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SAE J1847: A Standardized Test Method for Abrasion Resistance of Vehicle Exterior Graphics
SAE J1847 provides a uniform methodology for evaluating the abrasion resistance of decorative tapes, graphics, and pin striping used on vehicle exteriors. This recommended practice, originally issued in 1989 and stabilized in 2021, addresses the need for consistent and repeatable test results across laboratories. By following the specified procedure using a Taber abraser with CS-17 wheels, manufacturers and quality assurance teams can reliably compare material performance and durability.
Test Apparatus and Sample Preparation
The testing equipment required includes a Taber Abraser Model 174 (or equivalent) with a vacuum accessory, CS-17 Calibrase abrasive wheels, and 150-grit silicon carbide resurfacing pads. Test samples are mounted on clean cold-rolled steel panels (102 mm square, 1 mm thick) that have a central hole for turntable mounting.
The following table summarizes the key apparatus and conditions specified in SAE J1847:
| Parameter | Requirement |
|---|---|
| Abraser | Taber Model 174 or equivalent with vacuum |
| Abrasive Wheels | CS-17 Calibrase |
| Load | 500 g per wheel (using counterweights) |
| Conditioning Temperature | 23°C ± 2°C (73.4°F ± 3.6°F) |
| Conditioning Humidity | 50% ± 5% RH |
| Conditioning Duration | At least 40 hours |
| Test Panel | Cold-rolled steel, 102 mm square, 1 mm thickness, with 6 mm center hole |
🛠️ Engineering Design Insight
This test method provides a repeatable baseline to compare different material formulations and constructions. Designers should ensure that graphic films can withstand the abrasive forces of wiping, cleaning, automatic washes, and outdoor exposure. The standardized procedure helps in setting performance specifications and quality control criteria.
This test method provides a repeatable baseline to compare different material formulations and constructions. Designers should ensure that graphic films can withstand the abrasive forces of wiping, cleaning, automatic washes, and outdoor exposure. The standardized procedure helps in setting performance specifications and quality control criteria.
Conditioning and Testing Procedure
Before testing, the materials must be conditioned at 23°C ± 2°C and 50% ± 5% relative humidity for a minimum of 40 hours. The test itself should be conducted under the same conditions. Test samples must be mounted smoothly on the steel panels, avoiding any wrinkles, air bubbles, or dirt that could affect even abrasion.
The abrasive wheels must be properly prepared: new wheels are refaced for 100 cycles (or until a uniform surface is achieved), and used wheels are refaced for 25 cycles between tests. Refacing is done with the vacuum accessory running to remove debris. After refacing, the wheels should be brushed and handled carefully to avoid contaminating the abrasive surfaces.
⚠️ Important Note
Do not use the vacuum accessory during the actual abrasion test. It is intended only for the refacing process to remove residue. Using the vacuum during the test can introduce variability in the abrasion action.
Do not use the vacuum accessory during the actual abrasion test. It is intended only for the refacing process to remove residue. Using the vacuum during the test can introduce variability in the abrasion action.
The test panel is mounted on the turntable, the wheels are lowered, and the abraser is started. The sample is exposed to the specified number of cycles or until the end point is reached. After testing, use a soft brush to remove any residue. The wheels should be refaced between tests to ensure consistent abrasion.
Evaluating Results and Defining Failure
SAE J1847 leaves the definition of failure to the tester or specifier. Common evaluation criteria include:
- Visual appearance: loss of legibility, wear through to a second surface, or changes in pattern and color.
- Quantitative measures: weight loss of the sample after a predetermined number of cycles, or the number of cycles required to reach initial wear-through.
Abrasion resistance is judged qualitatively by its effect on the legibility, pattern, and color of the graphic marking. The standard emphasizes that consistent sample preparation, conditioning, and wheel handling are critical for reproducible results.
Frequently Asked Questions
Can SAE J1847 be used for testing labels or wood grain films?
Yes, the scope notes that this recommended practice may also have relevance to certain vehicle labels and plastic wood grain films, making it a versatile test for a range of decorative films.
What are common mistakes when performing this test?
Common errors include using a different abraser model, incorrect wheel refacing (not 100 cycles for new wheels or 25 between tests), poor sample mounting, improper conditioning, wrong load application (should be 500 g), and using the vacuum during the test. Following the details in the standard helps minimize these issues.
How is failure defined if the standard does not specify a single criterion?
Failure is left to the discretion of the tester. Typically, it is based on appearance (e.g., legibility loss) or performance (e.g., a specific number of cycles). The standard also allows measuring weight loss or cycles to initial wear-through as quantitative measures.
What is the significance of the vacuum accessory?
The vacuum is used only during wheel refacing to remove debris that could affect the abrasive surface. During actual testing, it should not be used, as it can alter the abrasion dynamics and introduce inconsistency.
