Purpose and Application
The Multi Grid Tester 508 Select is a multi-blow test instrument, and its special feature is the good repeatability and comparability of the test results obtained. The instrument is used to assess the ability of single and multiple layers of paints and similar coating materials to stand with the impacts caused by small bodies of low mass hitting the specimen at high speed as experienced on road and rail vehicles and other equipment used in the transport field.
Design and Mode of Operation
With the modular Multi Grid Tester 508 Select, the user only needs a basic device which can be converted with little effort for bombardment tests "according to VDA" or "according to SAE".
The clear arranged menu navigation via the touch panel has password-protected levels, which protect against unauthorized access (such as program changes).
Depending on the application, a VDA module (with manual or pneumatic specimen applying device) or a SAE module is selected. A change between the different modules designed as attachments is quick and easy, without spending lots of time.
Principle of the Test with VDA Module
The stone hammer blow tests according to VDA corresponds to the requirements of national and international standards.
The specimen is subjected to impacts by sharp-edged steel shot accelerated by compressed air. An air accumulator in the system eliminates effects of momentary pressure variations in the external compressed air supply. The shot is entered automatically using an adjustable vibratory feed.
To facilitate working, the VDA module is optionally available with a pneumatic specimen applying device.
Principle of the Test with SAE Moduel
In contrast to the VDA module, work is not carried out with steel shot, but usually with river gravel “watereroded gravel”.
A defined number of impact bodies of specified properties is made to impinge for a given period of time and with a defined energy at a determinate angle of impact onto the specimen.
The bombardment of the test panels is carried out with determinate grit (according to ASTM D 3170) which is accelerated by compressed air. Dependent of the specifications of further standards (mostly of car manufacturers) other shot materials can be used, too.
The shot is entered automatically using an adjustable vibratory feeding device.
An upstream compressed air reservoir compensates for fluctuations in the external compressed air network.
The SAE module is equipped with a specimen holding device with an adjustable impact angle. The adjusting unit for the impact angle allows to adjust the orientation of the test panel relative to the direction of impact in the range from 30° to 90° in steps of 15°.
In contrast to the "VDA" version, the sample to be tested is located completely within the test room, during the whole bombardment process
Norms
- DIN EN ISO 20567-1
- FORD FLTM BI 157-06
- RENAULT D24 1702
- PSA D24 1312
- DAIMLER DBL 5416
- SAE J 400
- ASTM D 3170
Accessories (optionally)
Technical specifications
