How to Get Better Melt Flow Index Results

The MFI test is used wide among the assorted segments of the industry. The difficulty is that any 2 labs will simply come back up with completely different results, making it tough to confirm whether or not a cloth meets a desired MFI verbal description. Here are some reasons why such discrepancies occur and what will be done concerning them.

The melt flow index (MFI), also glorious as the soften rate (MFR), determines the melt flow properties (measured in g/10 min) of a material at a particular shear stress (related to applied load) and temperature. An extrusion lactometer, more usually referred to as a soften trained worker, is used to see the MFI of virgin, compounded, and post-processed thermoplastics.

The melt flow index manufacturers check is used wide among the assorted segments of the industry. Resin suppliers, for example, look for MFI variations as a QC check to detect and troubleshoot variations in their polymerization and/or combining processes. As part of their materials-inspection procedures, some processors use the test to confirm the amounts of recycled material that may be utilized in their product whereas still maintaining end-product specifications. The difficulty is that any 2 labs will simply come back up with completely different results, making it tough to confirm whether or not a cloth meets a desired MFI verbal description. Here are some reasons why such discrepancies occur and what will be done concerning them.

There is really no agreement on that methodology is best; but there area unit some pointers that may be wont to create a alternative. Procedure A is typically most helpful for corporations that check occasionally, use a wide range of materials, use a variety of additives in their materials, or use regrind/recycled material. Procedure B requires a “melt density” price and is best for corporations that check the same material repeatedly and wish to attenuate the possibility of operator error. Others may notice that the different soften Volume rate (MVR) procedure, offered by both standards, is more helpful.

No matter what the procedure selected, it is common for 2 organizations {to check|to check} a similar material and are available up with two completely different test results, setting off a search to see the explanation for the difference. A variety of things have an effect on the preciseness and accuracy of a check. Is the melt trained worker in sensible operating order? Has the machine been label by a licensed metrologist—checking temperature, physical dimensions, and distance- and time-measurement accuracy? Is the machine clean? Are the operators properly trained and mistreatment a similar testing technique?

The chances of getting precise and correct check results are often greatly accrued by closely following correct testing procedures and needs, by machine verification, and by periodic testing of control materials or a customary reference material (SRM). Even so, “bad” or variable MFR results attributable to the instrumentality and/or procedures will still be encountered. Examining the actual industry check standards offers direction here. ASTM D1238 offers a Troubleshooting Guide in the Appendix of the document and also the following thoughts are based mostly upon it. (Consult ISO 1133 for appropriate dimensions and procedures once testing to that customary.)Some labs do use a Standard Reference Material (SRM) to crosscheck MFI test results. There is a limited supply of selected materials available from national metrological standards bureaus (including NIST in the U.S.) but they tend to be expensive and can only help verify testing for that particular material. Some labs maintain their own supply of reference material, which they use to maintain in-house quality programs. However, using a reference material raises the question, “Are you using material to test the machine or the machine to test the material?”