Patent DE-102008050328-A1 (DE)
Title: Determining a solder volume contained in a solder bath, comprises performing a reference measurement, filling the solder bath with a known initial liquid reference solder volume, and cooling the solder under reproducible given conditions
Inventor: BIRGEL DIETMAR
IPC: G05D9/00
Filed: 2008-10-07
Abstract: The method for determining a solder volume (V) (3) contained in a solder bath (1), comprises performing a reference measurement, filling the solder bath with a known initial liquid reference solder volume (V ref), cooling the solder under reproducible given conditions, measuring a reference flow TR(t), which represents a temporal flow of a temperature (T(t)) of the solder during the cooling process in a given temperature range including a melting temperature (T s) of the solder, and determining a reference parameter (KR) of the reference flow dependent of the solder volume. The method for determining a solder volume (V) (3) contained in a solder bath (1), comprises performing a reference measurement, filling the solder bath with a known initial liquid reference solder volume (V ref), cooling the solder under reproducible given conditions, measuring a reference flow TR(t), which represents a temporal flow of a temperature (T(t)) of the solder during the cooling process in a given temperature range including a melting temperature (T s) of the solder, determining a reference parameter (KR) of the reference flow dependent of the solder volume and then storing together with the reference solder volume, subjecting a solder operation, subsequently cooling the initial liquid solder under the given conditions used in the reference measurement for determining the actual solder volume present in the solder volume optionally changed based on the solder operation, measuring the temporal flow of the temperature (T(t)) of the solder during the cooling process in the given temperature range, determining a measurement parameter (K(V)) depending of the actual solder volume and corresponding to the reference parameter based on the temporal flow of the measured temperature, and approximately determining the solder volume to be determined based on the measurement parameter and the reference parameter. The reference solder volume corresponds to a volume minimum level (V min) given for the solder operation. The solder volume to be determined based on the measurement parameter and the reference parameter exceeds or falls below the actual volume. A first reference measurement is executed, in which the reference solder volume corresponds to the volume minimum level given for the solder operation. A second reference measurement is executed, in which the reference solder volume corresponds to a volume maximum level given for the solder operation. The solder volume to be determined is quantitatively determined based on the measurement parameter and the reference parameter using linear interpolation. The measurement parameters and the associated reference parameters are times, which require to cool the solder at a given reference temperature lying below the melting temperature of the solder during the cooling process, in which the temporal flow of the solder is minimum during the cooling process and at which a plateau-like passing section of the respective temperature flow ends. The measurement parameters and the associated reference parameters are time periods, during which the respective temperature flow is plateau-like. Independent claims are included for: (1) a solder plant for determining a solder volume contained in a solder bath; and (2) a method for operating a solder plant.