Method and device for quick and reliable tool changing in the process of friction stir welding

Abstract

Method and device for quick and reliable tool changing in the process of friction stir welding, comprising the following features: a) a robot (1) with a robot pivoting head (2) and a friction welding head (3) with a welding shoe (13), wherein the robot (1) can select a friction welding head (2) from a tool magazine (4), b) a device for sensing the mechanical forces at the welding pin tip (14) of each welding shoe (13) of a friction welding head (2), wherein a sensor (16) is attached to the frustoconical part of the tool (11), wherein a sensor (21) is provided, and wherein furthermore a sensor (25) is provided in the flared pin receptacle (26) and a piezoelectric force-measuring sensor (24) is provided in the longitudinal axis of the pin shaft (27) for measuring the axial force acting on the welding pin tip, c) an RFDI code provided on the pin shaft (27) of each welding shoe (13) for identification, d) a changing skid (28) provided on each welding shoe (13).

Claims

1. A device for tool changing in a friction stir welding process, comprising: a) a robot (1) having a robotic pivoting head (2) and a friction-stir welding head (3) which is fastened to the robotic pivoting head (2), having a welding shoe (13), wherein the robot (1) is adapted to select an appropriate friction-stir welding head (2) from a tool magazine (4); b) a device for detecting mechanical forces on a welding-pin tip (14) of each welding shoe (13) of a friction-stir welding head (2), wherein a sensor (16) is attached to a side of a tool bell (11) that is opposite a flow direction of the welding process, wherein a sensor (21) for measuring a torque engaging on a pin receptacle cone (26) and of a bending torque arising here is provided, and wherein furthermore a sensor (25) in the pin receptacle cone (26), and a piezoelectric force-measuring sensor (24) in a longitudinal axis of a pin shaft (27), for measuring an axial force acting on the welding-pin tip, are provided; c) an RFID-code for identification, attached to the pin shaft (27) of each welding shoe (13); d) a replacement runner (28) fastened to each welding shoe (13).

2. The device as claimed in claim 1, characterized in that the sensor (16) has an associated measurement amplifier (15) having an antenna which relays measured signals.

3. The device as claimed in claim 1, characterized in that the tool bell (11) has a sensor-signal amplifier having a rotary antenna (22) for receiving, for amplifying, and for relaying all detected measured values, wherein these measured values are routed onward from a static antenna (23) to a machine control unit.

4. The device as claimed in claim 1, characterized in that the tool bell (11) has an inductive power supply system, for supplying power to a measuring system, that is composed of a moving secondary coil (20) and a stationary primary coil (19) and a respective power supply.

5. The device as claimed in claim 1, characterized in that a welding-shoe replacement runner (28) is fastened to the respective welding shoe (13), on one side by way of a cam-shaped latching step, and on an opposite side of the cam-shaped latching step by means of a releasable mechanical connection (31).

Description

(1) The device according to the invention will be described in more detail hereunder. In the drawings and in detail:

(2) FIG. 1 shows a station for quick tool changing;

(3) FIG. 2 shows the employment of a special tool;

(4) FIG. 3 shows various dissimilar tools for friction stir welding;

(5) FIG. 4 shows the cross section of a tool bell;

(6) FIG. 5 shows a particular design embodiment of welding shoes 13;

(7) FIG. 6 shows an identification measure on the pin shaft 27.

(8) FIG. 1 shows a station for quick tool changing. The basic structure of a robot having a robotic pivoting head 2 and a friction-stir welding head 3 fastened thereto is identified by the reference sign 1 herein. A tool magazine 4 that is equipped so as to correspond to the intended welding job is located close to a universal chucking device 6 for receiving the components of a workpiece 5 that have to be joined.

(9) FIG. 2 shows the employment of a special tool. The robotic pivoting head 2, which in this FIG. 2 is connected to a tool receptacle and docking device 7 and to an adjacent docking plate 8 for the friction-stir welding head 3, can again be seen from above, wherein path readers 17 are disposed between the docking plate 8 and the friction-stir welding head 3. The path readers 17 serve for detecting the weight suspended from the docking device 7, substantially the weight of the friction-stir welding head 3. A fastening plate 9 for a tool-bell flange 10, next to the former, is next to the friction-stir welding head 3. The tool-bell flange 10 serves for mounting a tool bell 11 which by means of a union nut 12 holds a welding shoe 13.

(10) A welding-pin tip 14 is then mounted in the welding shoe 13, the former participating in the process of friction stir welding per se on the mating partners of a workpiece 5 that are to be joined.

(11) A sensor 16 of linear shape can be seen as a heavy solid line at the left periphery of the tool bell 11, said sensor 16 being attached to that side of the tool bell (11) that is counter to the flow direction of the welding process, and below which sensor 16 an associated measurement amplifier 15 having an antenna that relays the measured signals is identified.

