718 Mold Steel Automotive Interior Injection Mold

Large-Scale Tooling for Detailed Automotive Trim

An automotive interior injection mold must manage far more than part size. Door panels, instrument panels and center-console components often combine deep ribs, hidden clips, undercuts, storage features and broad decorative surfaces within one molded structure. Yijiang develops the tooling around these interacting details, with close attention to parting lines, slide movement, cooling balance and ejection stability.

The mold uses 718H pre-hardened steel, selected for its dimensional stability, machinability and response to polishing or texturing. Large gantry CNC machining establishes the main cavity geometry, while wire-cut EDM and mirror EDM form narrow slots, sharp corners, deep ribs and detailed inserts. Key mold dimensions can be controlled within ±0.01 mm during machining and assembly.

Technological Process

1. Product & Mold Design: Optimize parting lines, slides and cooling solutions based on automotive interior part structure, complete 3D mold design and 2D machining drawings.
2. Steel Cutting & Rough Machining: Cut 718H mold steel to size and perform rough milling to remove most of the excess material.
3. Semi-finishing & Heat Treatment: Semi-finish the mold components and perform pre-hardening treatment to stabilize 718H hardness at HRC32-36, improving wear resistance and polishing performance.
4. Precision Machining: Large-scale CNC finish the cavity, slides and guide pin holes; wire-cut EDM process inserts and holes; EDM finish sharp corners and ribs.
5. Surface Treatment & Texturing: Conduct texture, etched or high-gloss treatment according to OEM standards to restore the texture and appearance of interior parts.
6. Mold Assembly & Trial Molding: Complete mold assembly, conduct multiple trial moldings and adjustments to ensure product dimensions, appearance and assembly compatibility meet requirements before delivery.

Surface Control for Visible Interior Components

Automotive trim surfaces require consistent grain depth, gloss level and boundary definition across broad visible areas. The cavity can receive texture, matte, etched or high-gloss treatment according to the approved appearance specification. Careful steel preparation before texturing helps reduce uneven grain, polishing marks and visible transitions around inserts.

Trial molding checks more than overall dimensions. Each sample undergoes review for sink marks, flow lines, weld lines, gloss variation, clip formation and compatibility with adjoining trim. Cooling channels, vents, slide timing and local steel conditions can then be adjusted before final approval.

Core Advantages & Applications

Common Applications

• Door Panel Parts: Front and rear door panels, armrest panels, storage box molds
• Instrument Panel Parts: Instrument panel bodies, center consoles, air outlet molds
• Center Console Parts: Center console panels, cup holders, shift panel molds
• Other Interior Parts: Pillar trims, roof accessories, luggage compartment trim molds

Before release, the automotive interior injection mold passes assembly checks and repeated molding trials under defined process settings. The final review covers part appearance, fit points, moving mechanisms and production stability, supporting a controlled transition from mold development to scheduled trim-part production.

Specification Table