Typical screw speeds range from 50 - 150 rpm. Injection Speed A worn or contaminated check ring can limit the machine's ability to hold pressure and maintain a cushion.

BASE RESIN ABS Drying Temperature 80–90°C Drying Time 2–3 Hours Barrel Temperatures °C Rear Zone 180–210 Center Zone 190–220 Front Zone 200–230 Nozzle 210–240 Mold Temperature 50–80 Screw Speed Moderate Back Pressure 3–10 bar Cushion 5–15 mm Injection Speed Low to medium Injection Pressure Moderate to high Holding Pressure 10–30% of injection pressure Screw Type General purpose Screw L/D 20:1 Screw Compression Ratio 2.0:1–2.5:1 Non-return Check Valve Free flow check ring Nozzle Type Reverse taper Barrel Capacity 30–80% of barrel should be used STARTUP & SHUTDOWN RECOMMENDATIONS Purge Compound 2–3 melt flow PP or purging compound. PROBLEM CAUSE SOLUTION Incomplete Fill Melt and/or mold temperature too cold • Increase nozzle and barrel temperatures • Increase mold temperature • Increase injection rate • Check thermocouples and heater bands Shot size • Increase shot size • Adjust transfer position to 98% full • Increase cushion Mold design • Enlarge or widen vents and increase number of vents • Check that vents are unplugged • Check that gates are unplugged • Enlarge gates and/or runners • Perform short shots to determine fill pattern and verify proper vent location • Increase wall thickness to move gas trap to parting line Brittleness Degraded/overheated material • Decrease melt temperature • Decrease back pressure • Use smaller barrel • Decrease injection speed Gate location and/or size • Relocate gate to non-stress area • Increase gate size to allow higher flow rate and lower molded-in stress Wet material • Check moisture. Fibers on Surface (Splay) Melt temperature too low • Increase melt temperature • Increase mold temperature • Increase injection speed Wet material • Check moisture.

Processing Guidelines Base Resin PA6 Barrel Temperatures °F °C Rear Zone 440–470 227–243 Center Zone 450–480 232–249 Front Zone 460–490 238–254 Nozzle 470–500 243–260 Melt Temperature 470–500 243–260 Mold Temperature 120–180 49–82 Pack and Hold Pressure 50–75% of Injection Pressure Injection Velocity 0.5 in/s–3 in/s 13 mm/s–76 mm/s Back Pressure 50–100 psi 3.4–6.9 Bar Screw Speed 30–70 rpm Cushion 0.25 in 6.35 mm Drying Parameters 2–4 Hours @ 180°F 2–4 Hours @ 82°C Moisture % Allowable 0.08–0.18%* Screw Type General Purpose Screw Screw Compression Ratio 2.0:1– 2.5:1 Screw L/D 20:1 Non-return Check Valve Free Flow Check Ring Nozzle Type Reverse Taper Clamp Pressure 2–3 Tons/in² Barrel Capacity 30-80% of barrel should be used * Avient suggests measuring moisture using a Karl Fischer method or Vapor Pro® moisture analyzer that titrates only for moisture. Cut vent depths to 0.0007″–0.0015″ Draft Angle Maintain a minimum draft angle of 1° per side 4 Artisan Pre-Colored Thermoplastics Troubleshooting Recommendations Problem Cause Solution Incomplete Fill Melt and/or mold too cold • Increase nozzle and barrel temperatures • Increase mold temperature • Increase injection rate • Check thermocouples and heater bands Shot size • Increase shot size • Adjust transfer position to 98% full • Increase cushion Mold design • Enlarge or widen vents and increase number of vents • Check that vents are unplugged • Check that gates are unplugged • Enlarge gates and/or runners • Perform short shots to determine fill pattern and verify proper vent location • Increase wall thickness to move gas trap to parting line Brittleness Degraded/overheated material • Decrease melt temperature • Decrease back pressure • Use smaller barrel • Decrease injection speed Gate location and/or size • Relocate gate to non-stress area • Increase gate size to allow higher flow rate and lower molded-in stress Wet material • Check moisture. Splay Melt temperature too low • Increase melt temperature • Increase mold temperature • Increase injection speed Wet material • Check moisture.

15-3507 TPG, HIPS 15-3507 TPG, GPS OPQ

TPE SKYWAY 14-4112 TPG TPE TROPOSPHERE 17-3926 TPG

HMS LIVING CORAL (16-1546 TPG) HMS SMOKE BLUE (17-4412 TPG)

FLAMINGO 17-1937 TPG PAPAYA 16-1450 TPG

Check settings 2. Reduce screw speed 3. Check for wear on screw, barrel or check ring Delamination Process related 1.

Check paper type. Check with paper manufacturer for recommended shelf life and storage. Check air flow in dryer.

Injection Speed The injection speed for Gravi-Tech material is most often higher than what is used for other formulations. NON-RETURN VALVES Check Ring The check ring insures that material cannot flow back over the screw tip upon injection. FIGURE 48 - The Injection Unit Nozzle Non-Return Valve Heater Bands Barrel Screw Hopper Metering Zone Compression Zone Feed Zone FIGURE 47 - Non-Return Valve: Check Ring Check Ring Open Check Ring Closed FIGURE 49 - The Injection Unit FIGURE 50 - Non-return Valve: Check Ring Design Guide 45 FIGURE 48 - Non-Return Valve: Ball Check Ball Check Open Ball Check Closed Poppet Valve The final type of non-return valve is called a poppet valve.