Electronics Forum | Wed Jun 10 14:48:12 EDT 1998 | Chrys
| | Does anyone have any info./studies on what the percentage or PPM defect rates are for each part of the typical SMT process. | | Example: | | Screen Print = 45% of total defects | | Component Placement = 25% of total defects |
Electronics Forum | Tue Mar 05 20:00:47 EST 2002 | rwilliams
I have recently been handed all responsibility of our Reflow Ovens. Upon my inspection, I discovered that any possible device on the ovens that you would think would require calibration, has a sticker indicating no calibration required. The practice
Electronics Forum | Tue Jun 04 20:34:28 EDT 2002 | russ
Jason, Excessive thermal ramp rates, misprints, improper pad design, paste type, placement pressure, all can cause solderballs. Do the pads on this board meet IPC 782 criterias? I have found that too much pad underneath component can cause this. A
Electronics Forum | Mon Oct 14 17:28:08 EDT 2002 | msimkin
Russ, Thanks for the feedback. Yeh, we are placing them in production using a full ball detect Yamaha placement machine, 5 thou square stencil. etc.etc. The only reason I raised this concern was from a rework point of veiw (actually, the board desi
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 | Thu Feb 20 10:56:49 EST 2003 | larryk
Interesting topic, I got a side bar question. The epoxy companies suggest a lower consistant temp (something like 1 minute at 160 degrees) for curing. But we epoxy and paste our boards that get waved. (I know, why are ya pasting a board that goes t
Electronics Forum | Thu May 06 19:56:30 EDT 2004 | bruceatknoll
Here is some more info with regarding my Wave. 1. PCB .065" thick 2. leed length .20" (.135" protrution) I know this is high but we use many thousands and cutting each is not practical. 3. no clean flux by way of foam fluxer 4. wave machine is a HOL
Electronics Forum | Fri Jul 18 10:23:06 EDT 2003 | James
The parts adhere solder very well. It does not pertain to a certain part on the board either it is all over the board. I cant really say that it is oxidization all you can tell is that on certain parts of the pad still shows like white tin and that
Electronics Forum | Fri Dec 12 11:52:59 EST 2003 | Marc Simmel
I have encountered problems with a 90/10 tin-lead plated SMT component wicking all the solder paste off the pads on the substrate. Worst, the defect occurs randomly - adjacent leads may have 'good' joints, though heel fillets are poor. The solder pa
Electronics Forum | Fri Mar 19 12:09:17 EST 2004 | Primus
I'm just getting more involved with SMT, as I've been a through-hole operator for years. But I don't understand how one could reflow SMT components AFTER the through-hole insertion and solder wave are finished. How does one print paste over a board w
