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Quality control melt flow testing

A number of instruments are based on the extmsion principle, including slit flow and normal capillary flow (Table 6). These instruments are useful when large numbers of quality control or other melt viscosity test measurements are needed for batches of a single material or similar materials. When melt viscosities of a wide range of materials must be measured, rotational viscometers are preferable. Extmsion rheometers have been applied to other materials with some success with adhesives and coatings (10,161). [Pg.183]

The melt flow indexer. The melt flow indexer is often used in industry to characterize a polymer melt and as a simple and quick means of quality control. It takes a single point measurement using standard testing conditions specific to each polymer class on a ram type extruder or extrusion plastometer as shown in Fig. 2.45. [Pg.86]

In the manufacture of products, there is always a challenge to utilize advanced techniques, such as understanding the different plastic melt flow behaviors, operational monitoring and control systems, testing and quality control, and so on. However, these techniques are only helpful if the basic operations of fabricating are understood and characterized, to ensure the elimination or significant reduction of potential problems. [Pg.1103]

Melt flow index (MFI) or rate (MFR) remains one of the most popular quality-control tests for incoming raw thermoplastic materials [5]. [Pg.271]

Borras [14] to be accurate within 10% when compared with the test results obtained by two independent laboratories. It is not unrealistic to expect similar plots when other melt flow index conditions and different impact bar sizes are used. Thus, MFI can be used as an effective quality control parameter for inqiact strength. [Pg.361]

Until recently, the rheological measurements were confined to test labs for quality control, research, and development purposes. New techniques for on-line rheological measurements have been developed, bringing the analytical instrumentation to the production floor. This is accomplished by employing a closed-loop instrument which diverts a portion of the process stream to a measurement head and then returns it to the process. Within the measurement head, most of the material flows through a bypass channel and a fraction of the stream is pumped across a capillary die, using precision gear pumps. A similar concept, employed by another manufacturer, utilizes a slit die to measure viscosity. An open-loop on-line rheometer, which does not return the diverted melt stream to the process after measurement, splits the diverted melt stream to two capillary dies of different LID ratios... [Pg.184]

Receiving Inspection. Many types of tests have been devised for testing raw materials. Depending upon the severity of the need for inspection, the types of tests selected may vary from being basic and simple to sophisticated and complex. Some of the most common basic tests are the melt index test, specific gravity, bulk density, spiral flow test, and viscosity tests. Gel permeation chromatography, infrared analysis, thermal analysis, and rheometry are some of the more elaborate raw material quality control tests. These tests are discussed in detail in Chapter 7. Some processors also choose to mold test bars from a small sample of raw material and conduct physical tests such as tensile, impact, and flexural tests and then evaluate the results to see if they meet the preestablished specifications. [Pg.444]


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