To generate correct Gerber files always have been considered as kind of black magic, or something
very hard, which peoples learn after years of designins boards. The truth is that it's piece of cake
when you done it once correctly, and to tell you under secret we have seen many bad generated
gerbers/pcb files coming from huge companies and from peoples who have been involved for 20+ years in
the PCB design and production, so it's not how long you have dealt with this, but if you had good tutor
who to tell you what and how to do :) once you learn if wrong way you can continue to do it wrong way
- Where I can learn more for RS274X Gerber format?
- Excellent source is available here.
- My CAD have option to generate the pads as donuts, is it OK to send my files this way?
- No, please don't send pierced pads gerbers, they look good on your monitor, but are not good
- What is Composite gerbers and negative plots, how bad are they for my design?
- Composite layer is ancient way to generate your copper pour. This is still used by old CAD
software which don't have copper pour hatch stroke filling. Why is bad...pictures
- Should I check my Gerbers before send them for production?
- We highly recommend you to check always your generated gerber files with gerberviewer before
send them for production. This will save you money (wrongly generated files which lead to
production of board with errors) and time we check your gerbers only once per day, so if you
submit wrong files we'll report and if you submit new files will check them next working days.
- What is the minimum apreture I can use in the gerbers?
- Please don't use under 8 mils line widths in your Gerbers on the copper layers. Basically you
can use any line width size to fill your copper polygones, but practice shows that if the stroke
width is under 8 mils and the CAD program doesn't generate hatch filling simple stroke to stroke
filling the quality of the phototools printed is bad. Many CAD programs have 5 mils or 1 mils
line width for copper pour set by default so you have to check your settings as we'll put your
order on hold if your copper pour is made with under 8 mils stroke width.
- I designed my board in Inch (mm) units, in which units should I export my Gerbers?
- Always export your gerbers in the units you designed board to prevent rounding errors in your
Gerber generation due to the unit conversion.
- What is good number precision for gerber generation?
- 2.4 or 3.4 is OK. Some CAD products have default precision 4.2 or 2.3 which is pretty bad for
dense boards as the XY coordinates will be rounded to second digit after the decimal point in
- My CAD ask me if I want to add offset to XY when I generate my Gerbers, what number I shuold set?
- Please use offset 0,0 if you add large offset it will do nothing but make your XY coordinates
bigger and there may be errors due to rounding or to exceed maximum number which could be
present by the selected the precision.