| 摘要 |
What is described is an arrangement for monitoring the quality of electric welds on bodies (10) for the production of cans. Welding parameter values (Fi), which have been measured on a number of bodies (10) found to be good are statistically evaluated in an evaluation device (22). For this purpose, an average welding parameter profile is determined. Then a reject limiting-value band (Fg+-) enveloping the average welding parameter profile is determined from the mean values and the product of the standard deviation of the welding parameter values (Fi) assumed to be normally distributed and at least one sensitivity factor. A permissible number of erroneous rejects per one million of welding spots is selected as a criterion for the sensitivity factor so that, for example with 100 welding spots on a body (10) of a medium-sized can, every ten thousandth body will be accidentally rejected on the average. For bodies (10) produced following on the "learning phase", a comparator (26) ascertains whether a welding parameter profile measured for these lies within the reject limiting-value band (Fg+-). This quality control arrangement working on statistical methods is sensitive and precise since a fixed value is not simply selected for the width of the reject limiting-value band.
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