CadCam Corner: Choosing digital!
The UK dental industry is ‘going digital’ fast! We are buying scanners, milling machines and 3D printers. We all see the future is automation of our work, and fear the consequences if we fail to join the revolution.
But what we also see is endless choices of expensive equipment, confusing and sometimes conflicting information from suppliers, but no real route to the best profits for our particular laboratory business. A potentially lethal financial recipe…
With our embryonic knowledge of the equipment and processes available, it is all too easy to fall prey to the company that offers ‘everything’ in a handholding way, filling our digital-hungry heads with the apparent answer.
Comforting for a while, but I regularly see many expensive mistakes being made on the purchase of inappropriate machinery and processes. To make matters worse, we can be locked into certain systems, which gently move the potential advantages of digitising (i.e. profits) to the very company that provided the ‘ultimate’ answer to our needs.
So — how do we sort out this treacherous jungle?
First, be aware that there really are endless pitfalls to avoid, from fully closed systems that tie you into overpriced materials, maintenance, licence fees, updates, and consumables, to ‘partially closed’ systems that sometimes even purport to be open, but subtly restrict you, again with unnecessary fees, costly materials and overpriced spares.
For me, there is only one way to go: Fully open in every possible way. This means a scanner that produces STL files that you can easily send anywhere you choose. It means a scanner that once purchased, and therefore you own, ideally does not have endless compulsory annual fees much like a neverending lease.
If you do need to pay the maintenance fee, how much is it? Do consider the real cost of your scanner over, say, seven years to get a true cost comparison with other possible choices. This means a milling machine without dongles, with a sensible fixture (block holder) that holds economical discs/blocks that ideally you can source from your choice of competing suppliers. With certain materials that may be patented that may not always be possible unfortunately, so we must take extra care that the cost effectiveness of milling such materials is a genuine advantage to you and not yet another revenue stream for the manufacturer.
There may be another processing option which we will discuss later. With some milling equipment, the consumables (such as burs) are also very expensive and can also add to your costs month on month unnecessarily.
So, start your search with fully open machinery or be prepared to run up extra costs and efficiencies that if avoided, could be adding to your bottom line rather than someone else’s.
Secondly, look at what equipment you really need, which means analysing what products you make now, and then deciding what will help you make those products more efficiently. If that is cost effective, you have the basis of a decision.
Do not build a case on new products that you might be wanting to offer….they can be a bonus of course.
Your starting point is probably a scanner. How to choose?
- Open or closed? Should be open, or you will be tied to one company with limited options and higher costs.
- Structured light or laser? Structured light is a little less noise free than laser, and is an industry choice. The decision is not a vital one.
- Two cameras or more? Two cameras does the job. The ideal is to use the minimum number of cameras, at the minimum resolution, that will then collect the minimum number of points of noise free data that will still reveal the sharpest point, i.e. the margin line, accurately and quickly. More cameras and more megapixels are not only unnecessary to achieve superb results, but mean considerably more data points collected, more noise, and increased processing time. This is definite overkill that could make you favour one scanner over another for no good reason.
- Ease of software use. Some are easier to use than others, as you would expect. Ask actual users for opinions, or better still, try hands on yourself if you can.
- Speed of operation. The speed is usually affected by the amount of data collected (See answer 2).
- Licence fees. No one likes to pay an annual licence to operate what is your own paid-for equipment. But do you need the so-called updates? Some are really worth having but it is better if it is your choice and not forced upon you.
- Back-up on breakdown. This may be included in a licence fee. For some, that kind of insurance is worth having. But check out what will actually happen if your scanner fails. One of my scanners had to go to two countries for a small repair (a motor). Huge cost! I chose to bin it (six years old) and move on. Who will do the repairs if any, where will it be done, and what will I do without a scanner or is there a loan scanner available? There is not much to go wrong with a scanner, so here we choose to pay for a repair when necessary, and avoid annual fees.
- Technical back-up. This can be a vital resource. Ideally this type of back-up should be from a user of the same software. This will not only help you solve any user issues easily, but will also expose you to best practice and tricks of the trade.
- Installation and teaching. It goes without saying, that if 8. above is not available, then your initial training is vital, or you will be left to ‘discover’ the program on your own. Training should ideally be from an actual user, not just someone to show you the buttons.
- Any unique points. It is quite possible you have identified a particular use unique to a certain scanner, and then this will be a purchase you may have to make, despite the possible drawbacks of ownership. Just make sure the costs do actually work in your favour as much as possible.
