Desktop Metal, Inc.

Support structures are used in certain additive fabrication processes to permit fabrication of a greater range of object geometries. For additive fabrication processes with materials that are subsequently sintered into a final part, an interface layer is formed between the object and support in order to inhibit bonding between adjacent surfaces of the support structure and the object during sintering.

According to some aspects, techniques are provided for fabricating sinterable metallic parts through the application of directed energy to a build material. In particular, applying energy to a build material comprising a polymer mixed with a metal powder may cause the polymer to form a cohesive structure with the metal powder. As a result, the polymer acts as a “glue” to produce a metallic green part without local melting of the metal. The green part may subsequently be sintered to remove the polymer and produce a fully dense metal part. Optionally, a step of debinding may also be performed prior to, or simultaneously with, sintering.

Improved formulations of an interface material are described. These formulations may, in at least some cases, match and/or accommodate dimensional changes in the part and/or support structure throughout thermal processing (e.g., debind and sintering, or sintering only). Furthermore, these formulations may also maintain the property of resisting bonding between the interface and the part and/or support structure while also maintaining a physical separation between the part and support structure. In some cases, an improved interface material may accommodate strain associated with the shrinkage of a part (and optionally support structure) during sintering while also minimally impacting the ability of the part (and optionally support structure) to shrink or otherwise change in dimension. In some cases, the interface material may include one or more fugitive phases that are removed during thermal processing (e.g., through pyrolysis of the fugitive phase(s)).

Support structures are used in certain additive fabrication processes to permit fabrication of a greater range of object geometries. For additive fabrication processes with materials that are subsequently sintered into a final part, an interface layer is formed between the object and support in order to inhibit bonding between adjacent surfaces of the support structure and the object during sintering.

Support structures are used in certain additive fabrication processes to permit fabrication of a greater range of object geometries. For additive fabrication processes with materials that are subsequently sintered into a final part, an interface layer is formed between the object and support in order to inhibit bonding between adjacent surfaces of the support structure and the object during sintering.

According to some aspects, techniques are provided for fabricating sinterable metallic parts through the application of directed energy to a build material. In particular, applying energy to a build material comprising a polymer mixed with a metal powder may cause the polymer to form a cohesive structure with the metal powder. As a result, the polymer acts as a “glue” to produce a metallic green part without local melting of the metal. The green part may subsequently be sintered to remove the polymer and produce a fully dense metal part. Optionally, a step of debinding may also be performed prior to, or simultaneously with, sintering.

Mold lock is remediated by performing a layer-by-layer, two-dimensional analysis to identify unconstrained removal paths for any support structure or material within each two-dimensional layer, and then ensuring that aligned draw paths are present for all adjacent layers, all as more specifically described herein. Where locking conditions are identified, a sequence of modification rules are then applied, such as by breaking support structures into multiple, independently removable pieces. By addressing mold lock as a series of interrelated two-dimensional geometric problems, and reserving three-dimensional remediation strategies for more challenging, complex mold lock conditions, substantial advantages can accrue in terms of computational speed and efficiency.

Mold lock is remediated by performing a layer-by-layer, two-dimensional analysis to identify unconstrained removal paths for any support structure or material within each two-dimensional layer, and then ensuring that aligned draw paths are present for all adjacent layers, all as more specifically described herein. Where locking conditions are identified, a sequence of modification rules are then applied, such as by breaking support structures into multiple, independently removable pieces. By addressing mold lock as a series of interrelated two-dimensional geometric problems, and reserving three-dimensional remediation strategies for more challenging, complex mold lock conditions, substantial advantages can accrue in terms of computational speed and efficiency.

Techniques are disclosed for fabricating multi-part assemblies. In particular, by forming release layers between features such as bearings or gear teeth, complex mechanical assemblies can be fabricated in a single additive manufacturing process.

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.