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SMD on single sided board with Through Hole components? [message #170644] Mon, 05 June 2017 03:11 Go to next message
Augusto Garcia Cinsel
Messages: 3
Registered: June 2017
Junior Member
Hello. I'm new here as well as a new Eagle user.
Going straight to the point, I'm just a hobbyist. I transfer muy pcbs using transfer paper.

The thing is that I now need to use some SMD components on a pcb I'm making that also has through hole components. What I usually do is print the PCB unmirrored and transfer it to the PCB. That way, I can mount the components from the back. That is, solder from the bottom of the PCB. However you want to look at it.
Now that I have SMDs, I need the SMD pad, and only that, to be mirrored at the time of printing so that, when I transfer, it only this is left unmirrored.
But when I mirror a component, Eagle sends it to the bottom layer. And there is nothing I can do (that I know of) to bring it back to the top layer in this state. The only way is to unmirror it.
So basically, Eagle is forcing me to do a two layer PCB when a single layer is more than enough.

I hope I was clear enough... if not please ask,
Thank you!

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Re: SMD on single sided board with Through Hole components? [message #170645 is a reply to message #170644] Mon, 05 June 2017 03:45 Go to previous messageGo to next message
warrenbrayshaw
Messages: 1767
Registered: January 2010
Location: New Zealand
Senior Member
On 5/06/2017 3:11 p.m., Augusto Garcia Cinselli wrote:
> Hello. I'm new here as well as a new Eagle user.
> Going straight to the point, I'm just a hobbyist. I transfer muy pcbs using transfer paper.
>
> The thing is that I now need to use some SMD components on a pcb I'm making that also has through hole components. What I usually do is print the PCB unmirrored and transfer it to the PCB. That way, I can mount the components from the back. That is, solder from the bottom of the PCB. However you want to look at it.
> Now that I have SMDs, I need the SMD pad, and only that, to be mirrored at the time of printing so that, when I transfer, it only this is left unmirrored.
> But when I mirror a component, Eagle sends it to the bottom layer. And there is nothing I can do (that I know of) to bring it back to the top layer in this state. The only way is to unmirror it.
> So basically, Eagle is forcing me to do a two layer PCB when a single layer is more than enough.
>
> I hope I was clear enough... if not please ask,
> Thank you!
>
> --
> To view any images and attachments in this post, visit:
> https://www.element14.com/community/message/223493
>


Hi
Your description is less than clear so maybe the following will help.
Eagle is always a view from the top through the board.

Conventionally, if you were to design a one layer board with through
hole components you would place the components on the top side and
solder on the bottom layer. All your tracks (routing) are on the bottom
layer and hence any SMD will need to be there as well.

So for an SMD on the bottom layer, you need to mirror them. This has the
effect of making then present correctly (pin wise) as you view the board
from the top.

Then you print the lower layer mirrored so its correct for toner transfer.

HTH
Warren



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Re: SMD on single sided board with Through Hole components? [message #170646 is a reply to message #170645] Mon, 05 June 2017 03:51 Go to previous messageGo to next message
warrenbrayshaw
Messages: 1767
Registered: January 2010
Location: New Zealand
Senior Member
On 5/06/2017 3:45 p.m., warrenbrayshaw wrote:

>
> ..........Then you print the lower layer mirrored so its correct for toner transfer.
>
> HTH
> Warren


Woops - mistake!
No need to mirror the print for the toner transfer

You would mirror it if producing a component placement diagram for the
bottom view.

HTH
Warren


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Re: SMD on single sided board with Through Hole components? [message #170758 is a reply to message #170646] Fri, 16 June 2017 00:50 Go to previous messageGo to next message
Augusto Garcia Cinsel
Messages: 3
Registered: June 2017
Junior Member
Thank you Warren. Sorry for the (big) delay. As I said this is my hobby and so I don't have as much time as I'd like for it ...
I understand what you propose. I should mirror the SMDs (they would then be on the bottom layer) and route. Then print the top layer and bottom layer stacked and transfer them to a single-layer PCB.
However, I'd have to make sure no routes intersect between layers...
Here's an attachment that I made to help explain myself. I know I'm perhaps not being clear...
I want to have all the components on one side and route them on that side (perhaps this is not possible).
Thank you for your help!

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Attachments:
Expl.pdf
Re: SMD on single sided board with Through Hole components? [message #170759 is a reply to message #170758] Fri, 16 June 2017 03:14 Go to previous messageGo to next message
warrenbrayshaw
Messages: 1767
Registered: January 2010
Location: New Zealand
Senior Member
...Here's an attachment that I made to help explain myself. I know I'm perhaps not being clear...
I want to have all the components on one side and route them on that side (perhaps this is not possible)...

I think you have made an error in your diagram saying this is what you want and yet in your writing you say "I want to have all the components on one side and route them on that side". The diagram does not show that combination.

So for toner transfer, if you want all the components, both through hole and smd mounted on the top then you design the board with the through hole, SMD and routing on the top layer with no components mirrored and then print mirrored. You will need to ensure all through hole components can be soldered from the top.

If you want all through hole components mounted on the top and soldered to the traces on the bottom and any SMD mounted on the bottom, as they must be when all the traces are on the bottom then. Route on the bottom layer and mirror SMD components to the bottom. Print without mirroring for toner transfer.

HTH
Warren

Re: SMD on single sided board with Through Hole com ponents? [message #170760 is a reply to message #170759] Fri, 16 June 2017 03:47 Go to previous message
Augusto Garcia Cinsel
Messages: 3
Registered: June 2017
Junior Member
> ...Here's an attachment that I made to help explain myself. I know I'm
> perhaps not being clear...
> I want to have all the components on one side and route them on that side
> (perhaps this is not possible)...

Yes I made a mistake there. What I need is really what I drew in the attachment.

And here's the answer:

> If you want all through hole components mounted on the top and soldered to
> the traces on the bottom and any SMD mounted on the bottom, as they must be
> when all the traces are on the bottom then. Route on the bottom layer and
> mirror SMD components to the bottom. Print without mirroring for toner
> transfer.

Thank you!

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