Electroplating

Wiki

Safety:

The electroplating process works with EXTREMELY corrosive acids. While safe handling should make this a non issue, the same safety equipment that is recommended to work in the resin printing tent is recommended here with the added recommendation of a lab coat or other ‘disposable’ outer layer. You really don’t want the acid to touch you, so having extra layers on in case you do splash a little bit of acid on yourself is always a good idea.

In Short, you’ll want; a half mask respirator with P100 filter(s) (and full face shield preferably), Splash goggles if you don’t have a face shield respirator (not just safety glasses), and a lab coat or some additional (long) outer clothing layer.

In Practice; Make sure your parts are well supported and affixed at all times, and place your part slowly into the acid bath to avoid splashing.

The Basic Setup:

At the shop we have a power supply (PSU) and a metal conductor submerged in an acid bath. The positive electrode from the PSU connects to this conductor (and we call this the anode of the circuit). Your ‘conductor’ is where the metal that will be plating your part will come from. The negative electrode from the PSU connects to the part that you are trying to plate (and we call this the cathode of the circuit). The acid bath itself, called the electrolyte, will transmit the dissolved metal salts and conducts electricity. By giving the atoms of the Anode a positive charge they readily dissolve into our acid bath and are attracted to the Cathode, aka the part we want coated in our conductor metal (anode).

 

 

Image credit: https://formlabs.com/blog/electroplating-metal-plating/

In order to electroplate a metal onto something that is non-conductive (like a 3d printed part) you’ll need to first give it a conductive coating some other way. Popular methods are using metal aerosol paints and airbrushing graphite powder onto the surface of your part with airbrushing providing better surface finishes and finer detail. The airbrush and associated components are in the drawer underneath the mini paint booth. Spray painting should only be done outside.

Metals and Electrolytes:

Because each metal requires a specific acid bath and the anode metals become dissolved in the acid bath on their way to your part you can’t just swap metals at the anode and get to plating again. Denhac has a bath of sulfuric acid for plating parts with copper. No other anode metals can be used for plating yet.

Getting Good Results:

  • Use a Constant Current Source: You only want to run about 1 Amp of current through the bath for each square decimeter of surface area on the part you’re plating (I = 1A/dm^2). Determining the surface area of your part can be challenging but if you have a model file like an .stl or .3mf then the modeling program Blender can calculate it for you if you set the scale and everything as well.
  • High Voltage isn’t Necessary: Tune the power supply so that it’s only outputting between 0.5 and 1V at the amperage you need.
  • Surface Prep: Before plating, ensure your part has a clean, conductive surface. This may involve degreasing, polishing, and sometimes using an etching solution to create a better bonding surface. Polishing your parts before and after coating them with your conductive surface of choice can create a smoother and stronger plated surface.
  • Agitation: Finding a way to gently agitate the electrolyte and/or your part during plating can help ensure even metal deposition. We are still devising a way to do both of these things with our current setup.

Now that you’ve read through this page, post in the #help-electroforming channel if you’re interested in being trained to use this space.

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