100 percent measurements thanks to automation

Bone implants are a Swiss success story dating back over 60 years. "Switzerland has pioneered the surgical treatment of bone fractures and set standards that apply worldwide. The domestic precision industry has developed implant designs that are still valid today," says Lorenzo Zoccoletti, CEO of Genostis, based in Burgdorf in the canton of Bern. "We are continuing this tradition with a generic bone implant system produced 100% in Switzerland with maximum dimensions of quality."

In this case, generic means that the Genostis implants – are inspired by generic products in the pharmaceutical industry – and are based on well-known designs that are now patent-free. Thanks to the generic principle, the costs for research and development are negligible. "Our plates and screws are based on designs that have been tried and tested over decades. In an in-house reengineering process, we optimize them in line with today's requirements for patient-friendly application and efficient production," explains Zoccoletti. The president points out that the prices for his generic implants are significantly deeper than those of other well-known suppliers, without having to compromise on quality. "This means we can guarantee the highest possible product safety and can compete with the leading providers," says Zoccoletti.
As the largest cost block arises in production, those responsible there pay attention to very high efficiency. "We have very high labor costs here in Switzerland," says Carmelo Blandini, COO of Genostis. "That's why maximally automated production processes and the intelligent use of innovative production equipment are crucial to our success."
Metrology is a core element of production. "All of our implants must meet the strict legal requirements for medical devices, including the applicable EU Medical Device Regulation MDR 2017/745," explains Zoccoletti. "The CE mark is a prerequisite for marketing an implant in the EU. In order to obtain this, we have to provide various proofs that are tested by a certification company."
In addition to extensive validation measures, some measurement tasks are unavoidable, such as the initial sample inspection of individual products. In addition, measurements close to production are required, which Genostis has consistently integrated automatically into production. "Computed tomography seemed to us to be the most suitable measurement technology for our concept," explains Blandini. Conventional tactile 3D coordinate metrology was ruled out for him for various reasons: The time and costs involved in the clamping devices and measurements required were enormous, and the test specimens also had to be placed manually. An industrial CT machine would offer much better conditions for achieving the high level of automation he was looking for.
The Genostis managers opted for the Tomo Scope XS Plus 160 from Werth Messtechnik. "We were familiar with Werth as a renowned metrology provider that has been offering coordinate measuring systems for industrial computed tomography for a long time," says Blandini. The selected Tomo Scope XS Plus 160 meets all the basic requirements for measuring the Genostis implants reliably and quickly. It enables the scanning of small and medium-sized workpieces up to around 300 mm in diameter and 450 mm in length. A core element is the transmission tube in monoblock design, which enables a small focal spot even at high tube power, allowing fast measurements with high resolution.

Tube voltage allows the measurement of titanium plates
The maximum tube voltage of the machine is 160 kV. This means that workpieces with longer radiographic lengths and denser materials can also be measured. "As we need to capture the geometries of titanium plates and screws, this was an important decision criterion," explains Blandini. However, he also points out that the required cycle time for monitoring production was a challenge, as short times are important when capturing the workpieces. We had to invest some time until we had built up the necessary experience with the CT sensors." Genostis wanted to scan the titanium workpieces in multiple clamping, for example. "As the measuring objects influence each other during the measurement and this can result in image errors, so-called artifacts, we ran many tests regarding the number of parts and their positioning in relation to each other in order to get good results," explains Dusan Mirkovic, Head of Production & Automation. "The CT specialists from Werth actively supported us with their expertise, so that we were able to develop a lot of know-how and, ultimately, measurement strategies that were a perfect fit for our products."

Scanning time per titanium workpiece is between 2 and 5 minutes
Genostis has succeeded in reducing scanning times from an average of around 20 minutes to between 2 and 5 minutes per titanium workpiece. "These values depend on the products, their size, the resolution required and the measurements to be captured," explains the production manager. "On average, ten to twelve critical geometrical characteristics need to be captured during a measurement. The Tomo Scope XS Plus 160 provides the complete three-dimensional workpiece volume as a measurement result. The user can set the resolution to almost any level (up to 60 billion voxels). "The 3D nominal-to-part variation analysis is very good," praises Mirkovic. "We read in the 3D CAD model and compare it with the measured point cloud in STL format. The color-coded deviation plot allows us to quickly determine whether the workpiece is within tolerance. If we then determine a few critical geometrical characteristics, the values of which are also automatically stored in the measurement report, we can release the medical device for use within seconds." He adds another factor: "It is important for our use in medical technology that the measurement results are reliable and traceable. Werth Messtechnik guarantees this through standard-compliant calibration, including with a DAkkS certificate."
The Tomo Scope XS Plus 160 has other features that are valuable for use in production. For example, the monoblock design of the tube, voltage generator and vacuum generation ensures long maintenance intervals and a theoretically unlimited service life. This minimizes downtimes and operating costs. One of the strengths of all Werth CT machines is that the workpiece volume is reconstructed in real time while the image is being captured. This enables fast in-process measurements.
Programming, control and evaluation of the entire measuring process takes place in the WinWerth® measurement software. Genostis uses it not only on the Tomo Scope itself, but also on two additional workstations that are used for programming and evaluation. "This way, we never block the measuring machine with other tasks," says Mirkovic.

Measuring cell with a robot and a racking system with 135 spaces
Thanks to its compact design, the TomoScope XS Plus requires little space and its good accessibility makes it very easy to automate. Genostis installed a measuring cell with a robot and a racking system with 135 spaces. The interface between the measuring machine and robot controller ensures that the door of the coordinate measuring machine opens when the robot wants to feed or remove the feeding fixtures. The appropriate measurement programs created by Mirkovic are also imported accordingly.
Genostis is currently mainly measuring panels and screws. According to the further expansion of production, the Tomo Scope XS Plus 160 will also increasingly be used for validation and first article inspection. Blandini sums up: "As things stand today, we are very satisfied with our CT coordinate measuring system. The technology is great and the application is now tailored to our products. We get accurate measurement results with high reproducibility. Clamping devices that are easy to manufacture are sufficient, and the measurements are relatively fast thanks to the multiple clamping and automation in the process."