Castellated holes - Limitations on the shape of board

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roddines
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Castellated holes - Limitations on the shape of board

Post by roddines » Thu Aug 09, 2018 1:57 pm

I have read this: http://support.seeedstudio.com/knowledg ... ated-holes

But I am confused if I can have you manufacture odd shapes or if they must be rectangular or at least have parallel castellation.

1. A typical 2 sided castellated board (can simply be repeated in the X-> direction)
--------\/----------\/---------\/----------
|------------------------------------------|
| --------- circuit board ---------------|
|------------------------------------------|
--------/\----------/\---------/\----------

2. 3 sides - I assume one can be rotated and the two non-castellated sides can be panelized (max of two = 4 sides)
--------\/----------\/---------\/----------
|------------------------------------------|
> --------- circuit board ---------------|
|------------------------------------------|
--------/\----------/\---------/\----------

ie sort of like this:

--------\/----------\/---------\/---------- --------\/----------\/---------\/----------
|------------------------------------------| |------------------------------------------|
> --------- circuit board ---------------| |--------- draob tiucric----------------<
|------------------------------------------| |------------------------------------------|
--------/\----------/\---------/\---------- --------/\----------/\---------/\----------

3. More complex 3 sides - I assume one can be rotated and the two non-castellated sides can be panelized (as per example 2 above)
--------\/----------\/---------\/----------
|------------------------------------------|
>------------------------------------------|
> --------- circuit board ---------------|
>------------------------------------------|
|____------------------------------------|
+++++|-----------------------------------|
+++++|-/\----------/\---------/\--------|

Note: Where +++++ is blank space (as this forum/html removes additional repeated spaces)

4. Q1. But can i do something like this more complex 3 sides(with bottom side at two levels)?
and Q2. Can I also panelize this as per 2 and 3?
and Q3. If so, can I do in Fusion or must I use Advanced?
--------\/----------\/---------\/----------
|------------------------------------------|
>------------------------------------------|
> --------- circuit board ---------------|
>------------------------------------------|
|____------------/\---/\----/\----------|
+++++|-------|+++++++++++++|------|
+++++|--/\--|+++++++++++++|--/\--|

Thanks in advance for your reply?

Rod.

roddines
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Re: Castellated holes - Limitations on the shape of board

Post by roddines » Fri Aug 10, 2018 10:22 am

A more specific example is attachedImage
Attachments
2018-08-10 10_17_40-Manufacturing Preview.png
An example of a complex castellation PCB board
2018-08-10 10_17_40-Manufacturing Preview.png (37.39 KiB) Viewed 483 times

carmen.zheng
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Re: Castellated holes - Limitations on the shape of board

Post by carmen.zheng » Fri Aug 10, 2018 2:04 pm

Hello Roddines,

Thanks for your question, it's a very good question but I'll just stop you there for a moment. Manufacturing processes for prototyping and large batch production often differ. Also, while large batch production typically goes unchanged, prototyping processes often change to find the best balance between quality, processing efficiency and cost.

For large batch production, the method stated in the article still applies, but the process for our prototyping service has changed (and we forgot to update this, sorry).

For greater convenience, we now first make the entire plated through hole and then mill them in half. Because copper is a lot harder than the FR4 substrate, the milling bit wears easier and so we need to use high durability milling bits and use a faster drilling speed. This helps produce a clean finish and reduces the chances of sharp burrs being left behind. Regardless, each board goes through a dedicated inspection station for castellated holes where each board (and castellated hole) is inspected and burrs are manually removed.

The result? You can barely tell the difference between the two processes - but more importantly it means there are virtually no restrictions on the board shape since there is no dip plating process.

Hope that addresses your concerns! (and yes, we'll update the FAQ as soon as possible, thank you for pointing it out)

roddines
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Re: Castellated holes - Limitations on the shape of board

Post by roddines » Sat Aug 11, 2018 8:06 am

:D Many Thanks

carmen.zheng
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Re: Castellated holes - Limitations on the shape of board

Post by carmen.zheng » Mon Aug 13, 2018 11:08 am

No, thank you!

We've updated the FAQ accordingly. Feel free to let us know if you find any other problems.

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