Plated-through square custom forms

[lurgaci]

Halo, I have very similar problem to a question posted in other thread about an oval plated hole:

https://forums.autodesk.com/t5/eagle-forum/custom-plated-oval-hole-for-usb-micro-b-connector/m-p/695...

as what i need is a plated-through square, and in a close future other custom forms done in EAGLE.

I have usually made this as follows:

• Square via with smallest hole of the pcb manufacturer (0.35mm)
• Milling 0.01mm on layer 46 close to the external of the via (photo attached)

But should be a better way for a plated thru-hole square, right?

Pcb´s manufacturers after a few mails and up to a week, agree to do this forms but with lots of confusion,

but the minimum hole on pad confuses them and slows a lot the pcb manufacturing process.

Does making a library with 2 pad (top/bottom) and a milling, makes a platting connection?

I finally would like to learn to do it on a proper library,  establishing proper clearances by using the power of eagle.

I have good experience on ealge and eagle library making for HF/RF.

How would you suggest to do this?

Big thanks in advance!

[C.Nicks]

Hi Lurgaci,

Custom plated shapes should be supported by most houses, although there is no standard way of calling it out. What I have done previously in my own designs is used the layers 33 & 34 (tFinish, bFinish) to show where plating goes. Make sure to create a separate gerber for it and attach instructions for your board house to follow.

Remember that creating a true square cutout is not possible with standard board routing tools. You should ask your board house what their smallest routing bit is and that is the tightest you can make the corners. Use the MITER tool to round the inner edges to the smallest router bit supported. You may be able to find a fab house that can laser route to get very tight corners, but you'll usually pay extra and the board thickness may be limited.

In the example library part attached, there are SMD pads placed on both the top and bottom layer. Then the milled out hole is drawn in the milling layer. To show that the structure gets plated over, there are rectangles drawn over the pads on the tFinish and bFinish layers.

The example library part I created is for sample purpose and has not be tested with a board house. Please check with your PCB provider that this method is acceptable to them and that the documentation is clear.

The attached pictures show custom edge plating through a rounded slot, with the plate coming from the bottom and only extending to the top edge. This was a custom RF structure for an antenna.

I hope this helps.

- Cameron

[lurgaci]

Halo

Thanks for your answer Cameron.

a

It seems that I will keep doing the same way and as you menthioned adding the idea of the T/B finish layer comment.

Not sure 100% if i get correctly the "there are rectangles drawn over the pads on the tFinish and bFinish layers" sentence...

Does this method get easy to follow by the board house you choose? Os also you get some back and forth messages?

As I´m using now pcbshopper or similar search engine of pcb manufactures to get the best price option for specific short runs,

ususally delays my work...

thank you again!

Have a great week

/l