Joint reconstruction implants are subject to the same zero-defect performance and reliability standards as any other implant. However, because two components are always interacting with each other, dimensional accuracy is of particular importance.
Within the medical industry, surface finishing experts such as Rosler assist implant manufacturers in achieving the exact finish needed for each surface of the joint.
In addition to increasing product popularity and demand for the manufacturer and providing medical professionals with safe and dependable joint replacements, ensuring that orthopedic implants have the exact finishing required enables the joint to function longer and more comfortably for the patient.
Since 1984, Croom Medical has supplied global healthcare companies with outsourced manufacturing services of high-precision components and medical devices. The Ireland-based company is an industry leader utilizing high-tech, high-growth, cutting-edge medical device manufacturing technology.
When it came to the design, manufacture, and installation of its initial orthopedic implant finishing systems, Croom Medical chose Rosler as its strategic partner. As production and throughput of medical implants increased to the point of expansion, Croom once again turned to Rosler.
From the initial contact to the final installation and commissioning, Croom’s expansion occurred under somewhat complicated circumstances. Falling within COVID restrictions, extra care and consideration had to be paid to meet the project’s expected timelines and incorporate required safety protocols.
Fueled by more active lifestyles and increased life expectancy, the market for knee, hip, and other replacement body joints is on the rise. According to ORTHOWORLD, orthopedic product sales accounted for more than $55.5 billion in worldwide sales in 2022.
Thanks to significant advancements in materials and new or improved surface finishing technologies, today’s artificial hips and knees can last more than 20 years, giving the recipient decades of comfort and agility.
Parts that are finished using modern mass finishingand shot blastingmethods play a key role in extending the lifespan of orthopedic implants.
Rosler has extensive experience in these processes which often include cleaning, deburring/edge radiusing, surface smoothing, post-casting surface preparation, machining, CNC grinding, and, of course, final finishing. These finishing technologies make big differences in the quality and performance of such products.
Deep-drawn functional components are increasingly being utilized in the production of medical and pharmaceutical products. To meet the strict standards for manufacturing and quality management in the field of surface finishing, Hubert Stüken GmbH & Co. KG has relied on mass finishing solutions and consumables from Rosler for more than 30 years.
Founded in 1931, Hubert Stüken GmbH & Co. KG is a family-owned business with manufacturing operations at five locations in Europe, Asia, and the United States. Its product range includes stamped and bent parts, plastic-coated components, and complex assemblies.
Rosler works with Stüken Medical, the company’s medical business division which focuses on medical and pharmaceutical engineering, to meet the increasing demand for deep-drawn metal components.
Andreas Hellman, Manager of the ISO 13485-certified business division, explained, “Components used in the field of medical and pharmaceutical engineering must meet strict quality standards. The same strict standards apply also to the actual production operations. For this reason, we have pooled the required know-how for the development and production of such precision components at Stüken Medical.”
Due to their precision, efficiency, and economy, mass finishing and shot blasting are an indispensable part of the finishing process for a wide variety of orthopedic implants in different manufacturing stages.
These flexible machines can handle general cleaning; deburring; surface smoothing after casting, forging, stamping, machining, and heat treatment; surface preparation for polishing or coating; and the placement of the final finish on all kinds of implants and medical devices.
With an experienced partner such as Rosler, these processes are also capable of adapting to emerging trends with proper testing and processing trials.
Evolving Technology & Outlook
Orthopedic implant manufacturers are at the cutting edge of medical technology. New materials and manufacturing techniques and technologies are constantly evaluated to improve the performance and longevity of the implants and reduce the manufacturing cost. Two examples are the increased use of ceramics as base material or coating and additive manufacturing.
Like mass finishing, shot blasting is an exceptionally versatile surface treatment technology. Its applications range from general cleaning after casting and forging to shot peening and, even, cosmetic blasting for placing a fine, matte finish on the work pieces.
For shot blasting orthopedic implants, Rosler recommends mainly air and occasionally wet blasting systems. In each process, blast media is accelerated by compressed air and thrown at the work pieces through a blast nozzle, creating an extremely precise blast pattern compared to turbine blasting. Another advantage of air blasting is that it can be used with metallic, mineral as well as organic blast media.
These attributes and many more make this surface finishing method particularly useful in the medical industry.
Examples of Shot Blasting
Shot blasting is an impact system in which small metal or mineral pellets are thrown onto the surface of a work piece at speeds of 200-800 feet/second. The impact on the work piece surface produces the desired cleaning, peening, or texturing effect.
For medical applications, mainly air and wet blast systems are used which generally make a surface rougher. The smoothest finishes achieved with shot blasting are about Ra = 16-32 microinches (= 0.4 to 0.8 μm).
Mass finishing is a highly versatile finishing technology that can be used for a wide variety of different surface treatment operations including those in the medical industry. As a result, it is no surprise that mass finishing processes are utilized at practically every manufacturing stage for all kinds of orthopedic implants.
With decades of experience, Rosler leverages mass finishing technology and develops equipment to meet the tight tolerances required for orthopedic implants.
Common Finishing Processes
Mass finishing is a grinding system, utilizing the pressure between the media and work pieces, combined with the constant “rubbing” of the media against the work pieces. This generates a grinding and polishing effect, leaving a smooth surface finish that can be as low as Ra = 0.8 microinches (0.02 μm).
For the comfort of patients and effectiveness of the components, orthopedic implants must be finished to precise specifications.
While choosing the right implant material is of utmost importance, as discussed in our previous Orthopedic Implant Series post, the significance of optimum surface treatment throughout the entire implant manufacturing process cannot be overstated. This relates not only to the right surface finish, but also total compliance with the specified tight dimensional tolerances.
The functionality of an orthopedic implant is determined by the perfect match between the various implant components. This depends, to a large extent, on the surface treatment procedure(s).
For millions of individuals, orthopedic implants provide the ability to regain mobility and reduce pain. Just as surgical skill is required to implant these artificial joints, so is skillful construction and finish of the joint components themselves.
Our Orthopedic Implant Series continues with an overview of the most common materials used for these endoprosthetic implants.
To date, the most common materials have been titanium, titanium alloys, and cobalt-chromium alloys. Both materials are very tough, resistant to corrosion, highly biocompatible, and absolutely reliable.
Advancements in medical technology now allow for the development of Patient-Specific Implants (PSI). Specialized computer programs analyze x-rays, ultrasound, and MRI images to create surgical guides, tools, and implants tailored to the patient’s unique anatomy.
While still emerging, many medical industry suppliers have received FDA approval for PSI use. Like traditional implants, these implants must be carefully finished once created to ensure the work piece meets stringent medical safety standards while promoting patient comfort and long wear life.
The benefits of PSI use include shorter surgery times, better surgical outcomes, and cost savings.
True to its “apply innovation” tagline, Renishaw’s Medical and Healthcare Division has found great success in additively manufacturing PSI. Using CT scan-to-CAD software, one of the company’s most innovative advances is creating cranial plates using titanium powder.
When determining how to finish the implants to precise medical requirements and surgical demands, Renishaw trusted Rosler for help with mass finishing.