Is the engineering plastic polyamide adaptable to processing?

The processing adaptability of engineering plastic polyamide (nylon) needs to be viewed dialectically based on its process characteristics, and its core points are as follows:

1. Mainstream advantages of injection molding
Good fluidity: Medium viscosity in molten state, easy to fill complex tooth shaped molds, thin-walled gears (>0.5mm) can be formed in one go
Efficient molding: fast crystallization speed, shorter cooling cycle than most engineering plastics (such as POM), improved production efficiency
Smooth demolding: The shrinkage rate is relatively uniform, and when used in conjunction with demolding agents, it can avoid deformation during ejection

2. Hard threshold for drying treatment
Moisture content red line: The moisture content of particles must be less than 0.1%, otherwise high-temperature hydrolysis degradation (melt foaming, strength collapse) will occur
Drying trap: 80 ℃ hot air circulation requires>4 hours, excessive drying can cause surface oxidation and yellowing

3. Sensitive melting temperature control
Accurate temperature zone: The material barrel needs to be temperature controlled in sections (temperature difference from the back zone to the nozzle ≤ 50 ℃) to prevent local overheating and carbonization
Hidden danger of insufficient temperature: uneven plasticization of the melt leads to internal shrinkage of the gear, and stress cracking under dynamic load

4. The iron law of mold design
Channel optimization: Prioritize expanding the cross-section of hot or cold channels to avoid molecular chain breakage caused by high shear
Forced exhaust: Crystallization gas release requires an exhaust groove with a diameter greater than 0.03mm, otherwise there will be burn marks on the tooth surface
Corrosion prevention of steel: High temperature melt corrodes molds, requiring chrome plating or the use of stainless steel mold cores

5. Special requirements for post-processing
Moisture absorption and aging treatment: Moisture control treatment (boiling water/potassium acetate solution) to eliminate residual stress and prevent gear deformation in the later stage
Turning disaster: Turning processing is prone to producing burrs and fiber drawing, limited to minor adjustments on non mating surfaces

6. Deadly defects in recycled materials
Frequency limit: ≤ 15% mixing of recycled materials, molecular weight drops sharply after three repetitions, and gear fatigue strength returns to zero
Impurity exclusion zone: Trace metal shavings cause local coking of the melt, forming a root fracture source