Plastic injection process: PA66

- Mar 30, 2018-

Overview of PA6 plastics:

PA6 (polyamide 6 or nylon 6) is a translucent or opaque creamy crystalline polymer with excellent thermoplasticity, light weight, good toughness, chemical resistance and durability.

Because of its good mechanical strength and stiffness, it is widely used in structural components.

Because of its good wear resistance, it is also used in the manufacture of bearings.

PA6 plastic injection molding process conditions:

Drying: because PA6 absorbs moisture easily, special attention should be paid to drying before processing. If the material is packaged with waterproof material, If the humidity is greater than 0.2, it is recommended to dry in hot air above 80 ℃ for 16 hours. If the material has been exposed to air for more than 8 hours, it is recommended that the material be dried in vacuum for more than 8 hours at 105 ℃.

The melting temperature is 2: 230-280 ℃, and for the reinforced varieties it is 250 ~ 280 ℃.

Mold temperature: 80 ℃ 90 ℃. Mold temperature significantly affects crystallinity, which in turn affects the mechanical properties of plastic parts. Crystallinity is very important for structural components, so it is suggested that the mold temperature should be 80 ~ 90 ℃. It is also recommended that higher mold temperature be applied to the plastic parts with longer process. Increasing the mold temperature can increase the strength and stiffness of the plastic parts. If the wall thickness is more than 3 mm, it is recommended to use a low temperature mould of 20 ~ 40 ℃. For glass reinforced material, the mold temperature should be more than 80 ℃.

Injection pressure: generally between 750-1250bar (depending on material and product design).

Injection rate: high speed (slightly lower for enhanced materials).

Runner and gate: because the solidification time of PA6 is very short, the position of gate is very important. Gate aperture should not be less than 0.5*t(t as the thickness of plastic parts. If hot runner is used, gate size should be smaller than that of conventional runner. Because the hot runner can prevent the material from solidifying prematurely, the minimum diameter of the gate should be 0.75 mm. if the submersible gate is used.

Chemical and physical Properties of PA6 Plastics:

The chemical and physical properties of PA6 are similar to those of PA66, however, its melting point is lower and the temperature range is wide. It has better impact resistance and solubility resistance than PA66, but also has stronger hygroscopicity.

In order to improve the mechanical properties of PA6, a variety of modifiers are often added, glass is the most common additive, sometimes in order to improve impact resistance and the addition of synthetic rubber, such as EPDM and SBR.

For products without additives, the shrinkage of PA6 is between 1% and 1.5%. Adding glass fiber additives can reduce the shrinkage to 0.3% (but slightly higher in the direction perpendicular to the process.). Material crystallinity and moisture absorption. Actual shrinkage and plastic design, The wall thickness and other technological parameters are functionally related.

Features of PA6 plastics:

1. Combination of strength and durability, excellent rigidity and heat resistance;

2. Optimize component design, excellent coloring performance, perfect surface appearance, can be used in complex structure molding, and help design developers to develop new styling products;

3. Good processability, excellent fluidity and thermal stability make the material processing conditions more relaxed, make injection parts miniaturized;

4.The extremely high thermal stability, can not hang tin in the wave peak solder up to 270 degrees;

5. Wide range of temperature and frequency constant electrical properties to ensure the use of equipment 100% safe.