(12) FIG. 3 shows various dissimilar tools for friction stir welding. Herein, various dissimilar welding shoes 13 for dissimilar specialized welding processes are depicted in FIGS. 3a to 3d. In this way, FIG. 3c), for example, shows a welding shoe for processing materials of dissimilar thickness, and FIG. 3d) shows a welding shoe for processing fillet welds.

(13) FIG. 4 shows the cross section of a tool bell. Herein, a tool bell 11 having a pin receptacle cone 26 is illustrated in a stylized manner in cross section. Here again, the sensor 16, already described above, and the associated amplifier 15 having the antenna thereof can be seen in this lower half of the tool bell 11, shown herein.

(14) In the pin receptacle cone 26 shown, having the pin shaft 27, in the comparatively wide region thereof, a notch 18 in the cone for receiving a sensor 21 can be seen. The mechanical constriction of the cross section by the notch 18 in the cone and the placing of the sensor 21 at this location enables measuring of the torque engaging on the pin receptacle cone 26, and measuring a bending torque arising herein. The transmission of the signal of the measured values that have been detected by the sensor 21 is performed by way of a rotatable signal amplifier 22 that is connected to the pin receptacle cone 26 and by a rotary antenna. Receiving and relaying the measured values that have been detected by the sensor 21 is performed by a static stationary antenna 23. A further notch, not illustrated in more detail, which provides space for a sensor 25 and which enables measuring the axial force that acts directly on the pin shaft 27 and thus on the welding-pin tip 14, is located in the front region of the pin receptacle cone 26.

(15) A piezoelectric force-measuring sensor 24, which likewise serves for measuring the axial force and by means of which the length measurement of a welding-pin tip is also possible, is optionally located in the longitudinal axis of the pin shaft 27.

(16) An inductive power supply serves for supplying power to the described measuring systems, the stationary primary coil of said power supply being identified by 19 and the movable secondary coil thereof being identified by 20. It may furthermore be provided that inlet air and/or a cleaning liquid may be infed by means of a particular connector during or after the welding process.

(17) FIG. 5 shows a particular design embodiment of welding shoes 13. A side view of a welding shoe 13 which has a replaceable welding-shoe replacement runner 28 is illustrated in FIG. 5a, wherein rotationally symmetrical and plate-shaped inserts may also be found. Since the runner-shaped lower part of a welding shoe is subject to wear, it is provided that this runner-shaped lower part is designed so as to be replaceable. Such a welding-shoe replacement runner 28 shown on the left side herein is provided with a cam-shaped latching step, and on the opposite side is fastened by means of a releasable mechanical connection 31, for example in the form of a set screw. Furthermore to be seen herein are the pin neck 30 and the pin tip 29.

(18) In the view of FIG. 5b, the same welding shoe is illustrated, having been rotated so as to be perpendicular. The pin shaft 27 is furthermore identified in both illustrations. The welding shoe 13 of FIG. 5a, having the welding-shoe replacement runner and the mechanical connection 31, can be seen in cross section in FIG. 5c. FIG. 5d shows the welding shoe of FIG. 5b, in a view from the lower side. The welding-shoe replacement runner 28, the pin tip 29, and the pin neck 30 are again identified herein.

(19) In the illustration of FIG. 5e, the welding-shoe with the welding shoe replacement head 28 thereof can again be seen in a three-dimensional view from obliquely below.

(20) FIG. 6: shows an identification measure on the pin shaft 27. In order to be able to identify specially commissioned versions of the welding shoes according to the invention, it is provided that an RFDI code 32 is attached to each such welding shoe 13 in the pin shaft 27 of the latter. The pin neck 30 and the pin tip 29 are furthermore identified in FIG. 6.

(21) The complex control system of the motion sequences described requires a special control program.

LIST OF REFERENCE SIGNS

(22) 1 Robot 2 Robotic pivoting head 3 Friction-stir welding head 4 Tool magazine 5 Workpiece 6 Universal chucking device for receiving the workpiece 7 Tool receptacle and docking device 8 Docking plate for the friction-stir welding head 3 9 Fastening plate for the tool-bell flange 10 Tool-bell flange 11 Tool bell 12 Union nut 13 Welding shoe 14 Welding-pin tip 15 Amplifier of the measured signal of a tool bell, and antenna 16 Sensor on the tool bell (strain gauge) 17 Path readers for the docking plate 8 of the friction-stir welding head 3 18 Notch in cone, for receiving a sensor (elastic point) 19 Primary coil of the inductive power supply 20 Secondary coil of the inductive power supply 21 Sensor (DMS) for the tool-receptacle cone (pin) 22 Sensor signal amplifier and rotary antenna 23 Static antenna 24 Piezoelectric force-measuring sensor 25 Sensor for measuring the axial force 26 Pin receptacle cone 27 Pin shaft 28 Welding shoereplacement runner 29 Pin tip 30 Pin neck 31 Releasable mechanical connection 32 RFDI code