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RNETs and Lead Free

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RNETs and Lead Free | 6 May, 2008

We have a board that uses 0402x4 RNET packages that we are having a difficult time getting to solder consistently. Paste deposition is fine (using AIM WS353) and profile is dead-nuts. I'm starting to wonder if this is something that we're just going to have to deal with.

Are these generally difficult parts to deal with in a lead free process?

Any input appreciated.

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RNETs and Lead Free | 7 May, 2008

We are also having some issues with certain small parts. In our case this is tantalum caps and 0402 caps. We had a vendor admit after much discussion that the plating used from a particular orgin was different on the tantalums. The tehory is thatthsi causes outgassing. In addition we have some 0402 caps that are plated lead free, but stated by the vendor compatible with SnPb solder. I beleive this may be only partly true, but we'll keep experienting.

At this point I am leaning towards trying a diffent vendor solder (We currently use AIM 353 and 483 SnPb) to see if this helps.

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RNETs and Lead Free | 7 May, 2008

Interesting - We're using the same AIM products as you. On the lead free, 353, did you start out with it or did you try the WS485? That was the 1st product recommendation we got from AIM and we found that the lot to lot consistency was not good. This was following great testing results when we first qualified the material. 353 was the fall back material and it has performed fairly well but I wonder if we get the wetting force and activity that we might expect with another supplier's material.

On the positive side, the WS483 63/37 is lights out.

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RNETs and Lead Free | 7 May, 2008

The 483 is what we use on all boards except on one where the 353 improved wetting on resistor packs. It worked much better since the parts are LF and this is the same flux AIM uses in their LF solder. Yes, it was recommended by AIM when we discussed our problems with them. We have tried this for the cap issue, but it makes no difference for us.

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