The Gravelometer, or Chipping Resistance Tester, models EQNA-GR-ASTM/SAE and EQNA-GR-DIN/ISO/VDA, is designed to rigorously meet the technical standards of ASTM D3170, SAE J400, ISO 20567-1, DIN 55996-1, and VDA. For other standards, please contact us.
This equipment simulates the impact of projectiles on metal sheets and coated three-dimensional parts, with the aim of evaluating the coating’s resistance to chipping. The Chip Resistance Tester is engineered to accurately replicate the effects of impacts on an automobile’s surface, ensuring a close correlation with real-world operating conditions.
The primary purpose of the test is to evaluate the coating or organic surface system on flat test panels. However, this type of testing may also be extended to finished (3D) parts or other materials, such as anodized aluminum or coated plastics, as long as the results are interpreted within the limitations and intentions outlined in the original test procedures.
The process involves impacting standardized projectiles, propelled by a jet of compressed air that passes through a nozzle, under controlled pressure, onto the test specimen. These tests are typically conducted at room temperature or under subzero conditions (e.g., −29°C ± 3°C), ensuring that the compressed air, projectiles, and the entire system are at the proper temperature.
In some cases, test specimens are pre-cooled in a freezer and then quickly transferred to the Gravelometer at room temperature for testing. However, this practice is not recommended, as temperature discrepancies between the projectiles and the compressed air can lead to distorted results.
After testing, various methods can be used to evaluate the specimens. The most common approach is to compare the tested samples with reference images provided in the applicable technical standards.
EQNA GR DIN/ISO/VDA, EQNA GR ASTM/SAE
Gravelometer is built to meet the technical standards set forth by ASTM/SAE, or DIN/ISO/VDA.
This equipment simulates stone impacts on sheet metal or coated parts to evaluate the strength/resistance of the coating to projectile impact chipping.
The stone projecting equipment, also called a gravelometer, was designed to reproduce the effect of gravel or other projectiles impacting exposed paint or the surface of an automobile in close correlation with actual in the field conditions.
The specific intent of the test is to evaluate the coating or organic surface system on flat test panels, however, it may be possible to extend this type of test to finished parts or types of materials such as anodized aluminum or coated plastic if the results are interpreted with the limitations and intentions implied in the original test procedures.
The test consists of projecting standardized road gravel or other standard materials by means of a controlled air pressure jet onto a suitable test panel or part. Usually these tests are conducted at ambient temperature or at negative temperatures for example -29°C +/- 3°C.
After impact adhesive tapes are applied on the samples and strips are removed to check for loose inks on the adhesive tape, this method is detailed by technical standards such as adhesion test.
Standards:
DIN 55996-1, SAE J400, ASTM D 3170, DIN EN ISO 20567-1, Peugeot (PSA) D24 1312, Mercedes-Benz DBL 7381, VW PV 3.14.3, FIAT 50488/01, VOLVO STD 1024,7132, GMW 14700, Renault D24 1702, Hyundai MS 600-35, MAN M 3171, Nissan NES M0007.
