Electric heating – Metal heating – By arc
Patent
1991-09-26
1994-07-12
Albritton, C. L.
Electric heating
Metal heating
By arc
21912163, B23K 2602
Patent
active
053290917
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a weld monitoring device comprising an optical detection device which detects light emitted by a welding plasma and generates a signal corresponding to the ultraviolet emission portion and also comprising an analyzing device for processing this signal, which has at least one analyzing member for ascertaining those interruptions in the ultraviolet emission which exceed a predeterminable length of time.
Weld monitoring devices of this type are known from the state of the art. These operate with an analyzing member, the predeterminable length of time of which can be adjusted in accordance with the parameters of the welding to be carried out and which then immediately reports an interruption in the ultraviolet emission which exceeds this predeterminable length of time so that the welding process can be interrupted, for example, on the basis of this report.
The disadvantage of this device is to be seen in the fact that for each welding process the interrelations between interruptions in the ultraviolet emission and the welding quality have to be established in individual tests and series of experiments to ascertain what predeterminable length of time must be set, after which the welding is defective and therefore an interruption of the welding process is justified.
The object underlying the invention is therefore to improve a weld monitoring device of the generic type such that, in general, a documentation of a welding process with respect to the interruptions in the ultraviolet emission occurring thereby is possible without preliminary tests and this permits analysis following completion of the welding process.
This object is accomplished in accordance with the invention, for a weld monitoring device of the type described at the outset, in that the read-out means has a plurality of analyzing members, that the predeterminable length of time of the individual analyzing members differs from one another, that each analyzing member reports each interruption exceeding the respective length of time to a storage member and that each storage member retains the reported interruptions for a subsequent read out.
The advantage of the inventive weld monitoring device is therefore to be seen in the fact that any type of welding process can be carried out and that after completion of the welding process there is the possibility of ascertaining what types of interruption in the ultraviolet emission are present in order to evaluate whether or not the welding is faulty under retroactive consideration of the actual result of welding.
Consequently, there is, for example, the possibility of monitoring welding with the inventive weld monitoring device such that first of all a trial weld seam is produced, the number of individual interruptions with the individual predetermined lengths of time is established and by comparison with the actual weld seam produced it is possible to determine a quality standard so that when carrying out future weldings the quality thereof can be assessed immediately afterwards on the basis of the interruptions likewise ascertained.
In this respect, it is particularly advantageous for the analyzing device to digitalize the signal of the detection device by a digitalizing member comprising a threshold member and to transmit to the individual timing circuits a normalized signal 1 when the threshold value is exceeded and a signal 0 when this value is not reached. This facilitates a simple construction of the timing circuits as digital components.
It is even more expedient for the digitalizing member to transmit as normalized signal 1 an equidistant sequence of individual pulses having the same pulse width which can be processed by the timing circuits in a simple manner.
In this respect, it is expedient for the follow-on time of the individual pulses and the pulse width to be shorter than the shortest predeterminable length of time.
In addition, it has proven expedient for the analyzing device to ascertain the length of absence of individual pulses.
In an advantageous embodiment of the
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Albritton C. L.
Deutsche Forschungsanstalt fuer Luft - und Raumfahrt e.V.
Lipsitz Barry R.
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