Abstract: In a method of soldering a work-piece in a state where the work-piece contacts a wave molten solder, a soldering process is performed while controlling an immersion depth of the work-piece into the wave molten solder to be constant. The immersion depth control is performed by changing one of a height position of the work-piece and a wave height of the wave molten solder based on a displacement amount of the work-piece in a height direction thereof. Accordingly, the soldering process can be performed with high quality even when the work-piece is thermally warped.

Abstract: In a method of soldering a work-piece in a state where the work-piece contacts a wave molten solder, a soldering process is performed while controlling an immersion depth of the work-piece into the wave molten solder to be constant. The immersion depth control is performed by changing one of a height position of the work-piece and a wave height of the wave molten solder based on a displacement amount of the work-piece in a height direction thereof. Accordingly, the soldering process can be performed with high quality even when the work-piece is thermally warped.

Abstract: In a method of soldering a work-piece in a state where the work-piece contacts a wave molten solder, a soldering process is performed while controlling an immersion depth of the work-piece into the wave molten solder to be constant. The immersion depth control is performed by changing one of a height position of the work-piece and a wave height of the wave molten solder based on a displacement amount of the work-piece in a height direction thereof. Accordingly, the soldering process can be performed with high quality even when the work-piece is thermally warped.

Abstract: In a jet soldering method, a substrate is held by an actuator and pre-heated by a pre-heater. The pre-heater has a shield member or the substrate is swung to equalize temperature distribution in the substrate. The substrate is then transferred over a primary jet soldering bath while dipping a treatment surface of the substrate in a primary solder jet, so that solder stick to the treatment surface of the substrate. Then, the substrate is transferred over a secondary jet soldering bath while dipping the treatment surface in a secondary solder jet, so that the solder sticking to the substrate is shaped. The transfer conditions of the substrate are differentiated between transfers over the primary jet soldering bath and the secondary jet soldering bath.

Abstract: A frequency comparator for comparing the frequency of a predetermined clock signal with the clock frequency of a non-return-to-zero (NRZ) signal having a detector circuit for detecting a data change of the NRZ signal in an interval of one time period of the clock signal, and a comparator circuit for generating a comparison result only when a data change is detected by the detector. The detector includes a data change circuit for detecting a data change of the NRZ signal and a change position detector for detecting a data change position of the NRZ signal in a time period of the clock signal CLK by taking in the logic of a clock signal and an auxiliary clock signal having the phase delayed 90 degrees from that of the clock signal when a data change of the NRZ signal is detected. The comparator circuit has a setting circuit for setting a reference point for detecting the time period subsequent to the clock signal to generate the comparison result based on the reference point set by the setting circuit.