Electronics Forum: stencil (Page 416 of 540)

Solder paste change

Electronics Forum | Mon Apr 07 13:26:25 EDT 2003 | billschreiber

Dear Yukim, You may want to make sure that your presolder cleaning processes will support the change to a new flux. Many chemistries are vertically oriented and will clean only a selected few types of solder pastes. If you find that a new cleaning

0402 Adhesive Screen Printing

Electronics Forum | Tue Apr 01 11:18:47 EST 2003 | cyber_wolf

Is anyone out there successfully screen-printing SMD adhesive on an 0402 layout? We have successfully done 0603 and larger, but the deposition consistency on the 0402's is just not there. We don't always get enough epoxy on the board. We have tried a

Voids in solder fillet

Electronics Forum | Wed Apr 16 10:45:16 EDT 2003 | Takfire

Recent cross-section analysis for a customer complaint revealed voiding in the solder fillet. In some cases, the remains of outgassing were also observed. During the failure analysis, we also observed failures where the solder fillet wicked on the

low volume /semi-automatic solutions

Electronics Forum | Wed Jun 18 06:41:34 EDT 2003 | emeto

Hi Jipp, If we are talking about 200-500 boards per month the main question is"Is it reasonable to go for semi-automatic production?". You will nead at least 1.Manual stencil printer 2.P&P machine 3.Infrared dryer or reflow oven Most expensive par

Screen Printing for BGA

Electronics Forum | Thu Aug 21 09:34:57 EDT 2003 | davef

Woa. The more paste that you put a a BGA ball, the more likely that you'll bridge between balls. Why do you need to compensate for the size variance in BGA balls? How does using a 8 thou thick stencil to compensate for ball size variance? Fine pi

Screen Printing for BGA

Electronics Forum | Thu Aug 21 15:10:59 EDT 2003 | paulm

Such balls (=/- 0.004)size variance can occur in a single part. If I have a ball in a part that could be (according to vendor specs) 0.008 larger than another ball the only way I can insure that the smaller ball makes contact with the paste is to hav

QFP Coplanarity & Alloy 42

Electronics Forum | Wed Oct 01 13:39:13 EDT 2003 | arturoflores

They take the solder in a dip and look solderability test but when in normal reflow process we got some pins that do not get wet and the appearance is as follows: -Pillow effect on the toe(no front fillet is formed) -There is a sheet of flux between

BGA soldering

Electronics Forum | Mon Oct 27 16:58:34 EST 2003 | Stephen

The most common way is to screen print paste for the SMT placement, then then SMT placement then reflow then TH placement followed by wave solder. You won't be able to screen print for the BGA after reflow unless you use a mini stencil. Or you co

Soldering Lead-Free Globtop BGA to Pin-Socket Interposer

Electronics Forum | Wed Nov 19 16:35:27 EST 2003 | davef

We'd be incluned to dip the BGA ball in tacky flux, place the BGA on the PTH interposer, reflow that suka, and get on with things. [Take the people involved out to lunch with the money you save on not buying a stencil.] On damaging the glop top, we'

Stencil Printers

Electronics Forum | Sun Dec 14 14:24:46 EST 2003 | valuems

HI, We have seen a couple of statements that we just have to reply on. One is the trouble with MPM's in mexico. I feel most of that trouble is because of the technical support and the actual maintenance in mexico, not because of the MPM's. And MP


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