Karambit Knives on 1/2” Smoke Acrylic Double Sided Engraving

Stroonzo · November 7, 2020, 5:31am

My son (a boy obsessed with knives, ninjas, and the like) came in to the shop about an hour ago. He was watching me design this turn table corner of a work bench in CAD:

Then he started asking if it was possible to make a karambit knife on one of the machines (either the laser or the spindle).

The result was we used the laser and Lightburn to make the following:

Great edging on half inch acrylic (single pass):

Using the cut outs of the material, I flipped the knives and ran the job again setting the line cuts to no output to engrave the opposite sides:

File Attached:
Karambit.lbrn (240.0 KB)

Chrik · November 11, 2020, 3:33pm

Nice edges, what kind of Power/Speed have you used?

Stroonzo · November 11, 2020, 4:38pm

With a Reci W6 tube (slightly over 130w rated), I cut those (on a calibrated Laser PSU) with:

Speed: .2 in/sec (5mm / sec)
Max Power: 90%
Min Power: 90%
Single Pass
101 mm II/VI Lens in a modified lens holder tube
18 PSI Dried Air

Stroonzo · December 4, 2020, 5:45am

Update on this:

So my son convinced me to kick this up a notch and let me assure you, LightBurn’s camera functionality played a HUGE role in making this possible.

So even though Karambit V2 will only have laser inscription on it once the handle is finished with the 3D milling, the use of Lightburn was key in the capturing and tracing of the polymer knife’s profile, the capturing and tracing of the plasma cut blade, the 2D CAD work and placement of the objects, and exporting to SVG.

From all the Lightburn work I was easily importing into VCarve Pro to create the tool paths for the blocked handle.

Then I was able to take the same CAD work SVG from Lightburn into TimkerCAD to model the 3D contouring for the CNC mill. That STL then went to VCarve Pro.

All that’s left Is to finish the 3D tool path for milling the profile into the handle, stick a V bit into the mill and let her rip.

Of course I have a test specimen handle to run before putting the real work in.