A friction stir spot welding apparatus according to the present invention includes: a rotary tool; and a perpendicular-to-plane detector, which detects whether or not the rotary tool is positioned to be in a perpendicular-to-plane state relative to a joining target portion of workpieces. The perpendicular-to-plane detector measures distances to at least three measurement positions set around the joining target portion by means of, for example, position sensors. The measurement positions are set to be positioned at the vertices of a polygon on a reference plane to which forward and backward movement directions of the rotary tool are normal. The perpendicular-to-plane detector detects that the rotary tool is positioned to be in the perpendicular-to-plane state relative to the joining target portion of the workpieces if all the distances to the measurement positions are equal to each other.

A pressure welding method and to a pressure welding device (1) are provided. The pressure welding device (1) includes a plastification device (7), an upsetting device (8) and component mountings (34, 35, 36, 37) for the components (2, 3, 3′, 4) to be welded together and a machine frame (12). The pressure welding device (1) includes a machine head (13) which is arranged so as to move on the machine frame (12). The machine head (13) includes a rotatable spindle (54) and a component mounting element (34, 35) as well as an associated spindle drive (56). The machine head (13, 14) and the spindle drive (56) are separated from each other on the machine frame (12). A controllable mass decoupling (79) including an axially tolerant coupling (80), is arranged in the drive train (57) between the fixed or moveable spindle drive (56) arranged on the machine frame (12).

A pressure welding method and to a pressure welding device (1) are provided. The pressure welding device (1) includes a plastification device (7), an upsetting device (8) and component mountings (34, 35, 36, 37) for the components (2, 3, 3′, 4) to be welded together and a machine frame (12). The pressure welding device (1) includes a machine head (13) which is arranged so as to move on the machine frame (12). The machine head (13) includes a rotatable spindle (54) and a component mounting element (34, 35) as well as an associated spindle drive (56). The machine head (13, 14) and the spindle drive (56) are separated from each other on the machine frame (12). A controllable mass decoupling (79) including an axially tolerant coupling (80), is arranged in the drive train (57) between the fixed or moveable spindle drive (56) arranged on the machine frame (12).

A friction stir welding apparatus includes a probe, a shoulder, a recess part, and an annular member. The probe is pressed to a joint part of a plurality of joined members while being rotated. The shoulder is formed so as to surround the probe at an outside in a radial direction with respect to a rotation axis of the probe. The recess part is formed on at least one of an outer circumference of the probe and an inner circumference of the shoulder. The annular member is fitted to the recess part.

A method may comprise: placing a probe in a molten metal melt comprising a thixotropic metal alloy; injecting a gas into the molten metal melt to form a saturated slurry, the saturated slurry being at a temperature above a liquidus temperature of the thixotropic metal alloy after injecting the gas; removing the probe from the molten metal melt; and depositing the molten metal melt through an extruder of an additive manufacturing system.

A method of making an electrical connection is here proposed. The method includes the steps of joining a first contact member to a second contact member in a material-to-material contact. The method steps for the same include: providing the first contact part, which towards the second contact part has a male, first joining section as a solid component with an at least substantially rotationally symmetrical profile, providing the second contact part having towards the first contact part a female second joining portion with a hollow profile, inserting the first joining section into the second joining section, applying a friction welding tool (400) to or in an opening of the second joining section (121), and moving the friction welding tool relative to the first contact part and/or the second contact part to generate welding energy for at least partially plasticizing a part of the first joining portion and/or second joining portion facing the other contact part.

A method of making an electrical connection is here proposed. The method includes the steps of joining a first contact member to a second contact member in a material-to-material contact. The method steps for the same include: providing the first contact part, which towards the second contact part has a male, first joining section as a solid component with an at least substantially rotationally symmetrical profile, providing the second contact part having towards the first contact part a female second joining portion with a hollow profile, inserting the first joining section into the second joining section, applying a friction welding tool (400) to or in an opening of the second joining section (121), and moving the friction welding tool relative to the first contact part and/or the second contact part to generate welding energy for at least partially plasticizing a part of the first joining portion and/or second joining portion facing the other contact part.

A machine tool and a control method for the machine tool, which determine the degree of misalignment during friction joint, are provided. The machine tool (an automatic lathe 1) includes: a first spindle 10 rotatably holding a first workpiece (a workpiece W1); a second spindle 20 arranged to face the first spindle and rotatably holding a second workpiece (a remaining workpiece W2); and a controller 40a, while rotating at least one of the first workpiece or the second workpiece, relatively moving the first spindle and the second spindle so as to get closer to each other and pushing a rear end portion of the second workpiece against a front end portion of the first workpiece to frictionally join the first and second workpieces. The controller has a misalignment amount detector detecting a misalignment amount s of the second workpiece with respect to the first workpiece during the friction joint.

A machine tool and a control method for the machine tool, which determine the degree of misalignment during friction joint, are provided. The machine tool (an automatic lathe 1) includes: a first spindle 10 rotatably holding a first workpiece (a workpiece W1); a second spindle 20 arranged to face the first spindle and rotatably holding a second workpiece (a remaining workpiece W2); and a controller 40a, while rotating at least one of the first workpiece or the second workpiece, relatively moving the first spindle and the second spindle so as to get closer to each other and pushing a rear end portion of the second workpiece against a front end portion of the first workpiece to frictionally join the first and second workpieces. The controller has a misalignment amount detector detecting a misalignment amount s of the second workpiece with respect to the first workpiece during the friction joint.

A friction stir welding method for welding steel sheets together includes a heating device disposed ahead of a rotating tool in an advancing direction that preheats an unwelded portion before the welding thereof by the rotating tool and at the time of preheating, the surface temperature distribution in a direction perpendicular to the advancing direction in a position at which the welding by the rotating tool is initiated is set such that given that T.sub.Ac1 is the Ac.sub.1 point of a steel sheet, the maximum temperature (T.sub.U) thereof is 0.6×T.sub.Ac1<T.sub.U<1.8×T.sub.Ac1, and given that L is the width of the heating region exceeding a temperature (T.sub.L)=0.6×T.sub.Ac1, 0.3×d≦L≦2.0×d is satisfied with a diameter (d) of the shoulder.