TeraMetrix Demonstrates Simultaneous Measurement of Online Tire Ply Thickness and Cord Balance at Tire Tech 2019

Earlier this month, TeraMetrix’s Senior Research Scientist Jeffery White and  Bridgestone USA's Steven Jenkins presented at the 2019 Tire Tech Expo in Hannover, Germany. Both presentations focused on using TeraMetrix’s terahertz (THz) system to simultaneously measure the total body ply thickness and the balance of either steel or fabric cords.

The installation of a TeraMetrix THz system in the Bridgestone facility in Aiken, South Carolina continues to operate well, and the Tire Tech Expo was chosen as an opportunity to present the factory results to an industry wide audience. Steven Jenkins of Bridgestone notes that the use of the scanning THz sensor has allowed plant operators to both create flatter calender sheet profiles and continuously monitor the sheet total thickness.

The current, long-existing method to measure sheet thickness is to collect a physical strip of the sheet every 1000 m of production. Five round samples are punched across this strip and weighed. These sample weights are then converted to thickness based on a previously determined calibration factor. This process is very infrequent, labor intensive and while it helps the operators stay near target thickness, the results are not timely enough to provide good control of the flatness or the thickness. The terahertz measurement is a direct measurement of thickness,rather than conversion from a mass measurement as with x-ray and nuclear sensors. It also requires no safety controls, as the THz energy is similar to far infrared light.

Jenkins notes that if the overall thickness of the body ply can be reduced by just 0.0004 inches (.01 mm), then savings of greater than $500,000 per year in material costs alone would be realized.

White concentrated his presentation on the measurement of the “Balance” of the cords with the ply.  Balance is a measure of the vertical position of the cords within the ply. Typically, the cords should be centered, top to bottom, but there are cases when the cords are purposefully offset. The balance measurement is extremely important for the safety of the tire.  If the balance changes within the ply, especially if balance varies significantly on opposite sides of the tire, then vibration and friction forces will occur within the tire, potentially leading to catastrophic failure.

THz is the only measurement method that has demonstrated direct, real-time measurement of the balance of fabric cord ply products.  This is accomplished by measuring the TIME between reflections off interfaces in the corded body ply. The TeraMetrix system also has the ability to perform an on-demand, in-production material property check to ensure the THz measurement remains accurate, especially through material batch changes, shift changes, production stops / restarts and new product starts.

After successful presentations on the first day of the event, representatives from nearly every major western tire manufacturing company stopped by the exposition booth for further discussions and to see a demo of how the THz sensor is able to provide an immediate measurement of two-layer extrusions samples.  TeraMetrix is able to supply a solution to a current issue (balance measurement of fabric corded products), an improved measurement, leading to huge cost savings (optimum total ply thickness).

The conference also allowed TeraMetrix to learn of other unmet measurement needs from manufacturers like delamination detection and cord spacing measurements.  In addition, several manufactures were interested in multilayer extrusion material products (Uncured rubber components). Overall the conference was a success allowing TeraMetrix to share the benefits of THz measurement in the manufacturing process and meet with industry leaders to better understand their manufacturing needs.

To review both Tire Tech presentations and learn more how TeraMetrix THz measurement systems can help your manufacturing process, please see the links below:

Steven Jenkins (Bridgestone USA) Tire Tech 2019 Presentation

Jeffrey White (TeraMetrix) Tire Tech 2019 Presentation

TeraMetrix THz Application Note: Calendering Tires