Systems and processes for additive manufacturing with moisture compensation

Abstract

System for additive manufacturing with moisture compensation, the system comprising: a first memory (124) for an activator (130); a second storage (126) for a binder (126); a third storage area (136) for a building material (114); a kit (102); one or more depositing devices (108), each located within the modular unit (102) and connected to fluid with at least one of the first (124), second (126) and third storage units (136), such that each of the first (124), second (126) and third storage units (136) is connected to fluid with at least one or more depositing devices (108); a control device (118) which is assigned to the first memory (124) and configured to control a quantity of the activator (130) taken from the first memory (124); a humidity sensor (134); a control unit (132) in electronic communication with the control device (118) and the humidity sensor (134), wherein the control unit (132) comprises software instructions which, when executed, configure the control unit (132) to: receives data from the humidity sensor (134) indicating the ambient humidity level; and instruct the control device (118) to allow the withdrawal of a quantity of the activator (130) from the first storage container (124) based on the ambient humidity level.

Description

TECHNICAL FIELD

[0001] Example embodiments generally relate to controlling humidity balancing activators for additive manufacturing. BACKGROUND AND SUMMARY OF THE INVENTION

[0002] Additive manufacturing has become an increasingly popular alternative to traditional subtractive manufacturing. With the increasing adoption of additive manufacturing techniques such as 3D printing, the need for greater precision and consistency has increased.

[0003] An example type of additive manufacturing is binder jetting (also known as 3D printing). In binder jetting, a build material, such as sand or aggregate, is typically deposited in a build box. The build material may be pre-deposited, or a print head may apply the build material, often in layers. The build material may be premixed with an activator, or the print head may deposit an activator over the deposited material. The activator may saturate the deposited build material. The print head then deposits a binder where the resulting object is to be formed. The binder may be a resin. The binder may be activated by the activator and cause the surrounding build material to bond to form a section of the object.

[0004] Typically, a build platform is lowered after each layer of binder is deposited, and additional build material is deposited through a recoater. Another layer of activator can be deposited if the activator is not premixed. Subsequent layers of binder are applied where the sections of the object that will comprise the next layer are located. The process is repeated to form the entire object. When all layers are complete, the object is extracted (recovered). Such extraction typically involves digging, blowing away, grinding, breaking apart, or similar processes. Examples of such additive manufacturing machines are those from ExOne of North Huntington, Pennsylvania (https: / / www.exone.com / ). Such additive manufacturing processes and machines can be used in the foundry industry to produce sand cores, for example, for use with subsequent foundry work.

[0005] Humidity can affect the material properties of building materials. For example, an increase in humidity can cause certain building materials to clump or otherwise stick together. Building materials such as sand and aggregates are particularly susceptible to such clumping at relatively high humidity. This can affect the properties of the object being manufactured. Alternatively or additionally, this can affect the properties of the remaining building material that must be extracted to produce the object.

[0006] The document WO 2019 / 194 823 A1 relates to a system for producing three-dimensional objects, with a logic for: Detecting a moisture content for at least one container corresponding to a building material located in the at least one container; adjusting a moisture level and / or a temperature of a gas and a conditioning agent applied to the at least one container, wherein the moisture level and temperature are based on the moisture content and a temperature of the building material located in the at least one container; and to initiate the production of a three-dimensional object with the building material from the at least one container when it is determined that the moisture content of the building material in the at least one container is within a predetermined range.

[0007] The publication US 2017 / 0 297 263 A1 relates to a method for producing three-dimensional molded parts by layering. A particulate construction material is applied to a build space in a defined layer thickness using a coater. A binding liquid is selectively applied to the build material using a print head. The binding liquid is polymerized using at least one activator introduced into the sand, and the build space is lowered by the layer thickness or the coater is raised by the layer thickness. These steps are repeated until the desired molded part is produced. Agents that can be used to regulate the moisture content of the build material mixture are present in or incorporated into the build material, the binding liquid, and / or the activator.

