Production Of Automotive Armrest Bases Through The Injection Molding

Functionality Standards

1. Structural Stability:

• The customer requires that the product maintain a high degree of structural stability during use, avoiding any deformation or loosening.
• Acceptance involves mechanical tests such as pressure tests and torsion tests, ensuring the product withstands up to 1000 N of force without structural failure.

2. Assembly Precision:

• The product must have high assembly precision, with all clips and mounting holes perfectly matching other components.
• During acceptance, assembly tests will be conducted to ensure the armrest base fits seamlessly with other parts, with tolerances within ±0.1 mm.

3. Function Realization:

• The armrest base must perform all its designed functions, such as support and storage, in various usage scenarios.
• Acceptance includes simulating different real-life scenarios to verify the product’s functionality, ensuring it can handle weights up to 5 kg without performance degradation.

Injection Molding Defect Standards

1. Sink Mark Control:

• There should be no noticeable sink marks in critical areas such as joints and key structural points, ensuring the integrity of the appearance and structure.
• Acceptance involves visual inspection and measurement tools to ensure shrinkage does not exceed 0.5% in these areas.

2. Surface Defects:

• The product surface must be smooth and flat, free of visible flow marks, weld lines, bubbles, and other injection molding defects.
• Acceptance includes detailed surface inspections, ensuring defect-free surfaces with a roughness average (Ra) less than 1.6 µm.

3. Dimensional Accuracy:

• All design dimensions must be within specified tolerances, especially critical assembly positions and functional areas.
• Acceptance involves using precision measurement equipment to verify dimensions, ensuring they fall within a tolerance range of ±0.2 mm.

4. Warpage and Deformation:

• The product must not exhibit warpage or deformation, maintaining the designed shape and angles.
• Acceptance involves flatness and shape checks, ensuring warpage does not exceed 1 mm per 100 mm.

Q1. How do you ensure the durability and strength of the car armrest base during the injection molding process?

Material Selection: High-strength, impact-resistant materials such as ABS or PC+ABS ensure durability and strength.

Mold Design: Precise mold design with uniform wall thickness and well-placed ribs increases structural strength.

Process Control: Control injection parameters (pressure, speed, holding time) to ensure material density and strength. Optimize cooling system design to ensure uniform cooling and reduce internal stress.

Quality Testing: Rigorous quality tests (mechanical, durability, structural stability) ensure the product meets strength standards.

Q2. How do you produce car interior parts with complex geometries through injection molding?

Precise Mold Design:

• Use multiple sliders and inserts to form complex shapes and internal structures.
• Optimize gate location and venting system using advanced mold flow analysis software.

High-Precision Machining:

• Use high-precision CNC machining to ensure mold accuracy.

Optimized Process Parameters:

• Adjust injection speed, pressure, and holding time to ensure material fills the mold cavity evenly.
• Control cooling time and temperature to maintain stable shape and dimensions.

Multiple Trial Runs and Adjustments:

• Conduct multiple trial runs and adjustments to optimize process parameters and mold design.

Q3. What is the manufacturing cost of the car armrest base at First Mold?

Material Cost: High-quality materials like ABS or PC+ABS have higher costs but ensure quality and performance.

Mold Cost: Complex structures require high-precision CNC machining and multiple trial runs, increasing mold costs.

Process Cost: Advanced injection molding equipment and precise process control add to the costs.

Production Quantity: Low production quantities due to rapid tooling result in higher per-unit costs.

Q4. What materials are typically used for car armrest bases, and why?

PC+ABS Material:

• Advantages: Combines PC’s rigidity and heat resistance with ABS’s processability and finish.
• Application: Used for higher mechanical performance and aesthetic requirements.