Productivity and precision gains when checking orthopaedic implants before and after polishing.
For people with rheumatoid arthritis, osteoarthritis and similar conditions, a knee implant can be life-changing. These problems can affect people psychologically and physically. But a knee implant can dramatically reduce pain and increase mobility for decades. High-precision control is needed to guarantee 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 speed up measurement and increase productivity in knee implant testing.
The most common materials used in the manufacture of knee prostheses are metals and plastics. In general, the polyethylene component acts as a spacer between a metal femoral and tibial component. Depending on the patient's needs, the plastic component can be pivoted or fixed to the tibial component.
Accurate sizing is essential to the success and functionality of the knee prosthesis. That's why it's essential to check the size and profile with 100 % before and after polishing. During the preliminary phase, it is important to determine that the tolerance is respected so that there is excess material during final machining to enable polishing without deformation or damage to the part.
Demanding both maximum accuracy and full inspection, knee implants are difficult to measure, especially if batches of several thousand are manufactured. Typically, manufacturers use touch-trigger probes to achieve high accuracy. But this method risks deforming the part, even if the modulus of force applied is low.
Combining precision and speed to control knee implants
Non-contact measurement is the best solution for delivering the desired precision and speed. The ideal technology therefore combines GLOBAL S coordinate measuring machine (CMM) and HP-L-10.10 laser scanner from Hexagon. The HP-L-10.10 not only protects the part from deformation or damage, but also enables high quality, accurate data to be collected, at maximum speed, on many types of knee joint surfaces and finishes, using standard exposure parameters. This enables further efficiency gains by reducing the need for regular parameter changes during the measurement process: a frequent cause of time wasted in manual interventions when using more traditional solutions. What's more, 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 laser's working range during video viewing, and enables the technician to validate inspection routines when the CMM is running on its own. In this way, the operator can direct the line laser scanner to areas and features of the joint of particular interest.
The wide-angle camera also helps optimize traceability processes, which are crucial in the manufacture of knee prostheses. During the inspection routine, the camera captures images which can be added to the quality report to show surface properties and document defects. This streamlines the tracking and recording of historical information in line with the requirements of various standards organizations (such as the US Food and Drug Administration, FDA).
In combination with metrology software PC-DMIS 2021.2The HP-L-10.10 offers further productivity gains for knee implant manufacturers. PC-DMIS calculates the fastest, most accurate laser scanning path, automatically generating the probes, scans and movements required for optimal measurements, further reducing cycle times.
GLOBAL S features unique, customizable packages that enable manufacturers to combine technologies in an optimized way to achieve their objectives. With the Yield package, manufacturers producing large batches of knee joints can speed up testing while maintaining a high level of precision. In addition, the GLOBAL S includes extensive environmental monitoring and data analysis functions to give users greater confidence in process control. On the other hand, it also performs autonomous, fast and accurate joint measurements, enabling personnel to perform other tasks.
