V-cut engraving on uneven sword blade success!

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V-cut engraving on uneven sword blade success!

Postby jblakey » Mon Jan 23, 2012 9:51 am

Finally! I've been waiting to post this up:)

Last night, I finally fixed the last (obvious) bug in my code, and managed to complete the first 'nice' v-cut engraving on a sword blade. The thing with with Japanese sword blades that I've been working on is that they are not flat at all. There's a distal taper as well as an angled blade profile to deal with. This made getting a good v-cut engraving very tricky for me.

The number one problem was clamping - I could not figure out how to clamp this totally un-flat blade down. So, I thought about how traditionally softened pitch would be used to hold the work-piece, and that led to the Pour-Clamp 2000, a simple trough filled with casting resin to support the blade.

Next problem was adjusting the engraving to 'wrap' the uneven surface of the blade. I took a look at Pcb-Probe by Lee Essen, but it was meant to be a solution for PCB milling, not a general purpose tool. But it did give me some ideas.

So, I started writing some Perl code, and managed to merge the results of a gridprobe.ngc run with my gcode for my engraving. I had to learn about planer interpolation on the way, as well as the benfits of using a multi-dimensional array for point storage versus single dimensional arrays. It was quite frustrating, always another bug to fix - but the thing finally works! Check it out!:)

Note: You can see the grid of marks that the steel probe left on the aluminum blade. Next test I'm going to use tape to protect the blade during the probe run.

Btw, it takes about 3 hours to probe a 1" x 2.3" section of blade, and about 2 hours for the v-cut engraving to be run. I'm using a 60deg 1/8" .1mm point carbide bit for the cutting.

Note the difference between the 'mushy' foo-dog and the nice one - that's the difference that following the surface of the blade makes. Everything else was the same.

Thanks,
jason
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Re: V-cut engraving on uneven sword blade success!

Postby Crazyju » Mon Jan 23, 2012 1:16 pm

First Ninja stars, now ninja swords, now i have to find a weapon to make on my machine. Very nice!
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Re: V-cut engraving on uneven sword blade success!

Postby jblakey » Mon Jan 23, 2012 1:39 pm

It's getting there - I think I'm going to run my next test at about 1/2 speed, and see if I get cleaner cuts...

Thanks,
jason
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Re: V-cut engraving on uneven sword blade success!

Postby Xin » Mon Jan 23, 2012 1:51 pm

Jason

Nice work. Ever think about a spring loaded spindle? That will be probably more forgiven on uneven surfaces.

Thank you for posting.

Xin
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Re: V-cut engraving on uneven sword blade success!

Postby jblakey » Mon Jan 23, 2012 2:20 pm

well, i thought about it, but spring-loaded spindles are usually only used for diamond-drag engraving, not v-cut (where the spindle needs to spin).

Thanks,
jason
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Re: V-cut engraving on uneven sword blade success!

Postby jblakey » Wed Jan 25, 2012 10:25 am

Did some more tests, and switched to a 1/4 sign-making vbit (carbide, 60deg). Cuts were MUCH cleaner. I don't know if it's the point design, the extra mass, or the extra rigidity, or running it at half speed, but I'm happy with the results.

Also, I'll be finishing up my code for doing the z-axis transformations based on probe input this week and posting it up, if anyone is interested. Should be handy for many things, not just sword blades. I think it would probably work for PCB board work as well, or working on uneven surfaces generally.

Thanks,
jason
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Re: V-cut engraving on uneven sword blade success!

Postby marstewart » Sat Apr 14, 2012 4:27 am

"jblakey"
with respect to the pic you post.
the result of the engrave it is quite good.
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