Digitising is expensive at the moment, but it is getting cheaper,
and more accurate. Bench top scanning was unheard of a relatively
short time ago, now it's only a modest investment. Leonid's ring
can be broken down into primitives (head scratchers: primitives =
base shapes), and manipulated with boolean functions to get the cut
outs etc., so it can be remastered with a 3d application. I only
have to get one section of Leonid's ring perfect, the computer can
calculate the rest.
Rather than scanning and all that, probably much quickly to redraw
the thing in a decent jewelry CAD program. We use Matrix at work, and
a ring like Leonid’s design might take our CAD modeller (not the most
proficient such person you’ll ever meet either, but she gets the job
done) an hour or so to get it ready to mill on the Revo Mill. The
result would be a fine looking model which would be easy enough to
cast and finish up. But I’d never suggest that the finished piece
would come close to Leonid’s handmade piece. So long as you don’t
design with that aim in mind, and keep the limitations of the process
involved in the design process, you can get fine results. But that
doesn’t mean it’s the same in all respects. it just isn’t.
.. also wondered about injection waxes, high definition gravity
waxes may offer a solution to this unevenness that you speak of. I
was given a box of high definition gravity wax pour as a deal
sweetener, whatever you pour it into, it makes, it has a very low
viscosity (however it's as brittle as hell). Just an aside, anyone
know where to buy this type of wax (?),
Closest thing to that I’ve ever seen are some dental inlay waxes.
Dark blue, low melting point, Almost thin as water when melted. But
they do shrink some, air bubbles are a problem with plain gravity
pours… Not sure if this is the same as you’re talking about. The
other more recent product this reminds me of is a photosensative
polymer. Very thin liquid, you use it with transparent silicon molds.
inject it into the mold as a liquid, and spin it (the manufacturer
suggests putting the mold in the end of a sock and spinning it
around. Really. Not high tech, but it works.) Anyway, once the mold
is filled, and you can take as long as you like to get it there, you
then expose to U.V. light (that’s why the transparent silicone rubber
mold) to cure it to a fairly strong, rigid, no shrink plastic model.
Then the only shrinkage you have left is the cooling metal. Neat
product. Not so cheap, but doable if you need such. Last I looked,
Gesswein carried it, among others.
I don't think CAD, or rapid prototyping, is a solution for every
piece, but as I said it's getting better. I saw a smiley face made
with gold atoms the other day, I appreciate that kind of science,
because the logical conclusion from that research is that
eventually we will be able to make anything atom by atom (imo: cool
x infinity).
Yeah, maybe. That’l be the real iteration of what, when I was in
grad school mid '80s, was referred to as “santa claus machines”. They
were talking about RP modellers then, which were still at that point
fine for automotic prototypes, but not at all fine enough surfaces
for jewelry. it’s come a long way since. However, I don’t quite
expect everyone to be able to put a scanning electron microscope on
their desktop and manipulate gold atoms directly, at reasonable cost,
any time soon.
Personally, I won’t be happy with one till it’s as good as the star
trek replicators. Need a hot cup of tea? A fresh bottle of insulin?
An ounce of gold casting grain or heck, the finished ring, just punch
in your selections on the microwave oven like control panel nd
voila…
Oh, and printing direct to metal? I've not seen this done in gold
or silver or platinum yet to produce a solid piece of precious
metal in an alloy the same as we'd normally use. Have I missed
something? Given the pace of development, I might have blinked and
missed it. If so, I'd love to learn more...
But you have seen metal printing, if it was precious metal
printing, then our days would be numbered... only a matter of time
imo. Maybe we should be making works like it's our last piece? Make
every piece count?
You should do that anyway.
The direct metal printing I saw was not at all ready for prime time
jewelry. it produces a porous semi sintered object that then needs
secondary molten metal infill (Like filling a sponge with water).
It’s what Bathsheba Grossman’s sculptures, those being directly
printed, use. Semi sintered steel filled with bronze, if I recall.
Fine for her sculptures, but not only are the materials far from
anything like our precious metals, but the surface finishes are not
yet at all close to those from solidscape machines or good milling
machines, and these, as I’ve said, are themselves not the equal of
the finishes you get with good hand fabrication. Direct to metal is
intersting. But so far, of little use to jewelry. Another interesting
method is direct printing of what amounts to a ceramic shell mold,
suitable for casting. again, interesting, but not yet ready for
jewelry prime time.
