| I'm having problems with trying to get a good solder joint using a Ceramic PCB. We are using AMTECH hi-temp solder (ws-486 96.5/3.5ag). My profile looks great and I used the recommended profile from Amtech with a few adjustments. My max temp is about 250c. We have no problem with using the FR4 board, but the ceramic is sometimes having cold solder joints. We are using a 7 zone oven, soem joints looks good on the plcc and some have cold solder. We are also using a carrier made of compressed rock/stone from Stone Mountain Tool..I have no experience in using Hi-Temp solder paste or ceramic, I would appreciate any help I can get...Thanks!!!! | Michael: More information would be helpful.
1. Is the item that solders well the same as the item that solders poorly (less attractively)? 2. Was failure analysis performed? And if so, what was the result? 3. Has the manufacturer been contacted, provided samples of failed items, and provided a response? 4. Is the failed item from a single lot or from various lots? 5. Is the failed item from a single manufacturer or from various sources? 6. Is the failed item being used within the environmental and functional limitations of its specifications? 7. What is the history of this design? (is this a new product)? 8. What makes you so comfortable that the profiles you report are accurate?
As a flier, sometimes PLCCs from different suppliers have different solderability protectant materials on the component leads and reaction of these different materials with the solder can create different visual effects.
Good luck
Dave F
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