https://www.avient.com/sites/default/files/2020-09/surround-processing-guide-2020.pdf
TEMPERATURE
Material
Rear
°F (°C)
Center
°F (°C)
Front
°F (°C)
Nozzle
°F (°C)
Melt
°F (°C)
Mold
°F (°C)
Nylon 6,6
14% NiCF
540–570
(280–300)
530–560
(275–290)
530–560
(275–290)
540–570
(280–300)
540–570
(280–300)
200–300
(90–150)
Nylon 6,6
30% SS
540–570
(280–300)
530–560
(275–290)
530–560
(275–290)
540–570
(280–300)
540–570
(280–300)
200–300
(90–150)
PBT
14% NiCF
510–410
(265–280)
490–540
(255–280)
480–530
(250–275)
480–530
(250–275)
480–530
(250–275)
150–250
(65–120)
PC
14% NiCF
540–570
(280–300)
540–570
(280–300)
530–560
(275–290)
530–560
(275–290)
530–560
(275–290)
150–250
(65–120)
ABS
14% NiCF
470–520
(240–270)
460–520
(240–270)
460–520
(240–270)
460–530
(240–275)
460–530
(240–275)
100–200
(40–90)
PP
14% NiCF
440–480
(225–250)
440–480
(225–250)
430–470
(220–245)
420–460
(215–240)
420–460
(215–240)
125–175
(50–80)
DRYING
Material
Temperature
°F (°C)
Time
Minimum
Moisture
Maximum
Moisture
Nylon 6,6
14% NiCF
180 (80) 4–5 hours 0.05% 0.20%
Nylon 6,6
30% SS
180 (80) 4–5 hours 0.05% 0.20%
PBT
14% NiCF
250 (120) 6-8 hours 0.02% 0.03%
PC
14% NiCF
250 (120) 3–4 hours 0.02% 0.02%
ABS
14% NiCF
200 (90) 2–4 hours 0.05% 0.10%
PP
14% NiCF
180 (80) 2–4 hours 0.20% 0.30%
Equipment
• Feed throats smaller than 2.5" may cause bridging due to pellet size
- Larger feed throats will be more advantageous with long fiber EMI shielding resins
• General purpose metering screw is recommended
- Mixing/barrier screws are not recommended
• L/D ratio
- 18:1–20:1 (40% feed, 40% transition, 20% metering)
• Low compression ratio
- 2:1–3:1
• Deep flights recommended
- Metering zone 3.5 mm
- Feed zone 7.5 mm
• Check ring
- Three-piece, free-flowing check ring
• General purpose nozzle (large nozzle tips are recommended)
- Minimum orifice diameter of 7/32"
- Tapered nozzles are not recommended for long fiber EMI shielding resins
• Clamp tonnage:
- 2.5–5 tons/in2
Gates
• Large, free-flow gating recommended
- 0.25" x 0.125" land length
- 0.5" gate depth
Runners
• Full round gate design
• No sharp corners
• Minimum of 0.25" diameter
• Hot runners can be used
PROCESSING
Screw Speed Slower screw speeds are recommended to protect fiber length
Back Pressure Lower back pressure is recommended to protect fiber length
Pack Pressure 60–80% of max injection pressure
Hold Pressure 40–60% of max injection pressure
Cool Time 10–30 seconds (depends on part geometry and dimensional stability)
PROCESS CONSIDERATIONS
Recommended – retain fiber length (maximize conductivity)
• Low shear process
• Low screw speed and screw RPM
• Slow Injection speed
• Fill to 99–100% on first stage of injection
- Reduces potential nesting of fibers at gate location
- Improves mechanical performance near gate location
- Promotes ideal fiber orientation
Resin Rich Surface
• Achieved when using a hot mold temperature and longer cure times
≥ Max mold temperature recommendation
• Improved surface aesthetic
• Reduced surface conductivity
• Could reduce attenuation performance in an assembly
Fiber Rich Surface
• Achieved when using a cold mold temperature and shorter cure times
≤ Minimum mold temperature recommendation
• Improved surface aesthetic
• Reduced surface conductivity
• Could improve attenuation performance in an assembly
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