93
votes
Accepted
Why does a commercial PCB need this much rework?
This looks like it's due to a combination of bad engineering, bad management, and cheap labor.
Circuits don't always perform as expected when first designed. Even experienced designers make mistakes ...
- 315k
85
votes
Do dead weight 'components' exist?
Power your board from a 12V 7AH Sealed Lead Acid Battery. Then hot melt glue your board to the side of the battery.
Similar to the ideas shown by @DaveTweed I have mounted prototype parts to a piece ...
- 57.9k
73
votes
Do dead weight 'components' exist?
When prototyping, I often run into the same issue. What I usually do is find a sheet of suitable material that's larger than my board. It can be anything — wood, plexiglass, scrap PCB material, ...
- 178k
42
votes
Accepted
Why use kapton tape?
If you go through all the trouble to test and qualify something, like tape: check it doesn't unstick after a few years leaving glue everywhere, doesn't shrink, loosen, harden, or crack even if the ...
- 81.7k
38
votes
How to secure cables to a PCB
Zip ties are a good way to provide strain relief for cables attached to a PCB. You lay out a path for the cable on the PCB, and put adequately large holes on either side of this path for the zip tie.
...
- 178k
38
votes
Accepted
Connecting 10AWG wires to PCB
My general strategy for dealing with vibrating wires is to provide strain relief. I would consider adding holes in your PCB specifically for wire retention, like in the image below. You can use ...
- 2,281
32
votes
Why use kapton tape?
On top of being a good adhesive, it's chemically inert, thermally stable, and does not off-gas when it gets hot.
- 2,116
30
votes
Accepted
Hand soldering SMD 1206 components
You will likely find that 1206 are actually quite easy to hand solder. When you get used to SMD boards, you will find they are actually quite large.
With a standard iron, I find it quite simple to ...
- 12.2k
28
votes
Accepted
How to remove this component from PCB
You need a lot more solder, so as to cover all the eight contacts and heat them to their melting point. Think "solder pool." Once you pull the component, then you can remove the solder pool using ...
- 929
28
votes
Accepted
25
votes
Accepted
Why are there no BGA chips with triangular tessellation of circular pads (a "hexagonal grid")?
Unless you use via-in-pad, which costs more, you need room to put routing vias in between the pads, like this
- 6,208
25
votes
How to solder a stranded wire to a THT hole of a PCB as shock-resistant as possible
If the pcb is an automotive electronics solution, it should not only withstand slight shocks, it should also withstand vibrations and some harder shocks.
So you should use only those connectors ...
- 2,873
24
votes
What is the silver strip behind crystal in the PCB?
Here's a picture to help you understand better. The crystal's case can be soldered onto boards to secure them.
- 1,780
24
votes
SMD 0402 resistor flipped on its side
It's called "billboarding". The IPC standard is mute on the precise reason, but it notes that billboarding may occur during assembly. That condition is acceptable for all three IPC classes ...
- 23.1k
23
votes
Keeping SMD parts in place while soldering with paste and heat
they suggested was that I use a stencil to apply my paste more evenly. In other words, they blew off my question.
No, they didn't. They gave you correct advice.
If you have a lot of solder on one ...
- 315k
23
votes
Accepted
What are some reasons for hand painted dots on chips?
These are put there during assembly and test of the PCB and can mean anything the manufacturer wants to mark.
Often such a dot is put on a microcontroller, when the firmware is successfully programmed ...
- 9,749
22
votes
How am I supposed to solder this tiny component with pads UNDER it?
You use solder paste and hot air. This component is not possible to solder with a soldering iron.
Note that the word is "solder", not "weld"; welding is a very different process.
- 38.5k
20
votes
Accepted
Identify these wide ended tweezers
Looks like some wafer tweezer
These tweezers are especially designed for the handling of delicate and fragile silicon wafers, scintillation discs, glass slides, coverslips etc.
- 10.9k
20
votes
USB A mechanical orientation?
Yes. The receptacle tab goes on the top.
According to the USB specification, section 6.5.1 there are guidelines on orientation for USB-A receptacles:
6.5.1 USB Icon Location
The USB Icon is embossed, ...
- 1,598
19
votes
How to secure cables to a PCB
Cable ties are great. Just put two through holes in the PCB away from the connector.
There are also a variety of flat tie holders that can also facilitate zip ties. These can be pushed in or fastened ...
- 88.8k
19
votes
Accepted
Can extra long pads cause problems?
No, In fact there are different suggested footprints for hand soldering and for stencil applied paste soldering. https://forum.kicad.info/t/why-different-pcbnew-footprints-for-hand-soldering-smd-603-...
- 843
19
votes
Can extra long pads cause problems?
Short answer: in your case, there should be no problems.
Longer answer:
If you need impedance matching (high speed signals) the size/form of pads can have an influence on the signal quality. But as ...
- 3,842
18
votes
What is the silver strip behind crystal in the PCB?
I wish I could find an image of this, but that is a ground pad.
When mounting larger crystals, like the one shown in Peter's answer, it is normal to bend the leads so the can is laid flat on the ...
- 47k
18
votes
Accepted
Double-sided Assembly
You can find some good and relatively modern information in this document.
WEIGHT LIMITS FOR DOUBLE SIDED REFLOW OF QFNS
Sasha Smith, David Connell and Bev Christian
Although their tests were for ...
18
votes
Do dead weight 'components' exist?
Get some large nuts or bolts from a hardware store and glue them in. Not my invention, these have been seen inside commercial products to make them appear more robust.
- 172k
18
votes
Accepted
Soldering a thin spring steel wire to a PCB
We solder stainless steel from time to time. It needs more heat than I'm really happy bringing to a PCB, and the flux (we use a HCl flux, as you say) will quickly eat the tracks off the pcb if you ...
- 12.3k
18
votes
Accepted
Solder SMD on through hole
For DIY project, no problem.
If you manufactured a large quantity then you'd have to care about having a low number of defects which means taking care of all the details. But for one-off DIY projects, ...
- 81.7k
17
votes
How to solder a stranded wire to a THT hole of a PCB as shock-resistant as possible
A good way (but a bit late now...) is to have two holes for each wire, perhaps a half-inch apart - one large enough to pass the insulated wire, and the second of suitable size to pass the actual ...
- 60.7k
16
votes
Why did Axial Capacitors Fall Out of Use in the Industry?
Single-sided PCBs frequently required the use of wire links to bridge over other tracks on the board. With a suitable circuit layout, the use of axial capacitors (rather than radial) could be used to ...
- 468
Only top scored, non community-wiki answers of a minimum length are eligible