DE102012202355A1 - Apparatus used for automatically operating controllable welding torch, comprises detection unit to determine parameters representing position of torch relative to welding point, and control unit to store control values and/or coordinates - Google Patents

Abstract

The apparatus comprises a detection unit (30) for determining parameters representing a position of a welding torch relative to a welding point (20), and a control unit for storing control values and/or coordinates for causing the weld position for the welding point, when the parameters match a respective predetermined value. A distance of a contact point of the welding torch to the welding point is determined by the detecting unit. An angle of inclination of a longitudinal axis of the torch is determined with respect to a perpendicular plane in which the welding point is located. The apparatus comprises a detection unit (30) for determining parameters representing a position of a welding torch relative to a welding point (20), and a control unit for storing control values and/or coordinates for causing the weld position for the welding point, when the parameters match a respective predetermined value. A distance of a contact point of the welding torch to the welding point is determined by the detecting unit. An angle of inclination of a longitudinal axis of the torch is determined with respect to a perpendicular plane in which the welding point is located. The detecting unit comprises an optical measuring system. The optical measuring system comprises: three transmission units configured to emit light beams, which are circularly distributed around the longitudinal axis of the welding torch, lie in a plane perpendicular to longitudinal axis and are irradiated to the welding point to be measured; a reception unit for receiving the light reflected by the welding point; and an evaluation unit configured to determine light running times and to determine angle of inclination and spacing of the welding torch. The optical measuring system is arranged on an outside of a weld tube of the welding torch or arranged at a gas nozzle of the weld tube. The apparatus further comprises an indicator unit for an operator of the welding torch or for outputting the determined parameters, and an input unit. The control parameters include coordinates representing an arrangement of the welding torch in a space coordinate system.

Description

The invention relates to a device for operating an automatically controllable welding torch.

With a welding torch objects are joined together by heat cohesively. The distance traveled by the welding torch depends on the geometry of the objects to be connected. As a result, the welding path to be performed by the welding torch can not only be in one plane but also in three-dimensional space.

Welding torches are often mounted on industrial robots that cover a programmed welding path for welding the articles. For this purpose, a programming of the path of the welding torch is required. The programming is done so far hand-operated by a user by a welding path with the welding torch is traversed by hand. A computer stores the welding path and drives it off equally for all the following identical objects to be welded.

A problem of this "hand programming" is that over the total length of a welding path to be programmed a burner position relative to the objects to be joined (also referred to as weld metal) can not be kept constant or is. Deviations of the burner position relative to the weld metal, however, lead to deviations in the quality of the weld. In unfavorable circumstances, this can lead to a faulty welding result. Such errors must then be elaborately reworked by hand.

The programming of the welding path of a welding torch must be carried out at regular intervals, so that with a large number of identical welded joints to be produced, deviations in the welding quality can also occur due to the different "manual programming".

It is an object of the present invention to provide a device which allows a functionally improved programming of an automatically controllable welding torch.

This object is achieved by a device for operating an automatically controllable welding torch according to the features of claim 1. Advantageous embodiments result from the dependent claims.

The invention proposes a device for operating an automatically controllable welding torch. This comprises a detection means for determining one or more parameters, which represent a burner position of the welding torch relative to a welding point. Furthermore, the apparatus comprises a control means for storing control quantities and / or coordinates for establishing the burner position for the spot weld, if the parameter or parameters correspond to a respective default value.

The invention is based on the consideration that the welding quality in addition to the burner position of the weld directly influencing parameters such. As a current level, a gas volume, an arc, etc., depends. The burner position influences the welding parameters to be selected, and vice versa.

By means of the device according to the invention, the deviations from an ideal burner position occurring during manual programming can be eliminated on the basis of the envisaged detection and control means. As a result, the welding parameters can be adjusted to the predetermined burner position and thus kept substantially constant over a welding path to be processed. As a result, a movement of the welding torch can be realized, which corresponds to a predetermined value in terms of quality regardless of the geometry of the welding path over its entire length.

