DIfferences with a normal finished PCB:
This is a rough introduction about the “unfinished” quick PCB service (Let’s call it UQ-PCB in the following text), what it is? From the meaning of the name, it is not-yet finished, the board have these following differences with normal “finished” board:
- No solder mask and silk print on the UQ-PCB, looks rough.
- The vias and soldering pads are not metalized, which means the top side and bottom side are not connected. You will need connect them in your own. For this reason, make a simple single layer board will be more suitable for this technique.
- That’s it, two different points.
So here is how it looks like in real(UQ-PCB on the right), this is very similar to the board we made at home:
With these disadvantages, why it is still exist, well, things exist always for reasons, it has following good points:
- Very fast: normally factory will finished it in 24 hours or less, normal a fully finished PCB take at least 4 workdays, save you a lot of RD time.
- Cheap: we will only make 2 pieces for prototype, the price of a 5*5CM PCB will be 2 USD/2pcs, and a regular fully finished PCB takes at least 12 USD for 10pcs.
More details of a UQ-PCB:
Now finally the manufacturing limits:
We “guess” this manufacturing limits are caused by the manufacturing methods, this UQ-PCB is made via photosensitive exploring technique, using the UV light to remove the unused copper layer from the copper board, but normal finished PCB are made via either CNC milling, or maybe laser cutting sometimes, so in conclusion, the UQ-PCB made by photosensitive exploring technique can not have the better precision of a normal finished PCB.
If you are going to try, here is the differences:
- Single layer or dual layer
- Trace width and trace spacing – 0.25 mm / 10 mils (6 mil for a finished PCB)
- Soldering pads – 1.5 mm / 60 mils (don’t know, or not really limit this)
- Drillings – 0.6 mm / 24 mils (0.3 mm / 12 mil)
If you want to know how to try this, please contact us via email, firstname.lastname@example.org. Thank you.