Posted 21 Dec 2010 01:33
Polypropylene (PP) feed zone barrel temperature 30 ~ 50 ?(50 ? District 1 160 ~ 250 ?(200 ? District 2 200 ~ 300 ?(220 ? District 3 220 ~ 300 ?(240 ? zone 4 220 ~ 300 ?(240 ? District 5 220 ~ 300 ?(240 ? nozzle 220 ~ 300 ?(240 ? temperatures in brackets proposed as the basic settings, trip efficiency of 35% and 65%, mode piece flow length and thickness ratio of 50:1 to 100:1 melt temperature of 220 ~ 280 ?220 ?constant barrel temperature of 20 ~ 70 ?mold injection pressure has a very good flow properties, to avoid the use of high injection pressure 80 ~ 140MPa (800 ~ 1400bar); a number of thin-walled containers except for up to 180MPa (1800bar) holding pressure have reduced the wall to avoid the products, take a long time to dwell on the products (about 30% of cycle time); about injection pressure of 30% to 60% back pressure 5 ~ 20MPa (50 ~ 200bar) injection speed on the thin-walled containers requires a high injection speed (with accumulator); medium injection speed is often more applicable to other types of plastic products screw speed and high screw speed (line speed of 1.3m / s) is allowed, as long as the meet before the end of the cooling time can be measured to travel plastination process 0.5 ~ 4D (minimum ~ maximum); 4D measurement of stroke melt residence time long enough to provide is very important residual feeding amount 2 ~ 8mm, depending on itinerary and screw speed measurement does not require pre-drying; if poor storage conditions, the temperature at 80 ?for 1h to dry can reach 100% recovery rate can be 1.2 to 2.5% shrinkage; contraction high; 24h will not shrink after (post-molding shrinkage) gate or gate system point point gate; heated hot runner, insulation type runner, the pouring sets; gate location in the products, the thickest point, or prone to shrink big time machine downtime with other materials without special cleaning; PP barrel temperature rise standards for the screw device, the standard used Triple Screw; of packaging products, containers, mixing section and the shear section of the special geometry (L: D = 25:1), through the nozzle, non-return valve