|Ask the Experts Member|
Supplier Quality Leader
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 to notify this risk to customer and latent failure risk if customer ...
Concerns Replacing High Speed Components with No-Clean Solder
No clean flux residue may create noise in high speed circuit boards as well with very low voltage mV cases ...
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 better quality, reliability and keep working to reduce cost. The uneven ...
What Causes Component Rotation During Reflow?
Large SMD part tend to rotate is not new even though footprint as per CM as part being floating insider ...
Extending Shelf Life for Jars of Solder Paste
Expiration date mentioned by manufacturer is with recommended storage condition. It is not recommended to use expire paste, though if ...
BGA Joint Voids - Accept or Reject?
For specific BGA void acceptability recommend to refer IPC 7095 and incorporate same in Shop floor X-ray machine. This std ...
Through Hole Connector Solder Joint Hole Fill
Recommended refer IPC610-E vs D. To inspect 75% across 360 degree you can use X-ray having facility of x-ray head ...
ESD and Humidification
If all ESD precautions being taken care as well if shop-floor having ANSI ESD S 20:20 qualified, ambient air humidification ...
Zip-lock Bags vs. Heat Sealed Bags
First - Both are not acceptable provided bag is not vacuum sealed. Usually zip-lock type doesn't get vacuum sealing whereas ...
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
Question is Why conformal coating need to put on heat sinks where there is no evidence heat sink will have ...
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 copper layer as plane connected to capacitor PTH. Solutions-1. Design: ...
HASL vs. Immersion Gold
On nature ENIG is better than HASL with corrosive environment. Be careful upon migration to HASL if you are using ...
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 ...
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