Additive manufacturing processes can produce three-dimensional (3D) objects by providing a layer-by-layer accumulation and unification of material patterned from a digital model. In 3D printing, for example, digitally patterned portions of successive material layers can be joined together by fusing, binding, or solidification through processes including sintering, extrusion, and irradiation. The quality, strength, and functionality of objects produced by such systems can vary depending on the type of additive manufacturing technology used. Typically, lower quality and lower strength objects can be produced using lower cost systems, while higher quality and higher strength objects can be produced using higher cost systems.
Examples will now be described with reference to the accompanying drawings, in which:
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.
In some examples of three-dimensional (3D) printing, 3D objects can be produced by depositing and processing layers of build material. Layers of build material can be successively deposited into a work area such as on a printing platform. A fusing agent can be selectively applied to layers of the build material in areas where the build material is to be fused together. The fusing agent can coat the exterior surface of the build material and penetrate into a layer of build material. The work area can be exposed to fusing energy such as light radiation. The fusing agent is capable of absorbing the fusing energy and converting it into thermal energy. The thermal energy can fuse those areas of the build material on which the fusing agent has been applied. This process can be repeated as each layer of build material is deposited into the work area. Through this process, the work area can include a “build volume” that comprises fused and unfused areas of build material. A 3D object can be formed in this manner from the fused build material.
Three-dimensional printing and other additive manufacturing processes are often used to produce prototype objects. These additive processes are sometimes referred to as rapid prototyping (RP) processes because of their ability to generate complicated shapes within shortened lead times and without the use of special tools. However, the layering technique used in such RP processes, such as the 3D printing process described above, can involve lengthy build times.
The use of microwave energy in additive manufacturing processes can help to reduce the manufacturing time for each part by eliminating the layer-by-layer fusing operations used to bind together the layers of a 3D object. Microwave energy can penetrate opaque materials (unlike visible and infrared light/radiation) and therefore enables the application of energy to an object on a volumetric basis rather than on a layer-by-layer basis. However, when using microwave energy, achieving accurate and robust 3D parts can involve a precise placement of the microwave energy in order to locally fuse the desired build material.
In some examples, an inkjet printing process enables the placement of liquid functional materials with micron level precision to define and/or pattern build material that is to be fused together to form a 3D object. Liquid functional materials can include, for example, microwave absorbing materials called susceptors, and fusing aid materials. Susceptor materials function to heat the build material to enable fusing, while fusing aid materials function to lower the fusing temperature of the build material to enable the build material to be fused at a lower temperature. Susceptor materials can include, for example, ferromagnetic materials such as iron, nickel, cobalt, iron alloys, nickel alloys, cobalt alloys, and steel, or ferrimagnetic materials such as magnetite, nickel-zinc ferrite, manganese-zinc ferrite, and copper-zinc ferrite. Fusing aid materials can include, for example, silica and polymer nanoparticles. A build volume can be formed on a printing or build platform by layering powdered build material into the work area of the platform, as noted above. The build volume can be digitally patterned using liquid functional materials to form an unfused 3D object within the build volume. Defining or patterning an unfused 3D object within the build volume can include selectively jetting, printing, or otherwise depositing a desired liquid functional material, such as a susceptor, onto build material on a layer-by-layer basis as layers of the build material are deposited or spread into the work area of the printing platform.
A 3D object that has been patterned or defined within a build volume on a printing platform comprises an unfused 3D object when no fusing energy has been applied during the layer-by-layer patterning of the object. In some examples, therefore, the unfused 3D object within the build volume can be stabilized and securely removed from the printing platform work area for subsequent fusing. The build volume in which the unfused 3D object is defined can be transferred to a microwave furnace/oven where the unfused 3D object can be fused by a volumetric application of microwave energy to the entire unfused 3D object. During application of microwave energy to the unfused 3D object, the susceptor material facilitates the absorption of the microwave energy and the conversion of the energy into heat, which fuses the layers of build material to form a fused 3D object. As noted above, the fusing aid material can function to lower the fusing temperature of the patterned build material, enabling faster fusing of the 3D object.
In some examples, a method enables the removal of a section of the build volume from the printing platform work area so that an unfused 3D object within the removed section can be securely transferred to a microwave oven for fusing. The unfused 3D object patterned by liquid functional material should be kept stable when it is removed from the printing platform work area and transfer to the microwave oven in order to achieve an accurate and robust fused 3D object. Removing and transferring the entire build volume from the printing platform work area to the microwave oven can be cumbersome and make it difficult to maintain the stability of an unfused 3D object. Selective removal of the patterned, unfused 3D object from the printing platform work area avoids having to transfer the entire build volume to a microwave oven for fusing. Thus, a subsection or portion of the build volume in the printing platform work area that contains an unfused 3D part of interest can be removed and transferred to a microwave oven for fusing. Selectively removing a portion of the build volume that encompasses an unfused 3D object can include inserting a “core drill” container into the build volume to surround the object. The container can then be secured in a manner that stabilizes the unfused 3D object and the additional unpatterned build material within the container that surrounds the object. For example, a capping blade, such as a putty knife or bottom lid, can be slid under or applied to a bottom opening of the core drill container. In some examples a top lid can be applied to a top opening of the core drill container to help secure the undefined build material surrounding the unfused 3D object within the core drill container. The secured core drill container encompassing the unfused 3D object can then be removed from the printing platform work area and transported to the microwave oven for fusing. In some examples, a plurality of unfused 3D objects can be patterned within a build volume, and a corresponding plurality of sections of the build volume can be selectively removed from the printing platform work area using a plurality of corresponding core drill containers. In some examples, a single core drill container can be used to remove a section of a build volume that contains more than one unfused 3D object.
