LASER SOLDERING INSPECTION SYSTEM USING THERMAL IMAGING

REAL-TIME INSPECTION OF LASER SOLDERING SHOULD MONITOR THE CRITICAL THERMAL PROCESS INVOLVED IN THE OPERATION. HISTORICALLY, INSPECTION HAS RELIED INSTEAD ON VISUAL APPEARANCE WHICH HAS BEEN INADEQUATE TO PREDICT THE FIELD FAILURE OF SOLDER JOINTS. WE PROPOSE TO STUDY THE APPLICATION OF THERMAL IMAGING TO LASER SOLDING INSPECTION. SINGLE SPOT THERMOGRAPHY IS CURRENTLY USED ON A COMMERCIAL LASER SOLDERING SYSTEM SOLD BY VANZETTI SYSTEMS. THIS CAN SUCCESSFULLY MONITOR THE THERMAL HISTORY OF THE SOLDER JOINT, BUT CANNOT SIMULTANEOUSLY INSPECT THE THERMAL CONDITION OF THE COMPONENTS AND BOARD SURROUNDING THE SOLDER JOINT IN ORDER TO PREVENT DAMAGE OR NOTE ABNORMAL COMPONENT TEMPERATURES. FOLLOWING A THOUROUGH RESEARCH OF THE CURRENT STATUS OF SOLDERING SCIENCE WITH EXISTING SYSTEMS AND A SURVEY OF EQUIPMENT VENDORS, WE PROPOSE TO USE AN IR VISION THERMAL IMAGING SYSTEM TO ACQUIRE 2 DIMENSIONAL SPATIAL THERMAL SIGNATURES OF LASER SOLDERED JOINTS AND THE SURROUNDING COMPONENTS. THIS INFORMATION WILL BE USED TO ACCESS PROCESS CONTROL ALGORITHMS BASED UPON THERMAL HISTOGRAMS. WE WILL ALSO ACCESS INTERFACING OUR THERMAL IMAGING SYSTEM WITH THE VARIETY OF LASER SOLDERING EQUIPMENT CURRENTLY ON THE MARKET.