Hi Matt,
Get definitive answers!
Contamination on the HASL finish?: From the pix you posted, it looks like something fishy is going on. I�d reject them back to the board house and demand an answer. Most board houses and purchasing people will give you that confused dog look and ask what�s wrong with them. So, to test your process, take a sample board and try tinning them yourself with an iron and some wire solder. If it still doesn�t wet after an iron, you really have a board problem. If it does tin, solder wick it flat to take a closer look. If it�s OK, try pasting and reflowing. If it reflows OK, you localized the problem to the board and there�s nothing wrong with your stencil or paste. Unfortunately you still have a board problem.
Insufficient solder, not enough to cover pad? Stencil = - 5%: Look at the past history of this product. Has this always been an issue? If so it could be your stencil, although at �5% I doubt it. If it hasn�t always been a problem, then it�s either your board or paste. Your stencil is a fixed tool and cannot change under normal process conditions. You machine set-up could cause problems too and may need to be looked at.
Worn out paste. (50% new added this morning). Well, you can�t �wear out� paste, but it can dry out. This would cause the paste not to roll and you�d get poor prints. Check your print! If it doesn�t look good, change the paste. Does it look OK with new paste? If not, there may be something wrong in your set-up or the way you release the board print from the stencil.
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