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Ask the Experts Member

Ray Prasad

President
Ray Prasad Consultancy Group

Ray Prasad is the founder of Ray Prasad Consultancy Group which provides teaching, consulting and technical expert services in tin-lead and lead free technologies using SMT, BGA, BTC, fine pitch and through hole components. Mr. Prasad is a long time member of IPC, and is currently the chairman of BGA committee IPC-7095 "Design and Assembly Process Implementation for BGA" and Co-Chairman of recently created IPC-7093 "Design and Assembly Process Implementation for Bottom Terminations" surface mount Components (BTCs) such as QFN, DFN and MLF.

Ray Prasad has submitted responses to the following questions.

Stencil Pattern for LGA Power Pad
You should use “window pane” design- essentially breaking up in smaller pads. You should have gaps between different “windows” to ...

Looking for Long-term Component Storage Options
10 years is a really long time. The main concern is deterioration of solderability. But if you do have to ...

Exposed Copper Defect
No. Exposed copper is not considered a defect in J-Std-001 or IPC-A-610. It used to be defects ways back when ...

BGA Solder Ball Collapse
Yes they do assuming the their weights per ball are the same and they both use appropriate peak temp and ...

Reflow Profile for Mixed Lead-Free and Leaded
Solder paste determines the reflow profile. So if the paste is tin-lead and bare PCB is lead free (that is ...

Moisture Sensitive Components in Flooded Storage Facility
Don't discard. If they were in desiccant bags, you should expect no impact. And then there is option of baking. ...

Reflow Oven - 5 Zone or 8 Zone
If you are going to use lead free solder paste, minimum zone you need is 7. So Ho got 8 ...

Selective Solder System Purchased At Auction
Obviously you have to throw away your leaded solder since you cannot use it for lead free. But also make ...

Concerns With Silver Finish Component Leads
No. Immersion Silver surface finish on component leads should not cause any embrittlement problems. ...

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