GM9619P Cyclic Crumb Test

The GM9619P standard, developed by General Motors, defines a test method for determining the ability of a vehicle paint coating to withstand chipping in a corrosive environment. This standard was later repealed and replaced by the GMW 14700 standard. This new standard, whose full name is “GMW 14700 Stone impact resistance of coatings”, provides test methods for evaluating the stone impact resistance of organic coatings.

The GMW 14700 standard applies to coated metallic, plastic or composite materials and includes the following test methods:

• Method A is a closed test method in which the gravel meter is kept in a constant temperature freezer. This method uses a sufficiently large cold room or freezer where the gravlometer and test samples are kept at minus 18 plus/minus 2 degrees.
• Method B is the transfer method in which test panels are transferred from a freezer to a room temperature gravel meter. This method uses a freezer in which the test samples are cooled to a test temperature of minus 18 plus/minus 2 degrees. Preconditioning that causes freezing on the surface of test specimens should be avoided.
• Method C is a closed test method in which the pebblemeter is kept in a constant temperature chamber. This method uses a chamber where the gravlometer and test specimens are held at plus 22 plus/minus 5 degrees.

If this standard is used on uncoated panels, eg color molded plastic panels, alternative evaluation and rating procedures are required.

Essentially, no statement contained in the GMW 14700 standard is a substitute for applicable legal regulations. This standard is typically used in, but not limited to, exterior applications on vehicle bodies for substrates with different organic coatings. The standard is also used for other purposes. For example, chassis parts, under-hood parts and similar equipment are covered by this standard.

In short, the stone impact test is a standardized test method for investigating the durability of coatings and is required in the standards of a wide variety of vehicle manufacturers.

Among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors, our organization also provides testing services to determine the ability of vehicle paint coating to resist chipping in a corrosive environment, within the scope of the GM9619P standard, with its trained and expert staff and advanced technological equipment.