Nylon 66 (PA66)

(1) Barrel Temperature

Feed Zone:  60-90°C (80°C)

Zone 1:       260-290°C (280°C)

Zone 2:       260-290°C (280°C)

Zone 3:       280-290°C (290°C)

Zone 4:       280-290°C (290°C)

Zone 5:       280-290°C (290°C)

Nozzle:       280-290°C (290°C)

Temperatures in parentheses are recommended starting points at 35% and 65% stroke utilization and flow length to wall thickness ratio of 50:1 to 100:1. Temperatures in the Feed Zone and Zone 1 directly affect feeding efficiency; increasing them can promote more consistent feeding.

(2) Melt Temperature 270-290°C

(3) Barrel Residence Temperature 240°C

(4) Mold Temperature 60-100°C

(5) Injection Pressure 100-160 MPa (1000-1600 bar). Up to 180 MPa (1800 bar) may be required for thin-wall sections with long flow paths (e.g., cable ties).

(6) Holding Pressure Approximately 50% of injection pressure. Short holding time is sufficient due to relatively rapid material solidification. Reducing holding pressure minimizes internal stresses.

(7) Back Pressure 2-8 MPa (20-80 bar). Requires precise adjustment, as excessively high back pressure can cause uneven plastification.

(8) Injection Speed Relatively fast speeds are recommended. The mold must be well-vented to avoid burn marks.

(9) Screw Speed Generally high, with a peripheral speed of 1 m/s. However, it is preferable to set the screw speed lower, provided plastification completes before the end of the cooling time. Requires low screw torque.

(10) Metering Stroke (0.5-3.5)D

(11) Cushion 2-6 mm, depending on metering stroke and screw diameter.

(12) Pre-Drying 4 hours at 80°C (unless feeding directly from a sealed container). Nylon is hygroscopic and must be stored in moisture-proof containers and closed hoppers. A water content >0.25% by weight adversely affects processing.

(13) Regrind Up to 10% regrind can be used.

(14) Shrinkage 0.7-2.0%. For 30% glass-filled grades: 0.4-0.7%. If mold temperature exceeds 60°C, parts should be cooled gradually to reduce post-molding shrinkage, resulting in better dimensional stability and lower internal stress. Steam tempering is recommended. Stress can be checked using a solvent test.

(15) Gating System Pin-point, submarine, edge, and direct sprue gates are suitable; use blind holes and cold slug wells to trap cold material; hot runner systems can be used. Due to the narrow processing window, hot runners must provide closed-loop temperature control.

(16) Machine Shutdown No purging with other material required. Melt can remain in the barrel for up to 20 minutes; beyond this, thermal degradation is likely.

(17) Barrel Equipment Standard screw (special geometry available for higher plastification capacity), non-return valve, open nozzle. For glass-filled grades, a bimetallic barrel with high wear resistance is required.