How to control and protect the MSD component effectively!

The manufacturing craft of the MSD.

The MSD is affected only in the craft process of convection, convector/ IR, IR, the bulk re-flow of VPR. It is also certainly controlled to use in the craft process of dismantling or welding through heating part. In the other craft process such as the inserting component or the socket fixing component and the welding process through heating the pin, the MSD absorbs calories oppositely much less.

The marking and following of the MSD.

The right marking of the MSD is the first thing that should be taken into consideration to control it. Most of the component manufacturers do many beneficial works in the sealing and packing of the MSD and the marking of the damp-proof bag but not all of them follow the IPC/JEDEC principle, some of them only handwrite "MSL" on the bag, some of them note the MSL with a form code, some of them don't mark, even some of them don't pack the component by damp-proof bag. It is very dangerous that the materials are thought as un-sensitive to humidity when receive them and find that they don't packed by damp-proof bag or there's no marking in the bag. The unique measure to avoid this is to build up a database including all MSD to insure the right wrapping and there's no other more convenient methods to get the information of humidity sensitivity besides observing the label of the original packing. SO it is a challenge work itself to build up and maintain a database of MSD.

The next, it is difficult to confirm the component sensitive to humidity again once they are taken out from the damp-proof bag. In order to acquire any possible controlling measure, it is very necessary to provide convenient and dependable methods for the person handling the component and the operator to get the code and related information, including the sensitive grade of the to humidity. The most of MSD are sealed in the plastic IC tray according to the JEDEC/EIAJ standard. But the IC tray has no enough space for sticking the label and people always stick papers or gum labels on the shelf, the machine sending material, damp-proof cabinet or the bag to distinguish each tray. For the related information, the original label should be reserved after different processes. The huge difficulty will come out in the process of following the sealing and packing of the material in the tray and the artificial mistake leaded by it and the person who experiences the SMT production line has the emotional stirrings deeply.

Furthermore, the MSD is divided into six types and the controlling method of each type also differs greatly according to the standard. At the same time, there are more than one thousand operators in a factory and everybody's cognition and knowledge level is different yet, so it really is a difficult thing to guarantee each operator understand the MSD and not make mistake.

Added:  Tuesday, November 28, 2006
Submitter: meilysha | meilysha@126.com
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