Another PbF indicator?
On a recent "American" board , made in China, so no warning legends of PbF .
Don't know what its called, the sort of conformal coating final process at the pcb production phase is a staining coat , usually green these days. White rings showing around the solder pads after soldering may show elevated soldering temperature has been used or wrong composite material body , showing rings of plain white polyester+fibre board . The green staining having melded into the plastic or evaporated. From UL 6 digit E number and board type this is designated 260 deg C / 10 second solder dwell ( for conventional soldering) rather than 270 deg / 10 second dwell of proper made for PbF pcb boards. |
Another PbF indicator?
If anyone knows the significance of 288 degree C / 8 second soldering dwell
time pcb +soldering rating in comparison to 260/10 and 270/10, I would be interested to hear. |
Another PbF indicator?
IPC-TM-650 Test Method 2.4.24.1. would seem to be the test, should anyone be
interested Time to Delamination (TMA Method) 10 second solder float http://www.matrixusa.us/pdfs/solutio...ree_Basics.pdf http://www.ipc.org/4.0_Knowledge/4.1...t/2.4.24.1.pdf |
Another PbF indicator?
Wrong tests , more likely this test, as seconds not minutes, peel strength
not delamination Solder float peel strength: (no change after 288C/10 sec) eg http://www3.uic.com/wcms/images2.nsf...mage_Test_Plan. pdf/$File/2006_PCB_Damage_Test_Plan.pdf |
Another PbF indicator?
So I reckon the ul.com pcb classification is this test
http://www.ipc.org/4.0_Knowledge/4.1...t/2.4.8.3a.pdf with 10 second solder float for the heating stage Then passing 260 degree C for leaded solder use 270 deg C for PbF 288 deg C for high spec like polyimide/ N7000-1 /Pyralux |
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