[0008] US 2019 / 0 176 404 A1 discloses a powder feed device for providing raw material powder for a powder application device of a powder bed melting device. The powder feed device comprises a powder feed section configured to receive raw material powder, wherein the powder feed section comprises an outlet for providing the raw material powder to the powder application device.The powder dispensing device further comprises a first physical parameter determining unit arranged at a first location of the powder feed section and configured to determine a first physical parameter in the powder feed section, a control unit configured to determine whether the first physical parameter satisfies a first tolerance criterion, and a powder treatment unit, wherein the control section is configured to instruct the powder treatment unit to perform a powder treatment if it determines that the first physical parameter does not satisfy the first tolerance criterion.

[0009] What is needed is a system and method for controlling the amount of activator used during additive manufacturing based on ambient humidity. Systems and methods for controlling the amount of activator used during additive manufacturing based on ambient humidity levels are provided. The controller may be configured to receive humidity measurements from one or more humidity sensors. The controller may be configured to determine the amount of activator for deposition by a deposition device based on the humidity measurements. The controller may determine the amount of activator to be applied using a database that may contain the amounts of activator to be applied for a range of humidity levels or ranges.In exemplary embodiments, the higher the humidity level, the less activator can be deposited. The lower the humidity level, the more activator can be deposited. In this way, the moisture in the air, which can act as an activator, can be balanced to achieve more consistent results, preserve the activator, and allow for adequate drainage of excess build material. The amount of activator used can be selected so that the remaining build material can easily flow through a drainage system and / or be easily dissolved out.

[0010] Further features and advantages of the systems and methods disclosed herein, as well as the structure and operation of various aspects of the present disclosure, are described in detail below with reference to the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In addition to the above-mentioned features, other aspects of the present invention will be readily apparent from the following descriptions of the drawings and exemplary embodiments, wherein like reference numerals in the several views refer to identical or equivalent features, and wherein the Fig. 1 is a front view of an exemplary additive manufacturing machine with an activator control system according to the present invention; the Fig. 2 is a front view of another exemplary additive manufacturing machine with an activator control system according to the invention; and the Fig. 3 a flowchart with exemplary logic for the operation of the additive manufacturing machine from the Fig. 1 is. DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT(S)

[0012] Various embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the following description, details such as the detailed configuration and components are provided only to facilitate an overall understanding of these embodiments of the present invention. Therefore, it should be obvious to those skilled in the art that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Furthermore, descriptions of well-known functions and structures are omitted for clarity and conciseness.

[0013] Embodiments of the invention are described herein with reference to illustrations of idealized embodiments (and intermediate structures) of the invention. Deviations from the shapes of the illustrations, e.g., due to manufacturing techniques and / or tolerances, are therefore to be expected. Embodiments of the invention are therefore not to be understood as being limited to the particular shapes of the areas illustrated here, but may have variations in the shapes resulting, e.g., from manufacturing.

[0014] Fig. Figure 1 shows an example of an additive manufacturing machine 100. The machine 100 may be a 3D printer, although one is not required. The machine 100 may be configured to operate using binder jetting, although any type of additive manufacturing is contemplated.

[0015] The machine 100 may have a construction kit 102. The construction kit 102 may be any size or shape. A vertical movement device 104 may be located within the construction kit 102. A horizontal movement device 106 may be located within the construction kit 102. A deposition device 108 may be mounted to the horizontal movement device 106. The horizontal movement device 106 may be connected to the vertical movement device 104. In other exemplary embodiments, the deposition device 108 may be mounted to the vertical movement device 104 and the vertical movement device 104 may be mounted to the horizontal movement device 106. The vertical movement device 104 may be configured to control the vertical movement of the horizontal movement device 106 and / or the deposition device 108.The horizontal movement device 106 may be configured to control the horizontal movement of the vertical movement device 104 and / or the deposition device 108. For example, the vertical and horizontal movement devices 104 and 106 may include, without limitation, rails, motors, belts, gears, a combination thereof, or the like. The deposition device 108 may include a nozzle, a print head, a valve, a combination thereof, or the like.

[0016] A recoating device 109 may be provided. The recoating device 109 may be mounted to a second horizontal movement device 107. The second horizontal movement device 107 may be mounted to the vertical movement device 104, although in other exemplary embodiments, the second horizontal movement device 107 may be mounted to a second, independent vertical movement device. In other exemplary embodiments, the recoating device 109 may be attached to the vertical movement device 104 or the second independent vertical movement device may be attached to the second horizontal movement device 107. The second horizontal movement device 107 may include rails, motors, belts, gears, a combination thereof, or the like. The recoating device 109 may include a nozzle, a print head, a valve, a combination thereof, or the like.

