Detecting element for a welding device

• US 20040011775A1
• Filed: 05/01/2003
• Published: 01/22/2004
• Est. Priority Date: 11/02/2000
• Status: Active Grant

• Current Assignee: Fronius International GmbH (G&K Privatstiftung)
• Original Assignee: Fronius International GmbH (G&K Privatstiftung)
• Inventors: Bernecker, Gunther, Niedereder, Franz, Hackl, Heinrich
• Granted Patent: US 7,015,419 B2
• Time in Patent Office: Days
• US Class Current: 219/124.34
• CPC Class Codes: B23K 9/1087 Arc welding using remote control
• CPC Class Codes: B23K 9/124 Circuits or methods for feeding welding wire
• CPC Class Codes: B23K 9/1274 Using non-contact, optical means, e.g. laser means
• CPC Class Codes: G01P 3/806 in devices of the type to be classified in G01P3/68

Abstract

The invention describes a welding apparatus (1), which has a current source (2) for supplying electrical power to at least one electrode at a welding torch (10) and a control system (4) cooperating with the current source (2), linked to an input device (22) for entering settings for different welding parameters, several sensing means being provided for detecting various actual values of a welding process. At least one measuring device or system for sensing mechanical motion, in particular a welding wire displacement and/or a welding torch displacement or similar, is provided, which detects a surface structure of an object.

Claims

1. Welding apparatus, having a current source for supplying electrical power to at least one electrode at a welding torch and a control system co-operating with the current source, linked to an input device for entering settings for different welding parameters, several sensing means being provided for detecting various actual values of a welding process, characterised in that at least one measuring system (31) for sensing a movement, in particular a welding wire displacement and/or a welding torch displacement or similar is provided, which detects a surface structure of an object.

2. Welding apparatus as claimed in claim 1, characterised in that the measuring system (31) consists of a light source (32), in particular a controlled light source (32), and an optical receiver (33), which acts on a sensor (34), and the sensor (34) detects a roughness or a surface structure of the object, in particular the workpiece (16) and/or the welding wire (13) in multiple dimensions and stores it as a digital pattern.

3. Welding apparatus as claimed in claim 1 or 2, characterised in that the measuring system (31) is programmed to detect the surface of the object again after a pre-set measuring cycle time has elapsed and the sensor (34) has an evaluation logic for comparing the last detected pattern with the digitally stored pattern and the evaluation logic is programmed to detect a shift in the pattern and calculate a distance of travel or a changed position and/or the rate of the shift in the pattern.

4. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the controlled light source (32) is disposed so as to produce a measurable contrast when the roughness or surface structures of the object are illuminated.

5. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the sensor (34), in particular the evaluation logic, defines distinctive points or regions when evaluating the first stored pattern and fixes coordinates corresponding to them, and, when it detects the next pattern, recognises a shift in the pattern, in particular of the distinctive points or regions, and cumulates the altered positions of the coordinates to ascertain a travel path.

6. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the sensor (34), in particular the evaluation logic, is programmed to determine an entire travel path from the resultant cumulated changes in travel and to store the resultant cumulated travel changes in a table with a time stamp.

7. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the sensor (34), in particular the evaluation logic, is programmed to detect the speed and conveyed quantity of welding wire (13) as an instantaneous and effective actual value

8. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is connected via lines, in particular via a field bus, to the control system (4) of the welding apparatus (1) in order to transmit the detected travel path or position and/or the speed of the monitored object.

9. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is programmed to take a wire feed distance measurement and to calculate derived values based on a time differential such as a speed and/or an acceleration and/or a jolt of the welding wire (13).

10. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is programmed to take a measurement of the welding torch movement and to calculate derived values based on a time differential such as a speed and/or an acceleration and/or a jolt of the welding torch (10) above the workpiece (16).

11. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the control system (4) of the welding apparatus (1) is programmed to detect and calculate the actual quantity of welding wire (13) displaced on the basis of the data transmitted by the measuring system (31).

12. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is preferably disposed between the drive system (28) and a linking element (30) for a supply line (12) or a hose pack (23).

13. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is disposed in the welding torch(10), in particular upstream of a contact pipe (42).

14. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the control system (4) applies or runs a correction to at least one welding parameter during a welding process on the basis of the data from the measuring system (31).

15. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the control system (4) is programmed to detect any slipping in the driving gears (28) by correlating data from the measuring system (31) with data of the drive system (28), in particular the feed motor voltage and/or the feed motor transmitter values.

16. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is programmed to monitor and detect any twisting or impact of the welding wire (13) as it is fed to the contact pipe (42) and a forced contact made in the contact pipe (42).

17. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31), in particular the evaluation unit, is programmed to monitor contrast for the purpose of detecting flaking or rust or a material of the welding wire (13).

18. Welding apparatus as claimed in one or more of the preceding claims, characterised in that a guide mechanism (35) has a guide bore (36) for the welding wire (13).

19. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the guide mechanism (35) has an orifice (37) extending as far as the guide bore (36), by means of which the measuring system (31) is directed onto the welding wire (13).

20. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the controlled light source (32) and the optical receiver (33) are oriented in the direction of the welding wire (13) as it is fed past.

21. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is programmed to contactlessly sense and evaluate the motion of the welding torch (10) towards the workpiece (16).

22. Welding apparatus as claimed in one or more of the preceding claims, characterised in that the measuring system (31) is disposed on the welding torch (10) so that the light source (32) and the optical receiver (33) are directed at the surface of the workpiece (16) during a welding process.

23. Method of controlling and/or regulating a welding apparatus, in which various actual values of a welding process are detected by various sensing means and used to control and/or regulate the welding process, characterised in that a motion is sensed, in particular a welding wire displacement and/or a welding torch displacement or similar, in such a way that a surface structure of an object is detected and stored and after a predefined measuring cycle time has elapsed the surface structure of the object is detected again, after which the detected surface structures are compared by an evaluation logic of the measuring system and a corresponding shift in the surface structures is recognised and detected.

24. Method as claimed in claim 23, characterised in that the forward feed motion is detected by the measuring system and an optical receiver acts on a sensor which detects a roughness or the surface structure of the object, in particular of the workpiece and/or the welding wire, in multiple dimensions and stores it as a digital pattern, for which purpose the object, in particular the welding wire and/or the workpiece is illuminated by a light source of the measuring system, in particular a controlled light source.

25. Method as claimed in claim 23 or 24, characterised in that the surface structure of the object, in particular the workpiece and/or the welding wire, is detected by the measuring system again once a predefined measuring cycle time has elapsed, whereupon an evaluation logic in the sensor compares a first detected pattern with a digitally stored pattern so as to detect a shift in the pattern and calculates from this the distance travelled or a changed position and/or a rate of shift in the pattern.

26. Method as claimed in one or more of claims 23 to 25, characterised in that the object to be measured, in particular the welding wire and/or the workpiece, is illuminated by the controlled light source so that the roughness or surface structures of the object produce a measurable contrast.

27. Method as claimed in one or more of claims 23 to 26, characterised in that distinctive points or regions are defined by the sensor during evaluation of the first stored pattern, for which corresponding coordinates are fixed, and, when the next pattern is detected, the measuring system recognises that there has been a shift in the pattern, particularly in the defined points or regions, and detects the changed positions of the coordinates as a cumulated travel distance.

28. Method as claimed in one or more of claims 23 to 27, characterised in that the resultant cumulated change in distance is used to determine the total distance travelled which is stored in a table with a time stamp.

29. Method as claimed in one of claims 23 to 28, characterised in that the speed and the quantity of welding wire transported are detected as an instantaneous or effective actual value.

30. Method as claimed in one or more of claims 23 to 29, characterised in that the detected distance travelled or position and/or speed of the monitored object is forwarded by the measuring system via lines, in particular via a field bus, to the control system of the welding apparatus.

31. Method as claimed in one or more of claims 23 to 30, characterised in that a distance measurement of a wire displacement and its derived values based on time differential, such as a speed, an acceleration or a jolt of the welding wire, is run or calculated by the measuring system.

32. Method as claimed in one or more of claims 23 to 31, characterised in that a measurement of a welding torch displacement and its derived values based on time differential, such as a speed, an acceleration or a jolt of the welding torch, above the workpiece is run or calculated by the measuring system.

33. Method as claimed in one or more of claims 23 to 32, characterised in that the actual amount of welding wire fed along is detected or calculated by the control system of the welding apparatus on the basis of the data transmitted by the measuring system.

34. Method as claimed in one or more of claims 23 to 33, characterised in that corrections are run or applied to the welding parameters by the control system during a welding process on the basis of the data from the measuring system.

35. Method as claimed in one or more of claims 23 to 34, characterised in that the control system detects any slipping of the driving gears on the basis of the data of the measuring system correlated with the data from the drive system, in particular the feed motor voltage and/or the feed motor transmitter values.

36. Method as claimed in one or more of claims 23 to 35, characterised in that any twisting or impacts of the welding wire as it is fed towards the contact pipe and the forced contact in the contact pipe are monitored and detected by the measuring system.

37. Method as claimed in one or more of claims 23 to 36, characterised in that the contrast for detecting flaking or rust of a material of the welding wire is monitored by the measuring system.

38. Method as claimed in one or more of claims 23 to 37, characterised in that the controlled light source and the optical receiver are directed towards the welding wire as it is fed past.

39. Method as claimed in one or more of claims 23 to 38, characterised in that the motion of the welding torch towards the workpiece is sensed and evaluated by the measuring system without contact.

40. Method as claimed in one or more of claims 23 to 39, characterised in that the measuring system, the light source and the optical receiver are directed onto the surface of the workpiece during a welding process.