Lötmittelaufbringung.

摘要

The method and apparatus are provided to permit the accurate sensing of the height of a solder nozzle above a circuit board during operation of the solder nozzle. A non-contact limit switch 30, which provides an indication of the presence of a planar surface at a preselected proximity, is mounted in a fixed relationship with a solder nozzle 12 which is manipulatable by means of a robotic arm 18. A reference surface 38 is provided which includes a proximity sensor, such as a through beam fibre optic switch 42. The proximity sensor is mounted a predetermined distance above the reference surface and is utilized to detect the solder nozzle as it is moved toward the reference surface. By noting the position coordinates of the robotic arm at which the proximity sensor indicates the presence of the solder nozzle at the predetermined distance above the reference surface, and the position of the robotic arm at which the non-contact limit switch closes in response to the proximity of the reference surface, it is possible to accurately calculate a calibration offset value which may be utilized in conjunction with the output of the non-contact limit switch to precisely position the solder nozzle at a desired distance above a circuit board.