Electrochemical grinding

O

Otonel

Joined
Sep 10, 2017
Messages
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I would like to try to make a device for electrochemical sharpening and burr removal, I haven't found much information on the internet other than theory, but my problem would be to find a grinding wheel that conducts the current and is smooth so that I can achieve a smooth cut without burrs. I am posting a video and some information just to give you an idea of why I would like it to make
https://en.wikipedia.org/wiki/Electrochemical_grinding
 
I don t want to do a complex instalation, only a small electrochemical grinder and can use 3d printer parts to make it , The oven after you give me a good advice is on the right way💪
 
In did my math wrong in my head. It will probably cost around 50,000 leu to buy one.

I don't know if you can build one by 3-D printing, but have fun researching.
 
I have no idea what you could find in Romania, but a search should find the details. Before searching too much and gathering parts ... understand that this is not a knifemaking machine.

While a diagram of the machine looks somewhat simple, and similar to a fancy knife grinder, it is not.
The process uses a metal wheel coated with a conductive abrasive - usually diamond/AO mix or BN/AO. The electrolytes are often caustic (NaOH), and there are very tight tolerances in the equipment. Rater large DC current is applied, IIRC. Electrical isolation of the motors and cabinet are critical. It is not a hand grinding operation.

Also, while we grind on the circumference of the wheel, electro-chemical grinding is done on the flat side of the wheel. The process is for burr free machining and surfacing of machine parts and high hardness aerospace alloys. It would work to grind a knife blade.
 
I'm assuming you are just wanting to sharpen knives with this and not actually grind bevels? Are you wanting to do it free hand then? Mechanically sharpening a knife (without any human input) is extremely complicated.
 
Yes, I would like to sharpen the blades after they have been thermally treated and have high hardness, through the electrochemical process I would not heat the blade and I would not have problems with the strong wear of the bands. If I could do it by hand with the help of a spacer I would be an easy and practical construction. But if I manage to grind bevels it wouldn't be bad at all
 
Stacy E. Apelt - Bladesmith said:
I have no idea what you could find in Romania, but a search should find the details. Before searching too much and gathering parts ... understand that this is not a knifemaking machine.

While a diagram of the machine looks somewhat simple, and similar to a fancy knife grinder, it is not.
The process uses a metal wheel coated with a conductive abrasive - usually diamond/AO mix or BN/AO. The electrolytes are often caustic (NaOH), and there are very tight tolerances in the equipment. Rater large DC current is applied, IIRC. Electrical isolation of the motors and cabinet are critical. It is not a hand grinding operation.

Also, while we grind on the circumference of the wheel, electro-chemical grinding is done on the flat side of the wheel. The process is for burr free machining and surfacing of machine parts and high hardness aerospace alloys. It would work to grind a knife blade.
Click to expand...
I understand what you are saying, Mr. Stacy, but so far I have successfully used ECM to make different designs on blades or blade holes with high hardness, and as I am very pleased with what I have succeeded in, I said I will try to use ECM more in their construction, and for electroerosion, I used a computer source that, if I put my hand on the part with protective gloves, it does not present a great risk of electrocution
 
For sharpening a hardened blade, a more practical solution would be a wet-belt system using a spray setup like Cool-Mist.

Many folks use a wet belt to grind a knife from start to finish.
 
Interesting idea. Unfortunately, it doesn't work. Idea behind it is to grind parts with nice surface. Mechanical 10%, electric 90% material removal. Usually its using very high current. Average 1kA. But that 1kA is on a very small surface area. Just the contact point of the grinding wheel. What does that mean? The current is taking a lot of material that is impossible to manage on a sharp edge. Remember ionizers? Pointy metal creates discharge points. Ergo, the edge will loose way more material than the edge bevel. Ergo, no sharp edge, just rough edge surface.
If using low current per surface, like 2A, the time required to remove material and not damage the edge would be in hours. Still as the edge becomes sharper, more current will creep from the edge and destroy it.
Essentially, for sharpening it's a no go. For grinding bevels, it could work. But it would be way slower than a grinder with a 40 grit belt. Of course a kiloamp or more could be on par with a grinder but in a small format it's way to dangerous for the setup (I believe a human can take care of himself).
 
Normally people want advice on how to achieve a result in the cheapest, most efficient or most effective method. This does not consider that some folk just like creating and tinkering with tools more than building finished knives. I think of my time tinkering with CAD and a CNC router, it took loads of time and didn’t lead to a surge of production or easing making handles. Whatever benefits there might be are narrow, but it was kinda interesting anyway.

I am going to play a critic.
This concept for sharpening is meant to work without heat, no burr, on hard steel, and presumably to produce a polished edge of surpassing sharpness. Objectively something new Is worthwhile if it produces better results than existing methods.

How will the sharpened edge be assessed? How will sharpness be quantified so that the electrochemical method can be shown as better or worse than abrasive sharpening? The usual amateur subjective methods aren’t going to be good enough. A home made version of BESS Sharpness Tester maybe? Microscope?

How will it be assessed that it is better than another available abrasive method? For instance, I free hand sharpen, but a guided system will give more perfectly formed bevels, without developing a never before seen high tech method. Some of the hair whittling edges seen in the Maintenance forum are very impressive.

EDM methods that make permanent cuts in the knife that will survive for the life of the knife could make sense. The cutting edge though is going to get abrasive sharpened at some point. The first new owner, or the first time it dulls in the field.

Hard material isn’t really a justification in itself. Just look at Rockstead. Crazy hard steels polished to incredible finishes, by hand.

Personally I think there are many tools that one could work on that would make bigger contributions to the ease, effectiveness and quality of knives produced.

But if the real aim is to have fun inventing tools…I wish you the best of luck.
 
Reading around on it, it sounds like the grinding wheels used for this are your typical wheel with various types of abrasives available and the only difference being that they are infused with a lot of copper. I would say your best bet is to contact a supplier and see what is available. "Eagle Super Abrasives" appears to be one manufacturer.
 
Rather than grinding, has polishing been considered? I don’t know how it’s done, but there are chemically sharpened fish hooks that have wickedly sharp points. Would it perhaps be easier to make an electro chemical strop to test the effect on the blade apex?
 
I was wondering the same thing. I don't know a lot about it but I do know that electrochemical deburring is a thing. I would imagine it could work with a knife. The process probably requires a lot of fine tuning so it might only be useful for production work. I could be wrong about that though.
 
So a machine like this would kinda be like an EDM but with a wheel and conductive powder instead of a wire. Interesting , but like others have said -gonna be expensive as hell.
 
EDM in a 3D printer enclosure is made and it works. This could work the same. I question the science. Maybe high speed wheels could manage sharpening without etching the apex. A simple dremel motor can drive the wheel. If the whole knife is made with CNC, then the sharpening can be made with CNC. That's just programing. Getting the science right is a wrestle.
Otonel, keep us informed. :)
 
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