Hi,
What’s the layer spacing on the 4-layer boards? I’m talking between 1 and 2, and between 3 and 4.
Looking to do something with controlled-ish impedance “for kicks” 
Thanks,
-Randy
between 1 - 2 = 12 mils
between 2 - 3 = 28 mils
between 3 - 4 = 12 mils.
Jonathan
Can you route traces and split planes on the inner layers with the BatchPCB service, or are you limited to solid planes?
Thanks!
~inobla
Do anything you want on the inner layers.
Cheers,
–David Carne
Awesome! I hate asking questions if the answer is somewhere nearby already...but it appears the *Rules and Limits* section of your BatchPCB FAQ is a bit out dated.Do anything you want on the inner layers.
Thanks for the reply. I look forward to doing a lot more business with SFE!
Do all vias go all the way through the board? Or can you have hidden vias? I’m given this option in Altium Designer but I don’t know if it exists in Eagle since I don’t use it.
Also, are orders rounded up to the nearest square inch? At $8 per square inch, this could get very expensive very quickly…
Krogoth:
Do all vias go all the way through the board? Or can you have hidden vias? I’m given this option in Altium Designer but I don’t know if it exists in Eagle since I don’t use it.
Greetings Krogoth,
Vias between inner layers, that don’t penetrate the outer layers are called “blind vias”. I have not done anything beyond two layers with BatchPCB or EAGLE.
Krogoth:
Also, are orders rounded up to the nearest square inch? At $8 per square inch, this could get very expensive very quickly…
Yes. When the BatchPCB service started there were some customers trying to get exactly 1.000 square inches, because a minor error in size doubles the cost. This illustrates the offset applied by EAGLE to keep the active board area away from the board outline. You can fiddle with the XY offsets during the EAGLE CAD job, and then try running the project past the BatchPCB bot - if it’s important to your design.
The $8/sq inch includes electrical testing - important for multi-layer boards. The two-sided board service is “no touch” meaning only cursory visual inspection is done. They usually catch gross errors (missing or faded silk-screen) and replace defective boards.
Comments Welcome!
The $8/sq inch includes electrical testing
Wow. I didn’t expect that. Now I’m even more interested
I have some ideas that I want to do in the future that WILL need more than 2 layers for routing. Think a 5x5 mm miniBGA package with 256 balls. makes me shudder just thinking of the time I’ll spend routing. Though I’m not sure BatchPCB will be able to handle something like that, its quite the complex job. Course this is far far in the future for me, I’m still a beginner.
The E-test is why the 4 layer boards are so expensive. We could offer a service without, but due to the way we batch stuff up - its either all tested, or none.
Essentially, if you can fit it within our design rules, we can build it.
Cheers,
–David Carne
Is the clearance and trace thickness and hole size from the two layer option the same with the 4 layer option? I’m kinda using some really small components on a current project.
You can get away with 7/7 + 15 mil vias on a 4 Layer project.
Cheers,
–David Carne