Wiper blades must function reliably for drivers over an extended period — that means, throughout all seasons and under extreme weather conditions. To ensure this, Bosch has many other strict quality tests in addition to the prescribed standard tests that must be passed for acceptance into the program. These tests are divided into four categories: wiping performance, environmental influences, load tests, and durability.
Wiping performance on the test bench
To ensure the best possible wiping performance, the wipers undergo four testing scenarios: In the first scenario, the focus is on wiping quality. During the development phase, the wipers are tested on a windshield in the laboratory, and their performance is evaluated. The test engineers pay close attention to the formation of streaks or smears on the windshield, the presence of water residues, or any marks left behind by the wipers. Only when the test requirements are met, and the wiping pattern is flawless, are the wiper rubber or blades approved for production. The goal is to ensure that the wipers deliver impeccable results throughout their entire lifespan.
In the acoustic laboratory, the entire wiper system is tested to minimise any squeaks, humming, or noises during the wiping process on the windshield. The aim is to enhance customer comfort by reducing unwanted sounds. In the wind tunnel or on the test track, the examiners also verify that the wipers maintain contact with the windshield even at high speeds, ensuring their effectiveness during fast driving conditions.
Resistance against environmental influences
In additional testing scenarios, the wipers must demonstrate their ability to withstand any weather, no matter how extreme. First and foremost, the focus is on their resistance to sunlight. The wipers are exposed to UV radiation for an extended period. Furthermore, the resilience of the wiper rubber and its functionality during and after exposure to high temperatures are tested.
In the second step, the use of spray salt tests the wipers’ corrosion resistance. At the Bosch test centre, the wipers undergo multiple temperature cycling tests, ranging from extremely low to extremely high temperatures. All tests are considered successful if there are no cracks in the wiper rubber, no deformations, and no significant loss in wiping quality.
Load test at the limit
In particularly wintry regions, wipers are exposed to extreme stress. However, thanks to the load tests conducted at Bosch, even those living in particularly wintry regions can have peace of mind. In freezing tests at temperatures of -20°C and in snow-load tests, the wipers demonstrate their winter suitability. Durability is a crucial aspect for wipers, not only in the context of extreme temperatures. Therefore, endurance tests are also conducted, simulating 500,000 wiping cycles. Additionally, the mechanical robustness of the wipers and their individual components (e.g. adapters) is tested in other specialised tests.
A hidden threat to wipers lies in cleaners and chemicals that can find their way onto vehicle windshields. Therefore, the fourth and final testing category focuses on the wipers’ resistance. They are exposed to various aggressive chemicals, and afterwards, the test results are analysed under a microscope to determine if any traces of the chemicals remain.
Bosch experts evaluate all test results according to strict quality standards and continuously improve Bosch wipers. Only through this approach can the high quality standards of Bosch wipers be met, ensuring customers receive clear visibility and enhanced safety.