1. Raw Material Preparation & Pre-Treatment
Material Selection: Choose high-strength engineering plastics (e.g., PP, HDPE, ABS) based on the reel’s application (gardening, industrial, electronic use). Add color masterbatch, UV stabilizers, and anti-aging additives to ensure weather resistance and mechanical performance.
Drying & Dehumidification: Dry plastic pellets in an industrial dryer to control moisture content at ≤0.02%, preventing defects such as bubbles or silver streaks during molding.
Mixing & Blending: Mix the base resin with additives in the required ratio and feed the homogeneous blend into the injection molding machine hopper.
2. Mold Preheating & Equipment Setup
Mold Installation: Mount the custom plastic reel injection mold onto the machine, then perform mold clamping and alignment.
Parameter Configuration: Set key process parameters according to material specifications, including barrel temperature (180–220°C for PP), injection pressure, holding pressure, and cooling time, followed by trial runs to fine-tune settings.
3. Core Injection Molding Process
Plasticization: Pellets are heated and sheared by the screw inside the barrel, melting into a homogeneous polymer melt.
Injection & Filling: The melt is injected at high pressure into the mold cavity, ensuring complete replication of details like radial support ribs, the central bore, and edge locating notches.
Holding Pressure & Cooling: Pressure is maintained to compensate for material shrinkage during cooling. The mold’s cooling system rapidly solidifies the part to prevent warping and sink marks.
Mold Opening & Ejection: After sufficient cooling, the mold opens, and the finished reel is gently ejected by the ejector system to avoid defects such as whitening or cracking.
4. Post-Processing & Finishing
Sprue & Runner Removal: Trim excess material from the gate and runner system. Grind off any burrs or flash to ensure a smooth, snag-free surface.
Structural Inspection: Conduct dimensional checks on the central bore, rib integrity, and flatness to ensure compliance with design tolerances.
5. Final Inspection & Packaging
Full Visual Inspection: Check each part for surface defects including bubbles, sink marks, discoloration, and deformation, rejecting non-conforming units.
Functional Sampling: Test the concentricity of the central bore and the fit of the locating notches with customer mating components to ensure compatibility.
Protective Packaging: Package approved parts in anti-static/moisture-proof bags, then box them by batch for warehousing, with full production records archived.
? Key Process Control Notes
Critical Quality Control Points: Raw material moisture content, mold temperature, holding pressure, and cooling time directly impact dimensional accuracy and structural strength.
Efficiency Optimization: High-volume, consistent production is achieved through multi-cavity molds and automated part removal systems. Typical cycle time ranges from 20–45 seconds, depending on part wall thickness.