BACKGROUND

The wiper arm/blade forms an integral part of the windshield wiper system. Chatter is the phenomenon that occurs when the wiper blade does not take the proper set and "skips" across the windshield during operation, potentially causing both acoustic and wipe quality deterioration, which significantly affect the satisfaction of the customers.

The major quality concern, which inspired the robustness study, was the wiper chatter phenomenon in some of the windshield wiper systems. Customer expectations the good windshield wiper systems are:

• Clear vision under a wide variety of operating conditions

• Multiple level of wiper speed

• Uniform wiper pattern

• Quiet under all weather conditions

• Long life and high reliability

PROCESS

Instead of measuring wiper quality deterioration, a robust design approach was used by evaluating the actual time that a blade takes to reach a fixed point on the windshield at a given cycle. That means that the focus was on measuring the functionality of the system and not the end characteristics.

Nine control factors were used under all categories of noise factors. Eighteen design configurations were tested in this study. It is important to note that the confirmation runs of the study proved that there were no severe interactions among control factors to variability. This clearly shows the power of measuring the functionality of the system. While Taguchi Methods ^TM emphasize the need of measuring functionality, the traditional DOE (design of experiment) focuses on measuring the symptoms (output characteristics).

This difference is not...