A machine tool includes a first spindle, a second spindle, and a joining means for joining the axial ends of workpieces gripped by the spindles to form a joined workpiece. The machine tool further includes an electric servomotor for moving the first spindle in the direction intersecting the axis of the first spindle, a current value detection means for detecting the current value of the electric servomotor, and a misalignment detecting means for detecting misalignment of a first workpiece and a second workpiece in the joined workpiece, based on the current value detected by the current value detection means when the joined workpiece gripped by the two spindles is rotated.

The present disclosure provides a linear friction joining device which includes: a pressing device for pressing a second member onto a first member in a pressing direction; a vibrator for relatively vibrating the first member and the second member; a controller which is configured to bring the second member into contact with the first member by a position control, which depends on a measurement result of position sensors, to change the position control to a load control, which depends on a measurement result of load sensors, and to increase a pressing load toward a joining load; and a joining load reaching time adjuster which is configured to adjust a length of a joining load reaching time which is between the time when the position control is changed to the load control and the time when the pressing load reaches the joining load.

Drill collars may be constructed using solid-state welding processes. Solid-state welding produces robust drill collars with high fatigue lifespans and permits individual segments of the drill collar to be optimized based on their intended use. A drill collar may be formed of a first segment with a different material, density, modulus of elasticity and/or geometry than an adjacent second segment fused thereto. If a segment of a drill collar is damaged in use, the damaged segment may be removed and replaced, possibly without de-rating the drill collar. Methods of forming the solid-state welds may include friction welding adjacent segments to one another such that features in each segment are circumferentially aligned when the weld is formed. Supplemental energy sources may provide additional heat at the welded surfaces to ensure the segments are effectively fused.

A method of joining a first component to a second component at respective connection surfaces, comprising, in order, applying a local surface treatment to the connection surface of at least one of the first and second components in order to locally alter the microstructure to a depth of between 60 μm and 10 mm below the connection surface; and joining the first component to the second component using a welding process.

A method of installing a friction element includes driving the friction element through a top panel and friction welding the friction element to a bottom panel. At least one additional panel may or may not be between the top panel and the bottom panel. Also, at least one key friction element weld (FEW) parameter is controlled during installing of the friction element, at least one key FEW parameter is monitored during installing of the friction element, and the at least one key FEW controlled parameter is adjusted in real-time as a function of and in response to the at least one key FEW monitored parameter exhibiting completion of at least one key FEW process characteristic. Non-limiting examples of the at least one key FEW controlled parameter include RPM of the friction element and insertion force applied to the friction element.

A machine tool includes a first main shaft, a first drive source for moving the first main shaft, a second main shaft, a second drive source for moving the second main shaft, and a control means for carrying out a control so as to bring the workpiece held by the first main shaft and the workpiece held by the second main shaft into contact with each other while rotating them relative to each other, thereby to carry out the friction-heating, and to stop the relative rotation of the pair of workpieces and move only the second main shaft in the axial direction while holding the first main shaft stationary, thereby to carry out friction-welding of the pair of workpieces. The control means controls the operation of the first drive source upon the friction-welding of the pair of workpieces, so as to maintain the axial position of the first main shaft.

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 pressure welding method is provided and a pressure welding machine (1) is provided with a frame (10), two welding heads (13, 14), mobile along a feed axis (41), and two adjusting units (17, 18). The adjusting units (17, 18) include feed drives (23) for the welding heads (13, 14). The two adjusting units (17, 18) are mounted so as to be axially movable (41) on the frame (10) and are interlinked with an adjusting drive (25) by means of a common adjusting element (26) and supported in a closed system of forces while receiving the pressure welding forces, thereby relieving the frame (10). The common adjusting element (26) is configured as a continuous spindle (27) having two self-locking threads (28, 29) that run in opposite directions.

A pressure welding method and 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) further includes a plurality of machine heads (13,14), each having a component mount (34,35), which machine heads are movably arranged on the machine frame and are connected to respective upsetting drives (22). The machine heads (13,14) and respective upsetting drives (22) can be independently driven. An upsetting head or support head (27), which is preferably secured on the frame, is arranged between the machine heads (13,14).

The present disclosure provides a system and method for measuring energy conversion efficiency of an inertia friction welding (IFW) process in a non-contact manner. The system includes an IFW machine, a Hall sensor, a data acquisition module, a processing module and a stabilized direct current (DC) power supply. The stabilized DC power supply provides electrical energy for the Hall sensor. The Hall sensor is provided beside a flywheel of the IFW machine, so that the flywheel is within a detection range of the Hall sensor. A magnet is provided on the flywheel. The data acquisition module acquires a Hall electric potential change caused by a relative movement between the magnet and the Hall sensor during the IFW process, and transmits the Hall electric potential change to the processing module to calculate the energy conversion efficiency of the IFW machine.