Abstract:

A two⁃plate hot runner mold was designed for manufacturing the lower support plate plastic component of air conditioning outlets in new energy vehicles. The mold design faced two primary challenges： first， the complex geometry of the part complicated the configuration of the gating system， and second， the presence of numerous irregular structural features hindered automatic demolding. To address these challenges， CAE analysis was employed to optimize the mold’s gating system and contour cooling layout. The final design adopted a hybrid cold⁃hot composite gating system， utilizing a rectangular side gate with initial dimensions of 8 mm×2 mm. For cooling， 11 ϕ12 mm pipes were arranged in a contour configuration， with an initial inlet water temperature of 25 ℃. Optimization results confirmed that the injection pressure within the mold cavity remains below 28 MPa， warpage deformation of the plastic part is controlled under 2.275 mm， and the injection cycle is maintained below 30 seconds. The dimensional accuracy of the part meets the MT4⁃MT5 grade standard. To resolve demolding difficulties， the design incorporated four slider mechanisms and six lifter mechanisms for automated part ejection. Notably， an innovative cross⁃type lifter mechanism was developed， featuring a sliding lifter seat driven by an angle pin. This modification reduced the movement resistance of the angle rod and enhanced the mechanism’s durability. Critical design parameters include a sliding seat angle pin inclination （α）=12 °， a angle rod ejection angle （β）=9 °， and a sliding seat groove guide angle （θ）=15 °. These optimizations ensured reliable demolding performance while meeting stringent cycle time and precision requirements.

Key words: new?energy?vehicle air?conditioning, lower?board, hot runner, injection mould, slider mechanism, moldflow analysis, cross rod lifter mechanism, mould structure