In a particular example, a method of producing a three-dimensional (3D) object includes patterning an unfused 3D object within a work area of a printing platform. The method continues with stabilizing the unfused 3D object for removal from the work area.
In another example, a method of producing a three-dimensional (3D) object includes depositing layers of build material into a work area of a printing platform. A 3D object is patterned from build material within the work area by selectively depositing a liquid functional material (LFM) onto a portion of some of the layers. The 3D object is then enclosed within a removable container.
In another example, an assembly for producing a three-dimensional (3D) object includes patterned build material that forms an unfused 3D object. The assembly additionally includes a container encompassing the unfused 3D object and unpatterned build material surrounding the unfused 3D object.
Referring still to
As each layer of build material, or powder, is spread onto the printing platform 102 within the work area 104, an inkjet printhead 116 or printheads can scan 115 over the work area 104 in a back and forth manner or in a page-wide array configuration to selectively deposit a liquid functional material (LFM) 117 onto the powder layer in a pattern that forms part of an unfused 3D object 110. In some examples, a liquid functional material 117 can include a susceptor material that will absorb microwave radiation and convert it to heat when the unfused 3D object is transferred to a microwave oven. The heat generated by the susceptor material can cause fusing of the unfused 3D object. In some examples, a liquid functional material 117 can include a fusing aid to lower the fusing temperature of the build material. Examples of fusing aids include alumina nanoparticles, silica nanoparticles, and other materials that enable lower temperature fusing of ceramics.
When the patterning of an unfused 3D object 110 is complete, the work area 104 comprises a build volume 105 sometimes referred to as a powder cake. In some examples, when patterning of an unfused 3D object 110 is complete, additional layers of material can be spread over the object 110 to provide insulation when the object 110 is removed from the work area 104. Thus, as shown in
In some examples, once patterning of an unfused 3D object is complete, the top of the build volume 105 can be marked, for example, by a printhead 116 ejecting a pattern of ink onto the top layer of the build volume 105.
The build volume 105 within the work area 104 is made up of patterned build material (i.e., patterned powder) that forms an unfused 3D object, and unpatterned build material (i.e., unpatterned powder) that surrounds the unfused 3D object. The patterned 3D object is an unfused 3D object 110 because none of the patterned powder that makes up the 3D object has been fused together. The unfused 3D object 110 can then be removed from the work area 104 and transferred to a microwave oven for fusing. However, because the 3D object is not yet fused, it can be unstable and may suffer deformation or some other alteration if it is not stabilized prior to being removed from the work area 104.
Therefore, as shown in
The assembly 124 includes a bottom covering 120 as discussed above that can be implemented as a capping blade, a putty knife, a bottom lid, or another type of seal to secure the bottom opening of the core drill container 118. The bottom covering 120 enables the secure removal of the unfused 3D object 110 from the work area 104 and the transporting of the object 110 to a microwave oven for fusing. The assembly 124 also includes a top covering 122 as discussed above that can be applied to the core drill container 118 after the container 118 is inserted into the work area 104. The top covering 122 can comprise a lid or other type of covering that can be affixed to (e.g., screwed onto) the top opening of the core drill container 118 to further stabilize the unfused 3D object 110 by preventing unpatterned power 126 from coming out of the container 118 during removal and transport of the assembly 124 to a microwave oven for fusing. Each of the core drill container 118, the bottom covering 120, and the top covering 122 of the assembly 124 comprises a microwave-transparent material that enables the entire assembly 124 to be moved directly from the work area 104 of a 3D printing system 100 into a microwave oven for fusing.
Referring now to
The method 600 can continue as shown at block 608 with stabilizing the unfused 3D object for removal from the work area. In some examples, stabilizing the unfused 3D object can include inserting a container into a build volume within the work area to encompass the unfused 3D object, and providing a bottom cover for the container to support the unfused 3D object within the container, as shown at blocks 610 and 612, respectively. In some examples, as shown at block 610, prior to inserting a container into the build material, the build material can be marked to indicate a size of the container and a location in the build material for inserting the container. As shown at block 614, the method 600 can include removing the unfused 3D object from the work area by removing the container encompassing the unfused 3D object from the work area. In some examples, the method 600 can include constructing a transportable assembly within the work area, as shown at block 616. Constructing a transportable assembly can include inserting a container into the work area powder bed to encompass the unfused 3D object and some of the unpatterned powdered build material surrounding the unfused 3D object, as shown at block 618. Constructing the assembly can also include applying a bottom cover and a top cover to the container, as shown at block 620.
Referring now to method 700 of
The method 700 can continue with removing the microwave-transparent container from the work area, as shown at block 714. As shown at blocks 716 and 718, respectively, the method can include transporting the microwave-transparent container into a microwave oven, and applying microwave radiation to the microwave-transparent container to fuse the 3D object to create a fused 3D object.
Filing Document | Filing Date | Country | Kind |
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PCT/US2016/029034 | 4/22/2016 | WO | 00 |