Well i can not tell you what you need. I told you their function. Now you must decide if you want the features connected to them.
OK, at least I’m aware. THanks Mike
Rene already told the basics. I can add some practical notes which are not binding in any way, just my own preferences or experience.
Don’t draw on Silk layer on top of holes, pads or solder mask openings. Also keep some clearance from edges of holes, pads or solder mask openings to silk. This way the silk on your board is readable and nothing is messed up. After the layout is done I check the silk layer by turning off visibility of other than silk and mask (top) layers. Then I move references to nice places. Then I check with the 3D view, it shows quite nicely if silk is on top of a via. That may also make text or line messy if the size is small.
Use the actual component dimensions for the Fab layer outlines. If you mark polarities of components etc. in some way there in the footprints - pin 1 is already marked in many components in the official library - you can use it also as a chart when manually placing parts. I have even printed it to paper, but it may require resizing when printing. References and values may have to be resized for this.
Courtyard is something which you have to learn by making several boards, unless you follow some generic guidelines. You don’t have to care about +/-0.05mm differences. Very often pick’n’place machines can handle much tighter layout than the official library’s courtyards, but you can’t count on that, and you have to know what kinds of components allow which kind of courtyards. If you solder manually you just have to experiment to know what you can do. You may even learn to do the layout without the courtyard layer at all.
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Look to me because pick and place machine are operating by suck action, spacing between components aren’t issues. Only if you plane to to reword, and hand soldiering is the problem. And I think if courtyard can be configured base on % of the components high would be very help full. For example, if courtyard is extended 26% of part high from part body + thickness of your solider iron. This should guaranteed you to have an open space of 30 degree (+/-15 degree from straight down to the board) for soldiering without having trouble with surrounding parts (specially the tall one).
Using height would also require knowing from which direction the iron comes. It doesn’t make sense to create large courtyard around, say, a high capacitor, if all other components are 0.5mm high. Therefore the needed courtyard is highly (excuse the pun) contextual.
@eeik
Using it as guide, not rules will be better than eye bowling at them, don’t you think?
Also don’t you think you will having trouble with small SMD component around the tall cap? It would be very hard after you have that cap installed, and reword small component around it. I think the simple and stupid visual guide still better than nothing or a guessing by looking at the image on the screen.
I’m sorry, I don’t undersand that. But what comes to courtyards, I would just let them be as they are and use existing guidelines when drawing new ones. Then I can estimate the needed room by looking at the 3D view and move the components accordingly.
The problem with height affecting courdyard is that it’s very dynamic, contextual, depends completely on the situation and changes when you move components around. The height of the component itself doesn’t affect its own courtyard at all, it’s the heights of the neighbouring components which affect it. And because it depends on the positions of the components you just can’t draw a courtyard around a component when creating the footprint. Some kind of contextual courtyard would be very different thing and should be created dynamically.
I think you see courtyard differently.
That’s right, Rene. I’m talking about the courtyard which is “hard coded” to a footprint. That just can’t take account the other components in any given layout.
@eelik
I think you misread what I said. The court yard make in footprint should be fixed with whatever space you need. I’m talking about the pcbnew take original court yard from the footprint and add a boundary that can be configurable. Just like configuring trace minimum spacing, minimum trace with. It is dynamic, and depend on the need of each person project, but the courtyard from footprint never need to change.
Yes, I see now that you are talking about a different feature.
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Don’t you think that footprints like LQFP-44_10x10… should have changed their outline on courtyard?
From time to time I put some elements near LQFP corners (inside current outline). But my PCB software DRC didn’t checked it. If it is checked I think footprints would be more coherent with software if just not couse DRC complains if such solution is used.
I am using a distance about 10mils betwean small elements (0402) pads and its courtyard and about 15mils for bigger parts (0603 … electrolytic capacitor of 10mm diameter and more). And freaquently close to electrolytic I have 0603 100n as pararell to them and 0603 ferryte beads close to them. 0603 are assembled first and electrolytics last. I see no problem it they are close to each other. During last 30 years I don’t remember any situation these small elements among electrolytics had to be changed or any other work do to with them.
I assume, you are the very good designer :-). I use to have reword/change small components around tall one many times. Since, I can’t not have my hand soldering stay contact for 1 years (specially the high current one, or the very sensitive circuit down to uVolt levels).
I have written “I don’t remember…”. That can mean I am old enough to just not to remember 
My designs are mainly devices powered from 12…24V. Each PCB has typically only 2 electrolytics in CLC filter of power supply. However you put 2 electrolytics and some small components around them you will have really no problem with acessing that small components (if needed). L can be the third big element in triangle, but if really set in triangle close to each other there is no place among them for small elements and elements around them are easilly accessible.
But what could have happen there you would have to do something with that small elements. The 0603 100nF are for 50V so no chance to be damaged by overvoltage (at front there are 33V transils). The ferryte beads has very small DC resistance. To be damaged by too high current that current have to be really high. My devices consumes typically 0.05 … 0.3A so I often have 0.2 to 0.5A PTC at power input. Even if there would be any short in PCB (not happens) I think only PTC will be hot.
If my devices would be of different kind I would probably have different experience.
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