Hi Technetters!

A posting from my side after a long time.

I wish to get some information from those who have experienced tombstoning and that too because of improper reflow profiles. My query is that an improper profile can affect tombstoning in two ways! One: During the entrance of the PCB into liquidous. That
is, the entrant pad enters liquidous first and hence due to surface tension lifts the component since the other pad has still not entered liquidous. Two: During the entrance to cooldown.  The earlier exiting pad into cooldown cools down first and hence
contracts the solder and hence lifts the component since the other pad is still under liquid condition.

My question is: How to figure out as to which area of the profile is to be attacked? Assuming I don't have a realtime cam to view both the situations!

Forgive me if my question sounds stupid.

Thanks in anticipation.

Regards
Vinit Verma
Philips India Ltd., 9th Floor, Ambadeep Building,
14, Kasturba Gandhi Marg, Connaught Place
New Delhi-110001
Tel: -+91-11-3738791, 3324547; Fax: +91-11-3322859
Mobile: +91-9810208557
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