Senze-Instruments

Washability and Scrub Resistance Tester, Model 494

Abrasion is the result of mechanical phenomena, such as rubbing or/and scraping, onto matter. In practice abrasion appears continuously on a large variety of objects e.g.:
" blowing air carrying sand onto architectural and car paintings
" brushing during cleaning of architectural and car paintings
" rubbing by shoe soles, sometimes loaded with sand, onto floor coatings
" rubbing by cloth or human skin onto furniture finishes
" marring with harder objects (buttons, keys) of decorative finishes of furniture or cars.
The result is experienced either as marring or wearing. Marring is caused by a deformation of the surface without removing any material. Wearing or abrasion is caused by a permanent removal of the coating material.
Abrasion is related to mechanical properties of matter such as hardness and elasticity. This is why different test methods tend to give different results, depending on the proportion hardness/elasticity involved resulting in different removing mechanisms.

The Erichsen Model 494, a washability tester is a polyvalent machine designed for testing the washability, cleanability, brushability, wet scrub resistance or abrasion resistance of a large number of different materials such as paints, lacquers, inks, coatings, leather sheets, wood panels, plastics, printed materials, fabrics, etc.
The machine will linearly move an abrasive tool back and forth onto a test surface. The abrasive tool might be a brush (eventually containing an abrasive medium), a sponge or an abrasive pad. In some cases a stroke of emery cloth is fixed to the abrasive tool.
The machine will count the number of cycles (one cycle is a completed back and forth move) made in order to obtain a certain erosion effected to the test film.
The result might be expressed as the number of cycles needed to remove a film completely or as an amount (weight) of film material removed per unit of tested surface and per cycle.
Some definitions:
Cleanability: the ability of a dry coating film to withstand penetration by soiling agents and to be freed from them without an excessive amount of film being removed by the cleaning process.
Wet scrub resistance: the ability of a dry coating film to sustain less than a given loss in film thickness, averaged over a defined area when exposed to 200 wet scrub cycles.

Micro Dosing pump :





Rubber Lining

The Erichsen Model 494, consisting of basic instrument with base plate on adjustable feet for levelling, electric motor, pre-setting counter, including 1 glass plate, stainless steel trough with outflow connection, box level, spare pull cable, but without brush or brush holder, for connection to 230 V, 50 Hz main supply.
The Erichsen Model 494 works accordingly these different standards :
" DIN 53778
" DIN 53778 T2+B233
" DIN EN ISO 11998
" ISO 11998
" ASTM D 2486


To perform the tests different medias are at your disposition :

DIN-Equipment (see under)

ASTM-Equipment (see under)

Adapter Set for Scrubbability Tests (see under)

Micro-Dosing Pump
with drip arrangement (For dual tests with Dual Holders two Micro Dosing Pumps are required.)

Dual Holder
for two DIN-brushes for simultaneous testing of two specimens side by side

Dual Holder
for two abrasive pad holder plates acc. to DIN EN ISO 11998 for simultaneous testing of two specimens side by side

2. Abrasive Pad Holder Plate
for completion, for using the Dual Holder

Foil Thickness Gauge, Model 497
to measure the thickness of sheets, plastic foils, cardboards, paper, etc., measuring range: 0 - 1000 microns, graduation 1 micron

Abrasive tool for tests in accordance with DIN 53 778, part 2(replaced by EN ISO DIN 11998 in Dec 2001 but still used by a lot of customer)
Wild boar hair brush and stainless steel brush holder - standardised mass: 250g DIN-Equipment
include :
1 Pig bristle brush DIN,
1 Brush holder DIN,
1 Rubber lining

Abrasive tool for tests in accordance with ASTM D 2486 and SIS 18 41 64
Nylon bristle brush and stainless steel brush holder, standardised mass: 454g
Include :.
1 Nylon brush ASTM
1 Brush holder ASTM
1 Rubber lining
1 Clamping frame with rubber seal, length 430 mm
2 Sheet metal strips

Abrasive tool adapter set for scrubbability tests acc. to DIN EN ISO 11998
consisting of: mounting device to be clamped into the pull cable and abrasive pad holder plate, without pad
Stainless Steel holder, standardised mass: 135g