A three-dimensional object model is divided into slices that are targeted for an additive manufacturing process operable to deposit material at a variable deposition size ranging between minimum and maximum printable feature sizes. For each of the slices, a thinning algorithm is applied to contours of the slice to form a meso-skeleton. Topological features of the thinned slice are reduced over a number of passes such that a portion of the meso-skeleton is reduced to a single pixel wide line. Based on the number of passes, a slice-specific printable feature size within the range of the minimum and maximum printable feature sizes is determined. An adjusted slice is formed by sweeping the meso-skeleton with the slice-specific printable feature size. The adjusted slices are assembled into an object model which is used to create a manufactured object.

A photo-curable resin composition for three-dimensional shaping including: a resin component (A) containing a (meth)acrylate compound (A1) represented by General Formula (1)

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(where R.sub.1 is a hydrogen atom or a methyl group, and R.sub.2 is a linear, branched, or cyclic trivalent hydrocarbon group with one to eight carbon atoms which may have three or less heteroatoms), and a urethane (meth)acrylate compound (A2) having two or more radical-polymerizable functional groups; inorganic particles (B); and a photoradical polymerization initiator (C). 40% by mass or more and 90% by mass or less of the (meth)acrylate compound (A1) is contained in the resin component (A). 10% by mass or more and 60% by mass or less of the urethane (meth)acrylate compound (A2) is contained in the resin component (A).

Some variations provide a composition for additive manufacturing (3D printing) of metals, comprising: from 10 vol % to 70 vol % of a photocurable liquid resin; from 10 vol % to 70 vol % of metal or metal alloy particles, optionally configured with a photoreflective surface; and from 0.01 vol % to 10 vol % of a photoinitiator. Other variations provide a composition for additive manufacturing of metals, comprising: from 1 vol % to 70 vol % of a photocurable liquid resin; from 0.1 vol % to 98 vol % of an organometallic compound containing a first metal; from 1 vol % to 70 vol % of metal or metal alloy particles containing a second metal (which may be the same as or different than the first metal); and from 0.01 vol % to 10 vol % of a photoinitiator. Many examples of metals, photocurable resins, organometallic compounds, photoinitiators, and optional additives are disclosed, and methods of making and using the composition are described.

Articles prepared by additive manufacturing of preforms that are coated by electrodeposition of nanolaminate materials, and methods of their production are described.

A method for manufacturing an object, in particular an orthodontic appliance, by a 3D-printing device comprising a supply device for provision of a non-solidified material and means for illumination to solidify a layer of non-solidified material provided by the supply device at least zonally to fabricate the object, characterized by the following steps: a virtual model of the object to be printed is provided for the 3D-printing device, the supply device provides a layer of the non-solidified material, the means for illumination solidify the layer at least zonally, whereby the means for illumination comprises illumination pixels arranged in a grid, preferably with a dimension (between 10 μm and 80 μm, particularly preferred between 30 μm and 50 μm, wherein at least one dimension of the object represented by the virtual model is chosen to be aligned with the dimension of the illumination pixels.

Assemblies fabricated by additive manufacturing include an object and a base plate providing support to the object during the manufacturing process. The geometry of the base plate is defined to optimize space and material constraints. During sintering, the base plate is reduced in area in a manner complementing the reduction in the footprint of the object, preserving the fidelity of the finished object.

The invention provides a cross-flow separation element comprising a single-piece rigid porous support (2) having within its volume at least one channel (4.sub.1) for passing a flow of the fluid medium for treatment, which channel presents a flexuous flow volume (V1) defined by sweeping a generator section along a curvilinear path around a reference axis, and in that the reference axis does not intersect said generator section and is contained within the volume of the porous support.

The invention provides a cross-flow separation element comprising a single-piece rigid porous support (2) having within its volume at least one channel (4.sub.1) for passing a flow of the fluid medium for treatment, which channel presents a flexuous flow volume (V1) defined by sweeping a generator section along a curvilinear path around a reference axis, and in that the reference axis does not intersect said generator section and is contained within the volume of the porous support.

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.

Provided herein are curable compositions for use in a high temperature lithography-based photopolymerization process, a method of producing crosslinked polymers using said curable compositions, crosslinked polymers thus produced, and orthodontic appliances comprising the crosslinked polymers.