thank you very much Joan
just being bit extra care full before doing a PCB design
1 more questions:
1). how will the PCB fabricator know that he has to place so and so component on so and so foot print and its pin1 begins from this side/direction(either up,down,left,right) ?
for example this led
does the fabricator make out the direction from the silk screen layer and the REF** would actually be replaced by what is in the schematics is that correct ?
fabricator ?
assembly house will need to have the fab layer
or they will never mount your boards
you will have to hand solder them at home
ok assembly house
most component footprint by kicad do not have fab layer 
like the LED above
and just now Joan said fab layer is for our own ease
Unfortunately notā¦ have a thorough read here as you will be in a lot of head scratching for the next 2-3 weeks till you digested all of this and took appropriate measures and actions to get your part of the work done properly, so the assembler isnāt left alone and delivers what you want:
https://rheingoldheavy.com/category/education/kicad/
In particular:
KiCad BOM Management Part 1: Detailed Components
KiCad BOM Management Part 2: Clean Exports
Design for Manufacture in KiCad Part 1 ā Assembly
Essentially, if what you wrote about that LED is what you thought, you will be in for a big surpriseā¦
joan is wrong, hehe
if you go to assembly house you are dead meat without fab layer (assembly layer in rest of the world)
see my example of led.
the bar shown with red arrows is a must for them to know
also note the use of A and C for pad-numbers to avoid errors and missunderstandings between symbol and footprint
Oh, sureā¦ but if he doesnāt have a BOM that comes out of the schematic/libs he doesnāt need to worry about the Fab layer.
If the assembler is hand soldering he might be ok with a list of devices and the fab layer alone, if the board is not too complicatedā¦ if a machine is to do it, it will be better he follows the RH guides I linked up there.
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BOM is also mandatory
preferably in excel
sorted on refdes
hi nicholas
can you give me its kicad_mod file i will check what all layer you have for this led
i do not get why Kicad standard foot print skip these layers
i draw every single footprint myself
i never use kicad footprints
this led is in my osram library and only used for osram leds
i never use generic footprints even if this one looks to be that, but its only used for osram
if i where to use everlight i draw a new one according to their datahsheet and keep it in everlight library
i once made a lot of pulls (uploads toward kicad github) they got all rejected
i stopped that
OSRAM_0402.kicad_mod (1.7 KB)
because they all solder in the kitchen
I can see now why the Fab layer makes sense to have it for the assembly house now this REF** also present on the fab layer is this automatically copied from the schematics
Check with your board fabricator. I believe the most common practice is to provide a Gerber layer showing ONLY the edge outline. (They may also ask for internal cutouts to show on the same layer - i.e., everything that will be cut by a router bit in the final manufacturing step.)
Some of them may still ask for the board outline to show on some other specified layer, or even on all layers.
The assumption is that the board outline will be routed to the center of the lines defining the edge contour (plus or minus a tolerance), though in the past it was sometimes done to the inside edge of the line.
Dale
Yes it is.
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oh ok 
thanks nicholas and Joan for the help may be i need to fill all components with fab layer
In this LED footprint the Fab layer is touching the copper pad does that not affect the pad or is it ok
hi Joan in this diagram the F.Fab(yellow lines) is there any measurement you followed or just by looking at it you made a rough estimate?
hi nicholas
Questions:
-
Is there any standard height, width and thickness size for the reference designator on the Silk and fab layer so that it (Text) is visible on PCB and visible for the assembly house. for example 1mm height and 1mm width and 0.15mm thickness ?
-
i have attached this footprint with the Fab layer and silk layer present the datasheet for this device is http://www.mouser.com/ds/2/77/CM200C_250C-410.pdf
-
now the 4 yellow lines that go through all pads i just draw without any measurement just by looking at the SOLDER PAD LAYOUT in the datasheet can some one please tell me what must be length of the yellow lines or is it fine to draw an estimated line ?
please find my attached kicad_mod file
Crystal_SMD_4Pads.kicad_mod (2.3 KB)
- also what must the minimum yellow line thickness for the assembly house ease of visibility?