Thickness Measurement Explained

Thickness Measurement

Thickness measurement has long been a trusted source of determining strength and quality of a material.  There are several different kinds of thickness measurement ranging from destructive, to non-destructive.  Non-destructive thickness measurement has become increasingly popular in the last forty to fifty years as a reliable way of determining the quality, strength, uniformity of a material without destroying it.  Traditional forms of thickness measurement, would take samples and destroy them- for example a sample of concrete from a bridge support might be crushed to determine strength.  However with new types of materials always being developed there has risen a need for a form of thickness measurement that does not destroy the material.  Additionally, a need for thickness measurement that does not touch the sample for sterility purposes has risen, especially in the medical device industry.

Lumetrics, Inc. has steadily become the authority on dimensional thickness measurement using optical interferometry.  Much research has proven that light can be used to penetrate transparent, semi-transparent, and mesh materials to find the thickness, and uniformity of a specific sample.  The reason why thickness measurement using optical interferometry works so well for a medical device is because it can accurately provide real-time thickness measurement without touching the material or compromising the sterility.  This is crucial for many applications such as the measurement of IV blood bags, medical device packaging, stents, silicon wafers, and any other material that light can penetrate.

Since this technology has developed, products have been able to not only be inspected for safety and quality before use.  In light of the fact that this type of thickness measurement is so easily integrated into the manufacturing process, device companies have been able to get their product out in a timely fashion to meet the rising demands of the consumer market.  This not only improves healthcare, but saves lives.

In the future continuous safety regulations set forth by the FDA will ensure that products used in the health care industry, especially those that come in contact with humans, will prevent malfunction, thus improving patient care.

What is Optical Interferometry?

The principle of interferometry is the interaction of reflected light from materials with slightly different Indices of Refraction. The diagram attached explains it quite well.  A fancy animation of the process can be found on for your viewing pleasure.

Thickness Measurement using Optical Interferometry

Why is Optical Interferometry the best type of thickness measurement for some materials?

Optical Interferometry is a reliable form of thickness measurement.  It is the best form of thickness measurement for otherwise hard to measure materials.  Medical products can pose a challenge to many inspection systems. The medical products that are especially tricky to measure are those products composed of soft material or variable in shape and size.

In order to accurately measure for example, a medical balloon, you would need to know the wall thickness, concentricity, and ovality to gauge if the critical operation of the balloon is hindered by defects in the product.  A medical balloon that is not properly inspected can pose a risk- a very costly risk when being used in humans.   As far as industrial applications go, it’s necessary to measure glass, food packaging, adhesives, and electronic components.  Think of the vacuum-sealed Chicken you can get at Wegmans.  Would you want to eat Chicken that had a defect in the packaging?  Would it even be safe to eat?  Our technology allows for the accurate real-time measurement of these products to ensure safety in the world around us.  Our technology can also be integrated into the manufacturing process to cut costs.  Another material that needs to be inspected (and can be inspected very well using our technology) is a contact lens.  These can be measured to ensure the fit and comfort that the customer demands.  Without this type of measurement, nobody would really know if these products were otherwise safe or fit for use.  We’ve found that the principal of Optical Interferometry allows us to provide superior measurement solutions to our customers and any consumer that comes into contact with that product.

Thickness Measurement Explained