Abstract: Methods and systems for forming objects through photo-curing of a liquid resin in a tank by selective exposure (through a mask) to radiation, in which during printing operations the liquid resin in the tank is displaced relative to the build area along an axis orthogonal to that along which the object is extracted from the liquid resin in the tank. A volume of the photo-curing liquid resin may be cycled through a cooling arrangement by being extracted from the tank, cooled, and then reintroduced into the tank as printing of the object is taking place. The mask is preferably one in which charged colorant particles are dispersed in an optically transparent fluid within a plurality of bi-state cells.

Abstract: In vat polymerization printer, light is projected from a digital light processing (DLP) light source towards an opening in a tank containing photo-curable liquid resin. A mask is used to filter the light from the DLP light source, the mask having pixels configurable to be individually transparent or opaque to portions of the light from the DLP light source. In a build area of the tank, the filtered light is used to cure the photo-curable liquid resin so as to form a layer of a partially formed object. The operation of the DLP light source is synchronized with the operation of the mask, such that light from the DLP light source with high intensity is transmitted through the transparent pixels of mask and light from DLP light source with low intensity is blocked by the opaque pixels of mask. The mask may enhance the resolution of DLP light source.

Abstract: A 3D printing system may include a tank in which a bottom of the tank is formed by a flexible membrane. The flexible membrane may be stretched within a frame, which together with the flexible membrane may form a membrane assembly that is secured to the tank sidewall by one or more hinged clamps. Each of the hinged clamps may comprise an arm and an angled member. The distal end of the arm may comprise a hooked attachment member that is complementary in shape to a lip of the frame of the membrane assembly. The proximal end of the arm may be attached to the angled member by a hinge. The angled member may be attached to the tank sidewall by another hinge. The angled member and the arm may be positioned to clamp the membrane assembly to the tank sidewall, or release the membrane assembly from the tank sidewall.

Abstract: A 3D printing system may include a tank in which a bottom of the tank is formed by a radiation-transparent flexible membrane, a spill tray with an outer wall configured to contain liquid resin that inadvertently leaks out from the bottom of the tank, and a light source configured to project radiation towards the bottom of the tank. The spill tray may contain an inner opening that allows the radiation from the light source to pass through the spill tray to the tank. A 3D printing system may also include a mask assembly which comprises a mask with pixels configurable to be individually transparent or opaque to portions of the radiation projected from the light source and a mask assembly receiving member configured to receive the mask assembly. The mask assembly may also include a rigid guide portion that is insertable into a slot of the mask assembly receiving member.

Abstract: Described are methods and apparatus for the inspection of cured layers of an object during the fabrication of the object using a 3D printing system. A just-printed layer may be inspected by pressing the layer against a pressure-sensitive surface in order to collect information about the layer. For example, a tank may contain a photo-curing liquid polymer, and at its bottom are pressure sensitive elements (e.g., in a backing member or mask). An extraction plate to which the object is affixed may be adjusted so as to position a surface of the object adjacent to the pressure sensitive elements, which report a pressure distribution (e.g., by virtue of a force exerted by a localized region of the object on a localized region of the pressure sensitive elements).

Abstract: A design with multiple instances of a three-dimensional article is printed by first defining a unit cell that includes a single instance of a three-dimensional article that repeats in the design along with its nearest neighbor elements in both a plane of a build plate of a target printer on which the design is to be printed and a plane orthogonal thereto. The design is represented in an output file of a design application and a slicer application then generates instructions to manufacture the design by the target printer. The instructions (g-code) include directions to print, for each of a specified number of layers a number of instances of the unit cell that can be accommodated within a build envelop of the target printer per layer as determined by said slicer application. The design is printed by the printer according to the instructions from the slicer application.

Abstract: Methods and apparatus for forming three-dimensional objects by photo-curing a photo-curing liquid polymer exposed to a radiation in a space between a base transparent to the radiation and a supporting plate. The supporting plate moves progressively, in some cases continuously, away from said transparent base during the printing process, and that movement is characterized in that it is tilting, swinging, rotating, and/or swirling in three-dimensional space, based on the print geometry, in order to expedite printing speed and resin propagation throughout the build area. In one embodiment, the movement may resemble a spiral or helical path from the standpoint of points around its circumference.

Abstract: A tank assembly for a 3D printing system may include a membrane assembly that is releasably secured to a bottom rim of a tank sidewall of the tank assembly. The securing mechanism may include one or more of a friction-fit coupling and a magnetic coupling. The membrane assembly may include a frame, a radiation-transparent flexible membrane and a membrane securing member. A peripheral portion of the flexible membrane may be secured within a groove of the frame by the membrane securing member. The tank sidewall may include one or more components for supplying fresh resin to the tank assembly and one or more components for draining used resin from the tank assembly.

