To improve the yield of injection-molded nylon PA6 and nylon PA66 products, the following details the key molding points and precautions:
Injection Molding Key Points
Material Selection and Preparation: Modified reinforced nylon materials can significantly improve the yield when injection molding nylon PA6 and nylon PA66 products. Through specific modification treatments, these materials not only enhance their physical properties but also optimize their processing characteristics, making the injection molding process smoother and significantly improving the yield.
Before adding the plastic to the molten plastic tank, it must be thoroughly dried. Otherwise, excessive moisture content may cause it to become stuck in the feed groove, leading to feeding difficulties.
Processing Temperature and Pressure Control
Modified nylon materials have high requirements for injection and drying temperatures. During injection molding, the injection and drying temperatures need to be moderate to avoid scorching and overflow of the material. Simultaneously, appropriate back pressure and injection pressure should be maintained, generally controlled within the range of 50~150 kg/cm², to avoid injection failure due to excessive pressure and time.
When using other plastics for injection molding, the heating temperature of nylon exceeds 270℃, while that of general plastics is only around 200℃. The molten plastic tank heating system must be compatible with the nylon material to avoid injection malfunctions.
Mold Temperature and Cooling Management: During injection molding, precise control of the mold and nozzle temperatures is crucial to prevent the check valve from rupturing due to increased injection pressure during cooling. Proper temperature control at the nozzle is essential; it is recommended to use a controlled nozzle to prevent plastic from overflowing into the mold during feeding.
The shrinkage rate of fiber-reinforced nylon black material is approximately 1.5% to 2.5%, requiring careful attention to ensure appropriate shrinkage during injection molding. Temperatures at each stage must be maintained within specific ranges: nozzle temperature 235-265℃; front stage temperature 235-245℃; middle stage temperature range 210-240℃; and rear stage temperature set at 195-230℃. Meanwhile, the screw speed should be maintained at 100 to 105 revolutions per minute, and the mold temperature should be controlled at 35 to 40°C to ensure successful injection molding.