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Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

MSD classification


MSD classification | 19 March, 2004

Good Morning Everyone,

Lately, we have been recieving a growing number of components from manufacturers and distributors with a new moisture level classification. The problem is that we will recieve some with MSD packaging and label and some with out. I have contacted the manufacturer to clarify the issue. In some cases, the manufacturer is unable to specify (in a timely manner) if they are or are not MSD. It seems to me that manufacturers are starting to classify components as MSD just to cover their butts (for lack of a better term) I know that lead free is playing a large roll in this transition. It seems to me that an issue as important as MSD requirements should be listed on the component data sheet. So far I have found 2 instances of this out of hundreds of data shets.

Is anyone else experiencing this same problem? Does anyone know if there is any proposal in the works to address this issue?

Any Help Would be Greatly Appreciated.

Thanks In Advance

Christopher Lampron Cirtronics Corporation

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Mike Andrus


MSD classification | 19 March, 2004

We have the same problem here. MSL varies for the same component from different sources. It can also change throughout the lifecycle of a component from a one manufacturer.

All the literature and the wonderful software solutions assume you have accurate MSL data, but where does it come from?

I know that some operations simply go by what is printed on the package, and don't keep MSLs in a database. It's a simple approach, but maybe less than desireable.

I'd like to hear how other operations attempt to resolve this. Anyone???

Mike Andrus Tektronix, Inc.

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MSD classification | 21 March, 2004

We are also facing this issue. Normally we are baking all MSD 24 HRS @125�C. This may not be a standard practice. I have read that depending on the Package thickness Baking time and temperature varies apart from the storage conditions of the IC. IS there any ready reckoner table available to fix the baking time?

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MSD classification | 22 March, 2004

We too are baking required components at 125 degrees C. One of the problems that is comming up is components packaged in tubes. The tubes cannot stand the 125 degree requirement without melting. 50 degrees is a safe temperature for low temp carriers but requires a bake time of about 1 month!

I am desperately looking for any type of alternative.


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MSD classification | 22 March, 2004

Search the SMTnet Archives for suppliers of high temperature bake tubes, trays, and reels.

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MSD classification | 1 April, 2004


JEDEC J-STD-033A has a bake time/temp table based on different package thicknes.

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