Automotive Instrument Panel Injection Mold

Automotive instrument panel injection molds are precision tooling for molding plastic automotive instrument panels. Due to their large size, complex structure, numerous curved surfaces, high integration, and strict appearance requirements, the design and manufacturing of these molds represent the cutting-edge technical level of automotive interior injection molds.

 

I.Core Design Points

1. Product Structure Analysis

Overall Features：Mostly large, flat parts, typically over 1 meter in length, featuring complex curved surfaces, deep cavities, multiple steps, thin walls (commonly 2–3 mm), and irregular contours.

Internal Features: Densely equipped with reinforcing ribs, buckles, screw bosses, air duct ports, display/instrument mounting seats, speaker bosses, and numerous undercuts and narrow gaps.

Appearance Requirements：High-gloss surface free of weld lines, sink marks, and ejector pin marks; some require texture, matte, or piano-black finish.

 

2. Parting Surface Design

Parting surfaces must be placed at the maximum cross-sectional contour of the product, mostly adopting complex curved parting to fit the product shape.

Parting surface precision error controlled within ≤0.02 mm to prevent flash; reasonable overflow grooves and sealing strips shall be designed.

For deep-cavity and complex undercut areas, parting surfaces shall be split with core-pulling mechanisms to ensure smooth demolding.

 

3.Cavity Layout

Main instrument panel bodies mostly use 1 mold, 1 cavity

(to ensure dimensional accuracy and molding stability).

Small instrument panel components (such as air vents, decorative frames) may adopt symmetrical layouts of 1 mold 2 cavities or 4 cavities, with component spacing ranging from 25 to 45mm.

 

4.Gating System (Critical)

Mainstream Technology: Valve-gated hot runner + Sequential Valve Gating (SVG).

Gating Design: Multi-point gating (usually 4–8 hot nozzles), with gates located on non-appearance back surfaces (ribs or bosses).

Advantages: Sequential gate control eliminates or hides weld lines, ensures uniform filling, reduces internal stress, and shortens molding cycles.

 

5. Lateral Core-Pulling and Demolding Mechanisms (Technical Challenges)

Complex undercuts in multiple directions require combined core-pulling:

Front Mold: Large lifters, inclined core-pulling (Solve the problem of the front upside down).

Rear Mold: Hydraulic cylinder-driven internal core-pulling + slides + lifters + ejector pins (for internal deep cavities and multi-directional buckles).

Draft Angles: 1.5°–2°for appearance surfaces; ≥3°for Internal tendons / columns to prevent scuffing.

Ejection System: Combined equal-height ejector pins, ejector blocks, and push tubes for uniform force and no ejector marks.

 

6. Cooling System

Water Channel Spacing≤15mm.Adopt conformal / spiral water channels + insert zoned cooling; channel spacing ≤15 mm.

Mold temperature controlled within ±3°C to reduce warpage, ensure dimensional stability, and shorten cooling time.

 

 

II.Mold Material Selection

Part	Part	Hardness Requirement	Performance Requirements
Mold Core / Cavity	S136,718H,Nak80	58-60HRC(S136)	High hardness, wear resistance, good polishing property, corrosion resistance
Mold Base	45# Steel, 50# Steel	28-32HRC	High strength, anti-deformation
Slides / Lifters	SKD61,SKD11	52-56HRC	Wear resistance, high toughness, smooth movement
Inserts (High-Wear Zones)	Tungsten steel, cemented carbide	≥60HRC	Ultra-wear-resistant, long service life

 

III.Manufacturing and Process Key Points

Processing Equipment:5-axis linkage machining centers, precision EDM, wire-cut EDM to ensure accuracy of curved surfaces and details.

Surface Treatment: Mold core polished to mirror finish (Ra ≤0.02μm) or textured / sandblasted as required.

Use Moldflow to simulate filling, pressure holding, cooling and warpage, and optimize the plan in advance

Trial Molding and Debugging: Focus on hot runner sequencing, core-pulling motion, and cooling parameters to ensure qualified appearance and dimensions.

 

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