A method of processing a surface in additive manufacturing includes assembling a structure for a component by additive manufacturing out of a bed of a powdery base material, such that the structure is provided with an internal surface and a powdery base material covers at least a part of the internal surface, and actuating the base material relatively to the structure such that the internal surface is mechanically processed by the base material.

A method of processing a surface in additive manufacturing includes assembling a structure for a component by additive manufacturing out of a bed of a powdery base material, such that the structure is provided with an internal surface and a powdery base material covers at least a part of the internal surface, and actuating the base material relatively to the structure such that the internal surface is mechanically processed by the base material.

An apparatus and method for smoothing and polishing metals via ion transport by free solid bodies. The method includes connecting a part to be treated to a positive pole (anode) of a current generator and subjecting the part to friction with a set of particles comprising electrically conductive free solid bodies charged with negative electrical charge in a gaseous environment.

A method of providing an abrasive structure for additive manufacturing includes determining of a design of a portion of a powdery base material and selectively solidifying the portion in a bed of the base material according to the determined design such that an abrasive structure is generated, wherein the abrasive structure is still movable in the bed of the base material. Further, an additively manufactured component has an internal surface with a surface roughness of less than 100 μm, preferably less than 60 μm.

A method of providing an abrasive structure for additive manufacturing includes determining of a design of a portion of a powdery base material and selectively solidifying the portion in a bed of the base material according to the determined design such that an abrasive structure is generated, wherein the abrasive structure is still movable in the bed of the base material. Further, an additively manufactured component has an internal surface with a surface roughness of less than 100 μm, preferably less than 60 μm.

A hollow spring includes a steel tube in which the average of surface roughness is smaller than 10 μm across the entire inner surface of the steel tube and/or compressive residual stress is given to the entire inner surface of the steel tube. The hollow spring may be manufactured by a step of polishing the inner surface of the steel tube by flowing a viscoelastic abrasive medium (200) within the tubular member (10), between a first opening (11) and a second opening (12) of the tubular member (10). The abrasive medium (200) may include a viscoelastic base material and a granular abrasive. The inner surface of the steel tube is polished evenly to reduce the surface roughness and/or is given compressive residual stress to increase the fatigue life of the hollow spring.

A hollow spring includes a steel tube in which the average of surface roughness is smaller than 10 μm across the entire inner surface of the steel tube and/or compressive residual stress is given to the entire inner surface of the steel tube. The hollow spring may be manufactured by a step of polishing the inner surface of the steel tube by flowing a viscoelastic abrasive medium (200) within the tubular member (10), between a first opening (11) and a second opening (12) of the tubular member (10). The abrasive medium (200) may include a viscoelastic base material and a granular abrasive. The inner surface of the steel tube is polished evenly to reduce the surface roughness and/or is given compressive residual stress to increase the fatigue life of the hollow spring.

The present subject matter relates to a method and an apparatus in the form of a machine system (1200) for machining a component (100) with an internal passage (115). In an aspect, the method comprises periodically injecting 5 abrasive slurry back and forth through the internal passage (115) at a pressure ranging from about 25 bar to about 35 bar. The abrasive slurry comprises a mixture of abrasive particles having a size in the range of about 40 m to about 60 m, and a slurry medium. The volume fraction of the abrasive particles in the slurry medium is about 40% to about 50%. Further, the injection of the abrasive 10 slurry is performed for a predefined number of process cycles at predetermined time versus pressure changes to obtain the component having a final average surface roughness of less than about 3.0 m.

A method for smoothing and polishing metals via ion transport by free solid bodies comprises connecting a part to be treated to a positive pole (anode) of a current generator and subjecting the part to friction with a set of particles comprising electrically conductive free solid bodies charged with negative electrical charge in a gaseous environment.

An apparatus and method for smoothing and polishing metals via ion transport by free solid bodies. The method includes connecting a part to be treated to a positive pole (anode) of a current generator and subjecting the part to friction with a set of particles comprising electrically conductive free solid bodies charged with negative electrical charge in a gaseous environment.