1. Identify the mold type Two-plate mold: simple structure, single parting surface, suitable for products without complex demolding requirements (such as shells, covers). Three-plate mold: requires automatic demolding or multiple parting surfaces (such as point gate products), but the cost is relatively high. Hot runner mold: reduces waste during mass production, but the initial investment and maintenance costs are high. Multi-cavity mold: the flow channel and cooling system layout need to be balanced to ensure molding uniformity. 2. Product characteristics drive the design size and projection area: the mold frame size needs to cover the product projection area and reserve 20%~30% space (for exhaust, cooling and ejection system layout). Structural complexity: slider/elevator required → mold frame needs to reserve lateral movement space. Deep cavity/thin wall → mold frame needs to be strengthened to prevent deformation. Material characteristics: high shrinkage material (such as PP, PE) → mold frame needs higher rigidity to avoid dimensional deviation. High temperature material (such as PC, PEEK) → mold frame needs heat-resistant design (such as using P20 steel or higher grade materials). 3. Key Parameter Matching Parameter Selection Principles Mold frame size length × width ≥ product maximum projection area × 1.5 (multi-cavity molds need to be superimposed for calculation). Template thickness is calculated based on molding pressure (usually ≥ 2 times the product height) to ensure anti-deformation ability. Guide pin/guide sleeve high-precision molds use ball guide pins (accuracy ±0.01mm), and ordinary molds use sliding guide pins. Ejector system ejector stroke ≥ product height + safety margin (5~10mm). Products with complex cooling water channels require multi-circuit design, with a water channel diameter of 6~12mm and a spacing of ≤3 times the water channel diameter. 4. Cost and standardization balance Prioritize standard mold frames (such as LKM, HASCO): reduce costs and shorten delivery time (standard mold frame delivery time is usually 1~2 weeks). Custom mold frames: only used for special structures (such as special-shaped parting surfaces, oversized sizes), high cost and long delivery time (4~8 weeks).
"A"----Indicates the distance from the side of the insert to the side of the template.
"B"----indicates the distance from the bottom of the fixed mold insert to the bottom of the fixed mold plate. "C"----indicates the distance from the bottom of the movable mold insert to the bottom of the movable mold plate. "D"----indicates the distance from the product to the side of the insert. "E"----indicates the distance from the highest point of the product to the bottom of the insert. "H"----indicates the thickness of the movable mold support plate (when the mold frame is type A). "X"----indicates the product height.
5. Supplier and material verification Material requirements: The mold plate is commonly made of S50C (low carbon steel) or P20 pre-hardened steel, and the hardness needs to be checked (HRC 28~32). Guide pins/guide sleeves use SUJ2 bearing steel, and the surface is high-frequency quenched. Supplier evaluation: Provide 3D mold frame drawings, material reports and processing accuracy certificates (such as flatness ≤0.02mm). Give priority to suppliers that support rapid modification and after-sales service. 6. Dynamic verification and correction Moldflow analysis: Verify filling, cooling and deformation (such as Moldflow analysis) and optimize mold frame design. Feedback from mold trials: adjust the ejection system, cooling water circuit or mold strength according to the mold trial results. Summary of key points: Mold type determines structure: select two-plate/three-plate/hot runner according to product demoulding requirements. Product-driven design: size, material and complexity are directly related to mold frame parameters. Standardization is preferred: more than 80% of cases can be solved with standard mold frames. Verification is essential: mold flow analysis and mold trials are the key to avoiding design defects. The actual selection needs to be combined with production volume, budget and cycle for comprehensive decision-making, and coordinated with the mold factory to optimize the design when necessary!
