Electronics Forum | Fri Aug 10 07:33:32 EDT 2007 | davef
Tran Since we all agree that J-001 has no baking requirement, why are you baking the boards? What is the purpose of this bake process?
Electronics Forum | Wed Aug 08 17:26:40 EDT 2007 | htran
Hello All, I have been searching for the board assemblies bake out requirements acceptance criteria but unsuccessful. Does anyone knows if there are general guidelines for the percentage of the moisture absorption in the PWBs and PWAs? Thanks, Tran
Electronics Forum | Thu Aug 09 19:13:37 EDT 2007 | htran
DaveF, Our customer requirement is to comply with IPC-STD-001 but the J std doesn't specify the bake out temperature for populated boards and the moisture absortion rate. Right now we are baking the populated PWAs after aqueous wash at 80C at 18-48
Electronics Forum | Fri Aug 17 17:55:42 EDT 2007 | htran
My small reflow oven doesn't have the rails (only metal mesh). I personally don't think it was built for double side reflow assembly and there is vibration as well. We are a small low volume mfg house and our reflow oven doesn't have the capability t
Electronics Forum | Sat Aug 18 08:40:34 EDT 2007 | davef
Here's how to double reflow your QFP: * Reflow the first side with the QFP according to plan. * Paste second side and place components according to plan. * Lightly crinkle a small, QFP-size piece of aluminum foil. [Note: the degree of crinklization
Electronics Forum | Fri Nov 05 14:47:35 EST 1999 | Russ Cutler
We recently came to a cross roads... We have historically baked out ALL of our circuit cards, with a 2 fold purpose 1) to dry the part marking ink, and 2) to eliminate any moisture, which could result in measling further in the process of assembly.
Electronics Forum | Thu Aug 09 09:05:09 EDT 2007 | davef
There are no requirements acceptance criteria for baking of board assemblies. What are your customer requirements? The common reasons people choose to bake PCB are to prevent: * Delamination of multilayer boards * Measles, particularly on double si
Electronics Forum | Thu Aug 16 13:00:32 EDT 2007 | russ
Here is what you need to do if you can, Since you want to shporten the bake time you need to increase temp. weigh a board prior to your current bake process (you need very hi resolution scale for this) weigh the same board after current process a
Electronics Forum | Fri Aug 10 16:22:35 EDT 2007 | htran
Davef, The J Standard-001-DS(Ref. 4.9.3)does required board assembly bake out and the purpose of the bake out is to demoisturize the PWB and to prevent board delamination during reflow like you have mentioned earlier. Thanks for your inputs. I hav
Electronics Forum | Mon Nov 08 11:11:16 EST 1999 | John Thorup
Believe it! Although it might be necessary in certain rare cases, and as Ray says, as a bandaid, to routinely bake your boards is a mistake. For much more info, search the IPC technet archives over the last few weeks. It was a popular thread
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