making mechanical parts in metal, electroplating printed parts

[steveh2112]

hi all,i'm thinking of getting into making kinetic sculptures powered by gear motors and servos, pretty low power stuff, moving weights of up to about 2-300g. i will need to make things like gears, linkages, hinges and pivots, etc. i realize the best way to make durable, good looking metallic parts like gears is to 3D print then make a casting in brass or bronze or something. but that seems like a lot of work and expense.

so I'm more interested in trying to electroplate the 3D printed parts. I expect my largest parts will be around 300mm or so and I'd like them to last several year of use for an hour or so a day. I don't know if that is reasonable to expect from electroplated parts. what do you think?

Anyhow a few questions. I have zero experience 3D printing so please be kind.
1. what printer? I'm thinking Creality CR-10S. i like to stay under $500 for everything.
2. what kind of filament for stronger parts? polycarbonate? Carbon Fiber Filled Nylon?
3. what's the best way to smooth surfaces and remove printer lines prior to plating?
4. how to prep for electroplating? i see brush painted graphite power in acetone or ink are both popular options. is there nothing in a spray can that would work like copper spray paint? or could I spray graphite power in acetone in my spray gun?4. what plating metal(s) to use? pretty much everything on youtube is copper which is then treated with something called liver of Sulphur which i guess darkens it and stops it oxidizing. but I'm not sure that's the look I'm going for, and copper is quite soft. I'm thinking nickel on copper. What's best option for part durability and corrosion resistance?
thanks

[curious aardvark]

well a couple of things.
Copper is maleable, that's quite different to it being soft.

electroplated coipper is actually extremely hard.

It's also a real PITA and a very hit and miss process.

Talk to Gambo - he's the expert on electroplating.

don't buy a creality printer, get something better designed and less prone to problems.

As far as the gears goes. watch this video:
https://www.youtube.com/watch?v=UtRJ4lnNAXY
Good place to start.

he did not use polycarbonate, polycarbonate take a non-standard printer. It will need hi-temp nozzles, up to 300c and a heated enclosed chamber is also a massive advantage.
I suspect polycarbonate would be your best friend.

If you are going to electroplate and make your own plating 'paint', use abs.
You can make a reasonably succesful paint from acetone, graphite powder and a small amount of clear abs.

But you are probably better off with a commercial product for better conductivity and more consisten results.

You have also to bear in mind that the layer of metal is really rather thin and may not last very long.

So two options.

1) basic enclosed printer, make gears from abs and electroplate with a 'professional' kit.

2) get a better printer and use polycarbonate and some metallic paint :-)
gears made from solid polycarbonate would be incredibly strong, tough and durable.

3) a viable alternative to polycarbonate is ninjatek's armadillo. A hard polyurethane filament, that is damn near as strong(stiff) as polycarbonate and a lot tougher. An while it's not cheap, it has the advantage of being incredibly easy to print on just about any printer.
https://ninjatek.com/shop/armadillo/

https://www.amazon.com/Intelligent-I...277162&sr=8-14
Yes it's a bit over your unrealistic budget ;-)
But money spent on a machine capable of printing the tougher materials is money and time saved on buggering about with electroplating.

For a cheaper i3 - this looks pretty hard to beat. a few things I'm not keen on - but a decent machine at a budget price.
https://www.amazon.com/FoKoos-Odin-5...277424&sr=8-34


here's probably the best option within your budget: https://www.amazon.com/TENLOG-Hands-...78139&sr=8-165
Dual independant extruders, linear rails, direct drive extruders - all desireable stuff creality don't do.
decent print volume and you can buy the upgraded 300c extruders (I presume, as the larger tl-d3 has them and the idex setup is the same on both machines) Decent print volume and currently the best designed budget I3 printer you can buy.
No clue why the listing is in german ;-)

So if you are planning on polycarbonate - the qidi is your best option.
The tenlog is the best all round machine.
And the odin is a decent-ish cheapo i3.

I reckon, get the tenlog and go with solid armadillo for the gears, and you should be good to go :-)

[steveh2112]

thank you for the great info, that gear video was very interesting. my project probably doesn't need the strongest gears in the world, its not a jet engine, i'm going to try the BASF PLA from the video and try annealing it. as for electroplating, i'll just have to play around with it. i've watched a lot of videos and have some ideasi already ordered an Ender 3, arrives Monday. i'll get my feet wet with that and if my project gets more serous, i will splash out on a $500 machine.

[steveh2112]

i wonder if 2 part epoxy glue, like gorilla glue, is strong when used as a filler material for printed parts.my idea is to cut my printed parts in half laterally, print hollow parts with no top, then fill with 2 part epoxy, then glue the 2 halves back together with more epoxy. assuming 2 part epoxy glue is stronger than PLA, this should make a pretty strong part. for extra strength, i could place a 2mm threaded steel rod inside each half, bent to shape, to act like concrete rebar.


the other advantage of this idea is less printed material. i'm really just printing and outer shell to act as a mold for the epoxy. i could even melt the epoxy away when finished if necessary, just print a negative of the part.

[curious aardvark]

solid pla is probably stronger than most epoxy.

But get one that's got a little give and it could work :-)

And you've wasted the $200 on a machine that needs extensive upgrading and modifying and constant attention to work properly.
You'd have been much better off buying a machine that would actually do the job from the get go.