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CNC Mill Preference


#1

Over the past couple of months, I have been learning and using Rhino
to develop 3D models. I am at a point now where I am seriously
considering purchasing a mill, probably with a 4th axis rotary
table. From reading all the posts on Orchid, I know that there are
many users, some of which are also dealers/resellers of equipment.

I would like to know what machine(s) you are using and why you chose
the machine you are using. Would you buy the same mill again, or did
you replace your initial machine with another because it did not
serve your purpose? Has the reliability, accuracy and speed of
production met your expectations?

Models (jewellery size) I am contemplating would be made out of wax
or plastic, and possibly expanding into cutting small metal moulds.

Also, is there anybody on this forum from the Toronto, Canada area
that could provide some local referrals for dealers or users willing
to share their experience?

As always, I appreciate and welcome your comments.

Richard Dubiel
@Dubiel_Design_Studio


#2

Hi Richard

4 axis mills come in a wide price range, with one of the main
differences being in accuracy, meaning how closely the mill will come
back to exactly the same point over and over and over again, it’s
called REPEATABILITY, and this is one of the main criteria you will
want to keep in mind when assessing mills.

Taking mills from the lowest priced…

MaxNC, though most experienced machinists consider this mill a
doorstop, I had the opportunity to try one today at the University of
Iowa where I was giving a two day seminar to the Metal Arts Dept. on
jewelry making technology. I have been helping the students there to
learn Rhino for 3D jewelry design for the past few weeks, and today
we milled one of their models on the MaxNC. I was pleasantly
surprised to see a well cut model, and I didn’t expect it! This model
of the MaxNC has stepper motors set up with encoders for positional
feedback, and it works fairly well. Point is, don’t rule out the
MaxNC if you are very short on funds.

MicroProto (the Taig mill) is a little like a MaxNC on steroids. The
4 axis version can be had complete for under $3000! The specs it
boasts are formidable which is interesting as this mill (and the
MaxNC) both use dovetail ways instead of slides. The Microproto uses
adjustable gibs, and I’m unsure if the MaxNC has adjustable gibs, but
it might.

I haven’t seen a Sherline yet nor heard any feedback, so I won’t
comment on it.

There is now a jump in price up toward $10,000 for mills with highly
precise slides, both linear (more expensive, and standard (I forget
what to call them…)

ModelMaster mills boast phenomenal repeatability, better than .01 mm
and range in price from about $10,000 up to about $20,000. This is
the mill I recommended the University purchase when they requested I
suggest one.

There are quite a few tabletop mills, and I suggest you visit the
site http://www.desktopcnc.com/mill_table.htm for a rather complete
listing of price and capabilities.

Come to think of it, I should of just directed you there to begin
with, so I’ll stop at this point!

By the way, I’m still using the same 3 axis mill I bought 10 years
ago, the Roland CAMM3 PNC-3000. It’s a very well made little mill,
but I’m in the market for a new 4 axis mill myself. I need better
precision now (with 4th axis) that my models are becoming
ridiculously complicated and detailed… :slight_smile:

Jeffrey Everett


#3
    There is now a jump in price up toward $10,000 for mills with
highly precise slides, both linear (more expensive, and standard (I
forget what to call them...) 

The term you are looking for is box ways. Also there are different
configurations of linear guide ways also. The most accurate are
glass scales, but would be considered overkill for the desk top
application. I would not expect to find a table top mill with glass
scales, but it was worthy of a mention.

   and I'm unsure if the MaxNC has adjustable gibs, but it might. 

Yes they do. In the form of an Aluminium plate or shim, adjusted by
set screws. At least the ones that I have taken apart did :slight_smile:

Best Regards.
Neil George
954-572-5829


#4

Richard, There are many good mills out there, I use the Wolverine 3
from Align- Rite (www.alignritetool.com ask for Matt Dunn) after
months of shopping and comparing quality and price. Gem Vision
offers one “The Revo” that is excellent ( www.gemvision.com ) that I
would have considered if it was a available two years ago. Someone
mentioned the Model Master mill, my opinion is that is a very
expensive toy compared to other higher quality mills out there plus
MM customer service is the worst I’ve ever experienced. Just my
opinion. Charles


#5

The linear bearing ways that you refer to in these highly precise
mills are no more precise than a properly constructed dovetail way
but they have much less friction due to their low surface contact
area. This makes it cheaper to build for CNC as you can use less
powerful motors to drive them. However more of the cutting forces
will be transferred to the screws and motors and this can reduce
operational accuracy if heavy cutting is being done. You will find
once you get away from the desktop mills that industrial milling
machines all have some form of dovetail way. Dovetails are able to
handle the heavy forces of a mill cutting metal rather than wax or
plastic without deflection.

