Electronics Forum: stencil (Page 485 of 540)

CCGA solderability criteria

Electronics Forum | Sat Jun 21 23:15:07 EDT 2008 | mika

Also keep in mind that the CCGA column length tolerance is at minimum +/- 0.13mm from most part manufactures and they don't collapse in the same way as a BGA, therefore the paste height deposit could be critical in some rare circumstances. Board warp

Paste in hole question

Electronics Forum | Mon Aug 18 11:20:08 EDT 2008 | pjc

Stencil apertures are cut to deposit solderpaste onto the annular ring, provided its wide enough. Then you can place a solder preform if needed to ensure there is enough solder to fill the barrel. Here is some information on solder preforms: http://

Silver Immersion Problem

Electronics Forum | Sat Sep 27 10:40:24 EDT 2008 | hussman

Hello all, Just had a problem where the solder paste does not want to stick to the pad, thru the stencil. We have run this board for years with no problem, and this new lot of boards is giving us problems. I know it's a board problem because they

Volume and average height of solder paste after printing machine

Electronics Forum | Thu Oct 02 17:00:44 EDT 2008 | davef

Is that accurate? If so, what are your aspect & area ratios? [Similar to the JerryS comment above.] * You say, � � and the average height is very high: nearly 200 pct.� => Our troop can make paste that height too. They snap the stencil-off a fast as

BGA soldering & BGA ball formation

Electronics Forum | Mon Nov 17 09:47:25 EST 2008 | cisridn

I would not recommend doing BGA soldering with only a hot air gun. I have done it in the past, but the boards would eventually come back from the field because the solder joints did not form correctly and the BGA would have to be reworked again. I

High complex board manufacturing

Electronics Forum | Tue Mar 03 03:02:17 EST 2009 | emmanueldavid

25% out of Lands in PCB, Insufficient/Inconsistent Alloy deposition which causes for poor Tackiness between Device Spheres & Paste deposited. Also note that Aperture Opening Designs in Your Stencil draws a huge role for these defects. 4. Placement: P

0402 tombstoning and dewetting on QFP256 trade-off

Electronics Forum | Fri Mar 06 10:46:35 EST 2009 | davef

First, we agree with Loco that your QFP is nonwetting, rather than dewetting. Your sceen-shots look like ol' timey SnPb paste recipes. Turn-up the heaterometer dial. Second, on nitrogen: * We kinda think your O2 needs to be around 100ppm with 99.99%

SOLDER BALLS

Electronics Forum | Tue Apr 28 21:48:50 EDT 2009 | davef

Confirm the source of the issue. Run a coalescence test on both lots of paste. A simple coalescence test can quickly determine the condition of solder paste after prolonged use. Simply print a small disk [around 4-5mm diameter and 0.2mm thick - a bu

Need low cost pick and place machine for limited production

Electronics Forum | Tue Aug 18 10:17:15 EDT 2009 | grantp

Hi, You don't need X-ray and all that crap. I would get an old MYDATA TP9 or something like that, and a manual stencil printer and a batch oven or a small inline oven. Should do the trick and be very low cost. Should be simple to use as well. Tha

gpu removal

Electronics Forum | Wed Sep 16 15:12:08 EDT 2009 | squid

hi i have just brought a hot air rework station to remove a gpu on xbox 360 i have removed the chip but three of the pads have gone a brownish color and seem like solder will not stick to them ,does this mean the chip is ruined ? ,if so is it becaus


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