Altana Balanced Beam Manuel d'utilisateur télécharger pdf (Page 8)

The uncoated surface of any rigid material may be

tested for hardness by nding the load required to

make a visible scratch on the surface. The Needle

Stylus, Hoffman Tool or Rod Stylus are used for

this purpose.

The two Ball-Tipped styluses may not actually

scrape or scratch, but will depress a coating or

other material under sufcient load, creating a

groove in the surface. As with scratch resistance,

resistance to „grooving“ is a practical test because

the product may be subjected to forceful contact

with sharp and blunt objects.

The resistance of a surface to penetration by

too sharp and too blunt objects mayor may not

correlate.

The Spit Stylus is used for rubbing tests. A soft

object supplied by the user is impaled upon the

stylus and then rubbed against the test surface

under a certain load. Examples are rubbing an

eraser against printed characters on paper or a

piece of shoe leather against a polished oor tile.

Operation

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Altana Balanced Beam Manuel d'utilisateur Page 8