[dcarr]

Greetings,
I'd like to present my 2006 Nikola Tesla Sesquicentennial medal that I designed and sculpted digitally, and then I engraved the dies via CNC. This one is brass, 38mm in diameter. I also made some in silver and in a 63mm size.

[Switcher]

That looks GREAT!


.

[nemesis]

Well done, that is awesome.

Can you post the details of the tools you used, cutting times etc?

[wwendorf]

Now, where can I get one?

Wade

[Switcher]

Now, where can I get one?

Wade

Link


.

[diecutter]

I'd also like to know the selection of tools used and the toolpath strategy; looks like a combination of raster and spiral runs to eliminate tool marks and sharpen the image. I believe you also did the Ameros earlier posted on this site. They were also very high quality. I engrave coining dies manually with a Gorton P1-2 pantograph and am trying to step up to cnc with mixed results so far. Evidently you have a lot of it figured out. Great work.

[wwendorf]

Awww. They are all sold out.

[dcarr]

Well done, that is awesome.

Can you post the details of the tools you used, cutting times etc?

Thanks,

First I designed and sculpted the medal in 3-D using VS3D (which I wrote). I generated two tool paths from VS3D, both a spiral starting in the center. The first pass was a rough cut using a 15-degree "V" bit with a 0.015" radius tip (0.0075" step-over). The second pass was a fine cut using a 15-degree "V" bit with a 0.005" radius tip (0.001 step-over). Maximim depth of cut was about 0.030".

Both paths were run on annealed tool-steel die blanks. First pass took about 90 minutes at 4 IPM feed rate. Second pass took about 12 hours at 4 IPM.

After engraving, the dies were heat-treated (hardened), bead-blasted, and lightly polished.

The 38mm brass medals were stamped on a coinage press using about 150 tons.

[nemesis]

Thanks Daniel, that is exactly what I (and diecutter I suspect) wanted to see.
I am just starting out in this game, and this type of output is quite inspirational.
My CNC machine should be able to cope with similar degree of fine work, but I am having trouble locating engraving bits here in New Zealand. I might have to import some myself.
Do you recommend anyone in particular as a supplier?

Dave

[dcarr]

Thanks Daniel, that is exactly what I (and diecutter I suspect) wanted to see.
I am just starting out in this game, and this type of output is quite inspirational.
My CNC machine should be able to cope with similar degree of fine work, but I am having trouble locating engraving bits here in New Zealand. I might have to import some myself.
Do you recommend anyone in particular as a supplier?

Dave

I use Micro-100 tool bits http://www.micro100.com/

[diecutter]

dcarr, Thanks for sharing your information with us. As Dave said it's quite an inspiration. I'll have to look into your VS3D software since it evidently does the job well. Are you using a split point profile, or four flats coming to a point like a star when you grind your cutters? Each has it's advantages.

Also, when you receive your steel blanks, do you consider them soft as received or do you anneal them to further soften them? I checked out your site and it's very impressive. Keep posting examples.

[dcarr]

dcarr, Thanks for sharing your information with us. As Dave said it's quite an inspiration. I'll have to look into your VS3D software since it evidently does the job well. Are you using a split point profile, or four flats coming to a point like a star when you grind your cutters? Each has it's advantages.

Also, when you receive your steel blanks, do you consider them soft as received or do you anneal them to further soften them? I checked out your site and it's very impressive. Keep posting examples.

I use a double-flute "MRF"-style bit for the rough cut, and a typical 1/2 cone engraving bit for the fine pass.

Currently I'm ordering die blanks that are already annealed. I do the hardening and polishing after the engraving.