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Subrat Prajapati

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Supplier Quality Leader
Ge Healthcare

Subrat has 10 year of extensive experience in PCB assembly process optimizing for quality, process includes screen printing, wave, reflow. He has a copyright in stencil design published in Apex Expo2010 at Las Vegas US.

Subrat Prajapati has submitted responses to the following questions.
Problems with Insufficient Barrel Fill
One of CTQ aspect if not covered are under initial DFM - PTH connected Layer count,weight (oz). We have proved ...
HASL Surface Finish and Coplanarity
Hope you execute DFMA and its your responsibility tonotify this risk to customer and latent failure risk if customer want ...
Concerns Replacing High Speed Components with No-Clean Solder
Noclean flux residue may create noise in high speed circuit boards as well withvery low voltage mV cases as we ...
Octagonal Pads for 0402 Chip Caps
This type of design though not being evaluated bycomponent manufacturer either BGA/0402 but there's patent exists for same andyou can ...
Selective Printing for BGA Components
We should stick to rule to maintain equal or betterquality, reliability and keep working to reduce cost.The uneven space betweennon-print ...
What Causes Component Rotation During Reflow?
Large SMD part tend to rotate is not new even thoughfootprint as per CM as part being floating insider reflow ...
Extending Shelf Life for Jars of Solder Paste
Expirationdate mentioned by manufacturer is with recommended storage condition. It is notrecommended to use expire paste, though if you like ...
BGA Joint Voids - Accept or Reject?
Forspecific BGA void acceptability recommend to refer IPC 7095 and incorporatesame in Shop floor X-ray machine. This std has specific ...
Through Hole Connector Solder Joint Hole Fill
Recommended refer IPC610-E vs D. To inspect 75% across360 degree you can use X-ray having facility of x-ray head movement ...
ESD and Humidification
If all ESD precautions being taken care as wellif shop-floor having ANSI ESD S 20:20 qualified, ambient air humidificationrequirement should ...
Zip-lock Bags vs. Heat Sealed Bags
First - Both are not acceptable provided bag is not vacuumsealed. Usually zip-lock type doesn't get vacuum sealing whereas Heat ...
Voids with Back to Back BGA Components
BGA packages withback to back placement on double sided design are not recommended due toconsiderations of rework, testing, and reliability. ...
Conformal Coating Over Heat Sinks
Questionis Why conformal coating need to put on heat sinks where there is no evidenceheat sink will have environmental adverse ...
Blind Hole Pin Soldering
This is the best situation seen ever and hope you will get itstabilized by conducting said methods. 1st - In ...
Opens at BGA Component Corner Balls
There couple good feedback, apart I recommendcheck is Board finish HASL, ENIG. HASL finish has more prone of such defect ...
Insufficient Plated Hole Fill with Electrolytic Capacitors
Possible cause of not reaching 75% fillet is High thermal copperlayer as plane connected to capacitor PTH. Solutions-1. Design: Execute ...
HASL vs. Immersion Gold
Onnature ENIG is better than HASL with corrosive environment. Be careful uponmigration to HASL if you are using BGA, Fine ...
Soldering Wires to SMT Pads
IfI understood you are about to solder wire of specified AWG from a connector pinto other location on Board on ...