What color is the solder mask that OSH Park uses?
All fabrication services All our services offer purple soldermask over bare copper (SMOBC) and an Electroless Nickel Immersion Gold (ENIG) finish. These are suitable for a lead-free reflow process, and are RoHS compliant.
How much solder mask expansion?
The solder mask expansion standard is 4mil. In practice, things never align perfectly. The actual holes punched in the solder mask may be slightly less than what you specified (“shrinkage”), and the holes are always be placed in a slightly different location than what you specified (“movement”).
When should you not tent vias?
Tenting vias is not the most effective method for covering the via. One downside to tenting is that since the solder mask used is liquid, there is the chance of the LPI breaking and creating small holes in the tent. That small hole can trap in moisture and chemicals that can cause corrosion and damage the PCB.
Should I tent my vias?
Tenting is best used on small vias with a finished hole diameter of less than about 12 mil. The specific diameter limit depends on the LPI solder mask solution, and your fabricator should be able to recommend a maximum via diameter to ensure reliable tenting.
What is purpose of solder mask?
Solder mask is a thin layer of polymer that is put on a circuit board to protect the copper from oxidation and shorts during operation. It also protects the PCB from environmental influences such as dust and several other contaminants that may lead to shorts in the long run.
How big should the annular ring be?
Generally, the sweet spot for an annular ring’s diameter is 0.25mm. If you are unsure how big to make your via, you can always fall back on this size. However, the PCB house will usually specify the minimum size for a via or annular ring. Your annular ring should at least be this size or larger.
What kind of file is GBL?
Data output file created by Printed Circuit Board (PCB) CAD tools like Altium Designer and used by PCB manufacturing machines to designate electrical connections; contains data for multiple layer boards about the layout for bottom copper layers; similar to the .
Should vias be covered with solder mask?
Soldermask on Via Holes There are 3 ways our customers prepare their layouts with respect to covering via-holes with soldermask: Vias open (not covered by soldermask) on both sides of the PCB. Vias closed (covered with soldermask) on both sides of the PCB.