Fingertip & hand abrasion
Human hands and fingers are often in touch with products, e. g. mobile phone, car, watch, money, kitchenware, and so on. During the touching, or swiping or rubbing by human being, the surface is under special stress and creates a special type of abrasion, namely ABREX® – abrasion.
Special features of human fingertip & hand
· With curvature
· Rough structure with texture
· Inhomogeneous and nonlinear
· With dandruff/ dirt/ sweat/ fat/ lotion/ cream
A complete fingertip touch motion involves:
a. starting with 45o angle touch/hit on the surface instead of 90o perpendicular of the surface;
b. the touch/hit is done by a viscoelastic fingertip/ hand with an average load of 3.75N;
c. followed by one-direction friction;
d. repeat step a-c cyclically
This cyclic motion is often under various liquid environment (sweat, cream or lotion).