White Light Interferometry Applications Advance Capabilities and Precision
Over the past several years, exciting advancements have been made in the market for non-contact, light-based measurements for medical implants such as balloons and catheters. Emerging from the research and development in this area are more precise, automated, and standardized methods which use white light interferometry technology to overcome the limitations of the conventional micrometer gauge used for these purposes.
The ability to accurately measure the thickness of silicone coatings is key to the implant manufacturing process. Whether dip or spray coating methods are used the OptiGauge II can measure the additive thickness in process without the need for destructive testing.
Limitations of micrometer gauges for the thickness measurement of medical implants:
While micrometer gauges are simple and inexpensive, they have several critical drawbacks, especially when used to measure medical devices which require a minimum degree of accuracy. In addition, micrometers are often subject to operator variability and, by their nature, measure total thickness only and not the actual individual wall thickness of medical implants.
Another key limitation of micrometer gauges is that they require contact which may compress the part being measured. As a quality assessment tool, micrometers do not provide medical implant engineers with the precise and detailed information they need to develop and improve their product or production processes.
The benefits of white light interferometry technology for medical implant testing:
The emergence of white light interferometry technology into the market provides an extremely viable option which eliminates the subjective nature of micrometers.
Lumetrics, for example, has obtained thickness data in a series of interferometric measurements for a 2.25 x 8 mm medical implant balloon using its OptiGauge II. This demonstrates how easily this method can provide fast and accurate wall measurements using an all-fiber low-coherence time domain interferometer.
In its simplest form, this technology enables light from a low-coherence light source to be directed at the sample. For each new layer (interface) where it encounters a change in refractive index (RI), a small amount of light is reflected back into the system where sophisticated and proprietary software produces highly accurate measurement results.
Optigauge II is capable of measuring multiple layers with an optical thickness range of 16µm – 16mm. Actual physical thickness is a based on the refractive index of the material Lumetrics can determine the Group Refractive Index @1310nm using our Refractive Index Calculating System (RICS).
Transforming the traditional medical implant testing market with white light interferometry technology.
Ideal for non-contact, non-destructive testing of medical devices, white light interferometry applications are transforming the market with a superior testing method that delivers streamlined, safe and highly precise results. This directly contrasts the largely manual process of using a micrometer gauge, now an archaic measuring tool, which yields inconsistent results due to operator variability.
Given the extremely high level of accuracy, speed and integrity demanded of medical implant manufacturers, the advancement of available tools is an exciting new dimension which promises to provide product and production engineers with a non-contact inspection tool that has the potential to create a new paradigm of quality. This not only has the potential to benefit all organizations that are designing, producing and marketing medical implants, but perhaps most importantly, it can provide the highest standard of quality to support peace of mind for patients who rely on it when having a medical implant put into their bodies.