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Thinking 3D additive PCB thoughts

A project log for PCB /SMT MAKER LAB @ Home

This project outlines how to do advanced PCB making at home with proper tooling. Tooling includes a laminator and hobby laser.

mosaicmercmosaicmerc 10/05/2015 at 01:070 Comments

Having automated the doublesided PCB making, I find myself having to interconnect several boards using wire to board components and headers for more complex systems.

Using the same tools to make the double sided board with more leverage on the 40W laser cutter i believe I can design doublesided boards in layered stacks. Building multilayered prototypes in an additive fashion.

Now arduino type stackable modules come to mind, but for true high density systems I am looking at 1/32" thick FR1 PCBs or even flex PCBs which are etched in a manner to permit the 40W laser to cut the base material as required.

Then sidestepping the 0.1" pitch headers, the boards are designed to mate together so that components on the bottom of one do not align with the components on the sandwiching boards. By etching properly and then laser cutting notches for components, it's possible for the boards to lay flat on each other with no spacing!. Using the same stencil cutting technique we can have insulating 'separators' between these sandwiched smt boards. Vias can be soldered in stages as the boards are layered, even blind vias are possible.

Now this approach can potentially give a higher component density than regular multilayered boards as components can actually be 'embedded' inside a board sandwiched by multiple layers with other components stacked above embedded components in it once the intervening board layers offset the embedded component's height.

Consider a sandwich of 4 layers of 1/32" PCBs, then SMT components on the inner side of layer 1 can well be buried completely by layer 4, permitting more components on layer 4 to occupy the same location displaced vertically. Again, insulating laser cut transparencies provide inter-layer isolation as required. By using layer separator insulating material such as acetate transparencies, mylar or kapton sheets (laser cut with required slots/holes) it may be possible to place solder paste dots on different copper layers to create bond points between successive layers to be reflowed after the layer stacking is complete!

The out come of all of this could be a device perhaps 1/2" thick with up to 12 layers of double sided copperclad 1/32" material plus separators and several layers of stacked embedded components. All DIY @ Home, using the techniques described and the on hand tooling!

Faraday cage effects, reduced EMI minimal board inductance, reduced signal latency for high speed digital processing and minimal form factors are all benefits. This brings electronic micro manufacturing a bit closer to home with micro prototyping capabilities!

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