Quality Magazine

Quality Innovations: Address Metrology Challenges

July 31, 2009
Small part measurements can lead to big problems if done incorrectly. With parts getting smaller and tolerances getting tighter, it is important to consider the measurement method and device carefully. InsituTec’s MicroTouch sensor is able to measure micro and nanoscale parts and features that currently cannot be measured using other technologies. The sensor is a dimensional measurement scanning probe based on the company’s standing wave technology.

Aerogel is a manufactured material with the lowest density of any known solid. Components shown have a diameter of 2.5 millimeters with a step size of 0.01 micron. Source: Lawrence Livermore National Laboratories and InsituTec Inc.


Small part measurements can lead to big problems if done incorrectly. With parts getting smaller and tolerances getting tighter, it is important to consider the measurement method and device carefully.

InsituTec’s (Charlotte, NC) MicroTouch sensor is able to measure micro and nanoscale parts and features that currently cannot be measured using other technologies. The sensor is a dimensional measurement scanning probe based on the company’s standing wave technology.

The MicroTouch fills a need in the marketplace, explains Bethany Woody, president and co-founder of InsituTec. The technology behind the MicroTouch was invented by the company’s founders when they were graduate students at the University of North Carolina–Charlotte’s Center for Precision Metrology, as they saw a need to measure features at the micro or nanoscale level. Existing technologies are unable to meet current and future micrometrology needs, Woody says, as they are limited in their ability to measure deep narrow features such as holes, channels and gears.

The MicroTouch probe is small and slender enough to measure the form of a hole and extract form and surface features in one measurement. Previously, companies may have used two different types of machines, requiring two machines and two operators, Woody says.

With this probe, the data set gives operators both sets of information. It also provides the ability to combine three traditionally separate measurement capabilities into one instrument: form, surface finish and roundness. InsituTec says no other company supplies a single tool capable of performing all three types of measurements.

Contact force starts to be very important, Woody says, as the contact forces could actually scratch or damage the surface when measuring in nanometers. Because the probe is small with a very low contact force, it offers an advantage over other types of contact-based methods. This highly repeatable technology does not stick to the surface, can measure high aspect ratio features and provides high data rate scanning capability. In addition, the probe can measure different angles on a thread, discover how wear occurs and how a loading surface is wearing over time.

Woody says the sensor competes in two areas: microscale coordinate measuring machines (CMMs) and roundness/surface finish technologies.

“It is different than optical surface finish technologies,” Woody says. “Optical technologies will take a picture of the path, but aren’t able to measure shiny, highly polished surfaces or steep slope. This technology is a microscale CMM probe. It can analyze the form and surface finish.”

Applications include free-form optics, diesel injector spray holes, diamond tool tips, aerogels and other soft or biocompatible materials, turbine blade air foil cooling holes, miniature threads, and medical implants and medical device subcomponents.

It is not suited to every application. “Really large parts obviously aren’t a candidate,” Woody says. “Part sizes are on the order of millimeters with critical features on the order of micrometers with tolerances as low as nanometers.”

The probe has a 7 micron cross section that is more than 3.5 millimeters long, yielding a 500:1 aspect ratio. It contacts the parts’ surface with forces less than 100 nanonewtons and is capable of greater than 10 nanometer repeatability when equipped with a nano-motion platform.

The company’s AccuSurf gage head, when accompanied with the MicroTouch Sensor, enables measurement of 3-D form and surface finish in the same data set. Based on these two technologies, InsituTec offers a custom measurement service to measure microscale parts.

Pricing depends on the application.

Technology Contact

For more information, contact: Bethany Woody
InsituTec Inc.
2750 East W.T. Harris Blvd.
Suite 103
Charlotte, NC 28213
(704) 599-0836
info@insitutec.com
www.insitutec.com