Productivity and precision gains when controlling orthopedic implants before and after polishing.
For people with rheumatoid arthritis, osteoarthritis and other similar conditions, a knee implant can be life-changing. These problems can affect people psychologically and physically. But a knee implant can significantly reduce pain and increase mobility for decades. High-precision control is required to ensure the safety and performance of this medical device. Faced with the highest demands for efficiency and cost reduction, it has also become important for manufacturers to accelerate measurements and increase the productivity of knee implant control.
The most common materials used in the manufacture of knee prostheses are metals and plastics. In general, the polyethylene component serves as a spacer between a femoral and tibial metal component. Depending on the patient's needs, the plastic component can rotate on the tibial component or be attached to it.
The precision of the sizing is essential to the success of the knee prosthesis and its functionality. This is why it is essential to control 100% of the size and profile before and after polishing. During the preliminary phase, it is important to determine the respect of the tolerance so that there is excess material during the final machining to allow polishing without deformation and without damage to the part.
Requiring both maximum precision and full inspection, knee implants are difficult to measure, especially if batches of several thousand parts are manufactured. In general, manufacturers use touch-triggered probes to achieve high accuracy. But this method may deform the part, even if the applied force modulus is small.
Combining precision and speed in knee implant control
Non-contact measurements are the best solution to provide the desired accuracy and speed. The ideal technology therefore combines the GLOBAL S coordinate measuring machine (CMM) and the HP-L-10.10 laser scanner from Hexagon. The HP-L-10.10 not only protects the part from deformation or damage, but also allows data of a high level of quality and accuracy, at maximum speed, to be collected on several types of surfaces and knee joint finishes, with standard exposure parameters. This allows for additional efficiency gains by reducing the need to regularly change parameters during the measurement process: a common cause of wasted time on manual interventions when using more traditional solutions. In addition, the scanner contains a series of features that further streamline the verification of knee joints.
The laser scanner is equipped with a surveillance camera that allows live monitoring of the inspection process. A visual guide shows the working range of the laser during video viewing and allows the technician to validate control routines when the CMM is running on its own. The operator can thus direct the line laser scanner to areas and characteristics of the joint of particular interest.
The wide-angle camera also promotes the optimization of traceability processes, which are decisive in the manufacture of knee prostheses. During the inspection routine, the camera captures images that can be added to the quality ratio to show surface properties and document defects. This streamlines the tracking and recording of historical information in accordance with the provisions of different standards organizations (such as the U.S. Food and Drug Administration, FDA).
In combination with PC-DMIS 2021.2 metrology software, the HP-L-10.10 offers additional productivity gains to knee implant manufacturers. PC-DMIS calculates the fastest and most accurate laser scanning trajectory by automatically generating the dips, scans and movements needed for optimal measurements, further reducing cycle times.
GLOBAL S is characterized by customizable, unique packages that allow manufacturers to combine technologies in an optimized way to achieve their goals. With the Yield Pack, manufacturers making large batches of knee joints can speed up controls while maintaining a high level of accuracy. In addition, the GLOBAL S contains extensive environmental monitoring and data analysis functions to give the user more confidence in process control. On the other hand, it also carries out autonomous, fast and accurate joint measurements, which allows staff to perform other tasks.