To realize this, a respective burner position of the welding torch relative to a welding point is detected for programming the welding torch. This position is characterized by one or more parameters. Only if the parameter or parameters correspond to a respective default value, are control variables and / or coordinates stored to bring about the corresponding burner position.

If a multiplicity of such control variables and coordinates for respective weld points are determined along a welding path, the burner position can be kept constant relative to the weld metal over the entire length of the welding path.

By means of the detection means, a distance of a contact tip of the welding torch from the welding point can expediently be determined as a parameter representing the burner position. Another parameter characterizing the burner position is a tilt angle. Accordingly, it is provided that by the detection means as a burner position Representing further parameters, an inclination angle of a longitudinal axis of the welding torch in relation to a vertical of a welding plane in which the welding point is determined.

The burner position is preferably determined using an optical measuring system. This includes camera-based systems as well as systems that can actively determine the burner position in the room.

In an expedient embodiment, the optical measuring system comprises at least three transmitting units for emitting light, which are distributed around the longitudinal axis of the welding torch and lie in a plane perpendicular to the longitudinal axis and irradiate the weld point to be measured. Furthermore, the optical measuring system comprises a receiving unit for receiving the light beams of the transmitting units which are reflected by the welding spot to be measured. An evaluation unit is used to determine the light propagation times of the respective light beams in order to determine therefrom the angle of inclination and the distance of the welding torch.

The transmitting units may be diodes, for example. In particular, those transmission units are used which operate with wavelengths in the visible (red) range. For this purpose, in particular infrared (IR) diodes into consideration. Likewise, laser diodes could be used as transmitting units.

The receiving unit may be formed separately from the at least three transmitting units and provided in the optical measuring system. Likewise, the receiving unit and the at least three transmitting units may be spatially combined. The receiving unit may comprise one or more receiving units, in particular diodes.

It is preferred if the at least three transmitting units are arranged in a circle around the longitudinal axis of the welding torch.

The number of transmitting units is selected depending on a required accuracy for determining the burner position. That is, the higher a required accuracy, the greater the number of transmitting units is selected.

In one embodiment, the optical measuring system can be arranged outside a burner tube of the welding torch. Likewise it can be provided that the optical measuring system is arranged in the burner tube instead of a gas nozzle. Alternatively, the optical measuring system for the purpose of programming the automatically controllable welding torch could also be provided temporarily instead of the burner tube.

It is also expedient if the device comprises a display means, wherein with the aid of the display means for an operator of the welding torch or the parameters just determined can be output. On the basis of the information displayed on the display means, the operator can, for example, detect the angle of inclination just assumed relative to the weld metal and the distance. If these do not correspond to the respective default values, then the operator can correct the position of the welding torch relative to the weld metal, whereby the user is already provided with directions for correction on the basis of the displayed values.

It is also expedient if the device comprises an input means, wherein with the detection of actuation of the input means by the operator current control variables and / or coordinates for bringing about the burner position in a memory are transferable. The input means may be, for example, a button or switch which is actuated by the operator as soon as the latter receives parameters which correspond to the default values of the parameters via the display means. The spatial position of the welding torch is then stored by means of the control variables and / or coordinates.

The control variables and / or coordinates may be such information as is needed, for example, to drive the arm of an industrial robot. Depending on how many individually movable arms an industrial robot has or in how many different levels such an industrial robot can be moved, a corresponding number of control variables and / or coordinates must be stored.

In particular, the control variables and / or coordinates comprise direct or indirect information representing the arrangement of the welding torch in the spatial coordinate system. A direct information is z. B. the end position of the welding torch representing data. Indirect information is such data which makes it possible to reach the end position.

The apparatus of the type described above is used in particular for hand-controlled programming of a welding path by storing control variables and / or coordinates for bringing about the burner position for a plurality of spot welds.

