Electronics Forum | Mon Dec 21 17:50:55 EST 1998 | anamonus
| I have a mixed technology board ranging from 50 mil pitch devices to 20mil Qfp's to PBGA-352 at 1.27mm, and 6 Intel uBGA-48 at 30 mil pitch. With all these different package types i'm torn between using a 4 or 5mil thick stencil. The ball dia. is 1
Electronics Forum | Tue Jul 28 16:37:24 EDT 1998 | Terry Burnette
| I think that in general it's best to deposit paste in order to increase the part standoff. This helps improve the fatigue-life of the joints by providing more strain relief. But I know from experience that it's tough to deposit paste during the r
Electronics Forum | Tue Oct 09 20:27:13 EDT 2001 | davef
That�s a 672 BALL BGA, bud!!! It�s a BIG Mutha!!! [I know. I know. For some reason suppliers call balls "pins".] Let�s focus on: * Clarifying the units on your PCB and aluminum plate thickness measurements. * Describing your use of the aluminum pl
Electronics Forum | Fri Jan 16 07:06:47 EST 2004 | Mika
Component manufacturer often have recommendation for pad layout and process setup. This should be used as a guideline to help You to set up the process. Exactly what type of component is this, uBGA? We populate 64 I/O uBGA's on our pcb's with 0.3 mm
Electronics Forum | Wed Sep 08 15:59:25 EDT 2004 | kbayram
Hello, I'm looking for a lower end used machine that can place a 55x44mm sized bga component, placement speed is n't concern. At the moment I have only found the quad ivc to be capable although I'm worried about the placement accuracy and repeatabi
Electronics Forum | Sat Feb 26 20:44:46 EST 2005 | siverts
Some of the QFN's have/has? (sorry for the grammatics but I live in Sweden) a "ground pad" underneath the center of the body. Some of the manufactories have made a specification of how much solder fillet that needs to be covered on the center pad [f
Electronics Forum | Fri Apr 27 13:04:35 EDT 2007 | rmitchell
Hi, I am having some problems with my Fuji CP6 placement repeatability. The placement drifts during the build about .06-.10 mm on parts. It has happened on several different builds this week. It is enough to cause some defects after reflow on smal
Electronics Forum | Thu May 24 08:55:25 EDT 2007 | ck_the_flip
Here's some quick things to look for: 1. Does your solder paste feel like concrete, does it roll-up into your squeegee blades, and stick to your stencil? If so, your problem is the solder paste. The mixture of powder and flux, or metal load is ou
Electronics Forum | Sat Nov 10 21:15:04 EST 2007 | mika
make 4 square rounded corner apertures around the ground pad and the total reduction of 20 % (80 % solder paste). Then you still be able to solder the terminals around. We SMT-mount & reflow soldering various QFN packages onto our customers pcb:s wi
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
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