| 摘要 |
The present invention provides a method for evaluating a welding quality of a nut projection welding which is capable of accurately and non-destructively evaluating a welding quality of a nut projection welding. According to the present invention, a method for evaluating a welding quality of a nut projection welding comprises: a detecting step for detecting much welding information including welding time, a calorific value, average dynamic resistance (ADR), pressure, a current, and voltage in nut projection welding by using a single phase AC power; a determining step for determining whether the detected much welding information is satisfied with each standard range, which is predetermined, or not; a calculating step for respectively calculating average dynamic resistance (ADR) and instantaneous dynamic resistance (IDR) during the welding time in case the much welding information is satisfied with each standard range; a first comparing step for comparing a slope of the instantaneous dynamic resistance (IDR) with a first standard value which is predetermined; a second comparing step for comparing a variable ratio of the average dynamic resistance (ADR) calculated about the detected current with a second standard value which is predetermined; and an evaluating step for evaluating that a welding quality is good in case the slope of the instantaneous dynamic resistance (IDR) is bigger than the first standard value, and the variable ratio of the average dynamic resistance (ADR) comparing with the current is bigger than the second standard value in the first and the second comparing steps. [Reference numerals] (AA) START; (BB,DD,FF) NO; (CC,EE,GG) YES; (HH) END; (S101) Measure pressure, current, and voltage; (S103) Calculate average dynamic resistance (ADR), a calorific value, and welding time; (S105) Is much welding information satisfied with each standard range?; (S107) Calculate instantaneous dynamic resistance (IDR); (S109) Calculate a slope of the instantaneous dynamic resistance (IDR); (S111) Is the slope of the instantaneous dynamic resistance (IDR) bigger than a first standard value?; (S113) Calculate a variable ratio of the average dynamic resistance (ADR) comparing with the current; (S115) Is the variable ratio of the average dynamic resistance (ADR) comparing with the current bigger than a second standard value?; (S117) Evaluate that a welding quality is good; (S119) Evaluate that a welding quality is poor |