In this case, a welding path is formed from a plurality of welding points at which information about the burner position is transmitted to the welding robot. Between two such welds, the welding torch becomes constant or constantly proceed according to the stored control variables and / or coordinates.

The invention will be explained in more detail with reference to an embodiment.

The single FIGURE shows a schematic representation of a welding torch arranged above a welding plane.

One with the reference numeral 10 marked welding torch is in 1 illustrated in a highly schematic representation. In particular, only a burner tube 12 of the welding torch 10 shown. The welding torch 10 has a longitudinal axis 11 on which an axis of rotation of the burner tube 12 equivalent. At one, a welding level 21 facing opening of the burner tube 12 runs the longitudinal axis 11 through a contact tip 13 of the burner tube 12 , In a manner known to those skilled in the art is in the region of the contact tip 13 a welding wire is ejected, which is in the range of a welding point 20 the welding plane 21 is connected by fusion under heat supply cohesively with the objects to be joined. The welding point 20 lies here in an intersection of the longitudinal axis 11 and the welding level 21 ,

In the schematic representation of 1 the welding plane extends 21 vertically out of the sheet plane. With the reference number 22 is one in the welding plane 21 lying welding track marked. The welding track 22 created by movement of the welding torch 10 in denoted by the reference numeral 60 marked movement direction. The welding track 22 is for illustrative purposes only in one plane, namely the welding plane 21 , In practice, the welding path 22 according to the geometric shape of the objects to be joined together also have a curved, in particular a spatial, three-dimensional course.

For a qualitatively uniform and high quality welding track 22 To obtain, it is necessary that the position of the welding torch 10 in a spatial coordinate system (eg, a Cartesian xyz coordinate system, as drawn) meets certain specifications. For example, one between the longitudinal axis 11 and a vertical 23 to the welding level 21 formed inclination angle α and a distance d of the burner tip 13 to the welding level 21 observed. The default values for a and d over the entire length of the welding path 22 be respected.

The in 1 Welding torches shown only schematically are usually guided by an industrial robot (not shown). For this it is necessary to program the movements of the arm of the industrial robot. This can, as before, be done by hand, but also automated. However, in order to ensure that the default values for a and d are complied with over the entire length of the programming of the welding path, detection means are provided by means of a detection system designed as an optical measuring system 30 the distance d and the inclination angle α detected.

For this purpose, the optical measuring system may comprise, for example, at least three transmitting units, wherein 1 only two of them are recognizable. These are with the reference numerals 31 and 32 and in a plane perpendicular to the longitudinal axis 11 around the longitudinal axis of the welding torch 10 arranged distributed. From the transmitting units 31 . 32 emitted light rays are at the welding point 20 reflected, which can be determined due to the signal delay until receiving by a receiving unit distance and angle of inclination. The receiving unit can be realized, for example, in a structural unit with the transmitting units. The transmitting unit can also be realized as an external component.

It is understood that in each case the light transit time of the light beam emitted by each individual transmission unit is determined. Due to the different distances to the welding point 20 , resulting in the correct tilt angles different maturities. These can be calculated in a manner known to those skilled in the determination of the inclination angle α.

The just determined angle of inclination α and the distance d can via a display means 40 be visualized for an operator of the welding torch. The display means 40 , for example in the form of a display, can in the range of transmitting units 31 . 32 be arranged. These can be accommodated in a common housing. If inclination angle α and distance d do not correspond to the default values, then the operator can actuate the welding torch 10 Change inclination angle and distance. The current value is displayed on the display 40 visualized. If the default values are reached, then via an actuating means 50 the spatial position of the welding torch 10 to be confirmed in the room.

This procedure is used for a large number of welding spots along the welding path 22 repeated. In this way it is also possible to program a complex three-dimensional course of the welding path such that the angle of inclination and distance of the burner tube to the welding plane over the length of the welding path are correctly fulfilled.