- Cost over seven years. This is a realistic period to use and make a return on your scanner. So add in any extra license fees before you work out your costings, this will give you a true cost comparison with competitor products. Also, bear in mind the real speed of scanning your day’s work. You may find you need two scanners of one brand to do what just one other make can do on its own. The test is better over a whole case rather than just a single scan, which does not reveal the complete picture.
Let’s move on to milling machines. Some of the same points arise:
- Open or closed? Should be open again. There are many inflexible systems out there that constantly demand you purchase everything from the supply company, at a heavy and unnecessary cost to you. No doubt you will be offered large discounts to close the sale…beware!
- Dry or wet milling, or both? Dry milling will allow you to cut wax, pmma, zirconias, Peek, Fibre and so on. Wet milling is needed for glass ceramics and metals such as Titanium and Chrome Cobalt. However, there are some metal blocks that can be dry milled, if a little pricey at the moment. Why not buy a mill that does everything? On the face of it that appears to be the most cost effective and ‘future proofing’ answer. However, spindle wear is substantially increased when you combine such different materials: it’s not about just the cleaning. When you have milled zirconia, then use the mill wet, the remaining zirconia dust creates a very abrasive slurry. This is what wears the spindle. But let’s dig a little deeper and look at the practicalities and cost effectiveness. On practicality, it’s really down to looking in detail at what you will require your mill to do each day: if it’s a couple of zirconias, five glass ceramics and a stack of wax, how practical is it to keep cleaning down the machine for change of use? This needs to be looked at thoroughly. How long does it take to clean down? Can you really clean it down so there is no zirconia left to form that abrasive mix? Will you end up only using part of your mill’s capability, making it an unnecessarily expensive purchase? Something to consider based on what you actually mill each day or working week. Now consider this: How much does it cost to mill/grind glass ceramics both in the cost of the blocks and also in machine time? A very efficient laboratory workflow I have seen mills all the glass ceramic cases in wax, achieving a very high standard of occlusal carving every single time, then presses them. A mill that grinds glass ceramics uses only a 1mm bur to finish. This may not give you the occlusal detail you would expect and hope for. So perhaps combining the cost efficiency of pressing with the cheaper dry milling of wax is the way to go. Very profitable, very efficient and consistent, and very digital. Interestingly, this laboratory also has a second hand wet mill for the one or two cases that either need to be turned round fast for a patient, maybe the same day, and the odd remake that then won’t interrupt the workflow, and for spikes in work at peak periods. So before you jump in with an all singing, all dancing mill, consider your detailed workflow setup and analyse those costs. A few hours spent now will save you pounds every day going forward. Think how that can mount up! Another point worth considering if you do want to wet mill, is it may be a similar cost to buy two mills. Then you have twice the milling capacity and no compromises…
- Block type? This can be a clue to open or closed: can you get the blocks elsewhere at a competitive price? Or are you about to pay extra on every case you mill?
- Bur costs? Again, are you having to buy some ‘special’ bur from your supplier? May add to ongoing costs…
- Maintenance/Insurance? This may be worth having to cover you for parts and labour and even an exchange unit if the problem is over more than a day. Long breakdowns can be massively disruptive.
- Servicing and backup? This may be covered by point 5 above or may be a separate cost. Worth knowing exactly where you stand and what sort of costs are involved. Also try to check with current owners for their experiences.
- Technical backup? Worth being able to speak to a real user to get the best from the machine software (CAM) and the mill, although some systems will not allow you to change any parameters.
- Install and teaching? As with the scanners, being taught by someone who actually uses the equipment you have bought is again the difference between being shown the buttons or coached towards real user level.
- Unique points? Faster speeds, more tool holders….check out what you actually need for the products you intend to mill.
- 3 axis or 5 axis? 5 axis gives you better usage of blocks and the ability to mill undercut areas. Once again, check out what you actually want to mill: 5 axis software on some systems is literally double the price of others. We only cut a small percentage of cases that need the 5 axis in the milling centre here.
- Cost over 7–10 years. Lastly, check out those costs over a reasonable timespan. Probably 10 years for milling equipment, adding in any dongle or licence fees.
Finally, let me declare that Bristol Crown and Bristol Cadcam run several scanners, several mills and various software. We are also dealers for Medit
scanners, Exocad software, Roland mills, CamZero milling tools, Sum3D CAM software, the Vivid zirconia range, BOFA extractors, Nabertherm and Carbolite sintering ovens and various other consumables.
As technicians, having made plenty of mistakes ourselves, let us help you to avoid some as you go digital!
Tim Brothers, Director, Bristol Cadcam Co Ltd., Bristol Crown Company Ltd