Electronics Forum | Fri Mar 04 10:04:14 EST 2005 | jbrower
We use Alpha UP-78 (Older paste formula) and it works well for what we do. We standardized our stencils at 5mil with a 10% reduction on IC apetures and a home plate design on passive components. Additionally we use laser cut electro-polished stenci
Electronics Forum | Mon Apr 11 08:39:41 EDT 2005 | Grant
Hi, Yes, it's going to be hard. I was thinking a high end fine pitch placer could place the fine pitch accurately, and then slowly do the passives. That might do the trick, but unless he's prepared to spend at least half a million, it's going to jus
Electronics Forum | Tue Nov 15 21:06:04 EST 2005 | davef
Is your IMC purple? [The sure way to tell if you have the 'purple plague'.] Where does the failure occur? * At pad / wire bond * Up wire from the bond Tell us about the aluminum pad. * What is the plating specification? Is that what you actually r
Electronics Forum | Wed Jun 21 13:06:02 EDT 2006 | grantp
Hi, If your worried about them being lead free components, because it's "not clear" then you should be able to ask the manufacture of them if they are lead free, as they normally trace the batch code, and manif date and will know for sure. Most pas
Electronics Forum | Fri Mar 02 00:21:38 EST 2007 | AMS
Hello, I havea 0.4mm pitch TQFP with heat transfer pad on the bottom side of component. I will appreciate any suggestions with regards to: 1) stencil thickness (Rest of components on board are 0603 passives and few 40 mil pitch IC's) 2) Stencil
Electronics Forum | Tue Apr 24 02:56:12 EDT 2007 | chrispy1963
If the PCB you are using is a HASL pad finish and is a leaded assembly, we use homeplate pads with a 5 mil stencil. If the circuit has Enig finish and is PB-Free then we use 1:1 apertures with a 5 mil stencil Either method should provide no solde
Electronics Forum | Mon Apr 23 17:03:14 EDT 2007 | Theresa Spear
Thank you all for your feedback. Our backside are 99.9% with passive components. However, we do have a lot of through hole components on boards. To go totally selective soldering the equipment can be quite expensive. Most of the time, we left the com
Electronics Forum | Mon Feb 02 08:50:44 EST 2009 | steverog
I am looking for the following information or where I might find it? 1. In what year were the first SM passives (R, L and C only) made available? What sizes 2. What year for subsequent parts in smaller sizes. In essence I would like a time-line sho
Electronics Forum | Thu Feb 05 02:34:05 EST 2009 | sachu_70
Hi Manuel, most passives are chip components. These tend to self-center/align during the reflow process. However, you need to ensure that there is a uniform balanced solder paste deposit. I had tried few such ovals in earlier stencil designs and resu
Electronics Forum | Fri Apr 24 07:55:12 EDT 2009 | davef
TOMBSTONING OF 0402 AND 0201 COMPONENTS: "A STUDY EXAMINING THE EFFECTS OF VARIOUS PROCESS AND DESIGN PARAMETERS ON ULTRA-SMALL PASSIVE DEVICES" Michael Yuen, Heather Benedict, Kris Havlovitz, and Tim Pitsch, Plexus Electronic Assembly Corporation, N
.gif)
