All Questions
15
questions
4
votes
1
answer
283
views
SMT Reflow solder quality issue with SN42/BI58 paste
I have been doing hardware design and PCBA prototyping for a while and I have issues with quality of reflow soldering. I have a small lab including a pick'n'place machine, stencil printer (eC-stencil-...
- 453
0
votes
0
answers
77
views
QFN-28 REVERSE Breakout Board
I am trying to build a PCB board that I found on GitHub. In a rash we ordered few sets of the PCBs without inquiring about the parts availability. Turns out one of the parts is not available in all ...
- 109
0
votes
2
answers
201
views
Aligned vs not-aligned components: Which is better for PCBA process?
I am designing a Raspberry Pi hat PCB for a home automation control project.
It contains many SMD resistors and capacitors.
I was just wondering if aligned components have any benefit over not-aligned ...
- 73
2
votes
1
answer
1k
views
What could have caused this SMD capacitor failure?
I have an 0805 capacitor that has failed short circuit on a board. The maximum voltage it would see should be 16V. It has value 4.7uF, is rated to 25V and is X7R.
I don't understand why it might have ...
11
votes
7
answers
5k
views
Hand soldering SMD 1206 components [closed]
Because I tried to wire-solder a protoboard which failed miserable, I'm intending to order a PCB. However, to minimize the area, I want to use some SMD1206 components. I ordered some basic ones (...
- 14k
0
votes
1
answer
787
views
Surface Mount Adapter PCB With Castellated Holes
I have some prototype boards that I would like to modify. The modification includes removing a section of circuit and replacing it with another circuit. My theory on how to do this is to make an ...
- 111
3
votes
4
answers
2k
views
Beyond what is recommended by fabricators, how far should traces be from SMD pads?
Having followed a fabricator's DRC (this case being OSHPark), this distance between an SMD pad and a trace is considered acceptable (see attached images).
However, I wanted to inquire about what the ...
- 33
0
votes
2
answers
166
views
Automatic SMT Line PCB Soldering [closed]
I am planning to create few circuit boards. I am considering getting the PCB printed from a manufacturer and do the SMT via a machine my self. Do you think it is good idea.
The reason i an planning ...
- 101
3
votes
2
answers
1k
views
Stencil at home with extremely small parts?
I was amazed lately to find out about solder paste - so we can assemble our PCB prototypes at home relatively easily.
The process seems easy, but now I started to suspect I am going to have a problem ...
0
votes
2
answers
1k
views
Small 'blistering' under surface-mount soldering attempt - is this a problem?
I am very new to SMT soldering - and have started with a small project.
I used resin flux, followed by a small amount of solder paste and then a hot air gun at around 373 degress celcius to flow the ...
- 454
24
votes
4
answers
3k
views
Why are there no BGA chips with triangular tessellation of circular pads (a "hexagonal grid")?
Ball grid arrays are advantageous integrated circuit packages when a high interconnect density and/or low parasitic inductance is paramount. However, they all use a rectangular grid.
A triangular ...
- 8,661
1
vote
2
answers
282
views
How to determine which size of surface mount resistor for an ADMP441
I'm relatively new to reflow surface mount soldering and am unfamiliar with the various sizes of components.
The PCB design I ordered is here:
https://oshpark.com/shared_projects/ypqAU3CH
But I ...
3
votes
1
answer
1k
views
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 ...
- 17.6k
0
votes
4
answers
1k
views
What is the optimal way of clearing solder from surface-mount PCB pads for rework?
Say I have an assembled PCB with a QFP package on it. This device gets damaged and I need to replace it. Getting the device off is straightforward, but now all the pads have solder blobs on them. Is ...
- 17.6k
8
votes
5
answers
4k
views
PCB copper thickness with small pitch SMT components
I typically use 2 ounce copper as rule for all my PCBs. On a recent board I am using a 0.5mm pitch, relatively large micro, and noticed the pads aren't very flat. Assembly went fine with the protos, ...
- 3,844