All Questions
Tagged with manufacturing pcb-assembly
18
questions
1
vote
1
answer
76
views
Functional discrepancy within PCBA batch
When manufacturing a small prototype batch of an embedded system at EMS I have detected different behavior between the units. All units work as expected, except that some units fail to operate same ...
- 91
5
votes
3
answers
2k
views
Question on "Parts should be used within 5 days after opening." statement on component shipping package
I've been given the task of verifying a batch of ICs from a chinese broker, to see that the chips the company has bought are what the broker claims they are. The package we've received looks like this,...
- 5,301
1
vote
1
answer
301
views
Soldermask bridge gap too small - PCBWAY
I've got a PCB design which contains a chip that uses the QFN (7x7) package.
Because of the package size the pins are very close together and the pads are 0.2mm apart, which is smaller than the ...
- 806
0
votes
2
answers
99
views
If a PCB is inspected to an IPC-A-600 class higher than specified what are the negative impacts?
I have received several parts from a PCB manufacturer which should have been inspected to IPC-A-600 Class 2 but were instead inspected to IPC-A-600 Class 3.
I believe I have received PCBs inspected to ...
- 30.1k
4
votes
2
answers
1k
views
Placing through hole and SMT on the same side
I have a design with huge push buttons (with 6 TH holes.)
There's a few of them so they do take up quite a bit of space mechanically from the top.
I was thinking of placing the majority of the SMT ...
- 4,742
10
votes
3
answers
2k
views
What are some reasons for hand painted dots on chips?
I've seen lots of products with hand painted dots or markings on chips, what do they often mean? Obviously I understand everybody has their own reasons but could it be an industry common practice for ...
- 1,430
0
votes
1
answer
2k
views
Half-etched fiducials Vs through-cut fiducials
While making PCB, I added 8 fiducials (fids) marks so that pick and place machines use these marks as referent points on the PCB to position the surface mount components (Packages) during assembly.
...
- 183
6
votes
2
answers
666
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Specifying BOM substitutions / alternatives with Contract Manufacturer (CM)
I fear this question may be opinion based but I think it has some value to the general community - because this falls into the end of the design phase.
When working with a CM, they may have better ...
- 175k
12
votes
10
answers
4k
views
Is it practical for firmware to be uniquely identified in production
Are there systems available in large scale manufacturing that allow a unique serial number to be programmed into the firmware or some free memory space for each PCB that comes through?
I've found ...
- 643
11
votes
3
answers
3k
views
Can I assume counterfeit components?
I recently received a run of 10 PCBs from a manufacturer in China, and am worried they have begun to cut corners and source counterfeit parts. Here is why:
I had them do full turnkey production (PCB ...
1
vote
4
answers
378
views
Choosing a PCB Manufacturer/Assembler for the first time [closed]
I've just finished designing my first PCB, and I'm about to send out a batch of emails for quotes from manufacturing/assembly shops. My design is super simple: the only components are 7 identical SMD ...
- 303
9
votes
3
answers
2k
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Anyone know the premise of this PCB assembly note?
The assembly note states:
Bake bare PCBs in a clean and well ventilated oven prior to assembly at 125*C for 24 hours.
Why is this necessary?
CommunityBot
- 1
2
votes
2
answers
216
views
Connectors in high volume manufacturing?
How are connectors such as USB handled in high volume manufacture?
Would the panelized board leave room to place these connectors or would the panel be cut apart and the connectors added later. Is ...
- 38.3k
6
votes
1
answer
848
views
How do PCB fabrication houses make PCBs?
I know the different ways of making PCBs at home, but I can't seem to find a lot of information on how board houses professionally make their PCBs. Is this how they do it?: http://www.youtube.com/...
CommunityBot
- 1
1
vote
2
answers
177
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Nomenclature for tested PCB assemblies
I want to unambiguously refer to an assembled PCB that has been tested. I am familiar with the terms:
PCB - unpopulated printed circuit board
PCBA - PCB assembly, a PCB with all the parts fitted and ...
- 416