Technical Requirements for Injection Moulding Automotive Parts

The technical requirements for injection moulding automotive parts cover the entire process, including materials, molds, processes, post-processing, and quality control. The core requirements are as follows:

1. Engineering Material Selection Technical Requirements

Performance Matching: Select materials such as ABS, PC/ABS, and glass fiber reinforced nylon based on the component's function, comprehensively evaluating mechanical strength, temperature resistance, and cost factors.

Flowability Adaptation: The melt flow index of the material must match the complexity of the product structure to ensure complete filling of complex cavities.

Environmental Compliance: Prioritize the use of recyclable modified materials to meet the automotive industry's low-odor, low-VOC environmental standards.

Pre-treatment Specifications: Raw materials must be dried at 80-120℃ for 4-8 hours, with a moisture content controlled below 0.02%, and a feeding accuracy error not exceeding ±0.5%.

2. Precision Mold Development Technical Requirements

Mold Flow Simulation: Utilize CAD/C++. AE software completes mold flow analysis and optimizes the gating system and cooling channel design.

Material Hardness: The mold core is made of mold steel with a hardness of HRC52 or higher after heat treatment, ensuring dimensional stability in long-term mass production.

Precision Control: Mold manufacturing tolerances are controlled within 1/3 of the product standard tolerance. Standard parts have a dimensional tolerance of ±0.05mm, and precision parts can achieve a precision of ±0.01mm.

Structural Design: Reasonable draft angles and ejection mechanisms are set to prevent product deformation during demolding. Complex structures can utilize 3D printing conformal water channel technology to achieve uniform cooling.

3. Molding Process Parameter Control Requirements

Material Temperature Zoning: The barrel is temperature-controlled in three sections: feeding section 190-210℃, compression section 210-230℃, and metering section 220-240℃, ensuring full plasticization and preventing material degradation.

Injection Pressure: Standard section... Injection pressure is controlled at 80-120MPa. For precision injection molding, the injection pressure needs to exceed 25MPa, and in some high-pressure scenarios, it can reach 216-392MPa.

Multi-stage injection speed: A segmented injection strategy is adopted. The initial stage involves rapid filling of the runner at 30-50mm/s, the cavity filling stage reduces to 20-30mm/s to prevent jetting, and the final stage uses 5-10mm/s to complete the pressure holding switch.

Temperature field stability: Mold temperature fluctuations are controlled within ±1℃, cooling water temperature is controlled at 15-25℃, and temperature difference fluctuations do not exceed ±2℃ to avoid warping caused by uneven cooling.

4. Secondary processing and post-processing requirements:

Gate treatment: Laser gate removal or cryogenic trimming is used to avoid stress concentration caused by traditional punching.

Surface treatment: Plasma surface treatment improves the adhesion of subsequent coatings, especially for parts with high appearance requirements. Surface roughness Ra≤0.8μm

Internal stress elimination: Key load-bearing components require annealing to eliminate residual internal stress from the molding process.

Online inspection: An online inspection system is configured to achieve 100% inspection of key dimensions, ensuring consistency of batch products.

5. Full-process quality control requirements

Raw material inspection: Melt index testing and ash content testing are completed to control material performance from the source.

Process monitoring: SPC statistical process control method is adopted, with key process parameter CPK value ≥1.33.

Finished product performance testing: Tensile strength, weather resistance, and temperature resistance tests are completed to ensure that components can withstand temperature differences from -40℃ to 120℃.

Closed-loop adjustment: Real-time acquisition of melt pressure and temperature data through in-mold sensors enables closed-loop adjustment of process parameters, and the yield rate can be stably increased to over 99.2%.

Qingdao Xueyu Molding Products Co., Ltd. is mainly engaged in the design and manufacturing of injection molds, injection molding and secondary processing (spraying, pad printing, ultrasonic welding, stamping), etc. For more information about injection moulding automotive parts, please contact us.

Website: www.xyzmould.com

Address: No.18 Henan Head Road, Henan Head Community, Jihongtan Street, Qingdao Industrial Park, Shandong Province, China

Email: wangmiaotian8@163.com