There was, no doubt, a time in our craft when old timers, used to
fully hand making everything totally with hand power, bemoaned the
loss of quality that no doubt would come with these new fangled torch
things, electrical motor things, and what about those lights that
weren’t at all as good as sunlight… Some of what those craftspeople
knew how to do, has died with them, and a few of us now and then try
to rediscover what they knew. But the jewelry craft has survived more
or less intact anyway.
The new technologies will do many new things. Some of the ways we
work now will become obsolete. But don’t be so quick to kiss the
craft goodbye. It will change, as will the way goldsmiths work, but
the craft, I think, is not likely to die out.
And on the other side, don’t be so sure these future capabilities
will be here just tomorrow or next week. CAD/CAM and RP technologies
have been in developement and gradually being accepted and used for
the last 25 years or more, with our industry being one of the last to
really start to use it. It may seem overnight, for those to whom the
introduction is recent. But these things take longer to develop than
it may seem. I doubt you’ll see your atom by atom RP machine being
available to your desktop at an affordable price within your career’s
time, even if you’re just starting out. There will be many new
developments, incremental ones, and it may seem like it’s evolving
very quickly and overnight. But take it step by step. That atom by
atom one is more than just a few small steps, I think…
This is the point for me to see "if" I can make some thing that
looks the same. The 3d model will be symmetrically perfect, and
possibly be as cold as the machine that calculates its curves.
Perfect geometry doesn’t seem cold. Really good hand fabrication can
also exhibit very high symmetry and perfection of form, and it
doesn’t suffer from it. The CAD waxes also have their surface
texture. That’s a problem if trying to duplicate hand fabricated. But
if not, it can be wonderfully beautiful in it’s own right. Can look
like Moire patterns on the surface, or fine wood grain. Very cool
sometimes, especially on the higher resolution mills where some
textures can catch the light in an almost irridescent way.
I've seen some pretty detailed waxes, with internal machining...
probably going to cost me a small fortune, but I have to know, my
curiosity demands it ;-)
There are strict limits as to the capabilities of “internal”
machining, even with the most complex 5 or six axis CAM machines.
Jewerly CAD/CAM mills don’t generally carry it that far. (3 axis
normal mill plus rotary axis is the norm for the best of the jewelry
CAM mills). The bottom line is that you need to be able to reach the
desired surfaces with a standard slim taper mill of some sort. You
can reach less than you can see with a loupe, simply because of the
geometry of the tool. And current CAD milling software also doesn’t
let the mill attack the piece from all possible angles either. Trust
me on this. The CAD mills you can get a jewelry grade wax milled
from, won’t duplicate all the clean internal geometry of Leonids
piece, and even if it did, those would then be areas you couldn’t
even begin to remove the stair step texture from. if you want full
internal geometry, the only current method that’s good enough for
good jewelry waxes remains the solidscape type of machine, which
grows the waxes. They are not limited as to geometry. They can even
product fully closed hollow forms, though of course then you can’t
cast it that way without at least punching some holes in your form.
But as I said, these machines, wonderful though they are, generally
produce an even more pronounced stair step than can the good mills
running at highest resolution.
Your best bet, if you want to try and fully duplicate Leonids piece
via casting, is to use a CAD/CAM mill to produce the ring, but in
four seperate pieces. Inner surface, outer surface, and two sides,
exactly the same as the way Leonid hand builds his pieces in metal.
Then you can fully duplicate the geometry, and can finish the wax
surfaces inside and out. You could then assemble the componants in
wax and cast as one piece, but then you’d not get the interior
finished right. Or cast the four seperate pieces, finish in metal,
and laser weld or solder together just as leonid does. The advantage
is you still are letting the computer get all the layout and piercing
done accurately, saving you much time consuming and demanding work.
Done like this, you could pretty much duplicate the look of Leonids
piece. What it would not yet do, however, is give you the same
metalurgical integrity of his forged/rolled/drawn metal versus your
cast metal. You might still have porosity issues, and the metal
likely would be a little softer and less strong, depending on the
metal. In some, such as heat treatable alloys, you could come very
close indeed, since then you’ve got control over the final hardness
too. But it’s still a casting. Close enough? maybe. But not
guaranteed.
And it’s probably also worth mentioning that this particular test is
an extreme one. If you, as a CAD/CAM caster, are trying to produce
fine jewelry as good as much of the fabricated work out there, well,
that’s a lot easier than setting your target standard at the level of
expertise in hand fabrication, of someone like Leonid. It’s one thing
to want to run well enough to make your high school track team. it’s
another to want to make the U.S. Olympic track team… The one is a
laudable goal that not everyone can do, worthy of respect and
needing some work and drive. The second, well, that’s an order of
magnitude harder… your test is somewhat similar in nature.
Peter Rowe