The assessment of blow-extruded product quality
Polimery 2001, No 7-8, 540
SummaryThe correctness of manufacturing of Lublin II delivery trucks main fuel tanks (Daewoo Motor Poland) was studied in relation to blowing extrusion operating parameters. The tanks were blow-extruded from Solvay's Eltex RSB 714 MDPE on a Uniloy's M 100S processing line (Fig. 5). The weight of the tank was adopted as the criterion for tank quality. The temperatures in the individual heating zones of the plasticating system were 100, 205, 208 and 210 oC; the temperatures in the extruder head zones were 212 oC and 210 oC; the time of the complete blow extrusion cycle was 164 s. The empirical distribution of fuel tank weights (Table 3, Fig. 7) allowed to ascertain the theoretical probability distribution (Gaussian curve) (Fig. 8); the distribution pattern was disperse and shifted. This fact required the tank weight mean value to be displaced with respect to the center of the tolerance range and therefore the processing parameters to be modified. The piston stroke length in the extruder die's surge chamber had to be modified so as to increase the weight of the polymer charge to be blow-extruded in a single cycle. Fuel tank weight offers a very useful criterion for product quality.