systems. An embodiment of such a system is disclosed in U.S. patent application Ser. No. 16/209,778, filed Dec. 4, 2018, the entire disclosure of which is incorporated by reference herein.

Now that features of the invention and some embodiments of the invention have been described, Statements (non-limiting) of various embodiments of the invention are as follows:Statement A: An apparatus for removing support material from and/or smoothing surfaces of an additively manufactured part, comprising:a chamber;a support surface within the chamber, and configured to support an additively manufactured part (the “AM part”);one or more nozzles within the chamber, and configured for spraying a fluid at said AM part;a tank configured to hold a volume of said fluid, wherein the tank is positioned to capture the fluid after the fluid is sprayed at the part; anda diverter positioned in a flow path between the one or more nozzles and the tank.Statement B: The apparatus of Statement A, wherein the diverter has a shallow conical shape.Statement C: The apparatus of Statement A or Statement B, wherein the diverter is aligned so that the fluid being sprayed at the AM part impacts the diverter before the fluid reaches the tank.Statement D: The apparatus of Statement A, Statement B, or Statement C, wherein the diverter comprises an umbrella that diverts fluid outward towards a peripheral edge thereof.Statement E: The apparatus of Statement D wherein the peripheral edge of the umbrella is smaller than an upper open side of the tank, whereby fluid flowing off the umbrella falls over the peripheral edge into the upper open side of the tank.Statement F: The apparatus of Statement D or Statement E further comprising, a mesh screen mounted between the umbrella and the tank, wherein the mesh screen extends beyond edges of the umbrella to capture solid material entrained in the fluid before entering the tank.Statement G: The apparatus of Statement A, wherein the diverter comprises a diverter shield body that diverts fluid toward an opening in a center thereof.Statement H: The apparatus of Statement G further comprising, a drain member that connects to the opening of the diverter shield body and extends to the tank which is positioned away from direct spraying of the fluid, wherein the drain member provides a flow path for the fluid from the diverter shield body to the tank.Statement I: The apparatus of Statement G or H wherein the diverter comprises a bottom floor of the chamber.Statement J: The apparatus of any of the foregoing Statements wherein the diverter comprises a slanted surface that reduces or prevents accumulation of fluid thereupon.Statement K: A method of removing support material from and/or smoothing surfaces of an additively manufactured part, comprising:providing a chamber, a support surface within the chamber, one or more nozzles within the chamber, a tank beneath the one or more nozzles, and a diverter positioned between the one or more nozzles and the tank;placing an additively manufactured part (the “AM part”) on the support surface;spraying a fluid from the one or more nozzles at the AM part, wherein at least a portion of the fluid impacts on the diverter after being sprayed at the AM part; andcollecting the fluid in the tank.Statement L: The method of Statement K wherein the fluid is collected in the tank so that the fluid can be reused for spraying at the AM part.Statement M: The method of Statement K or Statement L further comprising:providing a mesh screen between the diverter and the tank; andcollecting solid particles entrained in the fluid flowing off the diverter in the mesh screen.Statement N: A method of reducing foaming in a process for removing support material from and/or smoothing surfaces of an additively manufactured part, comprising:providing a chamber, a support surface within the chamber, and one or more nozzles within the chamber, a tank beneath the one or more nozzles, and a diverter positioned between the one or more nozzles and the tank;placing an additively manufactured part (the “AM part”) on the support surface;spraying a fluid from the one or more nozzles at the AM part;collecting sprayed fluid in the tank; anddiverting forcefully sprayed fluid from directly impacting the fluid being collected in the tank, whereby foaming of the fluid in the tank is reduced.Statement O: The method of Statement N further comprising:providing a mesh screen between the diverter and the tank; andcollecting solid particles entrained in the fluid flowing off the diverter in the mesh screen.Statement P: The method of Statement N or Statement O further comprising, pumping fluid collected in the tank back to the one or more nozzles so that the fluid can be sprayed at the AM part again.Statement Q: The method of Statement N, Statement O, or Statement P, wherein the fluid is sprayed at the part at a high pressure.Statement R: The method of Statement N, further comprising providing a drainage flow path from the diverter from the tank, which is located spaced away from the spraying of the fluid.

In the foregoing description, example embodiments are described. The specification and drawings are accordingly to be regarded in an illustrative rather than a restrictive sense.

It will be appreciated that various aspects of the above-disclosed invention and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, and/or improvements therein may be subsequently made by those skilled in the art, and those alternatives, modifications, variations, and/or improvements are intended to be encompassed by the following claims.

Although the present invention has been described with respect to one or more particular embodiments, it will be understood that other embodiments of the present invention may be made without departing from the spirit and scope of the present invention. Hence, the present invention is deemed limited only by the appended claims and the reasonable interpretation thereof.