ISO 75-1-2020 pdf download

ISO 75-1-2020 pdf download.Plastics一Determination of temperature of deflection under load – Part 1: General test method. 6 Test specimens 6.1 General All test specimens shall be free of warpage. Due to differences in the cooling conditions for moulded specimens or any asymmetry in structure, for instance, the test specimens may warp during heating. i.e. bend without a load. This shall be checked by loading two test specimens on opposite surfaces. 6.2 Shape and dimensions Each test specimen shall be a bar of rectangular crosssection (length 1> width b > thickness h). The dimensions of the test specimens shall be as specified in ISO 75-2 or ISO 75-3. In each test specimen, the thickness and width over the central one third of the length shall nowhere deviate by more than 2 % from the mean value. Test specimens shall be produced as described in ISO 75-2 or ISO 75-3. 6.3 Specimen inspection Specimens shall be free of twist and shall have mutually perpendicular adjacent surfaces. All surfaces and edges shall be free from scratches, pits, sink marks and flash. NOTE lnection moulded test specimens usually have draft angles of between 1° to 2° to facilitate demoulding. Therefore, side faces in moulded test specimens will generally not be parallel. Injection moulded test specimens are never absolutely free of sink marks. Due to differences in the cooling history, generally, the thickness in the centre of the specimen is smaller than at the edge. Ensure that all cut surfaces are as smooth as possible, and that any unavoidable machining marks are in the lengthwise direction. The specimens shall be checked for conformity with these requirements by visual observation against straight edges, squares and flat plates, and by measuring with micrometer calipers. Specimens showing measurable or observable departure from one or more of these requirements shall be rejected or machined to proper size and shape before testing. 6.4 Number of test specimens Test at least two test specimens. To compensate for warpage effects, the specimens shall be tested pairwise with opposite sides facing the loading edge. If repeated tests are necessary (specified in ISO 75-2 and ISO 75-3), an additional two test specimens will be required for each repeat test. For quality control purposes or by mutual agreement between the interested parties, testing on only one side of the specimen is acceptable. In that case, indicate the side which was loaded in the test report....