Core issue focus

The difficulty in grinding engineering plastics such as ABS, PA6, PA12, and elastomers such as POE and EVA at room temperature mainly stems from their high molecular chain flexibility, moisture absorption, and heat sensitivity: PA6 has strong moisture absorption and is prone to clumping, TPU molecular chains are flexible and prone to thermal adhesion, and PP/PE is prone to agglomeration due to low hardness and thermal softening tendency.

Material pretreatment: solving adhesion hazards from the source

Precise drying and humidity control: With the goal of grinding powder moisture content ≤ 0.5%, drying is implemented according to material characteristics: PA6/PA12 (high moisture absorption) → hot air drying at 100-120 ℃/4-6 h+forced humidity control<30% RH; EVA/POE (heat sensitive) → low-temperature circulating air at 60-80 ℃/2-3 h. Case: Moisture affected PA6 (1.2%) has a moisture content reduced to 0.3% after drying at 110 ℃, and the grinding efficiency is improved by 40%.

Screening logic: Remove particles larger than 5mm (anti grinding blind zone) and fine powder smaller than 0.1mm (reducing viscosity), equipment: vibrating screen (adjustable 10-120 mesh)+magnetic separation for iron removal.
Data support: After the ABS production line adopts a 20 mesh coarse sieve+80 mesh fine sieve classification, the particle size dispersion decreases from ± 15 μ m to ± 5 μ m, and adhesion is reduced by 70%.

Equipment operating parameters: dynamically matching material characteristics

Feed speed control – avoid grinding chamber congestion
Step by step adjustment method: conventional plastic 5-6kg/min → difficult to grind materials first decrease to 3-4kg/min, and increase by 1kg/min every 10 minutes (monitoring motor current ≤ 80% of rated value).
Effectiveness: The feeding speed of TPU was increased from 5kg/min to 3kg/min, and the retention time in the cavity was reduced from 25s to 18s, significantly improving thermal adhesion.

Precise temperature control – balance between thermal sensitivity and hardness

Blade speed optimization – breaking the buffering effect of elastomers
Speed matching:
High elasticity material (POE/TPU) → 1200-1500r/min (↓ traditional 2000r/min), reducing friction and heat
Rigid material (ABS/PA) → 1800-2200r/min+serrated blade, increasing shear force
Empirical evidence: POE speed 1800 → 1400r/min+serrated blade → qualification rate 65% → 92%.