FIELD

The present invention relates to build materials and support materials for use with three-dimensional (3D) printing systems.

BACKGROUND

Commercially available 3D printers, such as the ProJet™ 3D Printers manufactured by 3D Systems of Rock Hill, S.C., use inks, which are also known as build materials, that are jetted through a print head as a liquid to form various 3D objects or parts. Other 3D printing systems also use an ink or build material that is jetted through a print head. In some instances, the build material is solid at ambient temperatures and converts to liquid at elevated jetting temperatures. In other instances, the build material is liquid at ambient temperatures.

Moreover, production of a 3D part in a 3D printing system often requires the use of a support material in conjunction with the build material. The support material is also jetted through a print head as a liquid and then subsequently solidified. However, unlike the build material, the support material is subsequently removed to provide the finished 3D part.

Removal of the support material can be administered through several processes. In some cases, the support material is heated to a temperature above its melting point. In other instances, a suitable solvent (aqueous or non-aqueous) is used to remove the support material. In still other cases, a soap or detergent may be used to remove the support material from a 3D part, including at elevated temperatures. However, it can be difficult to know whether all of a support material has been removed from a 3D part, particularly when the support material and the build material used to form the 3D part are the same color or similar colors. Therefore, there exists a need for improved support materials for 3D printing, including support materials that can be removed in a more facile manner and whose removal can be more easily monitored.

There also exists a need for improved build materials for 3D printing, including build materials that can provide visual effects and/or source identification information, including in a manner that may be invisible to the naked or unaided eye of an average human observer under normal or “white light” illumination conditions, but visible under other illumination conditions, such as illumination with an ultraviolet (UV) light source or other “excitation” light source.

SUMMARY

In one aspect, build materials for use with a 3D printer are described herein which, in some embodiments, may offer one or more advantages over prior build materials. For instance, in some cases, a build material described herein provide visual effects to a printed 3D article. A build material described herein, in some embodiments, can also be used to confirm or otherwise identify a source of a printed 3D article. Such confirmation or identification, in some cases, can be provided by the presence of a phosphor component described herein. More particularly, in some instances, a phosphor component described herein can provide “bar coding” information that associates the build material (or a 3D part formed from the build material) with a specific source (e.g., a manufacturer, batch, or facility location) of the build material. A phosphor component of a build material described herein can also, in some embodiments, permit the formation of readable indicia (e.g., letters, numbers, or other alphanumeric characters or symbols) within a 3D part or on an exterior surface of the 3D part. Such indicia can relate to the use or identity of the 3D part or can convey other information of interest to a user. Moreover, such indicia can, in some cases, be visible under ordinary white light illumination conditions or, alternatively, only when special illumination is applied to the 3D part (e.g., UV illumination or illumination with another “excitation” wavelength corresponding to an excitation wavelength of the phosphor component, such as illumination with a light source having a peak emission of 385-395 nm and a power of 15-25 W).

In general, a build material for use in a 3D printing system described herein comprises one or more components that provide mechanical structure to a printed 3D article formed from the build material, as well as a phosphor component. For example, in some embodiments, a build material described herein comprises at least 70 weight percent (wt. %) phase change wax component, optionally up to 30 wt. % additive component (differing from the phase change wax component), and 0.001-5 wt. % phosphor component, where it is to be understood that the weight percents/percentages are based on the total weight of the build material. In other embodiments, a build material described herein comprises 10-60 wt. % oligomeric curable material, up to 80 wt. % monomeric curable material, and 0.001-5 wt. % phosphor component, based on the total weight of the build material.

Moreover, in some cases, the phosphor component of such build materials has a peak photoluminescence (PL) emission wavelength of 430-750 nm or 450-750 nm, and a photoluminescence quantum yield (QY) of 0.10-1. In some instances, the phosphor component has a peak PL emission wavelength of 500-700 nm and a PL QY of 0.30-1. Further, in some embodiments, the phosphor component is present in the build material in an amount of 0.001-0.5 wt. %, 0.005-0.5 wt. %, or 0.01-0.5 wt. %, based on the total weight of the build material.

