Gravel Bombardment Test As Per ISO 20567-1
Gravel Bombardment Test According to ISO 20567-1: Ensuring Automotive Coating Durability
Introduction
- In the automotive industry, vehicle surfaces are continuously exposed to road debris, gravel, and harsh weather conditions, which can cause chipping, peeling, and damage to coatings. To ensure long-lasting durability, manufacturers rely on standardized testing methods like the Gravel Bombardment Test, defined in ISO 20567-1. This test evaluates a material’s resistance to stone chipping, ensuring that protective coatings can withstand real-world challenges.
What is the Gravel Bombardment Test?
The Gravel Bombardment Test (ISO 20567-1) is a controlled impact test that assesses the chipping resistance of coatings when subjected to high-speed gravel or stone impacts. It is used to evaluate painted vehicle surfaces, plastic components, protective films, and clear coats under simulated conditions.
Why is This Test Important?
✔ Prevents premature coating failure caused by stone chips
✔ Ensures compliance with automotive industry standards
✔ Enhances the durability of exterior coatings and protective films
✔ Improves product quality for OEMs and suppliers
ISO 20567-1: Standardized Testing Method
ISO 20567-1 provides a structured and repeatable process for evaluating stone impact resistance. The test follows a systematic approach to ensure reliable and comparable results.
Test Setup and Procedure
1. Sample Preparation
- The test panel consists of a metal or plastic sheet coated with primer, basecoat, and clear coat.
- The panel is fully cured before testing to ensure accurate results.
2. Gravel Impact Simulation
- A gravelometer is used to propel small stones at the test panel at a controlled speed and angle.
- The test is conducted under static conditions, meaning the panel remains fixed while being impacted.
3. Severity Levels
ISO 20567-1 defines three levels of severity:
- Severity A – Low-intensity test with fewer stone impacts
- Severity B – Medium-intensity test simulating real-world conditions
- Severity C – High-intensity bombardment for extreme durability testing
4. Post-Test Evaluation
After exposure to gravel bombardment, the test panel is analyzed for:
✅ Size and number of stone chips using microscopic analysis
✅ Coating adhesion quality (Tape Pull Test)
✅ Material integrity and protective effectiveness
Functional Requirements as per ISO 16750-1
Following the gravel bombardment test, the functional status of the coating must meet Class C as per ISO 16750-1, ensuring that the material remains effective even after experiencing severe chipping.
Applications in the Automotive Industry
The Gravel Bombardment Test is widely used by:
🚗 Automotive Manufacturers – To enhance vehicle paint durability
🔬 Coating Suppliers – To develop stone-resistant coatings
🛠 OEMs & Tier-1 Suppliers – To ensure long-term product reliability
Key Components Tested
✔ Exterior Paint & Clear Coats – Preventing chipping and fading
✔ Plastic Components (Bumpers, Grilles, Trim) – Ensuring impact resistance
✔ Headlights & Glass Protection – Evaluating surface durability
✔ Underbody Coatings – Protecting against gravel and debris
Conclusion
- The Gravel Bombardment Test (ISO 20567-1) is a critical quality assessment for the automotive industry. By following standardized testing protocols, manufacturers can develop durable coatings, enhance material performance, and improve vehicle longevity.