Sorry I have not had time to respond to your thoughts on the
Waxcutter system, I’ll try to address that subject as well as this
one about CNC waxes and molds.
Most of what I know about CAD/CAM has been learned from jewelers who
use ModelMaster CNC machines, so it’s been helpful to hear other
points of view on this subject. I was not familiar with the HD
molding system, so I will look into it.
Before I got into CAD, I worked as a craftsman for a couple of
custom- design shops here in CT. One did in-house casting and the
other sent out hand crafted waxes and metal prototypes to a casting
company. I preferred to clean up the outsourced castings because they
were cleaner and seldom had any porosity.This was not a reflection on
anyone’s casting skills. A professional casting house is more likely
to have the state of the art in casting equipment.
As Jim mentioned, going directly to a silicon mold from a milled wax
usually produces excellent results. What minimal shrink there is,
could be compensated by scaling up the CAD model by a few percent or
by adding a small fraction of a mm to certain dimensions of the
in the 3D drawing, if you thought it was necessary.
Considering the time it would take to make a mold, shoot a wax and
cast in metal, and the results that I would like, it seems to make
more sense to me to pay
$18 for a silicon mold and a little extra for the cost of the metal
alloy and get a very good casting delivered in 2-3 days. Since I
specializing in CAD design and modelmaking, I’ve found it’s a better
business decision for me to send waxes out to a casting house. I
chose Roni Castings, because they have a lot of experience with CNC
milled waxes and RP models… Roni recently did some castings for me
a medallion with intricate detail and lettering. As much as I trust
their work, the results greatly exceeded my expectations. Roni also
returned my milled wax in pristine condition after making the silicon
mold. Last night, my customer called to say she absolutely loved the
finished pieces, so when she orders more, I’ll call the caster…they
kept the mold, so I don’t need to send it back to them. If it’s a
one-off design and not a complicated model to mill, I don’t always
have a mold made.
Regarding the need to hand finish CNC milled waxes, yes, there is
some work that needs to be done, but the stepping effect that you
mentioned is not so much an issue depending on the machine and method
used to cut the wax…Surface quality is dependent on a few different
factors; the size of the tool chosen for a particular job in relation
to the detail of the model, the step-over of the tool and the feed
rate of the toolpath to the machine, all figure into the equation.
With a CNC milling machine capable of running a fast feed rate using
small tool, cutting with a small step-over without sacrificing
accuracy and repeatability, the time it takes to cut a wax and the
stepping effect or more precisely described, “tool markings” are not
so much an issue.
The light tool marks that can be seen with a loupe, are usually
negated by the level of surface detail that the regular casting
process can pick up and the normal finishing process. What I do
notice is that flat vertical sides of rings have some texture that is
better taken care of in the wax with a few passes of a sanding stick
or fine file, but I never touch the details of a design by hand after
the wax is milled. If I make a mistake by not telling the machine how
to do it right, I correct my error, and mill it over.
Intricate detail and symmetry with fine precision is the main reason
most people value CNC milled waxes, so if I’m in business to make
those kinds of models, why would I use a machine that can’t produce
those results? I usually use a cutting tool with a tapered flute
(cutting edge) that has either a 7.5 or 5 degree side angle, so the
taper of the tool as it plunges down into a deep azure, cuts a hole
down with a smaller diameter at the base. The azures can be opened up
by hand with a drill before the wax is cast, or a separate toolpath
with a tool called a straight end mill can be done to fully bore out
the azures. ArtCAM has a CAM option which mills certain areas while
not gouging the rest of the model, so it takes 2-3 minutes for an
end mill to jump in and out of a bunch of azures… I love watching
the mill perform certain aspects of the milling process.
On the subject of the WaxCutter system, first I’d like to thank the
gentleman who clarified the question as to whether it can do curved
surfaces. I understand better now that a ring shank can be given an
over-all convex or concave shape. However, in seeing the finished
jewelry on the site, it is inapparently not used to create surface
modulation on small details.
A method of creating a ring with surface modulation on small details
from a flat template can be accomplished in Rhino 4
There are a few video tutorials here, *http://tinyurl.com/2uhf4u
*demonstrating the process. They are both under the topic- Rhino 4.0
WIP UDT Sporph, in the August 2004 section. You will have to sign up
with an email address for a password to view the videos, but they’re
One tutorial shows how to flow a flat-drawn tapered ring shank to a
circle, in the other, a complex filigree pattern is flowed to a domed
ring surface…it looks like magic compared to the way we had to do it
in Rhino 3.0 ! In another section, a twisted rope effect is
flowed to the edges of a shank.
I can appreciate the approach of choosing a CNC system that will
enable you to make money with it quickly. If you can learn the
WaxCutter system without a significant investment of time and effort
and it fulfills your immediate desired results in terms of simple
designs and meets your expectations of what a system in that price
range should do, then all the better.
I have an friend who just ordered one of the lower cost mills that I
guess some people categorize as a"hobbyist mill" but I am going to
reserve judgment until I hear how he does with it. Jewelry isn’t his
main source of income, so if he can produce a few models a week on a
mill costing under 3K, more power to him.
On your question regarding whether one needs to spend 30K on a high
end CAD/CAM system, it’s a matter of personal preference, balancing
financial considerations with immediate and long range goals and the
option for creative growth and expandability using CAD, towards the
future. Just as something to think about, Model Master has the Micron
mill for 11K which is compatible with all the conventional jewelry
specific CAD programs. So, if one got off to a running start now with
a Micron and MoI or Rhino, and purchased their choice of one of the
more expensive jewelry CAD programs later down the road, they would
still come in at about 10-12K less, have a reliable CNC machine that
would serve them well for years to come and do everything they’d ever
need it to do. Also significant is that they would not be locked
into a particular CAD program/CNC mill as with a 30K system.