Electronics Forum | Wed Aug 21 20:11:34 EDT 2002 | mitch
We are going to begin using a 64 pin 10mm QFP with 0.5mm lead pitch. I was recently asked if we need to purchase our PCB with E3 coating instead of tinned pads when using the .5 pitch. The concept being suggested is that the E3 coating will give us b
Electronics Forum | Tue Aug 27 11:08:24 EDT 2002 | slthomas
We use an evaporator, so that we only have a sludge of flux residue and solder metal to dispose of via the hazmat handling service. We also route stencil washer waste water into it. We use a 30 gallon drum and have it hauled off maybe twice a year,
Electronics Forum | Fri Aug 30 00:47:53 EDT 2002 | TLe
Dave, you did not understand my problem right. We don�t get paste on the PCB in the printing phase of process. I have seen also poor wetting on OSP, as you descriped, but that is very unusual. I think generally OSP is better than gold/nickel if spea
Electronics Forum | Sun Sep 15 15:08:00 EDT 2002 | jersbo
My 2 cents... Screen printing may very well have a leg up on deciding SMT defects... however if you pay attention to your stencil (aperture size ratio etc..) and inspect your prints... I believe its a much lesser number... (paste MFG also plays a ro
Electronics Forum | Wed Sep 18 10:06:30 EDT 2002 | Bob M
I place 15-20 mil a lot. You need to look at your pad to apature reduction. Your stencil thickness. The type of paste your using. We use 2-5 mil reduction on each side as a general rule on fine pitch. This varies depending on pad width. We also use 5
Electronics Forum | Tue Oct 01 16:18:16 EDT 2002 | davef
Q1: Is this [paste in hole] feasible? A1: Yes, many people lower their operating cost by reflowing through hole components. Q2: What types of components are difficult to do this way [paste in hole]? A2: Types of through hole components that are d
Electronics Forum | Mon Oct 14 03:14:08 EDT 2002 | msimkin
Hi, Has anyone had expereince in the design or use of mini rework srtencils for uBGA applications? What was the deisgn guide lines used. I am looking to rework 0.7 & 0.65 mm uBGA parts with standard hot air, without split prism placement guides. It i
Electronics Forum | Mon Oct 14 09:31:46 EDT 2002 | russ
First off, are you planning on placing these parts with your placement machine since you mentioned that you do not have an alignment system for rework? I would be leery of handplacing a BGA into paste by steady hand and craned neck alignment. Seco
Electronics Forum | Wed Nov 06 12:56:10 EST 2002 | slthomas
What I'm seeing is an occasional pattern of tear drop shaped features in a sea of nice shiny solder. The little islands don't really have any relief.....it's more of a surface finish feature than a 3-dimensional feature. The wetting angles are good,
Electronics Forum | Wed Nov 06 16:31:59 EST 2002 | slthomas
I would also consider paste control (don't take it personally...I always have to get after people about this one), time on the stencil, time between print and reflow, solderability of the component leads, paste volume (that one really got us once....