Electric heating – Metal heating – By arc
Reexamination Certificate
2000-02-07
2001-08-07
Shaw, Clifford C. (Department: 1725)
Electric heating
Metal heating
By arc
C901S042000
Reexamination Certificate
active
06271500
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an arc welding monitoring device which monitors arc welding and controls welding quality.
DESCRIPTION OF THE RELATED ART
Conventionally, as a device for monitoring arc welding, there has been a welding monitoring device which detects a welding current and a welding voltage during welding, distinguishes whether or not the detected data are within the predetermined range, and issues an alarm when either of the detected data is outside the range. For example, this method is disclosed by Japanese Patent Publication No. 7-2275. In Japanese Patent Publication No. 7-2275, in a device for monitoring arc welding by an arc welder, an arc welding monitoring device is disclosed, which comprises a means for detecting a welding current or an arc voltage, and A/D converter for converting analog output signals of the detecting means to digital signals in terms of a sampling frequency, a means for setting an operator period and fluctuation pitch to obtain a fluctuation mean, a means for setting a monitoring value to monitor the fluctuation mean value of the welding current or arc voltage, a means for judging welding conditions or welding results by comparing the fluctuation means value of the welding current or arc voltage with monitoring values, and a means for displaying and outputting the judgement results of the judging means.
FIG. 3
shows one example of display screens of the detected data at this time, wherein the abscissa indicates a welding current, a welding voltage, and the ordinate indicates a period of time of welding. That is, this drawing is a graph showing changes in a welding current and a welding voltage with respect to welding time.
However, where, in welding made by an arc welding robot, welding conditions are monitored by a prior art welding monitoring device, it is possible to recognize whether or not any welding defect occurred, by acquiring changes in the welding current and welding voltage with respect to the elapse time of welding as shown in FIG.
3
. However, it is not possible to understand which program of the robot has been used, in other words, which kind of a welding work has been welded. In particular, in a case where a complicated work is welded, by using an arc welding robot, it was difficult to know at which part of the welding work a defect occurred even though a welding defect is detected by the welding monitoring device. To the contrary, in a case where a welding defect is found by observing the welding work, there is a case where it is desired to analyze how the then welding current waveform or welding voltage form are brought about. But, in such a prior art welding monitoring device, it is not clear to which part of the detected data the welding current and welding voltage corresponding to the range selected by a welding work belong.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an arc welding monitoring device by which it is possible to easily find the trajectories of a robot, in other words, how detected data such as welding current and a welding voltage, etc., correspond to welding line information of a welding work.
In order to achieve the above object, a first arc welding monitoring device, according to the present invention, is featured in being provided with, in an arc welding robot controlling device, a means for detecting at least either of a welding current or a welding voltage, a means for storing the detected data and trajectories of a robot, a means for displaying at least either of the welding current or welding voltage detected above on a display, and the trajectories of the robot stored by the abovementioned means, and a means for setting a range of displaying the detected data on the display.
A second arc welding monitoring device, according to the present invention, is featured in that parts of trajectories of the robot displayed on the above display are set by designating the parts thereof in the means for setting a range of displaying the detected data on the above display.
A third arc welding monitoring device, according to the invention, is featured in that, in the means for setting a range of displaying the abovementioned detected data on the above display, the setting is carried out by designating the range of data of the welding current or welding voltage, and parts of trajectories of a robot, which are designated above, are displayed with a different color from that of the other remaining parts thereof.
A fourth arc welding monitoring device, according to the invention, is featured in having a means for setting conditions of judging abnormalities in welding, and a comparator for comparing the conditions set by the setting means for judging abnormalities with the detected data, wherein, in a case where any abnormality or defect occurs when monitoring the detected data and judging any abnormality or defect, the range of data which was judged as abnormal welding is displayed with a different color from that of the other range.
A fifth arc welding monitoring device is featured in that the detected and stored data are date obtained by various types of sensors other than the welding current and welding voltage.
According to an arc welding monitoring device disclosed by the invention, the following effects and advantages can be obtained; wherein
(1) Welding current and welding voltage are correlated with and stored along with robot operation programs, wherein since not only a welding current and a welding voltage but also trajectories of the robot used for welding are displayed on a display screen it is possible to easily find to which welding work the welding current and welding voltage data correspond, or how welding lines of the welding work are taught.
(2) Since it is possible to check which part of data of the trajectories of a robot the data such as a welding current and welding voltage, which are displayed on a display screen, display, any unstable portion of the welding condition can be specified, and it is possible to find portions at which the welding conditions are to be changed or the welding posture of a robot is to be changed, thereby contributing to improvement in the welding quality.
(3) Since it is possible to specify a portion of abnormal or defective welding, it is sufficient to check the portions which are judged abnormal or defective, when conducting a visual defect detection on welding work.
(4) Since data such as a welding current and welding voltage at appointed portions of welding work can be displayed, it is possible to find patterns of the welding current and/or welding voltage at the portions where any abnormal or defective welding is visually found. Therefore, it is effective to analyze the arc welding phenomenon.
(5) It is also possible to monitor information such as, for example, wire feeding speed, gas flow rate, etc., in addition to the welding current and welding voltage.
REFERENCES:
patent: 5571431 (1996-11-01), Lantieri et al.
patent: 6096994 (2000-08-01), Handa et al.
patent: 54-64054 (1979-05-01), None
patent: 58-53374 (1983-03-01), None
patent: 1-197069 (1989-08-01), None
patent: 7-47471 (1995-02-01), None
Hirayama Takahide
Ohsawa Noriyuki
Okumura Shinji
Takaoka Keiichi
Armstrong Westerman Hattori McLeland & Naughton LLP
Kabushiki Kaisha Yaskawa Denki
Shaw Clifford C.
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