It is also interesting to note that some of the mills now being sold
to the desktop CAD CAM users are costing upwards of $25,000. A good
quality full size Haas CNC TM-1 tool room mill starts at $19,000. Of
course with accessories you will have a more investment in it but it
has a machining envelope of 30" x 12" x 16" and it has repeatability
of .0002" (.0051mm) and a positioning accuracy of .0004" (0102mm)
that is as good or better than the desk top mills and you can
accurately cut metal with it. The desk top mills are just too
flexible to hold tolerances in metal but can do a very good job in
wax and plastics.

Jim

James Binnion Metal Arts
Phone (360) 756-6550
Toll Free (877) 408 7287
Fax (360) 756-2160


@James_Binnion
Member of the Better Business Bureau


#6
    The linear bearing ways that you refer to in these highly
precise mills are no more precise than a properly constructed
dovetail way but they have much less friction due to their low
surface contact area. snip... 

James – Your excellent post finally clarifies the linear slide vs.
box ways debate for me. I have worked with larger mills (Milltronics
Partner series) that have excellent repeatability (and always home to
the same exact location), and they use dovetail box ways. I
understand that machine rigidity is an important factor in cutting
accuracy because of deflection. My Roland for instance, weighs about
150 lbs, and simply doesn’t have sufficiently rigidity for metal
cutting with all but the smallest tools and shallow passes. There
must be a reason why so many machines are now going to linear slides
though. The SolidScape 3D printers have moved to incorporating linear
slides because the less rigid bar slides (once again I forget what
exactly they are called) could not maintain sufficient accuracy.

Pricing, as you mentioned, is another issue. The heavier machines,
such as the Haas you mention, are moving a lot of weight around, and
the inertia present when making fast small moves might be somewhat
problematic, or so I’ve been told.

    Richard, There are many good mills out there, I use the
Wolverine 3 from Align- Rite (www.alignritetool.com ask for Matt
Dunn) after months of shopping and comparing quality and price. 
Gem Vision offers one "The Revo" that is excellent (
www.gemvision.com ) that I would have considered if it was a
available two years ago.  Someone mentioned the Model Master mill,
my opinion is that is a very expensive toy compared to other higher
quality mills out there plus MM customer service is the worst I've
ever experienced.  Just my opinion. Charles 

Charles – The German made “Revo” mill as sold by GemVision is
available without the legendary GemVision service and support and
their proprietary add-ons for about $10,000, close to half the price
GemVision sells at. I happened to be at GemVision HQ when they were
assessing mills, and they had a ModelMaster mill there along with
some others. It did not appear to be a “toy” to me, and it was the
mill they were using at the time for 4 axis testing. I’ve chatted
with the tech dept. at ModelMaster for hours regarding controls,
repeatability, positioning accuracy, and so on. I was so impressed
that I changed my opinion about them, and suggested their mill for
the University Jewelry dept. ModelMaster ‘service after the sale’ is
something I don’t know about so I can’t comment.

I would like to comment on the proMa Technologie mill (aka Revo). It
features an option for full 5 axis simultaneous operation, something
jewelers have wanted for years. I suspect this is why Jeff High
(GemVision) made this the mill of his choice. A movie of the mill in
full 5 axis operation is here (link at bottom of page)
http://www.proma-technologie.com/englisch/rundum_l/index_e.html

Had I known this about the 5 axis capability of the proMa mill I
probably would have suggested it instead of the ModelMaster. In
essence, the deciding factor was the inclusion by ModelMaster of 10
seats of ArtCam at no charge (a $75,000 value). I didn’t think the
university could pass up this excellent offer. They didn’t and the
grant was requested.

Jeffrey


#7

Aloha Charles, I have been out of the mainstream for a while, mostly
doing product development and helping our customers. After you post,
I thought I should ch ime in. I am sorry you felt your questions
were not answered effectively,and obviously by your choice to
purchase a CNC version of the Taig mill (Wolverine 3), they were not.
If you were shopping for price and not functunality, you made the
mistake many people made, including myself. It is very hard to make
an educated decision based on one output device and limited
I would actually like to hear more about your
experience.

The mechanics and the electronics of these systems make a very large
difference. If you compared your solution to a Servo-Impact, a
Cielle, a High End Roland, or a Prolight mill to ours (all of which
we also carry), I may not have even addressed this. Your example is
comparing apples to oranges or even more, analog to digital.

We manufacture our Model Master mills here in the USA and combine
them with the most powerful jewelry specific software in the world.
We have over 750 systems, World Wide. Names that you know. I can
provide 20 references at a time or 100. Ask the same from your other
CAD/CAM source. If you want to know mor e or find out the
difference, ask me. If you prefer to do this off list or on list, is
fine with me. Many people that are looking, would want appreciate
it, so they can make the best decision. But please tell me what
happened that le ad me down your road, so we may correct it in the
future.

