Barrel temperature setting

Figure 9.9 The effect of the zone 3 and 4 barrel temperature settings on the discharge temperature for the high-rate screw. The rate and screw speed were held constant at 230 kg/h and 58 rpm, respectively...

The response of the RTDs and the temperature of the screw were tested with the screw not rotating. For this experiment, the temperatures were first measured with the extruder at ambient conditions. Next, the barrel temperature set points were increased to 200, 220, and 240 °C for Zones 1, 2, and 3, respectively. The downstream die system was heated at the same time as the barrel and at a set point temperature equal to Zone 3 (240 °C). The temperature profile of the screw as a function of axial length is shown in Fig. 10.19 for select heating times. For heating... 

Start with the plastic melt temperature at the mid-point of your supplier s recommended range. Know the actual melt temperature (not the barrel temperature set points). 

The following conditions apply to Amitel COPE compoimds, for optimum product quality melt temperature range, 428 to 500°F (220 to 260°C) cylinder (barrel) temperature setting range, 392 to 482°F (200 to 250°C) mold temperature range for thin-wall products, 122°F (50°C) and for thick-wall products, 68°F (20°C). 

Reinforced PPS compounds may be extruded into profile shapes or sheets under carefully controlled processing conditions using a 24 1 to 28 1 LID standard metering screw with 3 1 compression ratio and a heated die clamp. Typical barrel temperature set points are about 285 to 310°C (545 to 590°F). Some extruded rods and sheets of reinforced PPS compounds are used as stock for machining small quantities of parts, as is compression-molded stock. Thermoforming of extruded sheet may be performed using conventional techniques at temperatures above the crystalline melting point of PPS of 285°C (545°F) [133]. 

If one would want to determine optimum temperature settings from data on the coefficient of friction at various temperatures, there is an additional complication that should be taken Into account. This complication is the frictional heat generation that occurs in the solids conveying zone. As a result of this frictional heat generation, the temperature at the interface between solid bed and barrel may be substantially higher than the barrel temperature setting indicates. 

Fig. 7.4 N-Q operating diagram for a 27-mm twin-screw extruder (TSE) with adiabatic barrel temperature settings...

Europrenes have thermoplastic polymer melt processing properties and characteristics of TPEs. At melt processing temperatures, they behave as thermoplastics, and below the PS Tg of 203 to 212°F (95 to 100°C) the copolymers act as cross-linked elastomers, as noted earlier. Injection-molding barrel temperature settings are from 284 to 374°F (140 to 190°C). Extrusion temperature at the head of the extruder is maintained between 212 and 356°F(100and 180°C). 

Figure 14.18 Extruder output as a function of zone 1 barrel temperature set point (unfilled SPS homopolymer 63-mm screw diameter 211/d, 90rpm, feed 5 diameters long, transition 10 diameters, metering 6 diameters [3]).

Table 1. Barrel Temperature Settings for Each Study...

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