[0017] The recoating device 109 may be in fluid communication with a build material reservoir 136. The build material reservoir 136 may include a build material 114. The build material 114 may include, for example, without limitation, sand or aggregate, although any type of material is contemplated. In other exemplary embodiments, the deposition device 108 may be in fluid communication with the build material reservoir 136. In such embodiments, the recoating device 109 may not be required, as the deposition device 108 may essentially serve as the recoating device 109.

[0018] A build platform 110 may be located within the build material box 102. The build platform 110 may be connected to a platform movement device 112, which may enable vertical and / or horizontal movement of the build platform 110. The platform movement device 112 may consist of rails, motors, belts, gears, a combination thereof, or the like. In exemplary embodiments, the build platform 110 may have substantially the same footprint as the construction box 102, although any size or shape is contemplated.

[0019] The deposition device 108 may be in fluid communication with a first reservoir 124. The first reservoir 124 may be comprised of a binder 126. The deposition device 108 may be in fluid communication with a second reservoir 128. The second reservoir 128 may include an activator 130. In exemplary embodiments, the first reservoir 124, the second reservoir 128, and / or the build material reservoir 136 may include one or more heating elements, cooling elements, a mixing device, a combination thereof, or the like.

[0020] A control device 118 may be interposed between the second reservoir 128 and the deposition device 108. In exemplary embodiments, the control device 118 may also be interposed between the first reservoir 124 and the deposition device 108, although this is not required. The control device 118 may include a valve, a filter, a pump, a combination thereof, or other mechanisms configured to limit or otherwise control the amount of activator 130 moved from the second reservoir 128 to the deposition device 108. The control device 118 may further be configured to control the amount of binder 126 moved from the first reservoir 124 to the deposition device 108, although this is not required.

[0021] The control device 118 may be in electronic communication with a controller 132. The controller 132 may be in electronic communication with one or more humidity sensors 134. The humidity sensors 134 may be configured to take measurements of the ambient humidity levels.

[0022] The controller 132 may be in electronic communication with one or more electronic storage devices 133. The electronic storage devices 133 may contain data indicating one or more amounts, densities, concentrations, a combination thereof, or the like of an activator 130 to be deposited, each of which may be associated with one or more humidity levels or ranges.

[0023] The controller 132 may be in electronic communication with one or more of the following devices: the vertical movement device 104, the horizontal movement device 106, the deposition device 108, the platform movement device 112, the second horizontal movement device 107, and the recoating device 109. The controller 132 may be configured to accept one or more computer-aided design ("CAD") files and control the movement of the deposition device 108, the recoating device 109, and / or the build platform 110 to control the location where the build material 114, the activator 130, and / or the binder 126 are deposited to form an object 116. The movement of the deposition device 108 may be controlled using the vertical and / or horizontal movement devices 104, 106.The movement of the recoating device 109 can be controlled using the vertical and / or second horizontal movement devices 104, 107. The movement of the build platform 110 can be controlled using the platform movement device 112.

[0024] A drainage system 111 may be provided in fluid communication with part or all of the construction kit 102. In exemplary embodiments, the drainage system 111 includes one or more drains provided around part or all of the construction kit 102. The drainage system 111 may facilitate the drainage of the remaining construction material 114, i.e., the unbound construction material 114 that is not coated with the binder 126 and / or forms the object 116.

[0025] Another exemplary embodiment of the additive manufacturing machine 100 is shown in the Fig. 2. The control device 118 may be interposed between the second reservoir 128 and the recoating device 109 such that the activator 130 can be mixed with the build material 114 prior to deposition. Such mixing may occur in a mixing chamber 120, but is not required. The mixing chamber 120 may contain one or more heating elements, cooling elements, mixing devices, a combination thereof, or the like. The first reservoir 124 may be in fluid communication with the deposition device 108.

[0026] The various storage devices, such as, but not limited to, the first storage device 124, the second storage device 128, and the building material storage device 136 described herein, may be located remotely from the building kit 102 and connected thereto via one or more pipes, conduits, valves, passageways, piping, a combination thereof, or the like. Various other components, such as the control unit 132, the control device 118, the mixing chamber 120, the humidity sensors 134, and the database 133, may be located remotely from the building kit 102 and be physically or electrically connected to the building kit 102. Each component described herein may be located remotely from one another.

