Blind Via virgin

[thompse]

I'm about to embark on a new voyage, the realm of blind vias. Can anyone offer some general guidelines? More specifically, how the heck do I document these suckers on a fabrication drawing?

TIA

[phillipr]

Documenting blind vias is relatively easy to do.
Make sure each of your vias has a different drill size (even if the top and bottom vias are the same size.
Then reference to the drill sizes on your drill drawing. for example

Blind via: layer1 - layer 2 =5
Blind via: layer12 - layer 11=6
standard via: layer1 - layer 2 =12

You might want to have 2 seperate drill drawings aswell.

Any more questions let us know.

[thompse]

I'm sorry to be so dense, but I'm not picturing what you're saying. Do you have an example of a fab. drawing you could share with me? A picture is worth a thousnad words and right now I need a lecture.

Scott

[randychase]

I think Philip's idea is this....a workaround of sorts. You create different drill size for each paired combination and then call out the layer pairs for each drill. There would not be a graphic representation of each layer pair as far as sheets of the drill drawing.

Note, this is something we are working on handling with a new DXF translator that will generate separate sheets for drilled layer pairs. But it's a few months off yet according to the programmer.

[phillipr]

I cannot give out any of our designs to show you so
I have crudely modified the preview PCB to look at.

areas to look at are

1. Via in pad and fanout under the component
2. drill Pairs and via padstacks
3. build drawing noting the drill sizes (buried vias are not on this pcb)
4. Cam files – drill drawings and nc drills for each via


Took a bit longer to do than i thought,
like everthing ;)

[phillipr]

Darn

Randy

I tried to attach the pcb but when i downloaded it i could no longer read it.
Where did i go wrong?

[phillipr]

i'll try it zipped

[phillipr]

Nope didn't work either
when i submit reply it doesn't change page
I left it for 10mins and still nothing
the file is small so it shouldn't be a problem

[randychase]

Something is corrupt in your Zipped file. Not sure why.

Try emailing me the pcb file directly. I will check it out. The PCB file is 203k which is over the upload limit for messages. The Zip file is under the limit.

randyc2@cox.net

[randychase]

By the way, we will be setting up a user FTP site soon, so that will make things like this a lot easier.

[thompse]

Phillip,

If you want to, you can email me the .pcb file directly at thompse@grayson.com. Thanks again for the response.

Scott

[randychase]

The download attachment files are now working in the previous posts.

[thompse]

Thanks for the info. Phillip and thanks for posting it Randy.

Scott