Combination of dental implants and coordinate measuring systems

The wbk Institute of Production Science at the Karlsruhe Institute of Technology (KIT) has partnered with Dentsply Sirona, the world renowned manufacturer of dental products and technologies, to achieve the same goal of noise and vibration reduction in dental instruments.

The project, named ProIQ, investigates function-oriented quality assurance of micro gears by integrating in-line measurement technology. The main objective is to adaptively control the hobbing process to improve component quality while limiting waste and scrap. In this project, the µCMM three-dimensional optical measuring machine from Bruker Alicona is the ideal instrument of choice.

Image Credit: Bruker Alicona

Key functions of complex products require high precision components

The increasing use of high-precision components with tolerances of a few µm and the trend towards miniaturization present significant challenges for manufacturing companies. Vivian Schiller and Daniel Gauder hold Ph.D. students from KIT’s wbk Institute of Production Science who are working to solve these problems.

For global dental manufacturer Dentsply Sirona, Schiller and Gauder research component matching strategies, intelligent quality control loops and measurement technology (in-line and in-process) for manufacturing high-precision components .

Their main purpose is to produce quality control loops for the purpose of closed loop manufacturing. Thus, the introduction of online metrology in production systems improves product quality and increases production efficiency.

The BMBF (German Federal Ministry of Education and Research) is providing funding for the project as part of its photonics program, which includes testing the suitability of Bruker Alicona µCMM three-dimensional optical measuring machine in such an environment.

Reduction of vibration of dental instruments

After the installation of the µCMM at the KIT Institute, it was directly integrated into the production environment of Dentsply Sirona in the workshop.

In the ProIQ project, we are measuring the surface topography of micro gears with involute profiles in the sub-0.3 modulus range, focusing on the tooth flanks. The geometric parameters are then extracted from the captured point clouds. Additionally, we derive function-oriented parameters, such as the deviation of the rotating path, from the point clouds.

Vivian Schiller.

For example, small deviations tend to lead to reduced vibration in dental instruments – which provides a benefit to both dentists and patients.

Particular attention should be paid to surfaces and steep sides of metal components due to reflections; as Vivian Schiller explains, “The root area of ​​the tooth poses the greatest challenge, as the opposing flanks of a tooth space converge in this area.”

Combination of dental implants and coordinate measuring systems

Image Credit: Bruker Alicona

Low measurement uncertainty and short measurement times

Other systems were also considered during the project preparation phase to help determine which was the right measurement system for the task. Generally speaking, criteria – such as information density, measurement speed and measurement uncertainty – play a key role in the field of micro gear measurement technology.

While for some time now tactile methods have exhibited low measurement uncertainties, in-line integration presents a particular challenge due to filigree geometries. Volumetric measurement systems offer a high level of information and facilitate 3D acquisition even with undercuts. They also have a relatively high measurement uncertainty, which means longer measurement times are required.

In the end, the µCMM scored with a shift in focus: “If the material of the part is optically cooperative and undercuts are not considered reasons for exclusion, the variation of focus offers non-contact two-dimensional measurement records with a high measurement point density” , says Viviane Schiller.

When considering the different systems, special consideration was given to the short measurement time and low measurement uncertainty.

Better component quality with less scrap

Among the significant advantages offered by the measurements, standard parameters (VDI/VDE 2612) and function description parameters (after VDI/VDE 2608 single flank rolling test) can be derived based on the measurement data recorded online.

It is also possible to achieve lasting quality improvements; from the evaluated parameters, the hobbing process can be adaptively controlled, which means better component quality with less scrap.

Artificial intelligence for the prediction of the functions of the whole product

In the near future, the KIT research team aims to introduce artificial intelligence (AI) into their research.

Moreover, in addition to the adaptive control of the hobbing process, an adaptive micro-gear assembly method is being developed. This is based on measurement data and features taken from scatter plots, from which AI models are able to predict the function of possible microgear pairs. Subsequently, an optimization algorithm can facilitate the individual or selective assembly of the produced gears.

Online capability as a prerequisite for closed loops

As the first all-optical coordinate measuring machine, Bruker Alicona’s µCMM uses a single sensor to establish the dimension, position, shape and roughness of components, regardless of material and surface finish.

Focus variation facilitates high-resolution optical 3D surface measurement at the micro and nanoscale, while for the first time vertical focus probing enables optical side probing of components (even with flanks exceeding 90°) over the entire surface.

With various system and technology features, it is possible to integrate the system into a closed-loop manufacturing strategy. The combination of robust technology and stable, production-grade hardware assembly of the measurement system and automation options enables repeatable measurements in production environments.

These features are complemented by simple, user-independent handling, specially developed for use in the workshop. For the different automation options, a robot arm can be installed to extend the µCMM, allowing you to pick up, place, measure and sort components. Thus, a complete automation process can be delivered in a short time.

Networks for self-optimized production

Given the possibility of connecting the measuring system to pre-existing computer systems and thus also facilitating the “machine-to-machine” communication concept, the requirement profile for the closed loop is complete.

Interfaces, such as .net remoting and different connection options (e.g. QDAS) or a CAD CAM connection, facilitate optimal networking and communication with existing machines, production systems and production management systems. quality.

This information has been extracted, revised and adapted from materials provided by xBruker Alicona.

For more information on this source, please visit Bruker Alicona.