In another aspect, support materials for use with a 3D printer are described herein which, in some embodiments, may offer one or more advantages over prior support materials. In some cases, for example, a support material described herein facilitates improved post-processing of a printed 3D article, including in relation to removal of the support material from the finished article after printing is complete. Specifically, in some instances, an excitation light source can be used to illuminate the finished article, where the excitation light source is capable of exciting the phosphor component of the support material with sufficient intensity, such that luminescence would be observed by the naked or unaided eye of a typical or average human observer if the support material were still present above a minimum threshold on the surface of the finished article. It is also possible for the presence of a phosphor component in a support material described herein to provide confirmation or identification of a source (e.g., a manufacturer, batch, or facility location) of the support material. In some cases, for instance, a phosphor component described herein can provide “bar coding” information that associates the support material (or a 3D part formed using the support material) with a specific source of the support material. A phosphor component of a support material described herein can also, in some embodiments, permit the formation of readable indicia (e.g., letters, numbers, or other alphanumeric characters or symbols) within a 3D part or on an exterior surface of the 3D part. Such indicia can relate to the use or identity of the 3D part or can convey other information of interest to a user. Moreover, such indicia can, in some cases, be visible under ordinary white light illumination conditions or, alternatively, only when special illumination is applied to the 3D part (e.g., UV illumination described herein or illumination with another “excitation” wavelength corresponding to an excitation wavelength of the phosphor component).

In general, a support material described herein comprises one or more components that provide mechanical structure to removable supporting portions of a printed 3D article formed from the support material, as well as a phosphor component. For instance, a support material described herein, in some cases, comprises 50-80 wt. % phase change wax component, 5-50 wt. % tackifier component, and 0.001-5 wt. % phosphor component, based on the total weight of the support material. Alternatively, in other embodiments, a support material described herein comprises 60-90 wt. % poly(alkylene oxide) component, 10-30 wt. % curable morpholine component, and 0.001-5 wt. % phosphor component, based on the total weight of the support material. The phosphor component of such support materials, in some cases, has a peak PL emission wavelength of 430-750 nm or 450-750 nm, and a PL QY of 0.10-1. In some embodiments, the phosphor component has a peak PL emission wavelength of 500-700 nm and a PL QY of 0.30-1. Further, in some embodiments, the phosphor component is present in the support material in an amount of 0.001-0.5 wt. %, 0.005-0.5 wt. %, or 0.01-0.5 wt. %, based on the total weight of the support material.

In still another aspect, compositions comprising a three-dimensionally printed article are described herein. Such an article, in some embodiments, is formed at least partially from a build material described herein. In other cases, an article is formed partially, but not completely, from a support material described herein. Moreover, in some instances, an article is formed from both a build material described herein and also a support material described herein. In such cases, the support material can form removable supporting portions of the article, as opposed to forming portions of the final, unsupported article. Alternatively, in some embodiments, the support material forms removable supporting portions of the article as well as forming portions of the final, unsupported article (such as portions of support material embedded within portions of build material.

In yet another aspect, methods of printing a 3D article are described herein. In some embodiments, such a method comprises selectively depositing layers of a fluid build material to form the 3D article on a substrate, where the build material is a build material described herein. In other instances, a method of printing a 3D article comprises selectively depositing layers of a fluid build material to form the 3D article on a substrate, and supporting at least one of the layers of the build material with a support material, wherein the build material does not necessarily comprise a build material described herein, but the support material does comprise a support material described herein. It is also possible for the build material to be a build material described herein as well. Further, in some embodiments, a method described herein further comprises removing the support material from the build material.

In another method of printing a 3D article described herein, the method comprises retaining a build material described herein in a fluid state in a container; and selectively applying energy to the build material in the container to solidify at least a portion of a first fluid layer of the build material, thereby forming a first solidified layer that defines a first cross-section of the article. Such a method can further comprise raising or lowering the first solidified layer to provide a second fluid layer of the build material at a surface of the fluid build material in the container; and selectively applying energy to the build material in the container to solidify at least a portion of the second fluid layer of the build material, thereby forming a second solidified layer that defines a second cross-section of the article, the first cross-section and the second cross-section being bonded to one another in a z-direction. As described further hereinbelow, the foregoing steps may be repeated any desired number of times needed to complete the 3D article.

In still another aspect, compositions comprising printed 3D articles are described herein. Such an article can be formed from any build material and/or support material and using any method described herein. Such printed 3D articles, in some cases, have can be formed more accurately and/or convey more information to a user, as compared to some other 3D articles.

These and other embodiments are described in greater detail in the detailed description which follows.

