[brian257]

My wife is a dental assistant and she wants to start a dental lab. I have been looking at some of the dental machines that are available for machining wax, zirconia, and metals and as you would expect they are very expensive. Average pricing seems to start around $20K.

I am thinking that I can make a small and very precise four or five axis machine for much less than buying one. I was wondering if anyone has built a small four or five axis machine for very small and precise work or another dental machine.

[Dan Falck]

I talked with my dentist a few months about this and he was planning on spending $100k for an Orec (sp?) system. I thought that was nuts. I looked at some youtube videos and still think that kind of price is out of this world nuts. This would be an interesting project, especially since I seem to live in the middle of a hub of dental offices near Portland Oregon (Beaverton).
Keep us posted on your ideas.
Dan

[johnohara]

I do systems work for a number of dental practices and they would love to bring their lab work in house. Especially crowns.

The Datron D5 is an interesting machine.

Dan Falck: Fully agree. Dental vendors are in serious need of disruption.

~john

[wizard]

I work in a regulated industry and thus know of some of the craziness the FDA throws at anything medical related. Unfortunately I have no interest at all in dentistry so can't offer any advice in that regard.

My wife is a dental assistant and she wants to start a dental lab. I have been looking at some of the dental machines that are available for machining wax, zirconia, and metals and as you would expect they are very expensive. Average pricing seems to start around $20K.

Considering the very small work area required you would think such machines would be a snap to build. However I'm not sure the machine is the hard part, translating from whatever they use for a ditial model to NC code might be where the sticky parts are.

I am thinking that I can make a small and very precise four or five axis machine for much less than buying one. I was wondering if anyone has built a small four or five axis machine for very small and precise work or another dental machine.

It all depends upon the precision required. I suspect price will ballon faster than you might think, especially if you do everything custom. Retasking a bigger machine might be the smarter move or at least re factoring the components from a larger machine.

I've worked on NC lathes in a production environment that two guys could pick up and carry around. They where cheap. It is amazing what a set of top grade spindle bearings will set you back. Even today some of the machines I work on are expensive beyond reason but when you go out to buy parts it is no joy. You could easily end up spending thousands per axis depending upon the accuracy and repeat ability required.

By the way I kinda doubt a machine doing dental parts has to be extremely precise but again no experience there.

In any event I still think the bigger issue is software. Productivity is a serious component when doing one off parts. Think of a dental lab as a machine shop that never does exactly the same part more than once.

[the4thseal]

I am familiar with these machines. The expense is in the software. Some of them are 5+ axes and include a scanning capacity. Not in the same machine but as a bundles product. The generation of the model and tool paths is very complex. Also the materials are proprietary. By the time you are finished with the whole thing as said earlier you will be surprised. Not only that but as an example the coolants and lubricants must be completely safe.

[harryn]

The dental industry locally is shifting more and more toward casting crowns than machining them and adding a ceramic coating and details. The newer ceramic materials which can be molded make this possible.

I have enough crowns in my mouth to trace the last 25 years of development, and the technology has changed considerably over that time. I would be very hesitant to invest in specialized crown making infrastructure right now unless I could achieve an ROI of less than 2 years, or the lack of infrastructure was seriously holding back my business.

[the4thseal]

My understand that these machines are being used to make large fillings as well as crowns. Also the turn around is quite fast not requiring a temporary to fitted.

[brian257]

My wife and I went to a dental lab show in Orlando on Saturday so I was able to look at several of the machines up close. Here are some of the tidbits I found out.

Most use a holder that holds a zirconium or wax disk that is about 4" diameter. Not real beefy and rigid holders like I expected, but you are using tiny bits and taking light cuts. I think my Sherline would be more than rigid enough for this work.

Some machines are five axis, but seems most machines and nearly all you need to make is 4 axis. Basically you are doing is machining one side of the disk then turning it over and doing the other side. Small sprues are machined in to hold the crown or bridge to the rest of the disk and you use a small pair of cutters to remove the part when done and hand finish the sprue. They do angle some for undercuts, but basically using three axis with a rotary holder.

Most of the machines used Jager spindles. The majority had a three to five station automatic tool changer, but some of the lower cost were manual tool change.

When asking vendors if they used G code they all looked at me like I was from Mars. I asked the Roland guy and he said they did use G code, but looking at their web site it says they use RML-1 code.

The software is the special part. They sell scanners starting around $12K that come with the software. Although you could use any scanner and then design your parts in any CAD/CAM and machine with Mach 3 that would not be a good idea. I think the dental scanner and CAD software to go with it is well worth the investment. An ameture can design a crown or bridge in 5-10 minutes from the scan with all sorts of special features to make it work correctly. An experienced dental tech that was good with a 3D modeling program would probably spend an hour or more getting one tooth correct and would be cursing the decision not to get the real dental software.

The make open and proprietary scanners and software. I have not figured out yet if you spend the $12-18K on the open scanner if it comes with the CAM module and if it does if you can configure it to output G code. They use STL files and I don't know if the software is making the cutting files or if they just dump the raw STL to the machine and the machine generates its own cam files. The software is very simple and you just tell it to mill and the mill works away and you can go back to scanning new parts and making new files while the machine works. Looks like there is just a USB cable from the computer to the machine.

I expected to see very rigid machines and was thinking of doing something starting with rigid granite surface plates, but they are not near that rigid. They pretty much all use aluminum frames with good linear slides mounted to them. They all use stepper motors. They don't have a lot of travel so looks like the mechanical part of making the machine will be the easy part.

[brian257]

Oh, and 90% of the machines work dry and can do zirconium or they do wax and the wax is used to cast metal parts. There are wet/dry machines that can also do titanium, but from what I am seeing that is not completely necessary to have. There are many milling centers where you can email your files and get back the titanium milled parts fairly cheaply. Building the machine for wet use would not be that much more, but not sure how often titanium is needed.

Oh, and one other neat feature of the software is that it can nest many parts in the disk. The disks cost about $120-150 in zirconium and you can make a bunch of crowns and bridges on one disk. You can either nest a bunch of parts on the disk through the day then mill them all at once or you can do one or two at a time and the machine keeps a model of the machined disk and the space left so when you add a part later you just plop it into an unused area.

[packrat]

Have you seen this? SIRONA CEREC 3D DENTAL CAD/CAM SOFTWARE DENTISTRY V3.01 New in Package | eBay For a little money it might let you see what you'll be up against.

[brian257]

Probably does not have a dongle or license number, but worth a few bucks to see. Thanks.

[johnohara]

brian257~

Have you made any progress with the dental machine?

~john

[brian257]

Just a little. I bought the dental software that was on Ebay and as I expected I can't do anything with it because it needs a dongle. It was worth the ten bucks though because it has several .stl sample files and a manual that gives me some good insight to how it works.

The major thing I have found out so far is that you get the design software when you buy the dental scanner. Even though I could probably adapt a much cheaper scanner it would be fairly useless without the dental design software. Yes, I could design a dental bridge in Rhino in a few hours, but for a lab doing it more than just once you really need the correct software that gives you a design in 5 minutes. The design software gives you just .stl files. Most of the milling machines take the .stl files directly with no cam software. I have found stand alone cam software also.

So far that is as far as I have gotten. I have several other major projects that are higher priority at the moment.