Cleaning knee implants

The European Medical Device Regulation (MDR) and the U.S. Food and Drug Administration (FDA) have imposed regulations and requirements governing product safety, process validation, and quality management on the medical device sector stricter than almost any other industry. This also affects cleaning processes for parts and components. To meet regulatory challenges, an international manufacturer of knee implants has replaced its intermediate and final cleaning equipment with the UCMSmartLine. The ultrasonic multi-chamber immersion cleaning system, based on standardized modules, can be individually configured for specific tasks and enables validated cleaning and passivation processes to be seamlessly monitored and documented.

With the introduction of the MDR, requirements for cleaning medical devices such as implants, as well as for validating, documenting, and tracing the respective processes, have become more stringent. However, the FDA is planning to harmonize its quality system regulations with the MDR. This will make it easier for medical device companies to comply with future requirements whether they manufacture their products in the U.S. or Europe or for export.

The exacting regulations imposed by the MDR require manufacturers and suppliers of parts and components to adapt their cleaning and passivation processes. This was also the case with a global manufacturer of titanium knee implants. A key stipulation made by the company was the new equipment for intermediate and final cleaning should be easy to validate, and the parameters of the validated processes should be consistently monitored and documented. Additionally, the equipment and processes had to be easy to duplicate for sites in other countries.

One system, multiple applications

After conducting research, the company opted for the UCMSmartLine system for both tasks. The system is made by Swiss company UCM AG, the division of the SBS Ecoclean Group specializing in ultra-fine and precision cleaning. The decisive factor was the concept of the ultrasonic multi-chamber immersion cleaning system based on standardized modules for cleaning, passivation, rinsing, and drying, as well as loading and unloading. The goods are transported by an integrated automated system, complete with servo drive, that’s standard. The electrical and control technology is integrated into each unit so extra space for a control cabinet is not needed. With a flexible, cost-efficient plug-and-play design, the systems can be individually configured for pre-cleaning, intermediate cleaning, and final cleaning applications. Equipped with modern sensor technology and additional methods for measuring parameters such as pH, conductivity, density, ultrasonic frequency, and output, all relevant process parameters can be recorded, controlled, and documented. The data is transmitted to the company’s manufacturing executive system (MES) via an interface with the UCMSmartLine’s PC-based controller.

Task-specific configuration

For batch-by-batch intermediate cleaning of the knee implants where residues from grinding or polishing processes are removed, the fully-enclosed system has six wet stations with tanks measuring 370mm x 420mm x 390mm. During the two cleaning and four rinsing cycles, multi-frequency ultrasound with 25kHz and 40kHz is used in addition to injection flood washing and pulsated pressure cleaning (PPC). The two-sided overflow developed by UCM also contributes to the consistently good cleaning result: media are introduced from below, transported to the top, and overflow on two sides. This creates a constant flow promoting intensive treatment of the parts and makes sure detached particles and other residues are immediately removed from the baths, minimizing the risk of parts becoming recontaminated when they’re removed. After drying in the integrated vacuum dryer, the implants are subjected to a full visual inspection.

Final cleaning

The UCMSmartLine configured for final cleaning has seven wet stations. A cleaning and rinsing step is followed by passivation where the quality of the medium is monitored by measuring its density. After subsequent neutralization, parts are subjected to three rinsing steps with corresponding water qualities. The cleaning and rinsing effect is also reinforced by injection flood washing, PPC, and ultrasound with a frequency of 40kHz during final cleaning. The newly-developed Acoustic Performance Measurement (APM) system provides in-line monitoring of the parameters of ultrasonic frequency and output at each processing station for each batch. Special directional microphones are used for monitoring, placed in a fixed position at the edge of each tank, and directed toward the center of the bath surface. Measurements are performed without movement or contact, ensuring reproducible results and enabling them to be precisely assigned to the batch concerned. Analysis, evaluation, and storage of the data are handled by the measuring system software. Thanks to the special lift-out function of the transport system, the parts are effectively pre-dried following the last rinse before being transferred to the vacuum dryer for the final drying step, ensuring a spotless finish.

At the outfeed section, the system’s connected to the cleanroom by a double airlock. Due to consistent monitoring of the process parameters and the continuous comparison with validated process data means bad baskets, where discrepancies have been detected can be removed from the product flow before reaching the cleanroom.

Due to the highly flexible design of the system and processes, the UCMSmartLine is suitable for a wide range of applications. The standardized modules simplify equipment certification and process validation and make it easier to duplicate the cleaning systems and processes for future sites.

SBS Ecoclean Group
https://www.ecoclean-group.net