Abstract: The invention relates to a printhead (1) for a 3D printer, particularly a metal printer, comprising a housing (3), a device (28) for supplying a metal (14), a reservoir (7, 27), a nozzle device (2) and a piston (5), the nozzle device (2) comprising a guide sleeve (11), a nozzle plate (9) provided with an outlet (10), and a clamping device (4). The nozzle plate (9) and the guide sleeve (11) are mutually elastically braced by means of the clamping device (4), and the guide sleeve (11) and the reservoir (7, 27) are mutually elastically braced by means of the clamping device (4).

Abstract: The invention relates to a piston (5) for a printhead (1) of a 3D printer, particularly a metal printer, comprising a piston rod (17) and a ram (18), the ram (18) having a discharge side (19) that has a convex or tapering surface (39). The invention also relates to a printhead (1) for a 3D printer, particularly a metal printer, comprising a housing (3), a device (28) for supplying a metal (14), a reservoir (7, 27) for a liquid phase (8) of the metal (14), a nozzle device (2) comprising a guide sleeve (11) and a nozzle plate (9), and a piston (5) according to one of the preceding claims, the ram (18), the guide sleeve (11) and the nozzle plate (9) forming a displacement chamber (21), and the ram (18) and the guide sleeve (11) forming at least one area (40) for conducting the liquid phase (8) between the reservoir (27) and the displacement chamber (21).

Abstract: The invention relates to a device (100) for the additive manufacture of three-dimensional workpieces, in particular a 3D metal printer, comprising a print head (1) and a device (40) for generating an inert atmosphere (22) within the print head (1) by means of a gas (55), in particular inert gas, wherein the print head (1) comprises a housing (3), a device (28) for feeding a metal (14), a piston (5), a reservoir (7) with an outlet opening (10) and an actuator device (12) for displacing the piston (5), wherein the reservoir (7) has a melt region (20) and a displacement body chamber (21) for a liquid phase (8) of the metal (14), wherein the melt region (20) adjoins the inert atmosphere (22) and is connected to the displacement body chamber (21) such that, as a result of the displacement of the piston (5), the liquid phase (8) of the metal (14) can be caused to pass through the outlet opening (10).

Abstract: The invention relates to a method for the rapid manufacture of a three-dimensional workpiece from a molten material (1), in particular a molten metal, in which method the molten material (1) is supplied to a compression chamber (2) and delivered in drop form via an injector hole (4) by means of a pressure pulse which is generated with the aid of a reciprocating piston (3) that delimits the compression chamber (2). According to the invention, the compression chamber (2) is degassed before manufacturing begins and/or during a pause in the manufacturing. In a first step, ultrasonic waves are coupled into the molten material (1) in the compression chamber (2), which generate a force (FBjrk) that makes the gas in the molten material (1) sink, and in a second step, after the ultrasonic excitation has ended, the piston (3) is introduced deeper into the compression chamber (2) in order to remove the rising gas via a conduit (5) of the piston (3).

Abstract: The invention relates to a print head (1) for additively manufacturing three-dimensional workpieces, comprising a housing (3), a device (28) for feeding a metal (14), a piston (5), a reservoir (7) with an outlet opening (10) and an actuator device (12) for displacing the piston (5), wherein the reservoir (7, 27) has a melt region (20) and a displacement body chamber (21) for a liquid phase (8) of the metal (14), wherein the melt region (20) adjoins the inert atmosphere (22) and is connected to the displacement body chamber (21) such that, as a result of the displacement of the piston (5), the liquid phase (8) of the metal (14) can be stimulated to pass through the outlet opening (10), said outlet opening (10) being mounted on an insert (11) of the print head (1). The invention is characterised in that the print head (1) comprises a device (50) for feeding a protective gas (60) to the outlet opening (10) of the print head (1).

Abstract: The invention relates to a method for the additive manufacturing of a three-dimensional workpiece from a liquid material (1), in which method the liquid material (1) is fed to a displacement chamber (2) and discharged in drop form via a jet hole (4) by means of a pressure pulse which is generated with the aid of a reciprocating piston (3) delimiting the displacement chamber (2). According to the invention, in order to optimise the wetting properties of at least one surface (5, 6) which delimits the displacement chamber (2) and/or the jet hole (4), sound waves are coupled into the liquid material (1) for a limited period of time with the aid of the piston (3) which is caused to vibrate for this purpose. The invention also relates to a device for carrying out the method according to the invention.

Abstract: The invention relates to a device (100) for the additive manufacture of three-dimensional workpieces, in particular a 3D metal printer, comprising a print head (1) and a device (40) for generating an inert atmosphere (22) within the print head (1) by means of a gas (55), in particular inert gas, wherein the print head (1) comprises a housing (3), a device (28) for feeding a metal (14), a piston (5), a reservoir (7) with an outlet opening (10) and an actuator device (12) for displacing the piston (5), wherein the reservoir (7) has a melt region (20) and a displacement body chamber (21) for a liquid phase (8) of the metal (14), wherein the melt region (20) adjoins the inert atmosphere (22) and is connected to the displacement body chamber (21) such that, as a result of the displacement of the piston (5), the liquid phase (8) of the metal (14) can be caused to pass through the outlet opening (10).

