Importance of Grid on the Layout?

[pal]

Hi,
Just wanted to learn from your experience what grid size should be used for footprint design, Layout, Placement, Routing ?
are they should be used different sizes for each of three operations ? or use same for these type of work?

it would be interesting and helpful if you can share how it helped your efficiency with the use of grid setting !

[robertferanec]

This is how I normally do it:
- footprint design: as required (depends on datasheet, units, sizes)
- placement: placement of big components e.g. 1mm, placement of small components 0.1mm
- layout and routing: I try to have vias on 0.1mm but for drawing tracks I can use also a smaller grid

In my opinion I try to use grid where it may help machines the improve accuracy e.g. placement machines, drilling machines etc. If there is no machine required (e.g. etching lines), I believe grid is not really important. But that is just my opinion.

[pal]

Thanks for sharing your thoughts Robert !
my experience
I work in inches/mils so I use 5 mils and 10 mils for routing and placement and 1 mils for footprint. But while routing traces I noticed that trace is not always align with from IC pin to say capacitor pin there is times jog in a trace, so I end up using 1 mils for placement as well but it takes more time in alignment to fix jog issue, did you experience similar ?

also how about schematic is it same 40/4 mils settings ?

[goncaloc]

For schematic I always use 100 mils grid and 50/10 mils for symbols.
For PCB I usually use a setup pretty much like robertferanec , the only thing is , if routing a mils component with lots of pins I change the grid on the components area to mils.

[pal]

Thanks for sharing your experience !

[qdrives]

For another viewpoint (high current, thicker copper, microcontroller, etc).
- Components: preferred 1mm, option 0.5mm
- Traces: preferred 0.25mm, option 0.1mm
- Via's: centered on the trace, for stitching: 0.5mm
- Text (designators): 0.1mm
- Schematic: 100mil, unless small needed (ie zener diode)