Conducting trays in elastic materials

Hi all,

i've already mentioned Galinstan ( [forums.reprap.org] ) - a nontoxic liquid metal replacing mercury in some applications, and we had some talk about Woods- or Field-metal or conducting pastes as conducting trays in fabbed PCB's.

A good idea for building elastic PCB's or 3D-objects embedding IC's and other active and passive components (for example in 'wearable' electronics) would be fabbing the body of the PCB from plastic with hollow trays between embedded sockets or electronic components, which will be filled with the liquid metal when ready.

The fluid trays are elastic too, so you can make 3D-PCB's from silikone or other resins, so the electronic module can be bended or twisted without malfunction.

Only an idea ... maybe other suggestions too?

Viktor

Just to check I understand the suggestion: The conductor would remain in a liquid state. If so how would we ensure that the joint between the components wires/legs/etc and the tray are sealed?

It seems unlikely that we could fab an interference fit at the moment. Could the component be placed during building and then the seal extruded to it? If the components were already placed some extra entrances would be needed to introduce the metal and release the trapped air.

For a flexible device wouldn't some form of 'expansion chamber' be needed for the displaced liquid when the tray changes shape, and hence volume?

... for connecting electronic components you could embedd them while fabbing, and/or pierce the legs into fabbed holes, which will be later filled by the fluid metall.

For populating and/or changing IC's (or other components too) after fabbing you can embedd single sockets per pin or complete pin-arrays as used for PCB's - but pin-arrays would counteract the elasticity of the main body, so they shouldn't be longer than 6 or 8 pins per segment.

Yes, you could fab expansion chambers, but when building with an elastic resin, then ist's not essential - you have only to fill the fluid metal with a slight over-pressure, so you wouldn't receive cavities, when expanding the cavity while bending.

Viktor

***EDIT***
PS: ... there were some tests with long hoses (until some meters) filled with the galinstan for conducting electricity or ultrasonic energy for acting and tooling in surgery or microtechnics ...

Edited 1 time(s). Last edit at 09/12/2008 06:53AM by Viktor.