Optical roughness metrology for joint implants
Joint implants are subject to strict requirements in terms of medical tolerability, service life, and wear. Standards such as ISO 7207 for partial and total knee joint prostheses specify the Requisite surface characteristics and thereby give guidance for the control of the production process. Especially for these high demands, NanoFocus developed the µsurf implant. Equipped with rotary axis, specially customized implant holding devices, automation software and a multisensor measuring head, the confocal measurement system is suitable for the deployment in the testing and development laboratory as well as for automatable serial measurements of implants close to production.
Finest roughness structures are acquired aerially and reproduced with highest accuracy with the confocal µsurf technology by NanoFocus. A comparison analysis with tactile roughness values (R-parameters) is possible without any conflicts, although 3D values have a much higher significance.
Multi-sensor measuring head combines high speed with precision
Implant components such as femur and tibia of an artificial knee joint are fixated on the rotary axis with the help of the clamping device. By means of barcode-scanning the individual product is identified and a predefined measurement recipe is retrieved. After an automated distance measurement, the measuring system moves to the specified positions and measures the test positions without any interference by the user. Metal, plastics and ceramics surfaces as well are acquired reliably with the measurement result being just a few clicks away.
The µsurf implant measurement system combines a chromatic distance sensor with a confocal µsurf sensor in one measuring head. The distance control is conducted by the fast point sensor. Afterwards, the defined measuring points are acquired areally with highest precision. Measurement results can be directly transferred to pre-defined evaluation protocols. They can also be exported to further relevant software, such as qs-STAT, Matlab or SAP data bases, via various data interfaces. An industry-specific rights management and an integrated audit-trail guarantee unmanipulated measurement results in compliance with certification requirements according to FDA regulations.
Powerful automation software
The position control and the automated moving to the measuring Points is supported by the NanoFocus automation software µsoft automation. This high-performance software allows the measurement and analysis of single samples as well as programmed serial measurements with flexible measurement and analysis strategies. A rights Management with strict separation between user and admin mode as well as an integrated Audit trail guarantee a safe handling and genuine results. Thereby, all certification requirements by FDA are fulfilled.
Examples of application
Accurately reproducing the profile of ultrafine roughness structures of metal, plastic of ceramic surfaces represents a central quality criterion of the confocal measurement Technology, the µsurf implant is based on. Surface structures are captured areally with highest repeatability. Roughness evaluations (s-parameters) according to ISO 25178 are possible as well as comparative 3D analyses analogous to a SEM. For 2D roughness evaluations, line profiles can be extracted.
Benefits at a glance
- Multicompatible sample holding
- Rotary axis
- Distance sensor for quick position detection
- High repeatability
- Automated series measurements
- Application-specific software package
- Collision protection
- Autofocus function
- Compliant with FDA regulations
- Can be used on metal, plastic, or ceramics