Various implementations utilize electromagnetic energy in the microwave and/or radio frequency (RF) spectrum to volumetrically solidify selective regions of a base material powder bed (e.g., polymer or ceramic). When they are dry, base materials utilized in powder bed fusion and other additive manufacturing processes are relatively transparent to microwave and RF energy, making it very difficult to heat them with those energy sources. However, mixing or doping the base material powders with conducting particles, such as graphite or carbon black, enhances energy absorption at microwave and radio frequencies, enabling heating and melting. Thus, volumetric additive manufacturing may be achieved by selectively doping a 3D powder bed with energy-absorbing particles in the shape of the desired object and exposing the powder bed to microwave and/or RF energy fields, such that the doped regions are volumetrically sintered into desired objects, leaving the surrounding powder unaffected.

Provided in one example herein is a three-dimensional (“3D”) printing method, comprising: (A) forming a layer comprising particles comprising a thermoplastic; (B) disposing over at least a portion of the layer a coalescent agent, which is radiation-absorbing and has a thermal decomposition temperature lower than or equal a melting temperature of the thermoplastic; (C) forming an object slice of a 3D object by exposing the coalescent agent to a radiant energy such that at least some of the coalescent agent thermally decomposes while causing at least some of the particles to fuse, wherein the object slice comprises the fused particles, and wherein the thermally decomposed coalescent agent is not radiation-absorbing; and (D) repeating (A) to (C) to form the 3D object comprising multiple object slices bound depth-wise to one another.

Provided in one example herein is a three-dimensional (“3D”) printing method, comprising: (A) forming a layer comprising particles comprising a thermoplastic; (B) disposing over at least a portion of the layer a coalescent agent, which is radiation-absorbing and has a thermal decomposition temperature lower than or equal a melting temperature of the thermoplastic; (C) forming an object slice of a 3D object by exposing the coalescent agent to a radiant energy such that at least some of the coalescent agent thermally decomposes while causing at least some of the particles to fuse, wherein the object slice comprises the fused particles, and wherein the thermally decomposed coalescent agent is not radiation-absorbing; and (D) repeating (A) to (C) to form the 3D object comprising multiple object slices bound depth-wise to one another.

Methods and apparatus for the fabrication of solid three-dimensional objects from liquid polymerizable materials at high resolution. A material is coated on a film non-digitally, excess material is removed digitally, by laser, leaving an image of a layer to be printed, and the image is then engaged with existing portions of an object being fabricated and exposed to a non-digital UV curing light source. Since the only part of the process that is digital is the material removal, and this part is done by laser, the speed of printing and the robustness of the manufacturing process is improved significantly over conventional additive or 3D fabrication techniques.

A stereolitography apparatus comprises a fixed vat (401) or a holder for receiving a removable vat for holding resin during stereolithographic 3D printing, and a radiation source (501) for generating radiation capable of polymerizing portions of said resin in said vat. (401). The apparatus comprises a shutter (502) between said radiation source (501) and said vat (401) for allowing only selected portions of the generated radiation to reach said resin, and a cooling channel (503) between said radiation source (501) and said shutter (502). The apparatus comprises a blower (504) configured to force coolant gas through said cooling channel (503).

In one example, a method of fabricating a three-dimensional object includes depositing a layer of build material, depositing a coalescing agent onto the layer of build material according to a slice of three-dimensional model data, irradiating the coalescing agent with microwave radiation such that the coalescing agent converts the microwave radiation into heat to coalesce the build material in which the coalescing agent was deposited.

In an example of a method for reducing oxidation of a build material during three-dimensional printing, a portion of a layer of a polymeric build material is patterned by selectively applying a fusing agent on the portion. A detailing agent selectively applied on a non-patterned portion of the layer. The detailing agent includes a stabilizer to reduce oxidation of the polymeric build material. The layer is exposed to electromagnetic radiation to fuse the portion to form a 3D object layer. The stabilizer at least minimizes discoloration of the non-patterned portion.

The present invention discloses a UV curing apparatus for a 3D printing product, including a base. A tray is disposed above the base. The tray is horizontally and rotatably connected around a vertical rotating shaft on the base. A hood concentric with the tray is disposed on the base. The tray is located in the hood, and UV light tubes are arranged on an inner wall of the hood. The tray provides a driving force by means of a driving motor. The driving motor is fixed in the base. As can be seen from the foregoing structure, according to the UV curing apparatus for a 3D printing product in the present invention, a UV curing apparatus applicable to a 3D product is provided, and the surface of the 3D product can be automatically and uniformly subjected to UV curing.

The present invention discloses a UV curing apparatus for a 3D printing product, including a base. A tray is disposed above the base. The tray is horizontally and rotatably connected around a vertical rotating shaft on the base. A hood concentric with the tray is disposed on the base. The tray is located in the hood, and UV light tubes are arranged on an inner wall of the hood. The tray provides a driving force by means of a driving motor. The driving motor is fixed in the base. As can be seen from the foregoing structure, according to the UV curing apparatus for a 3D printing product in the present invention, a UV curing apparatus applicable to a 3D product is provided, and the surface of the 3D product can be automatically and uniformly subjected to UV curing.

A method of making deflection members is disclosed. The deflection members are 3D objects that include cross-linkable polymers and are printed directly onto permeable materials utilizing at least two different printer settings.