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Keys for Moisture Sensitive Device Control
Board Talk
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TranscriptPhil Welcome to Board Talk. This is Phil Zarrow and Jim Hall, the Assembly Brothers, pick and place. Also known as ITM Consulting. Jim Here is a question close to our hearts. "Our customer is requesting documentation on our MSD program. We attach travelers to every group of MSD components whenever they are taken out of the moisture barrier bag; is this good enough?" Phil Well, it's a good start. I'll elaborate by saying at least you are trying to make an effort to do an MSD program. The traveler is a good start, but so many times we see cases where the times are not filled in or they guesstimated the times they put in the dry box or back in the bag with a desiccant. Jim Is it fair to say that in 15-20 years of auditing customer facilities we have found just 2 facilities that had an airtight MSD program in place. Most of them had some program, it just had holes in it. Phil Usually the most common hole we see is the lack of operator diligence. MSD is important. The problem has been around as long as we've had surface mount ICs. We see people starting to become aware of it and we see a lot of people that just don't even have programs. And very few are airtight, or vacuum-sealed in this case. What we find lacking is that they put the program in place, but nobody really understands it. They've got all kind of essential training on ESD and everybody understands what is about, they do it and follow the procedures. One of the most important things you could do is have an MSD training program, a boot camp, if you will. Bring everybody up to speed, what is this, why they have to be diligent about filling in the travelers and do that. And make sure the traveler is proper. I ran to this a couple weeks ago. Company had a traveler and they had it affixed properly, and they input dates on the bag. Jim What's wrong with that? Phil Let's give or take about 24 hours. No times were included, just the date. Jim At another facility they were having problems, but nobody bothered to subtract the hours and total the amount of time that the parts have been out of the bag. By their own documentation, parts exceeded the J-STD-033 limit for moisture sensitive level. So for type 3, that means it had been out of the bag more than seven days. Type 4, out of the bag more than three days. So if you are filling out a traveler and it's a type 3 part and it has been out of the bag more than seven days, the bag should be labeled, must be baked before reuse. Likewise, if a type 4 part has been out of the bag more than 12 hours continuously, it must be baked. Phil There are more elaborate systems. There is bar code systems that use bar code scanning of the parts, and there is even RFID code scans system. But regardless, it's only as good as the operators and technicians knowing what the MSD thing is all about. So the paper travelers can be a very effective methodology, but you've got to do the due diligence. You have to bring the team up to speed, why we are doing it and how we are doing it. Jim And people have to follow it. Phil Remember whether your reflow soldering level 3 or level 4 devices, don't solder like my brother. Jim And don't solder like my brother. |
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