Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [stencil]

31 questions
14
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1 answer

Why order a laser stencil?

Quick two part question on PCB manufacturing. I am looking to order a prototype PCB and all the manufactures I've gotten a quote from all offer to include a Laser stencil, some charge for the stencil some are given free with the board. After looking…
Jack
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How to clean solder stencils?

I have had great success in the past using the reflow soldering method, using a syringe and needle to apply the paste to the board. Since I found myself repeatedly making the same boards, I decided to purchase some stencils. I purchased a framed…
sa_leinad
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Solder paste stencil application

I am trying to do reflow soldering with a stencil for the first time. I have done some reflow soldering before, but every time I manually applied the paste using a small syringe + needle. These attempts went well and I was able to solder some QFN…
svUser
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1 answer

Why do I have shorts/bridges on QFN packages on PCBA during assembly? Stencil Printing problem

I am trying to do a home assembly of PCB but I have issues after reflow soldering. Especially I have bridges/shorts on the pins of QFN packages. I have assembled multiple boards other joins are okay but each time I have randomly bridged pins on…
D_Dog
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1 answer

How to apply solder paste with stencil in a 2 sided PCB?

I have seen lots of tutorials about how to apply solder paste using a stencil, but all of them only show how to apply the stencil to one side of the PCB. My current project is 2 sided and I would like to make 2 stencils (one for the top and one for…
mFeinstein
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Good practice when designing a PCB and stencil?

While I generally use nothing smaller that SOIC chips or 0603 passive components, I have to design a PCB with a WSON-14 IC with tiny 0.5mm pin spacing and with an exposed pad. While I generally use a syringe to apply solder paste I thought that, for…
user2233709
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What's a good plastic for self-cutting solder paste stencils on a laser?

I've tried making my own solder paste stencil using 4 mil polyester (for overhead projection slides) on a 45W Epilog laser cutter at the local TechShop maker space. I could not "cut" the stencil cleanly, because the edges charred and became…
Jon Watte
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Is there a pitch limit to applying solder paste through a PCB stencil by hand?

I've ordered two stencils from two different companies, two different materials. Both times I've been completely unable to effectively apply solder paste to the pads of a QFP-64. I end up with a mess of solder all along one side, instead of a…
Stephen Collings
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Solder bridging when reflowing QFP

Today I attempted to reflow solder a board using a solder paste mask and a hot air station but for a QFP chip, I got a of solder bridging. This has generally been my experience with trying to solder QFP chips with hot air - I can't seem to prevent…
Emil Eriksson
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1 answer

SMD Stencil Material Choice

We are planning to purchase a stencil for our LED boards. This will be my first stencil purchase so I don't have much idea about a good or bad one. The inquiries I received typically suggest two materials: Phosphor Bronze or Steel. Steel ones are…
C K
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Applying solder paste through stencil and with a machine dispenser

I am trying to apply soldering paste to a PCB using stencil but I am having issues with S-PQFP-G80 package with 0.5mm pitch. Whenever I try to apply the paste through the stencil I end up with paste being smeared all over the pads on the PCB. I am…
MarkoP
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What is etched half fiducial in PCB stencil ? How to use it?

On pcb manufacturer website, it is possible to opt for "etched half fiducial". Here is how it is explained : Fiducial Mark is an alignment mark for surface mount assembly machines.In General,machine assembly must have Fiducial marks.Fiducial marks…
doom
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How do you prevent solder paste from bleeding to nearby pads when using a solder stencil?

This is the first time I've done this but I've tried about ten times now: That particular image is of the pads for an ESP-32. It's not a perfectly representative picture because the bridging isn't always that bad. I followed this guide and in fact…
user875234
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Is it possible to manufactrure a stencil for this paste-mask using the usual stencil making methods?

I have this footprint from the KI-CAD footprint library (LFCSP-32-1EP_5x5mm_P0.5mm_EP3.1x3.1mm_ThermalVias). The paste-mask shows several circular paste areas under the thermal pad. The separation between the paste areas is only 1-mil. The areas…
user4574
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Dual fixture ( Stencil, SMT carrier...)

I have an output upgrade project on SMT, part of which is dual fixture (2 sides BOT & TOP on the same side). So is there anyone here with experience with this? Can u give me some advice on this?
Jonathan Chu UHAN
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