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Amber shaping


#1

Maybe somebody could advice - is it possible to shape amber with CNC
milling machines? Forms are not complicated, near the sphere. What
brands are better for such task. I want to automate process.

Kestutis Cesonis


#2
    Maybe somebody could advice - is it possible to shape amber
with CNC milling machines? Forms are not complicated, near the
sphere. What brands are better for such task. I want to automate
process. 

Although I’ve never tried it, it should be possible. However, I
doubt you would use a milling cutter. You want to grind instead of
cut, maybe using a diamond coated ball tool, and maybe even one that
is spring loaded. You also want to have a continuous flow of coolant.

Jeffrey Everett


#3

I haven’t tried it, but it shouldn’t be impossible. It won’t be
easy, though. One problem is fixturing the stock; amber is difficult
to hold onto securely. I’ve had bad results with conventional
hot-dopping - the material doesn’t like to be heated, and it’s
difficult to get the wax off once it’s adhered. Gentler techniques
(no pre-heat, softer wax, warm water instead of freezing off) could
work, though. Materials are usually held down to the bed of a CNC
mill with clamps, but that would be a touchy procedure with amber,
which cracks easily. There’s usually not a lot of extra material to
hold onto either.

Another problem is the tendency of amber to chip as it’s being cut.
While it cuts cleanly (unlike copal, which tends to gum up) it’s hard
to get a chip to separate without a conchoidal fracture which can
extend farther than one might want. Add to that amber’s tendency to
accumulate an electrical charge and explode spontaneously if
over-charged, and one starts to appreciate the difficulty of the
task.

As for the choice of machine; just about any commercially available
CNC mill would work, since sizes are small, and speeds don’t need to
be high. But if the shapes you’re cutting are simple convex shapes
like spheres, a standard (non CNC) cabochon preforming machine might
work just as well. These trace a master pattern mechanically, and
move a rough piece of stone into a grinding wheel to duplicate it. If
you wanted to reproduce a more complicated design, like a cameo or
intaglio, then I’d think CNC would be worth investing in.

Andrew Werby
www.computersculpture.com


#4

Gees:

Yall ever heard of silicone rubber? How about the adhesive that
holds sandpaper to the sanding disc?for that fact super glue will
work if you use sparingly add lightly heat the nail that you use (
10 penny works well] it will separate with little effort. My advice
is to use a wooden dop with silicone rubber and let it set well. A
razor blade will separate it easily.

Ringman