Werner,



Interesting point you make.

But that is not at all my experience.

Is it possible that the reflowoven is an important factor for a "succesfull"

tentprofile?

Highest setting, in our reflowoven, is 250°C for extreme boards (4.4 mm)

Normally 240°C is used for boards with different types (mass) of components.

Delta T on the board is 8 - 15°C depending on the assembly.

So there is no cooking issue.



Am I overlooking something?







Jowan











-----Original Message-----

From:	TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier

Sent:	woensdag 13 november 2002 1:42

To:	[log in to unmask]

Subject:	Re: [TN] Void in BGA



Hi Daan,

I am with you on your experience. The tent-profile is really bad

news--except

for assemblies with all the same compenents, because it maximizes

temperature

differences between thermally massive components withrespect to small

components and the PWB. It also requires a different paste flux formulation,

but that is not the problem. the problem is that in order to get large

componets hot enough, the smaller ones and the PWB are cooking.



Werner Engelmaier



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