MSL | Baking components after expired floor life

I'll answer the easy part. If you put low temperature trays in the oven at 120C, they will warp and partially melt. I have seen it more often with reels of LEDs. Someone is told to bake them before use so the put them in the batch oven and the next day all the reels are greatly deformed and the carrier tape is half melted.

As for oxidation, personally I have pretty much only seen it with really really old parts or SMT resistor networks.

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You can have a dry cabinet with or without heater. They use desiccants to take the humidity out from the parts. As you can imagine it will be a lengthy process. The ones with heater can do 40C, which will be preferred for plastic and paper tapes. I would follow J standard as it has been developed already. To use 60C , you will need to develop and prove your own standard and I can't see the benefit out of such extensive research and testing.

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I agree with Evtimov that sticking with the J-Std-033 is preferable to creating your own procedure at a different temp, especially if you need to pass an audit since the auditors will compare your process to the J-Std. My understanding is that oxidation and intermetallic growth only become concerns if you over-bake well beyond the recommended bake time. For example if you forget to remove components from the bake oven and they remain at elevated temp for a long time after the recommended bake duration has passed. I am not aware of problems if you remove the components at or soon after the J-Std's recommended bake duration. I work for Cogiscan and our MSD Control SW triggers an alarm when the bake duration is reached, to avoid over-baking. I am no expert on "vacuum-bake" systems, but that might be another consideration if you have components that are particularly sensitive to oxidation.

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I would like to Add that Mitch is very knowledgeable on this subject, I believe since 2008 this has been a topic of his .. different of low temp baking 40c 50c 60c vs 90c or 125c I do have some totech independent evaluation on the subject if you like to read it by no means a standard but worth reading and if you have any other evalutions please pass them along to others ..contact me I will send you the report

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I asked the Chairperson of the J-STD-033 committee about the 60C bake process several years ago. My recollection of his reply was that they HAD tested it but the difference between 60C and 40C was not sufficient to warrant adding the process to the standard. We do bake some tape/reel parts at 60C, but only per the manufacturer's recommendation (LEDs, usually). Otherwise we use 40 or 125, depending on whether it makes sense to de-reel/re-reel them. Depending on the part a 40C bakeout can be very lengthy but sometimes it's unavoidable.

JEDEC trays will have the temperature rating embossed on them. Historically I've found that blue trays are low temp and black ones can withstand the High temp bake cycle. If a tray isn't marked with a temperature rating, be careful; it could be an expensive lesson.

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