Abstract: The invention relates to a piston (5) for a printhead (1) of a 3D printer, particularly a metal printer, comprising a piston rod (17) and a ram (18), the ram (18) having a discharge side (19) that has a convex or tapering surface (39). The invention also relates to a printhead (1) for a 3D printer, particularly a metal printer, comprising a housing (3), a device (28) for supplying a metal (14), a reservoir (7, 27) for a liquid phase (8) of the metal (14), a nozzle device (2) comprising a guide sleeve (11) and a nozzle plate (9), and a piston (5) according to one of the preceding claims, the ram (18), the guide sleeve (11) and the nozzle plate (9) forming a displacement chamber (21), and the ram (18) and the guide sleeve (11) forming at least one area (40) for conducting the liquid phase (8) between the reservoir (27) and the displacement chamber (21).

Abstract: The invention relates to a printhead (1) for a 3D printer, particularly a metal printer, comprising a housing (3), a device (28) for supplying a metal (14), a reservoir (7, 27), a nozzle device (2) and a piston (5), the nozzle device (2) comprising a guide sleeve (11), a nozzle plate (9) provided with an outlet (10), and a clamping device (4). The nozzle plate (9) and the guide sleeve (11) are mutually elastically braced by means of the clamping device (4), and the guide sleeve (11) and the reservoir (7, 27) are mutually elastically braced by means of the clamping device (4).

Abstract: The invention relates to a bypass valve (1), in particular for an expansion machine (104) of a waste heat recovery system (100). The bypass valve (1) has a housing (2) with a valve chamber (9) formed therein. An inlet (3), an expander outlet (4) and a bypass outlet (5) are formed in the housing (2), which feed into the valve chamber (9). A closing element (6) is moveably arranged in the valve chamber (9). A valve seat (11) is formed on the housing (2). The closing element (6) cooperates with the valve seat (11) in order to open and close a first hydraulic connection from the inlet (3) to the expander outlet (4). A control valve (8) opens and closes a second hydraulic connection from the inlet (3) to the bypass outlet (5). The control valve (8) forms a first throttle point (21) in an open position. A second throttle point (22) is arranged between the valve chamber (9) and the bypass outlet (5). The control valve (8), the second throttle point (22) and the closing element (6) border a control chamber (9a).

Abstract: The invention relates to a bypass valve (1), in particular for an expansion machine (104) of a waste heat recovery system (100). The bypass valve (1) has a housing (2) with a valve chamber (9) formed therein. An inlet (3), an expander outlet (4) and a bypass outlet (5) are formed in the housing (2), which feed into the valve chamber (9). A closing element (6) is moveably arranged in the valve chamber (9). A valve seat (11) is formed on the housing (2). The closing element (6) cooperates with the valve seat (11) in order to open and close a first hydraulic connection from the inlet (3) to the expander outlet (4). A control valve (8) opens and closes a second hydraulic connection from the inlet (3) to the bypass outlet (5). The control valve (8) forms a first throttle point (21) in an open position. A second throttle point (22) is arranged between the valve chamber (9) and the bypass outlet (5). The control valve (8), the second throttle point (22) and the closing element (6) border a control chamber (9a).

Abstract: The invention relates to a waste heat recovery system (1) comprising a working fluid circuit (18), having a heat exchanger which is connected in an exhaust gas line (4) of an internal combustion engine (2). The heat exchanger is part of the working fluid circuit (18) together with an expansion machine (20) which has at least one working fluid bypass (21) that is controlled by a valve. According to the invention, a waste heat recovery system (1) is provided with improved functionality. This is achieved in that the valve is a directional valve which connects a fluid inlet (36) to an expansion machine fluid outlet (37) and/or a bypass fluid outlet (38), in particular a 3/2-way valve (22), and the connection of the fluid inlet (36) to the expansion machine fluid outlet (37) is leakage-free relative to the bypass fluid outlet (38), whereas the connection of the fluid inlet (36) to the bypass fluid outlet (38) exhibits leakages with respect to the expansion machine fluid outlet (37).

Abstract: An apparatus for conveying a cooling air flow for at least one motor vehicle heat exchanger has a fan frame, a fan wheel, a fan control unit, and a cooling body. The fan frame has a frame opening, which the fan wheel rotates within. The fan control unit is arranged in an edge region of the frame opening. The cooling body cools the fan control unit and has cooling domes. A first cooling dome is arranged entirely radially exterior to the frame opening and a second cooling dome is located partially radially within the frame opening and partially radially exterior to the frame opening. The first cooling dome exchanges heat with an auxiliary flow that flows radially exterior to the frame opening with respect to the center of the fan wheel when the fan wheel rotates.

Abstract: The invention relates to an apparatus for conveying a cooling air flow for at least one heat exchanger, especially for motor vehicles. Said apparatus comprises a fan frame (1) with a frame opening (2), a fan wheel (4) that revolves in the frame opening, and a fan drive unit with a fan control device (6) which is disposed in the peripheral zone of the frame opening (2) and can be cooled by means of a cooling member (7). At least one part of the cooling member (7) is arranged radially outside the frame opening (2) and can be impinged upon by a secondary flow (N) of the cooling air flow (L).