ERICHSEN 435, 435 S Operating Instructions Manual

testing equipment for quality management

Adhesion and
Resistance Tester
Model 435 S

Mar Tester

Model 435

3 Test Ranges:

0 - 3 N

0 - 10 N

0 - 20 N

Model 435

Model 435 S

Technical Description and Operating Instructions

Mar Tester, Model 435

Purpose and Application

Scars on surfaces are unsightly, especially on
smooth, glossy surfaces. Surfaces can be ruined so
easily - for example marks on the matt polished
surface of a table, by a fingernail, or on the shiny
bodywork of a Cadillac, by a twig. Great annoyance
can result from such small causes.

Marks can also be caused by metallic objects. The
culprits may be metal particles from coins, cutlery or
rings on fingers. Any of these can mar surface
finishes.

The traditional test for the resistance of surfaces to
such damage was to try to mark the surface with a
fingernail. With the Mar Tester, Model 435, the
quality of the surface can be measured accurately.

1. Rotating guide rolls

2. Fixed marking disc

3. Test force scale

4. Alternatives test dics

5. Force springs

6. Allen key

7. Locking screw slider

8. Help aid for fixing the locking
screw slider

Design and Function

The scaring tool in the form of a disc, with locking
facility, made of special plastic or metal, is mounted
on a screw and is under pressure from a helical
spring. This applies to a force which is adjustable
from 0 to 20 N. The instrument is placed onto the
surface so that it rests on the two guide wheels and
the marking wheel which is locked in position then
presses onto the surface with the pre-set force from
the spring. The range of spring forces available is
divided into three sections, each covered by one of
three exchangeable springs:

Test range 1: 0 - 3 N - Sensitivity 0,1 N
Test range 2: 0 - 10 N - Sensitivity 0,5 N
Test range 3: 0 - 20 N - Sensitivity 1,0 N.

Note:

The test discs will wear at the point at which they are
used. After 100 tests the discs should therefore be
moved round so as to bring a point about 2 mm
further along on the periphery into operation. The
point at which the marking disc is first used should be
marked by a scratch.

Method of Operation

First set up the selected test wheel depending on the
test required, i. e.

- the plastic disc for scar-resistance tests;

- the copper disc or other special disc for metal
marking.

After tightening the screw it must not be possible to
turn the marking disc. The spring is then set to
provide what is anticipated to be a suitable force and
the instrument is placed perpendicularly onto the test
surface and pressed down so that the guide wheels
touch the surface.

In this way the preset pressure of the test disc is fully
effective on the test surface.

The instrument is then moved a distance of a few cm
so that the wheels roll over the surface, in a rapid
motion appropriate for the scaring effect. The test
result is the spring force in Newton which is just
sufficient to produce a clear surface scar visible with
the naked eye but not a crack or scratch.

If the interest is in the so-called metal marking effect,
the result is expressed in terms of the spring force at
which the surface just shows a black or grey mark.