Purpose of Various layers in multilayer PCB

[s3034585]

Hi Guys

I am new to pcb design. Can any one pls tell me what is the purpose for various layers used in PCB. there are various signal layers, mechanical layers, overlay layers.
Can anyone pls tell me where can i find some information about this which will explain the purpose/ definations of there layers.....

Thanks in advance
tama

 

[House_Cat]

I recommend you get and read the PCB Handbook by Coombs. See the following forum link:

 

[touringmike]

Every software package has a different layering scheme than it's competitor.

The best way to answer this question, is to read the tutorials that come with the software packages.

If you have a particular package, post the name in your question, such that your question can be answered in more detail.

 

[Khabree]

Hi Guys

I am new to pcb design. Can any one pls tell me what is the purpose for various layers used in PCB. there are various signal layers, mechanical layers, overlay layers.
Thanks in advance
tama

You just consider each layer as a transparent plastic sheet. So your software put track on one layer. The layout (legend) on the other one. The pads on another layer and so on. When all the layer are on, it means you put all the sheets one upon the other. And when you turned off a layer, it means you simply (temparerly pull out that layer) so you can't see the things, which are on that layer.

I hope this will help to understand.

 

[s3034585]

Hi Guys
Thanks a lot for ur replies.
Regarding the software, i am using Altium Designer 6.8.. What i am trying to understand is that what is the purpose of these mechanical layers. In altium designer we have mechanical 1,4,5,13,14,15. Who decides what layer to be used for what. I read a couple of reviews on altium forums also. Everybody uses these layers in a diff manner. Can you pls help me undertand this.

Thanks
tama

 

[House_Cat]

Hi Guys
Thanks a lot for ur replies.
Regarding the software, i am using @ltium Designer 6.8.. What i am trying to understand is that what is the purpose of these mechanical layers. In @ltium designer we have mechanical 1,4,5,13,14,15. Who decides what layer to be used for what. I read a couple of reviews on @ltium forums also. Everybody uses these layers in a diff manner. Can you pls help me undertand this.

Thanks
tama

The mechanical layers are for you to use as you, or your company, require. Altium Designer has a total of 16 mechanical layers (1-16). Some of them are used in the standard library components supplied with the software. For example, some older library components use mechanical layer 1 for component body representation. The newer, IPC 7350, footprints use mechanical layer 15 for component bodies, and mechanical layer 13 for the the component courtyard - that has become the new Altium internal standard for the use of those two layers. The remainder of the layers are up to the user to assign.

I typically use mechanical layer 3 for the board outline, for example. I use mechanical layer 2 for mechanical mounting details and dimensions that I do not want to place on the drill drawing layer. I use mechanical layer 16 for my title block layer. I sometimes "pair" a mechanical layer with the top and/or the bottom layer of the board to illustrate assembly instructions.

The bottom line is that it is up to you how, or if, you use the mechanical layers. There is no mandatory assignment required.