Jordan Greenberg is a Dental CAD/CAM milling expert that has been heavily involved with digital dentistry for nearly a decade. Prior to joining DATRON Dynamics, he owned and operated a milling center in Skokie, IL. With a concentration on the in-house production of titanium implant parts, Jordan draws on his extensive CAD/CAM software and machining experience to implement turn-key milling systems throughout North America. He also works closely with other industry leaders on advancements for the D5 Dental Mill.
The Dental Lab Network is an online community where I’m often pulled into discussions regarding titanium implant milling using medium duty, dental-specific machinery. There was recently a thread where lab owners were inquiring about the accuracy of lighter weight benchtop models. Here is my response:
Just a few clarifications regarding the misconceptions I commonly hear within the dental industry related to milling titanium implant parts … some of which have popped up in this thread.
First of all, it’s important to note that a milling machine’s ability to cut titanium does not mean that same machine has the ability to produce implant parts. Implant geometries require a much higher level of precision and accuracy than crown and bridge applications. A couple factors (among many) that play an important role in milling implant bars and abutments successfully in titanium are machine rigidity and consistency at the tip of the tool (known as tool runout or concentricity). From my experience, a 5 micron dimensional adjustment to an implant hex has a significant enough effect between a part that fits and one that doesn’t. So if the tool’s tip is “wobbling” at 10+ microns, which can be the case in a direct shank tool-holding spindle, you’re not going to get accurate enough parts from your machine.
This is why we use Schunk Tribos HSK holders to secure the tool inside the spindle, yielding a tool concentricity of about 2 microns or less. This increases spindle life (spindle bearings hate vibrations), increases tool life, and most importantly … ensures the accuracy of the final milled part.
This is one of MANY machine attributes to keep in mind when you’re making the jump from simply milling titanium (as a preform or for crown and bridge applications) to complete titanium abutments and bars.
In the dental market, the D5 Dental Mill is on the only machine that utilizes this tool clamping technology. It goes to show how important DATRON’s industrial CNC experience plays a positive role in creating an easy-to-use system that still has features which increase a dental lab’s ability to produce highly precise implant parts in titanium.
“Isn’t the spindle power of the D5 (1.8 kW) too low compared to the 5kw spindles on similar level mills?”
I’m glad this question was asked for a couple reasons:
Different manufacturers have different ways of identifying a spindle’s power rating, and
Aside from power ratings, there are better ways to determine which spindle is appropriate for a certain application.
Here was my response:
Some spindle companies use maximum power to describe or identify their products. Others, like Jager, use continuous power. The liquid-cooled Jager spindle in the DATRON D5 Dental Mill, equipped with HSK-25 collets, has a 1.8 kW continuous power rating and a 5 kW maximum power rating. So, it’s no less powerful than the other mills. It’s just described differently.
However, what’s much more important than spindle power is the actual performance relative to your specific application — in this case, milling titanium parts for dental implants. I’ve never seen the power consumption of the D5 spindle exceed 24% while milling titanium bars or custom abutments. In fact, it usually hovers around 14-16%.
Another indication that a spindle is properly (or improperly) spec’d for a particular application is its bearing wear. There’s a vibration measurement device we use whenever performing preventative maintenance on any of our machines (dental or industrial) that indicates the level of wear on a machine’s spindle bearings. For example, we have a customer with over 9,500 hours on their 1.8kW D5 spindle that ONLY mills titanium parts for dental implants at their facility. The last test on their spindle revealed a wear amount that was almost negligible… after 9500 hours! That’s almost 5X the manufacturer’s warranty period.
A contributing factor to our customers’ success with the DATRON D5’s 1.8kW spindle, as described in the example above, is the extensive amount of development and collaboration with do our CAM partners to create a database of milling templates for titanium implant bars and custom abutments. They are designed to carefully balance total milling time and tool wear so that titanium dental implant parts are milled within a reasonable time frame without putting an excessive amount of wear on the machine components or milling tools. With over 100 DATRON D5 Dental Milling Machines being used by labs worldwide, we’re able to pull from an extremely large pool of data and customer experience to further enhance the efficiently and effectiveness of our machines and their specific components.