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0603 LED Tilt

Views: 1768


MSK

#69073

0603 LED Tilt | 27 May, 2013

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 Stencil

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#69077

0603 LED Tilt | 27 May, 2013

Suggest that you do search on this forum for "tombstoning".

Regards,

Bert

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#69078

0603 LED Tilt | 27 May, 2013

Interesting, I could not find anything via a website search some of the links came up as 404, others a "home" page and some never went at all (or took too long)

So I turned to google and found http://www.smtinfo.net/docs/tombstoning.pdf a 16 page article

We have had 1206 LED tombstone it appears to of reduced since the ex-boss slowed the oven speed down.

I see in the article it talks about "solder balls" we have a lot of this problem, on some panels. (Page 9) The foreman has a one track mind he says it is "the solder paste" what can you say?

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#69079

0603 LED Tilt | 27 May, 2013

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.

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#69080

0603 LED Tilt | 27 May, 2013

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.

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reflow oven profiler

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