Testing methods machine characteristics

Tables 4—6 Ust ASTM methods used for the characterization of PB and PMP. A number of specialized methods were developed for testing particular articles manufactured from polyolefins several of these determine the performance of PB and PMP film, including the measurement of the film s dart impact strength and tear strength. Dart impact strength is measured by dropping a heavy dart with a round tip on a stretched film. Tear resistance, which reflects the film s resistance to tear propagation, is measured with the Ehnendorf tear tester. Two values for the tear strength are usually reported, one in the machine dkection of the film and the other in the transverse dkection. Pipes manufactured from PB are tested by pressurizing them internally with water the time-to-burst failure is determined at various temperatures (46). The standard test method for haze and luminous transmittance (ASTM D1003) is used for the measurement of PMP optical characteristics.

There are basically two ways to test the wear characteristics in the extrusion process. One method is to run the actual machine under normal operating conditions and to measure the progress of wear at regular intervals. This approach is time consuming and expensive, but it does yield accurate and representative results. However, it does not allow a simple analysis of the parameters that influence the wear process. 

The proposed method has the following characteristics a) Independent calibration is only needed for the parameters related to the testing machine k, and m,) and the two related to the... 

The density was measured by Archimedes method. The flexure strength were tested by three point bending way using an INSTRON 5566 test machine (Canton, MA, USA) with a span of 24 mm and a crosshead speed of 0.5 mm/min. The work of fracture was obtained from the characteristic area under the stress-displacement curve divided by the cross section of the specimen. In order to determine the work of fracture effectively, we defined the characteristic area which started from initial point to the 60% drop of the curve. After the test, the silicon volume content was calculated... 

Control loop tuning was another important aspect that needed to be addressed to make the system widely applicable without requiring extensive testing or expertise on the part of the user, in particular, the dynamic characteristics of the process as seen by the measurement system depend upon the number of cycles between measurements, which is determined by the round trip time of the TCS. This depends upon the number of measurements made within a round trip, and therefore on the number of cavities and sections, which is both job and machine dependent To address this issue, an analytical method was developed and implemented to compute controller gains explicitly accounting for the actual TCS round trip time. 

---