Film standard debuts
A new standard for testing film is boosting sales of measurement products provided by SolveTech, a company that helped write the new rule. “We implemented the standard in our equipment as we were developing it,” sales engineer Rob Lawrence said.
In October, the plastics committee of ASTM International, West Conshohocken, Pa., began offering the new standard, “Standard Test Method for Determining Plastic Film Thickness and Thickness Variability Using a Non-Contact Capacitance Thickness Gauge.” It describes the necessary characteristics of measurement equipment for film samples with thicknesses between 2.5 microns and 250 microns. For example, in most cases, it prescribes allowing samples to reach temperatures of between about 70 degrees Fahrenheit and 77 degrees Fahrenheit before testing, with humidity levels between 40 percent and 60 percent. Readings should be taken at least as frequently as the width of the footprint of the film, so that, for example, if the film is 3 feet wide, a reading should be taken at least every 3 feet.
One preferred method of film measurement specified by the standard is called Gauge by Weight, though the proper procedures for other methods — including the Reference, Percentage and Contact Micrometer methods — also are described. The standard explains how to prepare samples and procedures for profiling film variability and provides several options for calibration.
“This standard is the most precise way to measure plastic film thickness and variability,” Lawrence said.
He added that the standard will primarily help film producers and film buyers, providing them with a consistent expectation for film thickness and variability.
The industry already is enjoying the benefits of implementing the new standard, he said.
“This way, material that was out of spec was never shipped in the first place, and it could be monitored during the production process so that it wasn’t produced in the first place. When the customer received it, they measured it, as well, and of course found it to be on spec,” Lawrence said several weeks ago. “It provides them a good way to distinguish between suppliers and to buy the plastic film that performs best. It was implemented only three weeks ago, and we’ve already had a huge response.”
The new approach eliminates film deformation and prevents dust and dirt from affecting the reading, Lawrence said.
SolveTech, which makes precision thickness gauges, is developing new gauging technology, but Lawrence declined to offer specifics. The new gauging technology is expected to be launched sometime next year.
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