CPC Class B33Y

A surgical instrument is disclosed comprising a shaft and an end effector rotatably connected to the shaft about an articulation joint. The surgical instrument comprises a plurality of rotation joints which can be simultaneously operated to maintain the alignment of a portion of the surgical instrument relative to the patient tissue.

Provided herein are crosslinked polymers useful in orthodontic appliances and light polymerizable liquid compositions and formulations useful for making crosslinked polymers. Also provided are methods of making an orthodontic appliance comprising a cross-linked polymer formed by a direct fabrication technique.

A nozzle for the additive manufacturing by spraying and fusion of powder along a hollow tapered stream. The nozzle includes an outer cone, an inner cone, and an intermediate cone. The powder is sprayed into the tapered annular space between the inner surface of the outer cone and the outer surface of the intermediate cone. The outer cone includes two portions detachably assembled along the axis of the cone by an assembler.

A powder circuit (36) for use in an apparatus (10) for producing three-dimensional work pieces by irradiating layers of a raw material powder with electromagnetic or particle radiation comprises a process chamber (12) accommodating a carrier (16) and a powder application device (14) for applying a raw material powder onto the carrier (16), the process chamber (12) being provided with a powder inlet (30) for supplying raw material powder to the powder application device (14) and a powder outlet (32) for discharging excess raw material powder from the process chamber (12). The powder circuit (36) further comprises a powder circulation line (34) connecting the powder outlet (32) of the process chamber (12) to the powder inlet (30) of the process chamber (12) and a conveying device (38) arranged in the powder circulation line (34) for conveying the raw material powder through the powder circulation line (34). A sensor arrangement (42) is adapted to detect at least one of a parameter characteristic of a powder supply to the conveying device (38) and a parameter characteristic of a powder discharge from the conveying device (38). A control unit (40) adapted to control operation of the conveying device (38) in dependence of at least one of the parameter characteristic of the powder supply to the conveying device (38) and the parameter characteristic of the powder discharge from the conveying device (38).

A three dimensional (3D) printing system includes a print engine, a first powder handling module, a sieve, a second powder handling module, and a controller. The controller operates the print engine to fabricate 3D articles of manufacture. The controller operates the first powder handling module to transfer excess powder from the print engine to the first powder handling module and to receive new powder. The first powder handling module dispenses powder to the sieve. The controller operates the second handling module to transfer powder from the sieve to the second powder handling module. The second powder handling module provides powder to the print engine.