topic How do I make a negative of these PCB traces in Fusion Electronics Forum

How do I make a negative of these PCB traces

coyt.barringer — Wed, 11 Dec 2024 01:02:08 GMT

I'm trying to simply make a body that is a negative of my copper PCB traces. I have a Fusion 360 electronics design that I pushed to 3D, then I imported the 3D board model into a new Fusion 360 design. Hiding all the layers except the copper layer, I want to make a new simple rectangular body in the design then extrude cut into it using the copper bodies as reference.

For some reason I can't do this. Fusion360 is grouping the copper traces into weird arrangements and the only way is to select hundreds of individual bodies and extrude each individually - not an acceptable solution.

I need to do this so I can export the singular "negative" body to a 3D printer utility to make an etched PCB on a SLA 3D printer.

Re: How do I make a negative of these PCB traces

coyt.barringer — Wed, 11 Dec 2024 01:23:53 GMT

Not ideal but I figured out a workaround.

I think the issue is that the copper bodies looking down onto the top surface of the PCB are for some reason different heights - as in SMD pads are at a different height level than traces or something. So it doesn't know how to handle extruding up from multiple different height surfaces at the same time?

I figured a workaround by doing everything from the bottom of the top copper layer. It's all flat on the bottom. I still had to select multiple of the isolated trace "bodies" but it at least let me extrude cut up all at once through a different body.

The other issue i'm having (might need a separate thread) is how to export a "body" that is really multiple isolated bodies. In this design, my outer ring is a copper ground ring but it causes the design to have multiple isolated bodies when you go to the make tool to export as STL this causes issues. I need this design to show in this manner on the lightbed of a SLA printer for exposing copper boards though - so if anyone knows a way around this please let me know. I understand this doesn't make sense for "3D parts" being printed, but it does for a 2D exposure.

Re: How do I make a negative of these PCB traces

jorge_garcia — Wed, 11 Dec 2024 18:08:33 GMT

Hi @coyt.barringer,

I hope you're doing well. I'm not strong in the modeling environment so what I'm about to suggest may be wrong for a reason I'm not aware of. Have you considered just projecting the copper geometry onto a new sketch and then extruding that?

Doing that way may solve both the different heights issue and the different bodies issue. It's just what come to my mind looking at your design.

This is differently an unusual application, if you would be willing to share more details maybe I could give you better guidance.

Best Regards,