Electronics Forum | Thu Dec 14 04:42:11 EST 2017 | jineshjpr
Can anybody suggest how can I achieve good solderability in convectional reflow oven If I reduced Convection Air Speed 80%. The whole purpose is to reduce 0402 LED tilting in the convectional reflow and the PCB having QFN with 60 to 120 sec soak, 30
Electronics Forum | Thu Dec 14 05:07:55 EST 2017 | tsvetan
picture of the problem would help people to speculate what you do wrong
Electronics Forum | Thu Dec 14 15:05:17 EST 2017 | emeto
I am pretty sure, you are looking into the wrong spot. Your paste is too much, or your part has very inconsistent narrow leads(that includes wrong pad design as well.)
Electronics Forum | Wed Dec 20 07:16:16 EST 2017 | stephendo
I agree with Evtimov. What he didn't point out is that the surface tension of the solder would vastly overwhelm any force from air flow.
Electronics Forum | Mon May 27 07:16:27 EDT 2013 | mskler
We have an LED 0603 package, We are using stencil of 5 Mil, Before Reflow placement is perfact but after reflow it tis found that there is more than 30% LED are tilt. Can the speed of Fan in Reflow can help or I have to reduce the PAD opening in Sten
Electronics Forum | Fri Nov 24 05:38:46 EST 2017 | jineshjpr
Can anybody suggest how to reduce 0402 LED tilting as I am using Convectional Reflow oven with 10 Heating zones and controlling the solder paste with 4.2 mills paste height
Electronics Forum | Mon May 27 14:34:33 EDT 2013 | bvdb
Suggest that you do search on this forum for "tombstoning". Regards, Bert
Electronics Forum | Mon May 27 15:56:50 EDT 2013 | nikyta
MSK, would help to know the exact type of LED you are talking about, and the size and spacing of the pads on pcb; and how and where the LEDs are reversed (always in the same direction or random ?) Also a picture might help.
Electronics Forum | Mon May 27 16:17:30 EDT 2013 | nikyta
Hi Eric, you have the right reduction on the stencils apertures? Also, a very oxidized solder paste can -and will do- promote and increase both the tombstoning as well as the solder balls.
Electronics Forum | Tue Nov 28 14:27:05 EST 2017 | emeto
Without the details I will tell you that you have too much paste. PCB Pad is probably way bigger than the contact lead surface of the part, you overprint, and in the oven this solder have nowhere to go and tilts your part. Check datasheet.Cutting sma
