What if you electroplated a plastic 3D print, and then melted off the plastic to leave just the metal behind? [HEN3DRIK] has been experimenting with just such a process, with some impressive results.
For this work, [HEN3DRIK] prints objects in a special PVB “casting filament” which has some useful properties. It can be smoothed with isopropanol, and it’s also intended to be burnt off when used in casting processes. Once the prints come off the printer, [HEN3DRIK] runs a vapor polishing process to improve the surface finish, and then coats the print with copper paint to make the plastic conductive on the surface. From there, the parts are electroplated with copper to create a shiny metallic surface approximately 240 micrometers thick. The final step was to blowtorch out the casting filament to leave behind just a metal shell. The only problem is that all the fire tends to leave an ugly oxide layer on the copper parts, so there’s some finishing work to be done to get them looking shiny again.
We’ve featured [HEN3DRIK]’s work before, particularly involving his creation of electroplated 3D prints with mirror finishes. That might be a great place to start your research if you’re interested in this new work. Video after the break.
Interesting…
I may need to take a look at the filament he used. I have used PLA for burn-out applications, but this might be a better choice.
Same. I usually use PLA because wax filament is such a pain to print with. Something that has decent dimensional accuracy like PLA but burns out a little better would be great. Although I’d for sure use a burnout oven rather than a blowtorch. I think you could even use a hot oil bath to really reduce oxidation.
There is also water soluble filament. It’s meant to be used mainly for supports, so you just drop the print in water and let the supports dissolve but it might work for this application and remove the need for a blow torch.
Oh duh. I didn’t realize that electroplating required the object to be submerged. That makes water soluble filament kinda useless
Yes, but water isn’t the only possible solvent. If the PLA can be “smoothed with isopropanol” can’t is be also be completely dissolved in it with more time and perhaps some heat? or Methanol? Ethanol? Acetone? MEK?
I’m quite impressed with the technique. I believe this can be quite useful for making custom sensors, or something. The flame was a bit clickbaity, as you can just melt most filaments at a modest heat instead.
I wonder if, to get the nooks and crannies better coated, you do another pass with all the easy parts covered in an insulator that you can remove much like the original print material. So, for example, paint on melted wax over the convex and flat areas and leave the deep convex areas exposed. The electric field will be forced to the exposed conducting areas.
Just idle speculation on my part, having never done electroplating.
That helps, but the current flow mirrors field density, so convex areas are highest, the sharper/more convex the higher. Concave areas tend to be shielded. An approach I have seen use is masking the convex areas, as you conjectured, and use a positive electrode in the concave region. The current density will be reduced, as the electrode needs to be small, but it does the job.
Maybe 3D print with sugar so it can be dissolved and then reused.
I can’t tell if you’re being facetious but I think you’ll have a hard time electroplating something soluble.
… in water since most electroplating applications use an aqueous solution.
There are materials that require a specific solvent to dissolve though.
So they are compounds that are relatively easy soluble but not with water for instance.
Come to think of it, blood is funny that way, dissolves easily with water but with some other cleaning agents it’s harder.
3D printing with blood.. has it been tried.. and do we want to know? probably not eh.
Seems like doing the blowtorching in a reducing or intert atmosphere would help a lot with the final finish. Copper is pretty reactive and these things have a lot of surface area to be doing this in plain old air.
Tell us more about blowtorching in “inert” atmosphere, please ?
I thought this was going in the direction of that old chemistry class demo of turning pennies “silver” and then heating them to turn them “gold”
I experimented with, and had decent results with, photopolymer printing a negative buck, then electroforming a positive part for shallow sinker EDM work. The best results were had using an bipolar asymmetric square wave. By running reverse current duration of 50-80% of the forward current duration the resulting formed parts were both crisper in detail and significantly more durable/lasting during edm usage. YMMV
Already have the rig, why not another thin coating of copper to get the original color back?
FFWD to 7:20 A light brushing and a dip in the acid bath did just fine restoring the shine. Trying to do a second plating over the oxide layer wouldnt have given nearly as clean a result.
I wonder if you could dissolve the filament out? You need fairly nasty stuff like dichloromethane for PLA but there might be better options.
If only you could find some way to speed up the PLA molecules and turn it into a liquid,
I’m unfamiliar with this filament. But why heat it at all? Why not just soak it in IPA and melt it out chemically?
I wonder could you put iron/steel nails, screws or filings into the plastic print. And then at the end when you want the plastic gone could an inductive heating coil be used. Like the large sheet of copper should heat up very little due to its low electrical resistance (1.68 x 10⁻⁸ ohm meters) and it is not ferromagnetic so does not have a Curie point but the tiny bits of iron (10 x 10⁻⁸ ohm meters) will heat up very rapidly, especially because it is ferromagnetic up to its Curie temperature at 770°C (1418°F).
giant induction coil large enough for the entire part thats now distorted into some bizzarro shape with all the embedded bits
or thinskin closely matching print dimensions, placed in the oven
K.I.S.S.
Not if you use a pancake coil. Think old style cooker heating coil shape.
which you will wave around the part trying desparately to maintain even inductance on random particles youve placed inconsistently into an irregular geometries?
Yeah that will work soooo much better than just sticking it in the oven.
It was just a random thought. My thinking was if the heat source was inside the plastic and could be precisely controlled that possibly the copper could end up with less oxidation, that the plastic (and ferromagnetic heating elements) would just drip out.
@truth
You wouldnt have anything close to precise control with the technique you propose. You want less oxidization, dont use a blow torch. If somehow an oven STILL has too much oxidization, A decent top loading kiln and a bottle of argon has you covered, though if you watched the video, he does a little brushing, then acid dips the parts and gets a nice clean result, even after going to the extreme of heat, using a blowtorch.
@DurDurDur
My thinking was if you precisely controlled the input voltage to the ZVS that should control the amount of energy that the output can put into the coil.