Electroplating 3D Prints Without Requiring A Big Vat

Electroplating 3D prints is a good way to get a pretty nice coating on even a basic PLA part, but generally you’re expected to dunk the entire part into a big vat with electrolyte after coating it with the requisite conductive paint layer. This is great for small parts, like a ring you’d put on a finger, but gets rather silly when it’s a much larger part, such as the one in [Hendrik]’s recent video. Out of curiosity he tried to see whether rotating the part through a much smaller vat would still get you an even coating, or not.

Perhaps ironically this process required building a custom vat out of acrylic, as well as an entire rig to hold up the part and gently rotate it. This highlights the main disadvantage of this approach, in that unless you’re doing a small production run or otherwise get to re-use the rig a lot it’s a lot of extra effort.

That said, the rotation is controlled by an ESP32 and a stepper motor along with a requisite stepper driver, with the most exotic part being the whole custom PCB and enclosure, all of which can be used repeatedly. With all of that tested and confirmed working, the part to be plated was sanded, sprayed with conductive paint and hooked up to the rotating rig for an overnight run.

Following that the part’s new copper coating was polished before more layers of electroplating were applied to get the desired two different colors from different metals. Along the way no issues were found with this method of rotating electroplating, so if you regularly struggle with oversized parts to electroplate, this would seem to be a viable method.

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The bed of a small CNC machine is shown. A plastic tub is on the bed, and in the tub is a sheet of metal under a pale green solution. In place of the spindle of the CNC, there is a rectangular orange tube extending down into the solution. A red wire runs to this tube, and a black wire runs to the sheet of metal in the tub.

Painting In Metal With Selective Electroplating

Most research on electroplating tries to find ways to make it plate parts more uniformly. [Ajc150] took the opposite direction, though, with his selective electroplating project, which uses an electrode mounted on a CNC motion system to electrochemically print images onto a metal sheet (GitHub repository).

Normally, selective electroplating would use a mask, but masks don’t allow gradients to be deposited. However, electroplating tends to occur most heavily at the point closest to the anode, and the effect gets stronger the closer the anode is. To take advantage of this effect, [ajc150] replaced the router of an inexpensive 3018 CNC machine with a nickel anode, mounted an electrolyte bath in the workspace, and laid a flat steel cathode in it. When the anode moves close to a certain point on the steel cathode, most of the plating takes place there.

To actually print an image with this setup, [ajc150] wrote a Python program to convert an image into set of G-code instructions for the CNC. The darker a pixel of the image was, the longer the electrode would spend over the corresponding part of the metal sheet. Since darkness wasn’t linearly proportional to plating time, the program used a gamma correction function to adjust times, though this did require [ajc150] to recalibrate the setup after each change. The system works well enough to print recognizable images, but still has room for improvement. In particular, [ajc150] would like to extend this to a faster multi-nozzle system, and have the algorithm take into account spillover between the pixel being plated and its neighbors.

This general technique is reminiscent of a metal 3D printing method we’ve seen before. We more frequently see this process run in reverse to cut metal.

Blowtorching Electroplated 3D Prints For Good Reason

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.

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Anodizing Titanium In Multiple Colors

[Titans of CNC Machining] wanted to anodize some titanium parts. They weren’t looking for a way to make the part harder or less prone to corrosion. They just wanted some color. As you can see in the video below, the resulting setup is much simpler than you might think.

The first attempt, however, didn’t work out very well. The distilled water and baking soda was fine, as was the power supply made of many 9V batteries. But a copper wire contaminated the results. The lesson was that you need electrodes of the same material as your workpiece.

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The Shuttle Engine Needed 3D Printing, But…

If we asked you to design a circuit to blink a flashing turn signal, you would probably reach for a cheap micro or a 555. But old cars used bimetallic strips in a thermomechanical design. Why? Because, initially, 555s and microcontrollers weren’t available. [Breaking Taps] has the story of NASA engineers who needed some special cooling chambers in a rocket design for the Space Shuttle. Today you’d 3D print them, but in the 70s, that wasn’t an option. So they used wax. You can see a video about the process, including a build of a model rocket engine, in the video below.

The issue is the creation of tiny cooling channels in the combustion chamber. You can use additional thin pipes brazed onto the engine. However, there are several disadvantages to doing this way, but early rocket engines did it anyway. Having the cooling path integrated into the system would be ideal, but without 3D printing, it seems difficult to do. But not impossible.

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Making The One Ring By Electroplating Gold On A 3D Print

Electroplating is a great way to add strength or shine to a 3D print. However, we don’t see too many people trying it with gold. [HEN3DRIK] isn’t afraid to experiment, though, and pulled off some amazing, high-quality jewelry-grade plating!

The design for the project was the so-called Ring of Power from Lord of the Rings. The print was created on a resin printer at a high quality level, washed thoroughly to remove any remaining resin, and then cured. The print was then post-processed with sandpaper to make it as smooth as possible. Conductive paint was then applied, ready to take on the plating layers. [HEN3DRIK] first started by plating copper to build up a tough base layer, then nickel to prevent mixing between the copper and gold. The gold is then finally plated on top. Plating the copper is done with the ring constantly rotating to get as even a coat as possible. In contrast, the gold plating is done with a brush to avoid wasting the highly-expensive plating solution.

The final result is a gleaming gold ring that probably feels strangely light in the hand. The technique is time consuming, thanks to the need to plate multiple layers, but the results are to die for. We’ve seen [HEN3DRIK]’s fine work before, too. Video after the break.

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Electroplated 3D Printed Sword: Shiny!

We all want to 3D print metals, but the equipment to do that is still beyond most home workshops. However, [HEN3DRIK] takes resin 3D-printed items and electroplates them. Might not be as good as printing in metal, but it sure looks metallic. As you can see in the video below, the sword looks like it was crafted from highly-polished steel.

The sword comes out in four pieces. He repeats several times that sanding is the key because you must have flat surfaces. Using sandpaper and steel wool, he worked the parts to a fine finish. The parts assemble along an M8 threaded rod to form a whole. The next step was to electroplate with copper.

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