For better placement, i understand for have a better routing, he is recommanded to gap in your component in mils and not in mm because is better for place tour trace enter pins. I moove my components with my grids in mils but my propriety placement X: 22mm Y;25 mm is in mm. In kicad 8.0.0 is possible to change propriety in mils ? And is it a good idea ?
In this screen exemple i moove my footprints with the propriety for have the same gap enter my component and i understand isn’t good to moove in mm because after my track can’t be exactly be enter two pins of pitch of 2,54 mm, without use a little grid. So i moove in mils with mm. And it’s not easy to know if i’m close to mils in rounded number or not. And for this, i prefer be in mils for this application not for hole or my edge cut.
If the pitch is 2,54, 1,27mm, the pitch is rounded number in mils. I believe for the placement is better to be in mils too. I can moove my grid or be less strict with my placement.
My question it’s: Is it possible to change unit in mils of my propriety ?
And I’m curious of your opinions about how you place your component on your board, what is your method, your criterion ?
I live in the EU, so I do nearly everything in metric. Except footprints and connectors that have a (historical) 2.54mm pitch. For those I always use a 2.54mm grid to maintain compatibility with matrix board.
Internally KiCad always works with metric (32 bit integers) on a nano meter resolution. It does not much matter which units you display in the PCB editor.
I don’t understand exactly a question.
When in 2017 I moved to KiCad I decided to have PCBs in mm (in previous program I used mils).
Internally KiCad counts everything (at PCB) in um (or nm - I don’t remember).
So I don’t know where from recommendation to use mils can come.
You use the term “components” which causes confusion.
When discussing Schematics, please use the terms “symbols” and “wires”
When discussing PCBs, please use the terms “footprints” and “tracks”
In this screen exemple i moove my footprints with the propriety for have the same gap enter my component and i understand isn’t good to moove in mm because after my track can’t be exactly be enter two pins of pitch of 2,54 mm, without use a little grid. So i moove in mils with mm. And it’s not easy to know if i’m close to mils in rounded number or not. And for this, i prefer be in mils for this application not for hole or my edge cut.
If the pitch is 2,54, 1,27mm, the pitch is rounded number in mils. I believe for the placement is better to be in mils too. I can moove my grid or be less strict with my placement.
My question it’s: Is it possible to change unit in mils of my propriety ?
And I’m curious of your opinions about how you place your component on your board, what is your method, your criterion ?
Yes, it’s possible and easy. With these three icons (from your own screenshot!) you change the display coordinates in the PCB editor.
This really does not matter very much at all. Internally the PCB always uses nanometers (which is a quite small measurement) and for track width and clearances, you shouls set up your design rules and net classes properly. And when you have done this preparation properly, you can just rely on DRC. The things I put on a mill grid are mostly for matrix board compatibility (I mostly do one-off hobby level tinkering). KiCad works quite easily with off-grid pads, and even rotated footprints (sometimes beneficial for routing wires) is nearly as easy as “straight forward” as right-angled placement.
I have all footprints defined with Courtyard rectangles in 0.1mm grid.
The only exception I remember are terminal blocks having 5.08mm (3.81mm) raster. Their left and right rectangle lines are in 2.54 (1.27) grid while top and bottom lines are in 0.1mm grid as all others.
For a case (DIN rail) I have at graphic layer drawing showing me exactly the positions for 5.08mm terminal screws so I position terminal blocks according to it.
The other footprints I group (outside PCB itself) by function blocks and in each group I position them (if possible) touching each other with their courtyard rectangles and route the groups. I work with 0.1mm grid. That way each group is as small as possible. Then I move all groups inside my PCB and route connections between groups.
