Electronics Forum | Wed Sep 16 00:03:55 EDT 2009 | linseeg
We encoutered few PCB after IR reflow the PCB pad change color from silver to yellowish / brownish. Our IR reflow peak temp is ~250 degree. The brownish cannot be remove with IPA as well. What is the main reason causing this issue?
Electronics Forum | Mon Apr 15 06:30:23 EDT 2019 | spoiltforchoice
Its not the max temperature that is the issue, its how much energy the oven is capable of transferring to the PCB inside the 4-6 minute window of a typical profile. In a conveyor oven this is achieved by having zones of different temperatures, but th
Electronics Forum | Tue May 25 07:03:34 EDT 1999 | Milan Z.
After reflow proces in convection-IR oven we find broken body of SOT23 elements. There is no problems on other elements (SOIC, chip R,chip C, etc) Where is the problem? Thanks in advance!
Electronics Forum | Thu Jun 27 03:03:57 EDT 2019 | SMTA-David
Hi, I have a small assembly line that consists of a Semi-Automatic Stencil machine, a Samsung Pick and Place, a small IR reflow oven and a wave soldering machine. The reflow oven is presenting the biggest bottleneck. The machine is a small IR (T960
Electronics Forum | Thu Sep 17 04:48:51 EDT 2009 | grahamcooper22
The colour you see on the pads is tin/copper intermetallic layer. In your reflow the immersion tin coating and the copper pad underneath react to form in intermetalic layer. The effect is worse the hotter the pcb or area of the pcb gets. In IR reflow
Electronics Forum | Fri Sep 18 07:32:53 EDT 2009 | karthikthebest
I agree with Graham cooper's input. Also note that the brownish color is incremental w.r.t to number of days you hold after the thermal cycle(example: after the reflow)so try to complete all thermal cycles ASAP to lessen the discoloring.
Electronics Forum | Wed Sep 16 13:32:05 EDT 2009 | davef
Questions are: * What is the solderability protection on the pad that changes color? * What is the distribution of this issue?
Electronics Forum | Wed Sep 16 22:41:51 EDT 2009 | linseeg
PCB finishing is immersion white tin. The brownish is at random location at PCB pad. The issue only affect visual reject but no solderbility functional failure.
Electronics Forum | Thu Jul 18 13:19:32 EDT 2019 | emeto
Basic rules: 1. The longer the oven the better(if you have the space)- better temp control, better repeatability, better throughput. 2. Only convection - don't get IR heaters 3. Buy reputable brand machine
Electronics Forum | Tue Mar 21 16:16:51 EST 2006 | gipos
Dear All, We shall be more than thankfull if someone who worked with Universal IR reflow-curing owen (model 4816 CRS) can help. The owen is powering up but needs 4 digit acess code. It is acquired from a closed factory. Maybe it dose have some secr
winsouce.jpg)
