The Whole Development Process of New Energy Structural Component Molds for China Plastic Molding Industry
1 Pre-project DFM Review & Quotation Confirmation
New energy structural parts mainly include battery housings, electronic control shells, charging pile bases and plastic cladding parts for integrated automotive die-casting components. These parts are subject to strict requirements such as vehicle lightweight design, flame retardancy and high dimensional precision, which determine that the mold development process must connect product review, structural design, steel selection, machining, trial mold revision and mass delivery in sequence, matching the production management mode adopted by domestic plastic mold manufacturers. At the initial stage of a project, designers conduct DFM review for products, select plastic materials such as modified PA, PPA, LCP and flame-retardant PC/ABS with high temperature resistance and hydrolysis resistance according to actual service conditions of automotive components. Engineers check potential design defects including uneven wall thickness, stress concentration at sharp corners, difficulty in demolding undercuts and assembly tolerance deviation in advance. For sealing structures of battery packs, the layout of exhaust grooves and parting schemes are preset to avoid common molding defects such as short shot, burning and burrs on sealing surfaces during mass production. After the DFM report is finalized, detailed mold quotation and project schedule will be released simultaneously, clarifying mold opening cycle, trial mold nodes and acceptance criteria of each phase.
2 Mold Structural Design & Mold Flow Simulation
In the mold design phase, high-strength molding requirements of new energy parts are fully considered. Cavity inserts adopt corrosion-resistant mirror mold steel like S136H, STAVAX and NAK80, which can resist corrosive gas precipitated from flame-retardant plastics during injection molding. Multi-point hot runner gating system is applied to large battery shells to reduce weld lines and improve overall structural strength of shells. Hydraulic cylinder core pulling combined with wear-resistant sliding blocks is arranged for lateral undercuts, while ejector pins and sleeves are densely distributed at thin rib positions to prevent whitening and deformation during ejection. Conformal cooling channels are laid close to the cavity surface to control the mold temperature difference within ±2°C, ensuring flatness and dimensional consistency of new energy structural parts. After finishing 3D drawings, mold flow analysis is carried out to simulate melt flow paths, trapped air positions and shrinkage deformation tendency. Gate positions and exhaust structures are optimized based on simulation results before finalizing processing drawings.
3 Precision Machining & Mold Assembly
Mold machining is divided into rough machining, heat treatment, finish machining and polishing procedures. Pre-hardened forged mold bases are selected to lower deformation risks in subsequent processes. 0.3mm finishing allowance is reserved after CNC rough milling of mold inserts, followed by quenching and tempering heat treatment. Electrical discharge machining is adopted to process tiny rib grooves and engraved marks after finish milling, and mirror surfaces are polished to A2 grade. During assembly, workers repeatedly check sliding block clearance, ejection smoothness and water channel tightness to eliminate water leakage, mold jamming and sliding block scratching problems. Strict quality inspection is implemented in every working procedure to guarantee assembly precision of molds for new energy parts.
4 Trial Molding, Revision & Certification
Basic injection molding parameters including material temperature, mold temperature and injection speed are debugged in gradient mode during the first trial molding. Molded samples are sent for three-coordinate dimensional inspection, air tightness test and high-low temperature cycle test. Battery shells must pass air leakage detection to verify sealing performance. Aimed at excessive deformation, warpage and insufficient weld strength, engineers optimize cooling channels, increase packing pressure and adjust gate positions respectively. After 2 to 5 rounds of trial molding and modification, samples will fully meet vehicle certification standards proposed by customers. Each revision record is archived to form a closed-loop problem solving system, greatly shortening the debugging cycle of new energy molds.
5 Mass Production Handover & Post-service Maintenance
Once molds pass acceptance inspection, they will be handed over to mass production workshops together with customized injection molding operation instructions and mold maintenance manuals, specifying cleaning cycles of cooling channels, lubrication frequency of sliding blocks and models of vulnerable spare parts. On-site mold maintenance service is provided after delivery. Reserved modification allowance is designed on molds to adapt to iterative upgrades of new energy vehicle models, so structural molds for updated products can be quickly modified in later stages. Chinese plastic mold factories gain competitive edges in the new energy industry via full-process closed-loop management. Early DFM optimization cuts modification costs in later periods, while mature technologies of conformal cooling channels and hot runners stabilize mass production yield. Such complete development system satisfies strict precision standards of automobile manufacturers and adapts to the fast iteration rhythm of the new energy industry.
