Electro-chemical machining is very close to anodizing, simply because it involves much of the same equipment and electro-chemical processes. Obviously this is of interest to me since I am invested in the aforementioned equipment for the making of the Q. The benefit of this technology is the near perfect finish it leaves. Basically, an electrolyte is pumped down a cathode "form" or "tool" and the metal is removed via "reverse galvanism" (anti-plating) imposed by a high current, low voltage PWM DC current pumped through the electrolyte. Not much info is available on the technology, as it was mostly developed behind the Iron Curtain.

This sounds too dangerous to not try! This thread will represent my attempts at "non-contact metal removal".

Advantages of Electrochemical Machining

* The components are not subject to either thermal or mechanical stress
* There is no tool wear during Electrochemical machining
* Non-rigid and open work pieces can be machined easily as there is no contact between the tool and workpiece
* Complex geometrical shapes can be machined repeatedly and accurately
* Electrochemical machining is a time saving process when compared with conventional machining
* During drilling, deep holes can be made or several holes at once.
* ECM deburring can debur difficult to access areas of parts.
* Fragile parts which cannot take more loads and also brittle material which tend to develop cracks during machining can be machined easily through Electrochemical machining
* Surface finishes of 25 μ in. can be achieved during Electrochemical machining

Material that can be cut with Electrochemical Machining

Conducting materials and alloys can be machined using Electrochemical machining.

Sounds amazing!

I bet it's also environmentally friendly!

It should be, as long as you use something like sulfuric acid, magnesium sulfate, or saline for the electrolyte. Whether any of these actually work well I have no clue. It should be fairly easy and fun to find out, and I might be able to do a few experiments tonight.

Isn't this EDM? Or is that another animal? There's a great DIY book on EDM I've seen recently at my brother-in-law's.

Nope, EDM (the D stands for "discharge", ew) is a different technology that can not finish pieces with precision like ECM. Both technologies were developed in this country, ECM about 1929. They only caught on around the 50s, and EDM was cheaper (but not better), so ECM went underground and was mostly developed behind the Iron Curtain. The tech is currently enjoying a renaissance since the fall of the Wall, yet information is rather dearth.

Thanks for clearing that up brain. I did find the book I was thinking of here: http://www.lindsaybks.com/bks9/edm/index.html. If you don't think this belongs here just gimme the word but perhaps it's a good point of comparison?

Some very good info:

http://www.eod.gvsu.edu/eod/manufact/manufact-281.html

In this image, the top piece is the tool (cathode), and the bottom piece is the work (anode).