[0027] The Fig.Figure 3 illustrates, by way of example, the logic for the operation of the additive manufacturing machine 100. The build material 114 can be placed within the build box 102. The build material 114 can be deposited by the deposition device 108, the recoating device 109, a pre-deposition, a combination thereof, or the like. In exemplary embodiments, the build material 114 is deposited onto the build platform 110.

[0028] The controller 132 may be configured to collect one or more moisture readings from the moisture sensor 134 simultaneously or after the deposition of the building material 114. If more than one moisture sensor 134 is used, the controller 132 may be configured to average or otherwise combine the various moisture readings, or to select a single one of the various moisture readings. The controller 132 may be configured to retrieve from the electronic storage device 133 the amount, density, concentration, type, ingredients, properties, combinations thereof, or the like of the activator 130 based on the moisture readings from the moisture sensor 134.In exemplary embodiments, the controller 132 may transmit the humidity level determined by the humidity sensor 134 to the electronic storage device 133, and the electronic storage device may retrieve and transmit the corresponding amount, density, concentration, type, ingredients, properties, combinations thereof, or the like of the activator 130 to be used.

[0029] The controller 132 may be configured to transmit commands to the control device 118 to cause the requested amount, density, concentration, type, ingredients, properties, combinations thereof, or the like of the activator 130 to be deposited onto the deposited build material 114. The deposition of the activator 130 may occur using the deposition device 108. In such embodiments, the activator 130 may be deposited throughout the entire build box 102 and seep into the deposited build material 114 such that substantially all of the deposited build material 114 is saturated with the activator 130. In other exemplary embodiments, the deposition of the activator 130 may occur in the mixing chamber 120 or otherwise with the build material 114 prior to deposition in the build box 102.

[0030] The controller 132 may be configured to apply the binder 126 to the areas of the build material 114 corresponding to the portions of the object 116 being formed. The binder 126 is preferably deposited onto the build material 114 after the activator 130 has been deposited and allowed to soak into the build material 114, although this requires a timing adjustment.

[0031] If the object 116 is not yet completed, the build platform 110 can be lowered and an additional layer of build material 114 can be deposited. Preferably, the build material 114 is deposited by the recoating device 109 from the material in the build material storage 136. The remaining build material 114, i.e., the unbound build material 114 that is not formed into the object 116, can flow into the drainage system 111. In this way, the remaining build material 114 can be continuously removed from the build material box 102. Alternatively or additionally, the drainage system 111 can only be made accessible once the object 116 is fully or partially completed.

[0032] The amount of activator 130 to be deposited can be selected or programmed into the electronic memory 133 so that the remaining build material 114 can flow through the drainage system 111. If the amount of activator 130 introduced is too small, the build material 114 may continuously flow into the drainage system 111 or elsewhere, resulting in the object 116 not being properly formed. If the amount of activator 130 deposited is too high, the remaining build material 114 may clump together and may not drain and / or be difficult to remove. This may then require manual removal work and / or result in damage to the object 116. In exemplary embodiments, the drainage system 111 may be in fluid communication with the build material reservoir 118 so that the remaining build material 114 can be reused.

[0033] Moisture in the air can act as an activator. Increased ambient humidity results in a lower demand for activator 130, as the moisture in the air can act as part of the required activator 130. For example, the increased humidity may result in the building material 114 not requiring as much activator 130 to prevent inadvertent runoff into the drainage system 111. Likewise, lower ambient humidity may require more activator 130 than in the absence of humidity. For example, more activator 130 may be required to prevent the building material 114 from inadvertently and / or prematurely running into the drainage system 111.The amount of activator 130 to be used for a particular moisture level and / or range may be selected to optimize the flow rate of the remaining construction material 114 into the drainage system 111 by other components of the system 100, properties of the resulting object 116, combinations thereof, or the like.

[0034] Once the structure 116 is completed, the structure 116 may be excavated from the remaining excess construction material 114 as needed. Such excavation efforts may include, but are not necessarily limited to, dewatering the remaining construction material 114 through the drainage system 111. Alternatively or additionally, such dewatering and / or excavation may occur or be performed throughout the construction process.