The optical measuring head comprising the transmitting units can also be used instead of a gas nozzle in the burner tube in an alternative embodiment variant (not shown) 12 be installed. Likewise, the measuring device for the purpose of programming the welding path instead of the burner tube 12 to the welding torch 10 to be assembled. This is, for example, using a screw, as this for mounting the burner tube 12 is usual at the welding torch, possible.

In another variant, also not shown, an automated control of the path of the welding torch could instead of manual programming 10 using the data collected and determined by the measuring system.

The proposed procedure makes it possible to keep the burner position constant relative to the weld metal along the weld path. This makes it possible in a simple manner, further welding parameters, such. As a current level, a gas flow, an arc, etc. better adapt to the welding process. Since no or fewer variations of the burner position can occur, the other welding parameters change less or not, as a result, an improved weld results.

LIST OF REFERENCE NUMBERS

10

welding torch

11

longitudinal axis

12

burner tube

13

contact tip

20

WeldingSpot

21

welding plane

22

sheeting

23

Perpendicular to the welding plane

30

Detection means / optical measuring system

31

transmission unit

32

transmission unit

33

Light beam of the transmitting unit 31

34

Light beam of the transmitting unit 32

40

display means

50

actuating means

60

movement direction

α

tilt angle

d

distance

Claims (12)

Device for operating an automatically controllable welding torch ( 10 ), comprising - a detection means ( 30 ) for determining one or more parameters (α, d) which indicate a torch position of the welding torch ( 10 ) relative to a welding point ( 20 represent); and a control means for storing control quantities and / or coordinates for establishing the burner position for the spot weld ( 20 ), if the parameter or parameters (α, d) correspond to a respective default value. Apparatus according to claim 1, characterized in that by the detection means ( 30 ) as a parameter representing the position of the burner (α, d) a distance of a contact tip of the welding torch ( 10 ) to the welding point ( 20 ) is determinable. Apparatus according to claim 1 or 2, characterized in that by the detection means ( 30 ) as a parameter representing the position of the burner (α, d) is an inclination angle of a longitudinal axis ( 11 ) of the welding torch ( 10 ) with respect to a perpendicular of a welding plane ( 21 ), in which the welding point ( 20 ) is determinable. Device according to one of the preceding claims, characterized in that the detection means ( 30 ) comprises an optical measuring system. Apparatus according to claim 4, characterized in that the optical measuring system comprises: - at least three transmitting units ( 31 . 32 ) for emitting light, which around the longitudinal axis ( 11 ) of the welding torch ( 10 ) are distributed and in a plane perpendicular to the longitudinal axis ( 11 ) and the weld point to be measured ( 20 ), a receiving unit for receiving the spot to be measured ( 20 ) reflected light rays ( 33 . 34 ) of the transmitting units ( 31 . 32 ); An evaluation unit for determining the light propagation times of the respective light beams ( 33 . 34 ), from which the angle of inclination (α) and the distance (d) of the welding torch ( 10 ) to investigate. Apparatus according to claim 5, characterized in that the at least three transmitting units ( 31 . 32 ) circularly about the longitudinal axis ( 11 ) are arranged. Device according to one of claims 4 to 6, characterized in that the optical measuring system outside a burner tube ( 12 ) of the welding torch ( 10 ) is arranged around this. Device according to one of claims 4 to 6, characterized in that the optical measuring system in the burner tube ( 12 ) is arranged instead of a gas nozzle. Device according to one of the preceding claims, characterized in that it further comprises a display means, with the aid of the display means for an operator of the welding torch ( 10 ) or the just determined parameters (α, d) can be output. Device according to one of the preceding claims, characterized in that it further comprises an input means, wherein with the detection of actuation of the input means by the operator current control variables and / or coordinates for bringing about the burner position in a memory are transferable. Device according to one of the preceding claims, characterized in that the control variables and / or coordinates comprise direct or indirect information which the arrangement of the welding torch ( 10 ) in a space coordinate system. Use of a device according to one of the preceding claims for programming a welding path by storing control variables and / or coordinates for bringing about the burner position for a plurality of spot welds.

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