Best Regards,
Christian

Christian Grunewald
Precision Modelmaking Technologies Hawaii
(808) 622-9005
Applications / Technical Representative
http://www.modelmaster.com


http://www.3dclipart.net


#8

Aloha Charles, I have been out of the mainstream for a while, mostly
doing product development and helping our customers. After you post,
I thought I should ch ime in. I am sorry you felt your questions were
not answered effectively,and obviously by your choice to purchase a
CNC version of the Taig mill (Wolverine 3), they were not. If you
were shopping for price and not functunality, you made the mistake
many people made, including myself. It is very hard to make an educa
ted decision based on one output device and limited I
would actually like to hear more about your experience.

The mechanics and the electronics of these systems make a very large
difference. If you compared your solution to a Servo-Impact, a
Cielle, a Hig h End Roland, or a Prolight mill to ours (all of which
we also carry), I may not h ave even addressed this. Your example is
comparing apples to oranges or even mor e, analog to digital.

We manufacture our Model Master mills here in the USA and combine
them with the most powerful jewelry specific software in the world.
We have over 750 systems, World A0Wide. Names that you know. I can
provide 20 references at a time or 100. Ask the same from your other
CAD/CAM source. If you want to know mor e or find out the
difference, ask me. If you prefer to do this off list or on list, is
fine with me. Many people that are looking for a CAD/CAM solution,
would appreciate it, so they can make the best educated decision.
But, please tell me what happened, that lead you down your road, so
we may correct it in the future.

Best Regards,
Christian


#9
    Someone mentioned the Model Master mill, my opinion is that is
a very expensive toy compared to other higher quality mills out
there plus MM customer service is the worst I've ever experienced. 
Just my opinion. Charles 

Dear Charles, As an independent representative of Model Master and
more importantly as a daily operator of a Model Master CNC 1000 mill,
I know first hand of the quality of the machine. To quote a
statement from a fellow CAD/CAM jeweler, “MM mills are built as solid
as a rock”. I’ve spoken to jewelers running MM mills in high
production environments non-stop for 4 years straight with only
routine lubrication and maintenance. Conversely, on a jewelers
CAD/CAM message board I often frequent, I’ve heard reports from
owners of other mills who have had to replace major hardware
components after a year or so of regular use.

At the MM production shop in Canton, GA., I’ve seen the
sophisticated level of engineering, the highest quality of materials
and parts and the excellent workmanship that goes into manufacturing
these mills, so your statement leaves me baffled. You will not find a
better value in terms of consistently superior CNC milling results
and long term worry-free machine usability.

Model Master has the largest satisfied successful customer base of
any company producing CNC mills for jewelers, with 600 in the USA and
a total of 750 worldwide. Some of the most prominent and recognizably
"big name" jewelry companies in our industry have purchased 2nd and
3rd MM mills to accommodate their production needs…For that matter,
several smaller but highly successful, independent jewelers have
added an additional MM mill or a MM laser scanner to keep up with
their workload.

Charles, what I’m getting to is, I was surprised to hear that you
were unhappy about your experience with MM. Earlier today, I spoke to
Mike Adams co-owner of MM about your comments. Perhaps your dealings
with MM occurred when you were with another company name, because
Mike checked, and he could not find a reference to Charles Bahringer
in Model Master’s extensive customer database.

One of the things I find so invaluable about the Orchid community is
that, as online forums go, there is an unusually high level of
discourse here, as well as a remarkable absence of unsubstantiated
"pot shots". With that thought in mind, I hope you’ll address the
issue with us, on this open forum.

Model Master prides itself on good public relations and excellent
customer support, so it would be very helpful for us to know the
particulars of your experience, so that we may better serve our
customers according to their individual needs.

Thank you, Jesse Kaufman JDK Jewelry Design CAD/CAM Technology
Handcrafted Originality www.jdkjewelry.com


#10

Richard, Selecting a mill can be an objective experience using
quantifiable factors of the various components that make up a mill.

Here are a few things you can compare when selecting a mill.

Type of spindle

Size of the motors, the quality of the bearings, and whether they
have much backlash or not.

Type of screws, their accuracy, and the pitch of the screws

Rotary table or not

Tail stock or not

solid milled construction or lightweight extrusions

Capability of the electronic controller

Whether software is included or extra - this could be expensive

The warranty

Users references concerning the reliability of the machine, the
speed at which it cuts, warranty service, and the quality of the
parts.

A competent vendor should be able to compare the features and let
you know how their components and construction compare to other
machines on the market.

The Modelmaster machines look to be solidly built.

A lot of the machines under $10,000 look like variations on the
Sherline machine, an inexpensive hobbyist machine. There is a point
where you probably do get what you paid for.

You might wish to have some models built on the machines you are
contemplating, so you can see for yourself what the finished models
look like. ASk how long the model took to cut, and with what sort of
tool.

No offense to any vendor, but you might want to get models from a
real user. They might be more forthright in letting you know the
nitty gritty plusses and minuses of the machine.

Carl