Arbitrary Pad Shapes

On 4/1/2013 12:29 PM, Dave Wills wrote:

Hi,

 

Last June, I posted about arbitrary pad shapes.  I was eventually able to

solve my problem and go to fab on my board.  There were 2 problems which

apply to the new issue I describe below.  One is line width and the other

is placement of the arbitrary pad shape on the final layout.

 

My new issue is I'm using a device which has through holes which are

basically rectangles with rounded corners.  I can create the hole using the

milling layer as described in the manual.  The problem (again) has to do

with the arbitrary pad shapes.

 

There are a couple of issues:

 

- In my previous post, the device was an SMT so a single pad wasn't a

problem.  But my board is 6 layers.  It seems (to me, a complete Eagle

novice) that this is a big deficiency in Eagle.  The reason is you need to

create the pad in each layer, making lots of work.  Another big problem

with this is the pad is not associated with the library part.  So if you

move the device, you need to move the pad in every layer you've built it.

Wouldn't it be better to build the pad in the library part itself and then

have Eagle place the pad in all the layers, as it does with "normal"

devices?

I'm a little confused by the above. If you have a surface mount part

then the SMD pad will only be on the top or the bottom it doesn't need

to be drawn on the other layers.

In the case of a through-hole pad, if you need a weird hole shape or a

weird pad shape then you use the milling layer to make the whole shape

and then use polygons to make the arbitrary pad shape on top and bottom

that it. When the board house plates the the modified hole it will

connect to whatever inner layers it's supposed to connect to, so you

don't have to draw polygons on the inner layers.

This is all handled in the library, nothing has to be done on the board.

The pad will follow whenever you move the component, and keep in mind

that I'm assuming V6 here.

 

- Line width is still an issues.  It seems that since everything inside of

the lines of the pad are the pad itself, then zero width lines should be

allowed.  Then you could specify the outer limits of the pad, preventing

the pad from encroaching on other devices, without having to calculate how

far outside the line the pad goes, or whether the line width is going to

violate the design rules.

When defined in the library EAGLE will maintain the proper clearances

without your intervention.

 

I expect that any responses to this will essentially be "Yeah, that's the

way it is.  Deal with it."  But any advice on how to make this easier would

be greatly appreciated.

 

Thanks!

 

Dave

 

Hi Dave,

See my responses in line above. Let me know if there's anything else I

can do for you.

Best Regards,

Jorge Garcia

Hi Jorge,

Thanks for the reply.

Yes, I'm using version 6.4.

Yes, for an SMD I was able to do what I needed.

For the odd shaped through-hole, I am able to create the hole with the

milling layer.

I can create through-hole pads of various standard shapes.  If you do info

on through-hole pads, it just shows the shape with no information on

layers.  You can't create arbitrary shaped through-hole pads.

SMD pads can have arbitrary shapes.  You can specify which layer the pad is

on.

So maybe this would work:

- Create the odd shaped hole in the milling layer, as I'm doing.

- Create an arbitrary shaped SMD pad for the top layer.

- Copy and paste that SMD pad and change to the bottom layer.

Would that solve the problem?  If that's true, then this isn't as bad as I

thought.

Thanks again.

Dave

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On 4/10/2013 2:23 PM, Dave Wills wrote:

Hi Jorge,

 

Thanks for the reply.

 

Yes, I'm using version 6.4.

 

Yes, for an SMD I was able to do what I needed.

 

For the odd shaped through-hole, I am able to create the hole with the

milling layer.

 

I can create through-hole pads of various standard shapes.  If you do info

on through-hole pads, it just shows the shape with no information on

layers.  You can't create arbitrary shaped through-hole pads.

 

SMD pads can have arbitrary shapes.  You can specify which layer the pad is

on.

 

So maybe this would work:

 

- Create the odd shaped hole in the milling layer, as I'm doing.

- Create an arbitrary shaped SMD pad for the top layer.

- Copy and paste that SMD pad and change to the bottom layer.

 

Would that solve the problem?  If that's true, then this isn't as bad as I

thought.

 

Thanks again.

 

Dave

 

Hi Dave,

Your process is almost correct. Instead of starting with an SMD you

start with a regular through-hole pad in the library. This gives you the

foundation for a drill hole that can connect to all of the inner layers.

You create the arbitrary through-hole pad by drawing polygons on top and

bottom which extend the default pad to whatever shape is necessary. If

instead of a circular drill you need a slot, then you can add features

in the milling layer to get what you want.

This process gives you a custom through-hole pad that can connect to any

of the internal layers.

Let me know if you need any further clarification.

Best Regards,

Jorge Garcia

On 4/10/2013 2:23 PM, Dave Wills wrote:

Hi Jorge,

 

Thanks for the reply.

 

Yes, I'm using version 6.4.

 

Yes, for an SMD I was able to do what I needed.

 

For the odd shaped through-hole, I am able to create the hole with the

milling layer.

 

I can create through-hole pads of various standard shapes.  If you do info

on through-hole pads, it just shows the shape with no information on

layers.  You can't create arbitrary shaped through-hole pads.

 

SMD pads can have arbitrary shapes.  You can specify which layer the pad is

on.

 

So maybe this would work:

 

- Create the odd shaped hole in the milling layer, as I'm doing.

- Create an arbitrary shaped SMD pad for the top layer.

- Copy and paste that SMD pad and change to the bottom layer.

 

Would that solve the problem?  If that's true, then this isn't as bad as I

thought.

 

Thanks again.

 

Dave

 

Hi Dave,

Your process is almost correct. Instead of starting with an SMD you

start with a regular through-hole pad in the library. This gives you the

foundation for a drill hole that can connect to all of the inner layers.

You create the arbitrary through-hole pad by drawing polygons on top and

bottom which extend the default pad to whatever shape is necessary. If

instead of a circular drill you need a slot, then you can add features

in the milling layer to get what you want.

This process gives you a custom through-hole pad that can connect to any

of the internal layers.

Let me know if you need any further clarification.

Best Regards,

Jorge Garcia

Hi Jorge,

I think that's probably close enough.  My pad is actually rectangular with

4 radiused corners.  I could probably make the pad larger than recommended

with no impact though.  The slot is the same shape, just 0.4mm smaller than

the pad.  I did the slot with arcs and lines then setting the milling

layer.  I assume I can do the same with the pad, one top and one bottom.

Thanks again,

Dave

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