In the field of precision injection molding, mold quality directly determines product accuracy and production efficiency. This article provides an in-depth analysis of the processing requirements for three key components in precision molds: mold base, core, and runner systems.
I. Mold Base System: The Foundation of Precision Molds
Precision mold base processing must meet the following core requirements:
Material Selection and Heat Treatment
Advanced mold steels such as P20 or S55C with hardness of HRC30-35
Stress relief treatment to prevent deformation during subsequent processing
Machining Accuracy Control
Flatness requirement: ≤0.02mm/300mm
Guide pillar/bush clearance: 0.01-0.015mm
Parallelism error between plates: ≤0.02mm
Positioning System Precision
Square rail positioning system with clearance ≤0.005mm
Four-corner pillar interference fit for precise alignment
II. Core Processing: Ensuring Molding Precision
As direct molding components, cores demand exceptionally strict processing requirements:
Material and Heat Treatment
Premium mold steels including S136, NAK80
Heat treatment hardness: HRC48-52 for wear resistance
Machining Process Requirements
Multi-stage process: roughing, semi-finishing, finishing, polishing
Finishing allowance: 0.05-0.1mm
Surface polishing: mirror finish (Ra≤0.1μm)
Dimensional Accuracy Control
Critical dimension tolerance: ±0.005mm
Cavity profile requirement: ≤0.01mm
III. Runner System: Key to Quality and Efficiency
Runner system processing directly affects injection efficiency and product quality:
Hot Runner System
Nozzle/heater clearance: ≤0.01mm
Runner diameter tolerance: ±0.02mm
Temperature uniformity between nozzles: ≤±2℃
Cold Runner System
Surface roughness: Ra≤0.4μm
Gate size accuracy: ±0.02mm
Balanced filling through optimized runner layout
IV. Equipment and Inspection Requirements
Essential equipment for precision machining:
Precision CNC machining centers (positioning accuracy ±0.0025mm)
Precision EDM machines (surface roughness Ra≤0.2μm)
CMM (measuring accuracy ±0.001mm)
V. Process Control Essentials
Environmental Control
Constant temperature workshop: 20±1℃
Humidity control: 50%±5%
Tool Management
Diamond-coated tools for improved accuracy
Strict tool life management system
Through these rigorous processing requirements and control measures, precision molds can achieve expected service life and molding quality. In actual production, appropriate process adjustments and optimizations should be made according to specific product requirements.
