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A better blender A newly proposed ASTM International standard for measuring film thickness will help processors produce thinner and higher- quality films. So says Doug Lawrence, an ASTM member helping to write the new standard. Lawrence is president of SolveTech Inc., Wilmington, Del., which makes capacitance-based, non-contact gauging equipment. Lawrence says the proposed non-contact test method will help film processors get precise and accurate measurements on thin films and allow for a reproducible set of data points on film samples that correctly characterizes the extrusion process in both the cross-web and machine directions. Thickness and vari- ability are critical to film performance and good roll formation. Adds Rob Lawrence, SolveTech v.p. of sales and marketing, "The new standard is necessary because the existing stan- dard, D 6988, focuses on a contacting method. If you are making a 0.5-mil film, for example, the accuracy of the contact measurement is about 10% of your overall thickness. When trying to measure variability of ±10%, a contacting method falls short." SolveTech recently concluded a gauging repeatability and reproducibility (R&R;) study whose results were independently confirmed by several of its customers. On 0.8-mil blown film, the study compared contact and non-contact technologies, the latter using SolveTech's PR2000 gauge (photo). Typical thresholds for acceptable R&R; are 30%; an R&R; below 10% is considered a good result. With the non-contacting gauge, SolveTech achieved an R&R; of about 3%, while the contacting micrometer achieved approximately 69%, the company said. "The existing standard calls for a precision of 1 micron (0.04 mils), but this becomes a significant percentage of the variabil- ity of a thin film," Rob Lawrence states. "Our technology, on the other hand, is precise to better than 0.1 micron (0.004 mils). Now you can get a much better picture of the variability of 0.5-mil film. It is also much less affected by dust and dirt, which is a problem mentioned often in D 6988." States Mike Ponting, president of PolymerPlus, Valley View, Ohio, which extrudes high-precision nanolayer films for optical and electronic applications, "Advanced technologies continue to move toward miniaturization, requiring thinner films. We produce films as thin as 0.1 mil. We needed a gauging solution that could handle our high-precision layered films while avoiding issues associated with alternative gauging approaches, including optical reflection or x-ray based tech- niques. We found that solution with SolveTech's PR2000, and it helped us create market-leading thin films." (302) 798-5400 • gauging.com New ATM Standard Proposed For Film-Thickness Measurement T E C H N O L O G Y A N D I N D U S T R Y N E W S St ar t ing Up