| 摘要 |
A method is provided for non-contact and contact sensing of phase changes of a solder material. By adding solder to a preexisting solder joint or substrate, an infrared sensor with limited resolution capability is able to discriminate between various solder characteristics at the solder enhanced site and other thermally distracting components when the solder transitions from a solid to a liquid phase or from a liquid to a solid phase. One type of contact sensing of solder reflow is accomplished by holding a thermocouple against a solder joint. When the pre-existing solder volume is insufficient to produce the desired results, additional solder is added to the solder joint or lead. The additional solder may be solid solder, a solder pre-form, or solder paste. Contact sensing may also be achieved by placing a spring loaded probe against the solder and detecting the probe's movement as the solder softens. In another contact reflow detection technique, a thermocouple sensor is housed in a protective sleeve fillable with solder paste or molten solder. The sensor is placed against a substrate adjacent a solder joint, and is heated simultaneously with the solder joint. Detection of solder reflow in the sleeve by the thermocouple signals reflow of the adjacent solder joint.
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