What is Polyoxymethylene?
Polyoxymethylene, commonly referred to as POM or acetal, is a thermoplastic polymer that possesses exceptional material properties including high strength, rigidity, low moisture absorption and excellent machinability. These properties have led to its increasing use in a variety of medical applications where reliability and durability are critical.
Mechanical Properties Enable New Device Designs
With a tensile strength comparable to many metals, POM allows for the miniaturization and lightweight design of medical equipment without compromising durability. Instruments like biopsy forceps and needles can be made narrower and more precise while still withstanding high stresses. Medical Polyoxymethylene rigidity also enables complex geometries to be molded into single pieces rather than assemblies of multiple parts. This reduces manufacturing costs and the potential for component failure from loose connections.
Biocompatibility for Implants and Direct-Contact Devices
For any material used in medical devices, biocompatibility is paramount. POM has been shown to be non-toxic and well-tolerated when implanted short or long-term in the body. Its low moisture uptake rating also makes it resistant to degradation within the human environment over time. These properties have led to the approval of POM for use in applications requiring direct patient contact such as dental aligners, surgical guide plates and sutures.
Reduced Lubricant Concerns
As a material that inherently possesses self-lubricating properties, POM reduces the risks associated with lubricant degradation or leeching over the device service life. This is particularly important for implants and instruments used in sensitive areas like orthopedic joints or laparoscopic ports. The lack of lubrication concerns simplifies the regulatory approval process and provides assurance of long-term biocompatibility.
Superior Sliding and Wear Performance
POM’s low coefficient of friction allows components to smoothly slide with minimal friction. This has enabled its use in applications requiring sliding or rotating interfaces that must withstand high cycle lifetimes. Examples include cams and linkages in diagnostic imaging machines as well as tubing, valves and connectors in equipment like dialysis machines and C-arms. Medical Polyoxymethylene high wear resistance also means these parts will maintain dimensional tolerance and smooth operation throughout their service life.
Customization Through Molding
As a thermoplastic, POM offers designers and manufacturers the ability to mold complex medical components in high volumes with tight tolerances. Intricate geometries can be replicated that would be difficult or impossible to machine from a metal or even fabricate from multiple assembled parts. Molds can also be designed to incorporate identification markings, surface textures or other customized features specified by the end user. This simplifies manufacturing and reduces costs compared to alternative production methods.
Improved Ease of Processing and Assembly
The moldability of POM provides a smooth, glossy finish without secondary operations like coating or plating needed. Its machinability also means minor modifications can easily be made to molded parts if needed. POM components feature consistent dimensions between batches and do not require treatments or curing like some thermosets. Devices and equipment can be rapidly assembled from standardized POM parts without extensive fitting or finishing.
Expanding Application Space
Propelled by the advantages above, developers continue identifying new ways to leverage POM’s profile of properties. Recent innovative uses include 3D printed POM surgical guides and stereotactic frames offering patient-specific fit without compromising durability or accuracy. POM tubing is now commonly used for fluid handling in medical equipment due to its pinhole resistance at thin walls. Even complex assemblies like small motors are being molded from POM to simplify production of diagnostic and surgical tools. Its versatility has positioned POM as a material ideally suited for the rigorous and regulated medical industry.
As healthcare technologies advance, the requirements for materials will become increasingly stringent in terms of reliability and longevity under acute operating conditions. POM stands out for its performance profile combined ability to be processed into sophisticated, Close-tolerance geometries in high volumes. Its use in devices spanning surgical instruments to capital equipment will only expand in the years ahead as new applications leverage its mechanical properties and processing advantages. Suppliers continue enhancing POM grades as well to address the evolving needs of innovative medical designs. The future remains bright for medical polyoxymethylene as a critical material enabling state-of-the-art healthcare technologies.