Phil,

Are you facing with all the 0402 components tombstoning from different 
suppliers on the same board, or from the only one supplier ? 
I hv once faced with tombstoning issue with one of the component supplier, 
but not the rest. I realised the effect was caused by different degree of
solderability on the 2 terminations from the same component. The supplier 
recommend us to use flux with 2 % chloride. We did follow as we are doing 
no-clean process. 

I also once faced with the air tubulence from the Hot Air reflow oven.
I fixed a variable resistor to the blower fan of the reflow zone. So that
air flow can be tuned down (of course not too much) till it will not cause
any disturbance to the component. Anyway, I need to re-plot the profile again. 


Poh Kong Hui 
Nera Electronics
Phone Number: 7796161 ext. 181
Email Address: [log in to unmask]