Write some text on PCB

[SnoZek]

Hello,

I got some basic question about PCB :

I want to put some text like that (white text ) do you know how it work ? And how work the varnish ? I never did that before

Does have i to put the varnish before doing text ?

Thank you guys

[Rene_Poschl]

All the white things on your photo are part of the so called silk screen. In kicad simply add elements to the F.Silk or B.Silk layers and then send these as part of your gerbers to the fab. (depending on if you want it on the front or back side of the PCB)

[SnoZek]

Thank you, and does the varnish have an influence ? It’s the fabricant who do the varnish or i have to do something on kicad ?

[Rene_Poschl]

what do you mean with varnish?

[SnoZek]

The green part of the card (on the pictures) for isolation and protection (i don’t know the word in english)

[eelik]

Solder mask

[SnoZek]

My question is : Does i have to do something on KICAD for the Solder mask or i just have to ask it to the contructor ?

[eelik]

What is the meaning of the layers in pcb_new and in the footprint editor?

A pcb is a 3-dimensional object with different materials stacked on top of each other. If a designer talks about designing a 2 layer board then they typically mean that this board has two copper layers. A 4 layer board has 4 copper layers and so on. In addition to these copper layers there are other technical and documentation layers available. A good introductory read is this post by @dchisholm : https://forum.kicad.info/t/any-way-to-make-the-screen-more-understandable/13295/6 In KiCad the f…

If you use footprints which come with KiCad the mask layer is created automatically correctly because pads include solder mask openings. When you export gerbers - assuming you communicate with your contract manufacturer using gerber files and not KiCad files directly - you should inspect the gerber files and check that every place you want exposed copper (mostly pads) have colored area in the mask layer gerber file.

[eelik]

Of course you should do similar inspection for silk screen layer. There are a couple of easy ways to check if the silk screen markings are located properly.

1. Hide all layers in KiCad except front mask and front silk and maybe front Fab layer. That way you can see where pads are (because there are mask layer markings where pads are) and can move silk markings, namely reference designators, elsewhere.

2. Use the 3D view. You can get a realistic view of the board surface. Check that reference designators aren’t under SMD components or on top of vias. Vias may suck the white material and will make it look distorted or or make it unreadable.

With the Mask layer you should note that the generated gerber file (used by the manufacturer) may be a bit different from what you see in the layout editor. You should set two values in Board Setup:

Solder mask clearance: the solder mask opening needs to be a bit larger than pads because positioning of the physical mask layer is inexact. If you use zero the manufacturer probably sets it to a value which is fitting for them, and that’s probably good. Otherwise set it to e.g. 0,051 mm.

Solder mask minimum width: there may be thin stips of the mask material between pads which may peel off and in the worst case go under component pads in the assembly phase. 0.15 mm should be a safe value; KiCad’s default 0.25mm is too large.

[hermit]

@SnoZek

or i just have to ask it to the contructor ?

While you have gotten good advice let me just add the usual bit. Anything you aren’t sure of needs to be asked of the PCB folks. They also do their own checks before making a board and should catch obvious errors. But Kicad should automatically take care of most of the basics for you.