[0035] While binder jetting is primarily discussed here, other types of additive manufacturing are contemplated. The fluid communication described herein may be achieved through one or more tubes, pipes, valves, connectors, conduits, a combination thereof, or the like. All components of machine 100 may be located locally or remotely from machine 100, and in particular from kit 102.

[0036] Each embodiment of the present invention may have all of the features of the other embodiments of the present invention. The exemplary embodiments disclosed herein are not intended to be exhaustive or to unnecessarily limit the scope of the invention. The exemplary embodiments were chosen and described in order to explain the principles of the present invention so that those skilled in the art may practice the invention. Having shown and described exemplary embodiments of the present invention, those skilled in the art will recognize that many variations and modifications may be made to the described invention. Many of these variations and modifications will achieve the same result and remain within the spirit of the claimed invention. It is therefore intended to limit the invention only as indicated by the scope of the claims.

[0037] Certain operations described herein may be performed by one or more electronic devices. Each electronic device may include one or more processors, electronic storage devices, executable software instructions, and the like, configured to perform the operations described herein. The electronic devices may be general-purpose computing devices or special-purpose computing devices. The electronic devices may be calculators (personal computers), smartphones, tablets, databases, servers, or the like. The electronic connections and transmissions described herein may be wired or wireless.

[0038] Systems and methods for additive manufacturing with humidity compensation are provided. A first reservoir for an activator, a second reservoir for a binder, and a third reservoir for a build material that can be deposited into a build kit using one or more deposition devices are provided. A controller receives data from a humidity sensor indicative of the ambient humidity level and instructs a controller connected to the first reservoir to adjust an amount of activator withdrawn from the first reservoir based on the ambient humidity level.

