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The importance of hygiene applies to every aspect of patient care – from the sanitary environment where patient treatment takes place to the range of medical devices used in treatment. The quality of materials and equipment used in treatment can also improve patient outcome. For implants, dental care, and medical devices, a smooth surface with fewer burrs reduces the number of surfaces where contaminants can cling, accumulate, and flourish.

Benefits of a smooth surface

– Biocompatibility is a major concern for implantable devices. Materials must be contaminant-free and not produce immunological responses when exposed to bodily tissues or fluids.

Implantable devicesCutting tools, drills, blades – Smooth surfaces promote greater accuracy and minimize risks, including burrs breaking off during use, device corrosion, and contaminant and pathogen contaminant.

Disposable medical devices – Less expensive processes popular with disposables, such as additive manufacturing or metal injection molding, often produce less-than-optimal surface finishes that are not appropriate for medical devices. They often result in inconsistent quality, as well as higher patient rejection rates during testing.

Surgical instruments – Any precision instrument found on an instrument tray needs to be as smooth and clean as possible to meet strict quality and sanitation requirements. Surface anomalies such as threads on bone screws, knurling detail on instruments, or ground points on a trocar can lower precision. Medical imaging and diagnostics – Cathodes, focus cups, and shields provide medical and dental practitioners with data to accurately diagnose conditions. Burrs or imperfections on instrument surfaces can produce arcs in the flow of the electrical current that runs through the X-ray tubes, distorting images. A lack of smooth conductivity that interrupts the path of the current, especially when high voltage is being used, can damage costly equipment.

Laser marking – The U.S. Food and Drug Administration (FDA) has recently updated and made more stringent regulations regarding Unique Device Identification (UDI) on medical devices. To reduce the possibility of identifiers being removed or counterfeited, or interfering with the device’s functionality, they must be applied as laser markings, directly onto each device.

Surface finishing methods

Popular techniques used to finish the surface of metal parts include:

  • Chemical passivation – Chemical process primarily used to improve the corrosion resistance of metals; may require additional pre-passivation steps; does not remove discoloration or oxide scale; does not result in the smoothest or shiniest surface
  • Tumbling/vibratory finishing – Abrasive media cleans the surface of metal parts as they are tumbled in a barrel or bowl; typically useful for smaller rigid parts; not suited for fragile, complex parts
  • Parts blasting – Parts are blasted using aluminum oxide or glass particles; impinges the surface to mask surface defects, creates a matte uniform finish; subsequent cleaning required to remove contaminants
  • Electropolishing

    A process that addresses many issues associated with medical and dental devices manufacturing is electropolishing. Often referred to as a reverse plating process, electropolishing combines chemicals and electrical current to remove the outermost layer of metal in a highly accurate manner per manufacturers’ requirements. Electropolishing removes burrs and surface contaminants, makes the surface smoother, and creates corrosion resistance, resulting in a bright, aesthetically pleasing finish. Electropolishing can accommodate parts of any size and will not damage fragile parts.

    Switching to electropolishing

    For medical device manufacturers using other methods for finishing, switching to a new process can be daunting. A new process, such as electropolishing, should be tested. Once desired outcomes are achieved, the existing processes can be revisited.

    For companies looking for long-term assurance of proper finishing and a simplification of the finishing process, electropolishing may be the best answer.

    Able Electropolishing Co.