Bob brings up very good points here.
MOST bench-top mills are not of the construction required. Our Versamill however IS a bench-top machine that can be added to his list of capable machines that can repeatedly produce high-quality dental bars with the accuracy, fit and finish they require – for about ONE-HALF the cost mentioned.
Relative to the amount of machining knowledge required. Bob is correct; IF the customer or his supplier does not have the knowledge required to provide the technology or adequately support their customers in this area. (which is what we see is most often the case).
That is why it is important to work with a partner such as Axsys Dental Solutions that has this knowledge. Just as with abutments, it is OUR job to leverage our 30-plus years of CAD/CAM/CNC experience to train our customers and develop machining templates that enable them to quickly and easily produce the wide variety of designs/configurations that exist – and we do this.
Just as our tag-line says: “It’s more than just about the machine”
While many bars can benefit (in terms of cycle time) by using more cutting tools, it is not necessary to utilize 8 or more tools to produce a bar. In fact, as in the case referenced in the video below, we have done so with as little as 5 tools – in SIGNIFICANTLY less than 5 hours.
Inaccuracies built up (what is referred to as “stack-tolerances”) in:
- Machines (including all-important fixturing)?
Absolutely a consideration; not a problem with the Versamill (I could go on and on regarding this topic).
- Scan Flags, Scanners, Data etc.
A very big issue. Assuring quality of INPUT data is essential. The machine only cuts what is provided to it. Just as the old truism states: “garbage in, garbage out”.
- Tool configurations & tool wear
Always an issue with any restoration, it is important to use the right tool for the right job and be vigilant on its performance. This of course should be covered in detail with the customer by their supplier during the training process.
And there are more…
The biggest challenge we see in the manufacturing of dental bars is the actual design of the bar itself.
What we see is technicians designing bars that quite frankly are either not manufacturable, would require extensive bench-work or when machined, would never function for the intent in which they were designed. Further we see designs with extraneous geometry and even incorrect geometry included in key areas of the designs.
These problems are typically the result of: untrained or improperly trained users, CAD limitations and/or poorly defined or inaccurate designs provided.
We provide solutions (and training of course) to enable customers to identify and modify problem areas in designs to assure manufacturability.
I recently prepared a presentation to give at the Greater New York Dental Meeting on this very subject entitled “Manufacturing Considerations in Dental Bar Design”. I thought it might be appropriate, given the content of this thread to provide a link to a video of the presentation itself. The video basically runs though the presentation but spares the viewer listening me provide the “meat” to the potatoes. Warning: some of the timings are off due to PowerPoint “features”.
I should probably “cease and desist” now. Please PM me if you have any questions.
Sorry for the length of this post. I really tried to make it shorter…
Steve