- e-mail: contact@LeggDental.co.uk
- phone: 01278 424107
“Our successes can be gauged in customer satisfaction”
A talk with René Hamisch, Head of CADCAM Milling Production Europe.
Mr. Hamisch, in addition to dental technicians, mechatronics engineers have also been part of your team since 2009. Why?
The qualitative and technical requirements in the CADCAM field are continually rising. Anyone wanting to produce continued outstanding quality also has to meet these requirements in manufacturing technology. Mechatronics engineers are specialists in complex mechanical-electronic systems. They help us to further optimize existing manufacturing and to test new technologies and automation processes such as now while introducing new applications and materials.
Where do you see quality in dentures?
In whether they fit precisely. Although we use machines in production, each unit is unique. The customer must not be required to undertake any further grinding. And, least of all, he must never be forced to criticize something! That is our quality claim. For instance, we have customers in Australia. If people at the other end of the world are to unpack and seat the dentures we have manufactured, they need to fit without any compromises.
Straumann customers can be fully confident of quality in this regard?
We do our utmost. Our laboratory customers often accompany dentists they collaborate with on guided factory tours. A laboratory customer always has a parcel with him, originally packaged and sealed by us, he opens it in full view of everyone, seats the dentures into the plaster model and they fit perfectly. That of course impresses people. Since I am exactly aware of our complaint rate, I enjoy these little demonstrations. I know how many work steps we routinely perform to assure and check quality before products leave our plant.
Isn't using CADCAM actually rather virgin territory for dentists?
Everyone in our business has heard of "CADCAM" before, but the technology and fascinating options for daily work have not yet really dawned. Many dentists assume that production is a manual process. When they go on to visit our CADCAM centre, they are usually very impressed. They get to view a clean line production with computers precisely controlling all the tools and the nearly finished product issuing at the end.
The keyword line production: the demand for manual work decreases, the demand for quality rises. Is that right?
Definitely. Today we also use microscopes in quality control. Tiny tears or nicks are not acceptable. There is hardly any margin for tolerances. Modern dentures do not have to sit 99% on the model, but 100% into the patient's dentition. This also involves wall thicknesses and bridge widths to tolerances of one hundredth of a millimetre. One way to constantly improve quality and nevertheless work economically is milling strategy.
What should we take that to mean?
By milling strategy we mean accurately programming the CNC machines that we work with. Tools, rev counts, feed rates and other parameters need to be exactly matched so that the quality is right and economic aspects can be considered at the same time. For example, CNC milling machines use milling tools that are subject to wear and tear and require regular replacement. We therefore perform hundreds of test cycles at the beginning to find out and statistically assure as of when a tool is worn. If we detect, for example, that the 49th crown no longer fits in the test, we deduct several additional millings to be on the safe side. This establishes after how many milled crowns the tool has to be swapped.
So you also collaborate closely with tool manufacturers?
If something does not fit properly in the optimization process, we always wonder where the error is. We use lasers or optics to analyze very exactly whether a tool is still sharp. The idea here is to obtain thresholds and much other data. To achieve this, we have now set up real engineering with our mechatronics specialists. So liaising with tool manufacturers is vital. There is just no other way. Modern high tech production such as ours has to include all our partners both internally and externally.
The milling strategies are developed in the CADCAM centre in Gräfelfing. How do you then continue?
The milling strategies are developed by our specialists in Gräfelfing near Munich. The staff use their own machinery for it. In reflection of our strict quality management we only perform extensive tests here on-site in order to properly implement Gräfelfing’s specifications. So we test everything first and then give the corresponding feedback.
Can deviations in milling results still occur?
They can arise and are then noticed in quality control. Finding the reason for such deviations sometimes requires painstaking detective work. An example: Here we have large glass fronts; which means it gets correspondingly warm in the summer. This causes an expansion in the milling machines. A spindle gets 0.005 mm longer with each additional degree of Celsius - or correspondingly shorter if it turns colder. This has a corresponding effect on production. If you consider the degree of high precision we are working to here, it becomes clear that the deviations are relevant to us and need to be respected. Then the solution is again relatively simple: We have been air-conditioning our rooms for a long time. None of our customers notice any of this.
Are production and quality teamwork?
Producing quality is definitely teamwork. We not only constantly improve and further develop scanners and software, but also production. The work of a dental technician, our customer, is ultimately gauged by the finished product. We achieve successes which directly affect customer satisfaction and can therefore be measured.