Claims

[1] A humidity-balanced additive manufacturing system, the system comprising: a first memory (124) for an activator (130); a second reservoir (126) for a binder (126); a third storage (136) for a building material (114); a construction kit (102); one or more deposition devices (108), each located within the kit (102) and in fluid communication with at least one of the first (124), second (126) and third reservoirs (136), such that each of the first (124), second (126) and third reservoirs (136) is in fluid communication with at least one or more deposition devices (108); a control device (118) associated with the first reservoir (124) and configured to control an amount of the activator (130) withdrawn from the first reservoir (124); a humidity sensor (134); a controller (132) in electronic communication with the control device (118) and the humidity sensor (134), the controller (132) comprising software instructions that, when executed, configure the controller (132) to: receives data from the humidity sensor (134) indicative of an ambient humidity level; and instruct the control device (118) to enable the removal of an amount of the activator (130) from the first reservoir (124) based on the ambient humidity level. [2] The system of claim 1, wherein the control device (118) comprises a valve. [3] The system of claim 1, wherein the control device (118) comprises a pump. [4] The system of claim 1, further comprising: a mixing chamber (120) fluidly disposed between the third reservoir (136) and the first reservoir (124), wherein the control device (118) is fluidly disposed between the first reservoir (124) and the mixing chamber (120). [5] The system of claim 1, wherein the control device (118) is fluidly disposed between the first accumulator (124) and the second accumulator (126). [6] The system of claim 1, further comprising: a database (133) in electronic communication with the control unit (132) comprising humidity levels or ranges each associated with data representing an amount of the activator (130); and additional software instructions at the controller (132) that, when executed, configure the controller (132) to query the database (133) with the ambient humidity level received from the humidity sensor (134) to retrieve a corresponding amount of the activator (130), wherein the controller (132) is configured to instruct the control device (118) to allow the removal of the amount of the activator (130) from the first memory (124) that is consistent with the corresponding amount of the activator (130). [7] The system of claim 1, further comprising: additional software instructions on the control unit (132) which, when executed, configure the control unit (132) to instructing the control device (118) to increase the amount of activator (130) that may be removed from the first memory (124) when data is received from the humidity sensor (134) indicating a decrease in the ambient humidity levels; and instructing the controller (118) to decrease the amount of activator (130) that may be removed from the first memory (124) when data is received from the humidity sensor (134) indicating an increase in ambient humidity levels. [8] The system of claim 1, further comprising: a drainage system (111) which is in fluid communication with the kit (102). [9] The system of claim 1, wherein each of the one or more depositing devices (108) is movably attached to one or more vertical and horizontal moving devices (104, 106). [10] The system of claim 1, further comprising: a build platform (110) configured for vertical movement within the kit (102). [11] A method for providing humidity compensation for additive manufacturing, the method comprising the following steps: Depositing a building material (114) in a construction kit (102); Receiving data from a humidity sensor (134) indicative of an ambient humidity level; instructing a control device (118) to enable the withdrawal of an amount of the activator (130) from a first reservoir (124) based on the ambient humidity level; Depositing the activator (130) on at least portions of the building material (114) in the construction kit (102); withdrawing resin for a second reservoir (126); and Depositing the removed resin on areas of the building material (114) in the construction kit (102) that correspond to the shape of an object to be created. [12] The method of claim 11, further comprising the steps of: Receiving further data from the humidity sensor (134) indicating an increase in ambient humidity levels; and command the control device (118) to reduce the removal of the activator (130) from the first store (124). [13] A method according to claim 11, further comprising the steps of: Receiving further data from the humidity sensor (134) indicating a decrease in the ambient humidity levels; and Instructing the control device (118) to enable increased withdrawal of the activator (130) from the first reservoir (124). [14] A method according to claim 11, further comprising the steps of: Removing the building material (114) from a third storage (136), wherein the building material (114) is deposited in the construction box (102) by means of a depositing device (108); and Drainage of building material residues from the construction kit (102) via a drainage system (111). [15] The method of claim 14, wherein: the activator (130) is deposited within the kit (102) by means of an additional deposition device (108); and said resin is deposited by means of said additional deposition device (108). [16] A method according to claim 14, further comprising the steps of: Mixing the activator (130) with the building material (114) before depositing it in the construction box (102). [17] A method according to claim 11, further comprising the steps of: Querying a database (133) with the ambient humidity level to retrieve the amount of activator (130). [18] A method according to claim 11, further comprising the steps of: Lowering a construction platform (110) within the construction kit (102). [19] A humidity-balanced additive manufacturing system, the system comprising: a first memory (124) for an activator (130); a second reservoir (126) for a binder (126); a third storage (136) for a building material (114); a mixing chamber (120) fluidly disposed between the first reservoir (124) and the third reservoir (136); a construction kit (102); a build platform (110) configured for vertical movement within the kit (102); a drainage system (111) in fluid communication with the construction kit (102) and configured to enable the selective removal of construction material (114) from the construction kit (102); one or more settling devices (108), each located within the modular system (102), movably mounted on one or more vertical and horizontal movement devices (104, 106) and in fluid communication with one of the second reservoir (126) and the mixing chamber (120), such that one of the second reservoir (126) and the mixing chamber (120) is in fluid communication with at least one of the plurality of settling devices (108); a control device (118) in fluid communication with the first reservoir (124) and configured to control an amount of the activator (130) withdrawn from the first reservoir (124); a humidity sensor (134); a database (133) in electronic communication comprising humidity levels or ranges, each of which is linked to data representing the amount of activator (130), the amount of activator (130) being selected to prevent premature emptying of materials deposited within the kit (102) while an object within the kit (102) is under construction; and a controller (132) in electronic communication with the control device (118), the database (133) and the humidity sensor (134), the controller (132) comprising software instructions that, when executed, configure the controller (132) to receives data from the humidity sensor (134) indicative of an ambient humidity level; querying the database (133) with the ambient humidity level received from the humidity sensor (134) to retrieve a corresponding amount of the activator (130); instruct the control device (118) to enable the removal of an amount of the activator (130) from the first reservoir (124) and into the mixing chamber (120) for mixing with the building material (114) prior to deposition in the building box (102) based on the ambient humidity level; instructing the control device (118) to change operating conditions to enable the removal of an increased amount of the activator (130) from the first store (124) when subsequent data is received from the humidity sensor (134) indicating a decrease in the ambient humidity levels; and instructing the controller (118) to change operating conditions to enable the removal of a reduced amount of the activator (130) from the first store (124) when subsequent data is received from the humidity sensor (134) indicating an increase in ambient humidity levels.

Images