Markforged, Inc.

Rick Bryan Woodruff

Gregory Thomas Mark

David Steven Benhaim

Abraham Lawrence Parangi

Benjamin Tsu Sklaroff

Keith Durand

Michelle Ling Chao

Benjamin Hodsdon Gallup

According to one aspect, embodiments herein provide a furnace for debinding and sintering additively manufactured parts comprising a unitarily formed retort having at least one open side, a heater for heating a sintering volume within the retort to a debinding temperature and to a sintering temperature, an end cap sealing the at least one open side, a forming gas line penetrating the end cap for supplying forming gas at a flowrate, and a heat exchanger within the retort, outside the sintering volume, and adjacent a heated wall of the retort, the heat exchanger having an inlet connected to the forming gas line and an outlet to the sintering volume, wherein the heat exchanger includes a heat exchange tube length sufficient to heat the forming gas to within 20 degrees Celsius of the sintering temperature before the forming gas exits the outlet.

Sintering furnace

Apparatus and methods for debinding articles. The apparatus and methods may transform binder from furnace exhaust before the exhaust is discharged to the atmosphere. The apparatus may include a furnace retort and a reactor. The furnace retort may be configured to: exclude ambient air; and receive a carrier gas. The reactor may be configured to: receive from the retort (a) the carrier gas and (b) material removed in the retort from the article; and combust, at a temperature no greater than 750° C., the material. The material may be decomposed binder. The material may be hydrocarbon from binder that is pyrolyzed in the retort. The carrier gas may include gas that is nonflammable gas.

Catalytic thermal debind furnaces with feedback control

In a method for additive manufacturing, a multi-strand core reinforced filament including a flowable matrix material and substantially continuous reinforcing strands extending in a direction parallel to a length of the filament is supplied. A first consolidated composite swath of a height less than &#xbd; the width of the filament is deposited in a first reinforcement formation including at least one straight path and at least one curved path against a deposition surface, and a second consolidated composite swath of a height less than &#xbd; the width of the filament is deposited in a second reinforcement formation against the first consolidated composite swath. Each deposition flows the matrix material and applies an ironing force to spread the reinforcing strands within the filament against the underlying surface and/or previously deposited swath.

Composite filament 3D printing using complementary reinforcement formations

According to one aspect, embodiments of the invention provide a method of 3D printing, comprising depositing a model material in successive layers to form a part, the model material being a metal composite including greater than 50% by volume metal powder and less than 50% by volume a first removable binder, depositing the model material in successive layers to form a support structure adjacent the part, depositing a sinterable separation material between a surface of the part and a surface of the support structure, the sinterable separation material formed from 10-40% by volume ceramic powder and greater than 50% by volume a second removable binder, debinding the first removable binder of the model material and the second removable binder of the sinterable separation material, and sintering the part, the support structure, and the sinterable separation material at a temperature profile that sinters the model material and the sinterable separation material.

Sinterable separation material in additive manufacturing

A method comprising receiving a first 3D toolpath defining a fill material curved shell, receiving first 2D toolpaths defining support material flat shells, receiving a second 3D toolpath defining a long fiber composite material curved shell, the long fiber composite material including a filament having a matrix embedding fibers having a length longer than two times a diameter of the filament, actuating a fill material deposition head to trace the first 3D toolpath to deposit the fill material curved shell non-parallel to a printing substrate, actuating a support material deposition head to trace the first 2D toolpaths to deposit support material in a succession of substantially flat shells, and actuating a long fiber deposition head to trace the second 3D toolpath non-parallel to the printing substrate to deposit the long fiber composite material curved shell to enclose at least a portion of the fill material curved shell.

Multilayer fiber reinforcement design for 3D printing

According to at least one aspect, embodiments of the invention provide a 3D printer comprising an anisotropic head that solidifies, along anisotropic toolpaths, fiber swaths having an anisotropic characteristic oriented relative to a trajectory of the anisotropic tool paths, an isotropic head that solidifies, along isotropic toolpaths, a substantially isotropic material, a motorized drive for moving the anisotropic head and a build plate supporting a printed part in at least three degrees of freedom, and a controller configured to control the 3D printer to build the printed part by solidifying the isotropic material along the isotropic tool paths, solidifying the anisotropic material in fiber swaths tracking a non-concentric set of anisotropic tool paths for at least a first sequence of parallel shells, solidifying the anisotropic material in fiber swaths tracking an outer concentric set of anisotropic tool paths for at least a second sequence of parallel shells.

In a 3D composite printer, toolpaths defining fill material shells are received, as are toolpaths defining support material shells. A 3D toolpath defining a long fiber composite material curved shell is also received. A fill material deposition head traces the toolpaths to deposit some of the fill material shells or support material shells at least in part non-parallel to a printing substrate. A long fiber deposition head traces the 3D toolpath at least in part non-parallel to the printing substrate to deposit the long fiber composite material curved, concave, ring, tube, or winding shells to enclose, surround, or envelop at least a portion of the fill or support material shells.

Multiaxis fiber reinforcement for 3D printing

A three-dimensional geometry is received, and sliced into layers. A first anisotropic fill tool path for controlling a three dimensional printer to deposit a substantially anisotropic fill material is generated defining at least part of an interior of a first layer. A second anisotropic fill tool path for controlling a three dimensional printer to deposit the substantially anisotropic fill material defines at least part of an interior of a second layer. A generated isotropic fill material tool path defines at least part of a perimeter and at least part of an interior of a third layer intervening between the first and second layers.

A three dimensional printer incorporates a kinematic coupling between the build platform and movable stage which holds the build platform, of three curved protrusions attached to one of the build platform or the movable stage and six locating features formed in receivers of the other. At least two flexures differentially change a Z position of each of two of the curved protrusions. 3D printing is paused at a preset level of completion, and the build platform may be removed for external operations. A print resume circuit resumes printing of additional printed layers at the previous position in response to a return detection circuit that responds to an input (e.g., a touch screen confirmation).

Growing community of inventors

Cambridge, MA, United States of America

Rick Bryan Woodruff