Abstract: A 3D printing system may include a tank in which a bottom of the tank is formed by a radiation-transparent flexible membrane, a spill tray with an outer wall configured to contain liquid resin that inadvertently leaks out from the bottom of the tank, and a light source configured to project radiation towards the bottom of the tank. The spill tray may contain an inner opening that allows the radiation from the light source to pass through the spill tray to the tank. A 3D printing system may also include a mask assembly which comprises a mask with pixels configurable to be individually transparent or opaque to portions of the radiation projected from the light source and a mask assembly receiving member configured to receive the mask assembly. The mask assembly may also include a rigid guide portion that is insertable into a slot of the mask assembly receiving member.

Abstract: An optimal printing speed and orientation for an object to be manufactured using an additive manufacturing process in which a photo-curable resin is cured through exposure to radiation are estimated by determining, for pixel maps defining cross-sections of the object, a critical size of a convolution kernel which provides an activation map having a maximum activation pixel value less than or equal to a predetermined threshold value. For each respective pixel map, a printing time is estimated as a function of adjusted base lift velocity and base lift height of the printing apparatus. The optimal printing speed and orientation are then estimated as a minimum value of a sum of a function of printing times for all respective pixel maps of the cross-sections of the object at each of a plurality of possible orientations of the object.

Abstract: Multi-material membranes for use in vat polymerization printers. The membranes include a fluorinated ethylene propylene (FEP) or polyolefin polymer film bonded to a layer of silicone rubber. The layer of silicone rubber is coated to reduce its surface energy. Coatings such as a silicone elastomer or polytetrafluoroethylene (PTFE)-based material may be used. The coatings are preferably sprayed on and allowed to cure or dry after the FEP or other film has been bonded to the layer of silicone rubber.

Abstract: An optimal printing speed and orientation for an object to be manufactured using an additive manufacturing process in which a photo-curable resin is cured through exposure to radiation are estimated by determining, for pixel maps defining cross-sections of the object, a critical size of a convolution kernel which provides an activation map having a maximum activation pixel value less than or equal to a predetermined threshold value. For each respective pixel map, a printing time is estimated as a function of an adjusted base lift velocity and base lift height of the printing apparatus. The optimal printing speed and orientation are then estimated as a minimum value of a function of the printing times for all respective pixel maps of the cross-sections of the object at each of a plurality of possible orientations of the object.

Abstract: Three-dimensional objects are formed by photo-curing a liquid polymer by exposure to a radiation in a space between a sheet transparent to the radiation and a supporting plate. On a side of the sheet facing towards the photo-curing liquid polymer, a membrane is arranged. The membrane is transparent to the radiation and covered by a layer of liquid lubricant. The membrane is displaceable with respect to an area in which said liquid polymer is undergoing curing by exposure to the radiation, which radiation (e.g., at 410 nm) may be provided by a collimated light source composed of an array of light emitting diode (LED) sources, an array of baffles, and an array of lenses. The baffles limit beam widths of each individual LED source in the array of LED, and the array of lenses is located one focal length from said array of LED sources.

Abstract: A design with multiple instances of a three-dimensional article is printed by first defining a unit cell that includes a single instance of a three-dimensional article that repeats in the design along with its nearest neighbor elements in both a plane of a build plate of a target printer on which the design is to be printed and a plane orthogonal thereto. The design is represented in an output file of a design application and a slicer application then generates instructions to manufacture the design by the target printer. The instructions (g-code) include directions to print, for each of a specified number of layers a number of instances of the unit cell that can be accommodated within a build envelop of the target printer per layer as determined by said slicer application. The design is printed by the printer according to the instructions from the slicer application.

Abstract: A vat polymerization apparatus configured with a resin circulatory system that includes pumps arranged to extract used photo-curing resin from a tank and refresh or replace it with new resin, another fluid, or a combination of new resin and the fluid. Resin flow is regulated using a plurality of valves which are opened and closed to achieve a desired circulation process. Additional aspects of the apparatus include a membrane assembly in which a radiation-transparent flexible membrane is supported in a frame that stretches the membrane. A lip of the frame is secured to a bottom rim of the tank; thus, when the membrane assembly is in place it forms a bottom of the tank. A tension adjustment mechanism may be employed to adjust the tension of the membrane within the frame. The frame may be aligned with the tank with the aid of magnetized alignment aids distributed about the frame.