October 23rd, 2018 – Wilmington, DE USA – One of plastic film’s most important characteristics is its thickness and thickness variability, and disputes about thickness and thickness variability have been common throughout the plastic film industry’s history. Because plastic film thickness is difficult to measure, film buyers have a hard time knowing what they are getting. Contact measurements are often not precise and repeatable enough to give the buyer good information.
Equipment for incoming product inspection, like the PR2000 Profiler can help, but not all film buyers are able to make the investment in advanced measurement equipment.
Measurement standards are in place to help facilitate film buying and selling transactions, especially in cases like this. However, before October 2017, there was no standard for defining plastic film variability. Every buyer and supplier had to develop their own methods.
With the release of ASTM D8136 last year, there is now an ASTM standard for defining plastic film variability in a standardized way. This is game changing for plastic film buyers because now they can make an apples to apples comparison of different film suppliers based on this specification. Variability was often previously provided in film specifications, but it was not always meaningful. The method for measuring it with a contact micrometer was not reliable, repeatable and reproducable leading to fuzzy data.
Buyers can now more easily identify high quality film and select better film suppliers. This can have a big impact on converting processes and it can save the suppliers money. More uniform film opens the door to downgauging while maintaining film performance, and it can help converting processes run with less issues and failures.
For those who buy and convert film, it can be critical that the material is delivered as specified. Measuring using this quality standard can also reduce film rejections and help buyer’s and seller’s form better relationships. The new standard should help push the industry in general to be more quality conscious since buyers will be able to see uniformity differences and quantify it more easily.
Another area of dispute is average film thickness. The new standard also addresses this using a NIST traceable calibration for the instrument. The instrument can tell the buyer how thick a film strip is on average, typically within +/- 1%.