Electroplating
Electroplated screw (generated with https://github.com/hzeller/gcode-multi-shell-extrude ; this is printed with lock-offset, this is why it has the little offset at top and bottom. ).
(This is a followup experiment of one of my earlier posts https://plus.google.com/u/0/+HennerZeller/posts/QJraphZVBng
See preparation of item there)
This time with proper ‘standard’ bath (CuSO₄, H₂SO₄, few ppm HCl, some PEG) and moving electrolyte (with aquarium air bubble pump). About 200A/m² (in this case about 50cm², so about 1A).
There are small dimples on the surface, and some more sanding can make it shiny, however, that is not really easy in intricate shapes.
So, next step would be to figure out formulations to decrease need for post-processing, i.e. less dimples.
So I might try less current for slower depositioning.
Also there seem to be some improved chemistries that help improving that as well. Does anyone know papers that describe improved, smooth depositioning ?
Nice try, in my job I do it regularly.
For better plating results you need more special chemicals liks brightener.
But an easy way to archive better results is pulsplating.
Its only. A controller and a H-bridge (mosfets)
You change periodically your DC current, to reverse so it dissolve a bit of copper. Next cycle it puts in forward mode copper onto your object and so on.
Forward cycle is a bit longer as reversed cycle.
Thanks @Sebastian_Schmidt , I’ll try that when I do my next experiment.
This process made me think of an idea that might be worth pursuing in a separate thread. This example is probably a non-starter but it will give you the general idea. Imagine printing the shape of a coil on your 3d printer and then electroplating it to get your coil?
@Tony_Hine_Nifty_Acce depends on later use of that coil.
But problems would be the space between each winding and you only can make one layer core.
But for some special uses it can be worth a try.
A think a big help would be if we find someone for build and design a coil winder machine. Its much like a 3d printer so we can use the same parts, same electronics ans only a few specialized part most or all can be 3 d printed.
Also the parts that hold the coil and core and parts at that you build them can be printed 
@Henner_Zeller But the work is realy good quality.
Hi, if you message me your address I’ll drop a sample of brightener in the mail. I beat my head against the problem you’re having for months. A teaspoon of brightener in a 1 gallon bath will get you the result you want. Alternating the current as someone suggested is helpful, but only part of the solution. Also, PEG is a vital part of the additive you’re looking for. But, the remaining variable in the equation is an industry secret. I noticed that a post was deleted from the http://finishing.com forums because the guy included results of tests he ran with a mass spectrometer… (One step short of busted knee-caps.)
@Bradley_D_Woods if you interested in the recipe of brighteners a good tip are the patents but the chemicals involved are often hard to get ,but you can talk to firm in your near that has in example a copper plating bath. Maybe the sell you little amounts.
But if you are lucky, a problem remains, that chemicals need adjusted and that realy exact in ranges like 10g /litre
Normally you titration, but you can do it with a so called “Hull-cell” but that needs trying and experience.
And sad to hear I miss a good post on http://finishing.com. I had it loved to see his results
