PV 3952 (2002)

Testing of Scratch Resistance

PV 3952

Konzernnorm Descriptors: plastic, interior, component, scratch resistance, crosscut test, test

1

Scope

This test standard serves to determine the scratch resistance of painted and unpainted plastic interior components. A scratch test (crosscut test) is performed on the surface of the component to this end. 2

Designation

Scratch resistance acc. to PV 3952 3

Definition

The scratch resistance of plastics is defined as the resistance offered by the material to a mechanical stress, e.g. scratching motion of a sharp edge or rounded object. 4

Requirements

Requirements and deviations from the test procedure according to the technical supply specification and/or release. 5

Test

5.1

Principle

A machine-guided scratching gouge scratches a grid with a spacing of approx. 2 mm onto a painted/unpainted plastic surface. Each scratch is produced by one movement in one direction. A colorimeter is then used to determine the chromatic aberration in relation to the unscratched surface. 5.2 -

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Form FE 41 - 12.00

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Test equipment and auxiliary equipment Scratching device (e.g. motor-driven crosscutting tool, from Erichsen, model 430; see Figures 1 and 2) Scratching gouge (e.g. hard metal tip ∅ = 1 mm; the engraving tip of the 318 hardness testing device from Erichsen is suitable) Colorimeter acc. to DIN 5033-4 Measurement shapes acc. to DIN 5033 –7 section 3.2.1 - 45°/ 0° or section 3.2.2 - 0°/ 45° (ideal 45° circular) Other shapes are also permissible upon agreement with the test laboratories. Visual evaluation under standard light acc. to DIN 6173 Parts 1 and 2 Standard light D65 (minimum requirement: quality grade 2)

Page 1 of 4 Fachverantwortung/Responsibility K-QS-31

Frau Radon

Normung/Standards (EZTN, 1733) Tel:-31886

Frau Hager-Süß Tel: +49-5361-9-49035 Sobanski

Vertraulich. Alle Rechte vorbehalten. Weitergabe oder Vervielfältigung ohne vorherige schriftl. Zustimmung einer Normenabteilung des Volkswagen Konzerns nicht gestattet. Vertragspartner erhalten die Norm nur über die zuständige Beschaffungsabteilung. Confidential. All rights reserved. No part of this document may be transmitted or reproduced without the prior written permission of a Standards Department of the Volkswagen Group. Parties to a contract can only obtain this standard via the responsible procurement department.

 VOLKSWAGEN AG

Norm vor Anwendung auf Aktualität prüfen / Check standard for current issue prior to usage.

August 2002

Plastic Interior Components

g

The English translation is believed to be accurate. In case of discrepancies the German version shall govern.

Klass.-Nr. 55 10 4

Page 2 PV 3952: 2002-08

5.3

Specimen

The specimens must be removed from the components under test and should be of a shape and size that ensures plane contact with the specimen holder and the supporting table of the respective spectrophotometer. The test surface must be plane parallel with the contact surface. 5.4

Specimen preparation

The surface of the specimens must be homogeneous and must have no foreign matter. Specimens should only be handled with clean, grease-free hands. 5.5

Conditioning

The specimens must be conditioned for a minimum of 48 h in a standard climate according to DIN 50 014-23/50-2. 5.6

Procedure

The test is performed at (23 ± 5)° C. A scratching tool is used to scratch a grid (crosscut grid) of at least (40 x 40) mm. See Figure 3. Testing parameters: -

Contact force

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Scratching speed Grid spacing Scratching gouge

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F = 5 N and 10 N (for unpainted components; F is dependent on the position in the vehicle and the component specifications) F = 10 N (for painted components) v = 1,000 mm/min 2 mm Ø 1 mm (e.g. engraving tip from the 318 hardness testing device from Erichsen)

Page 3 PV 3952: 2002-08

Specimen mounting

Figure 1 -

Figure 1

Figure 2

Page 4 PV 3952: 2002-08

Grid spacing 2 mm

Grid width approx. 40 mm

Figure 3 5.7

Evaluation

The measured values for dL*, da*, db* and dE* of the unscratched area from the scratched area, determined using colorimetry, are used for evaluation (measured value = mean of at least 5 individual measurements). Measuring method acc. to DIN 5033-4 Color change acc. to DIN 6174 Illuminant: D65 / 10° Measuring field diameter: ≥ 7 mm In addition, a test of the measured values for plausibility of the optical impression must be performed (even when the measurements indicate an evaluation of OK). 6

Referenced standards

DIN 50 014

Climates and Their Technical Application; Standard Climates

DIN 5033-4

Colorimetry; Spectral Method

DIN 5033-7

Colorimetry; Measuring Conditions for Object Colors

DIN 6173-1

Color Sampling; General Color Sampling Conditions

DIN 6173-2

Color Sampling; Lighting Conditions for Artificial Medium Daylight

DIN 6174

Colorimetric Determination of Color Intervals with Object Colors According to the CIELAB Formula