EN 14447:2005 – Fibre reinforced plastics – Glass mat reinforced thermoplastics (GMT) – Determination of flowability and solidification
5 Sampling
Three specimens shall be selected from the elementary unit or from the laboratory sample. NOTE 1 GMT is normally delivered in stacks of blanks, not in the full width of sheets as manufactured.
Their size and shape may influence how the sample is taken. If the blank is of sufficient size, take all three specimens from the one blank, one from the left, one from the middle and one from the right. If the blank is not large enough to take all three specimens from the one blank then take only one specimen per blank, selecting three blanks successively from the stack.
NOTE 2 If the blank is not large enough to take a single complete specimen, arrangements should be made with the manufacturer to supply sufficient number of larger blanks from the same production lots to enable this test to be undertaken. To define the influence of possible orientation, documentation of the production direction relative to the sampling direction is required.
The product specification or the person ordering the analysis may require that such determination is to be performed on more specimens or at specific places of the elementary unit or laboratory sample. 6 Conditioning Specific thermoplastic matrices may require conditioning. Details of the conditioning process shall be defined with the person ordering the test in accordance with EN ISO 291.
7 Apparatus
7.1 Hydraulic moulding press A hydraulic moulding press with a closing speed of 15 mm/s and capable of a pressure of 14 MPa loaded onto the moulding material. For the purpose of this method the respective press shall be used purely as force controlled and must not be speed controlled. The closing force must be measured with a sensor and be adjustable to an accuracy within 3 % of the stationary value. The pressure build up time (tested by closing the press without material in the mould) to reach 80 % of the nominal closing force must be (0,60 ± 0,05) s. A stationary force value of 100 % of the nominal closing force shall be reached after 1,0 s.
7.2 Temperature controlled plate mould A temperature controlled plate mould (see Figure 2) with a minimum width of 200 mm and a length of 590 mm, fixed onto the press described above. This shear edge mould contains three pressure sensors; on the middle, and one on each of the cavity’s corners.
The sensors shall be built in secure and level with the surface. Outside the mould, a displacement sensor shall be installed, capable of detecting mould movement up to 25 mm.
The displacement measurement shall indicate the thickness of the material in the cavity (see also EN ISO 12115). The shear edge shall be adjusted to c.a. 0,03 mm.
NOTE For pressure measurements in the cavity piezoelectric sensors are recommended. To acquire data as viscosity etc., essential for simulation software, isothermal tests may be required. In this particular case, the mould must be capable of operating at temperatures above 200 °C.
EN 14447:2005 – Fibre reinforced plastics – Glass mat reinforced thermoplastics (GMT) – Determination of flowability and solidification