Hi Richard,
I stumbled into this thread yesterday, so I’m trying to figure out
(A) what’s going on, and (B) why everybody’s so wound up about it.
Question one: Are we still going on about Leonid’s “Make me a CAD
ballerina ring” thing? (Or was it an eternity ring?) Question two:
did that ever get designed?
The inside took no time at all (you're welcome to the.stl if you want it), the problem was not being able to see the rest of the design, in enough detail. I could have mocked up something, but didn't want to make something different, and then get accused of not following the design.
Anyone with years of fabrication experience knows that CAD can be similar but not exact, either in form or function. The bitching and moaning was the second reason reason it could not be done.
Huh? I do have years of fabrication experience, as well as enough
CAD experience to be a threat to myself and others. I’m not entirely
sure what you’re talking about. CAD absolutely can map out exactly
the same shapes as are produced via hand fabrication. Whether or not
that makes any sense to do is an entirely separate point. CAD
(meaning Computer Aided Design) can make digital models of
whatever form you like, to whatever level of precision you like. CAM
(meaning Computer Aided Manufacturing) may or may not be able to
output those forms in any way that makes sense, but again, that’s a
separate issue, and depends largely on what sorts of gear you’ve
got, and how much money you want to throw at the problem.
The skill to do the fabrication and the skill to do the CAD are not equal, therefore the results cannot be equal. There is something CAD cannot accomplish that fabrication can.
That’s sort of like saying that the skill of sailing is unequal to
the skill of riding an elephant. Both get you from point A to point
B, but they’re not really related beyond that. OK, what can CAD not
accomplish that fabrication can? (given that there are all sorts of
parts out there produced by CAD/CAM methods that are then fabricated
into the final assembly.)
I do understand your point that (at least in precious metals) there
are a lot of CAD/CAM processes that are stupidly inefficient, but
that doesn’t make them impossible, just expensive. Equally, if I’m
willing to go the LONG way around, I can rig up CNC processes that
will exactly mimic the formed metal properties of a particular
fabricated piece of metal. I’d probably have to waste a mountain of
gold, and build a custom machine to do it, but it is possible. (Just
stupidly expensive.)
If the CAD design was carved out of a solid block, the only way the metal structure could be similar to the fabricated piece, the tools used cannot compare to the results of the forged, drawn, and brazed process.
Again, see above. You could (if you were nuts enough) build a
machine to draw a tube, then machine that down, which would give you
the same hardness state. Probably even better, as the machined one
wouldn’t be annealed from soldering. But horrifically expensive
and inefficient.
On the other hand, remember that the Bonny Doon presses do have a
deep draw rig set up for drawing 12Ga tube, specifically for
machining solid rings. So it’s not as far out in science fiction as
you’d think. (Or, just forge down a big block of gold, and machine
that. Fully hard, nice tight grain structure, and about 95% wastage.
Stupid does not equal impossible.)
As another example, when I stop procrastinating, and send this
message, I have to go back to designing a pair of dies to take a
disk of silver, and ‘wave’ it, sort of like the ‘skirt’ on a
ballerina ring. The dies will be machined by a CNC mill. So the form
produced will be (technically) produced by the evil of CAD. (ack!) On
the other hand, they’ll be much more accurate, and make a much
better form than the hand filed dies that my client was using
before. Which means that the final handles (made up of stacks of
these waffled disks) will be much more accurate and attractive than
they were before. So how is that bad?
If I had a customer that wanted a fabricated piece, do you think a CAD piece would be honest or ethical?
Depends on what you sold her. Did you sell her a gold ring, or did
you sell her a piece of performance art?
The manufacturing process has dumbed down the skill level needed to produce jewelry. Manufacturing by other than fabrication has changed the expectation of the public. People are willing to sacrifice quality for price.
That I’ll give you: many customers care more about the bottom line
than anything else. But those aren’t really the ones you want
anyway. Getting into a race to the bottom with Asia isn’t a winning
strategy. Meanwhile, what about the “quality” of the umpteen million
cast ring parts that get slapped together every day into
“fabricated” pieces of jewelry? Arguably, those are of much lower
quality than a CNC produced part. Even better, the original masters
of a great many of those parts may well have been produced by CAM
processes. Does that ‘original sin’ contaminate the whole finished
piece, forevermore?
Antique Roadshow will not have segments in 100 years showing furniture and jewelry brought for appraisal because everything produced now is crap. The internet allows us to publicly expose ones self as a victim of our own folly.
Everything produced now is crap? So Daniel Brush, Kevin Coates, or
a whole list of other artists are producing crap? Perhaps the baby’s
a bit bigger than this tub of bathwater, no?
Meanwhile, historical jewelry is a hobby of mine, and one thing you
notice when looking at ancient (archaeological) jewelry, is that
there were mountains of crap produced in any given time period. It’s
only the truly outstanding examples that get preserved. Looking at
just those survivors, we get a skewed view of what was actually
produced. So, will ‘Roadshow 2200’ be looking at Swatches or Pandora
bracelets? No. On the other hand, there will still be a large number
of very nice pieces that will survive.
To pull back from some of the ‘stupid doesn’t equal impossible’
examples, and get back to the sorts of things that sane people might
actually try, you’re both right and wrong in saying that CAD can’t
equal fabricated work. You’re right in saying that CAM (as distinct
from CAD) can’t equal hand fabricated parts at any realistic price
point, (currently), but wrong in saying that it can’t do it at all.
(and the prices are coming down…)
CAD/CAM is a tool, no better or worse than a vulcanizer. In the
hands of a schlock merchant, a vulcanizer is a truly horrible thing,
enabling the wholesale copying of designs without the least thought
for what shrinkage will do to the mechanics of the design being
copied. In the hands of a skilled operator, a vulcanizer lets one
make pieces that would simply be impossible any other way.
The old computer joke about “Garbage in, Garbage out” applies.
Ultimately, the quality of the piece is up to the guy designing it.
If he doesn’t know what he’s doing (and they mostly don’t) you get
garbage. For the few who do, the machines will sing.
Regards,
Brian
