Precautions for PA6 Injection Molding
2026-03-07 11:51:05
Injection Molding
PA6 is a widely used engineering plastic with good toughness, strength, wear resistance, and flowability. It is used in automotive parts, electronics, housings, and mechanical components. However, PA6 has high moisture absorption, fast crystallization, and high shrinkage, making it sensitive to molding conditions. Improper processing leads to bubbles, sliver marks, warpage, brittleness, and flashing. Strict process control is essential for stable production.
Material Drying
PA6 absorbs moisture rapidly. Undried material causes bubbles, pores, and degradation. Dehumidifying drying at 80–90°C for 3–4 hours is required. Moisture content must be below 0.04%. Materials in the hopper must remain heated during production.
Temperature ControlBarrel temperature: rear 210–230°C, middle 230–250°C, front 220–240°C. Nozzle temperature slightly lower to prevent drooling. Over-temperature causes degradation. Mold temperature: 40–60°C for standard parts, 60–80°C for precision parts to improve crystallization and reduce stress.
Injection Pressure and SpeedPA6 has good flowability and does not require high pressure. Excessive pressure increases internal stress and flashing. Injection speed should be moderate, using a slow-fast-slow profile. Pack pressure and time should be minimized to avoid over-packing.
Mold Design
Sufficient venting with 0.02–0.03 mm depth prevents burning and bubbles. Large draft angle of 1°–3° eases demolding. Uniform cooling and balanced ejection reduce deformation.
Processing Glass Fiber Reinforced PA6GF-reinforced PA6 requires wear-resistant mold materials: H13, SKD61, S136. Moderately higher pressure and temperature improve filling. Shear should be controlled to protect fiber length.
Post-TreatmentAnnealing at 70–80°C for 2–4 hours relieves internal stress and stabilizes dimensions. Proper handling and storage prevent deformation.
ConclusionPA6 injection molding success relies on thorough drying, precise temperature control, low-stress molding, and proper mold design. Strict adherence to these guidelines ensures high quality, high yield, and stable long-term production.
