ISO 11443-2014 pdf free download.Plastics一Determination of the fluidity of plastics using capillary and slit-die rheometers.
5 Apparatus
5.1 Test device
5.1.1 General
The test device shall consist of a heatable barrel, the bore of which is closed at the bottom end by an interchangeable capillary or slit die. The test pressure shall be exerted on the melt contained in this barrel by a piston, screw, or by the use of gas pressure. Figures 1 and 2 show typical examples; other dimensions are permitted.
5.1.2 Rheometer barrel
The barrel shall consist of a material resistant to wear and corrosion up to the maximum temperature of the heating system.
The barrel can have a lateral bore for the insertion of a melt-pressure transducer close to the die entrance.
The permissible deviations in the mean bore diameter throughout the length of the barrel shall be less than ±0,007 mm.
The barrel shall be manufactured using techniques and materials that produce a Vickers hardness preferably of at least 800 FIV 30 (see ISO 6507.1 and Note 1) and a surface roughness of less than Ra = 0,25 pm (average arithmetic discrepancy, see ISO 4287).
NOTE 1 For temperatures up to 400 °C, nitrided steel has been found suitable. Materials of hardness values lower than that specified but of sufficient corrosion and abrasion resistance have been found to be acceptable for construction of the barrel and dies.
NOTE 2 An increase in barrel-bore diameter increases the number of measurements that can be made with a single barrel filling and increases the shear rate range of the instrument. Disadvantages of using a larger barrel- bore diameter are that larger sample masses are required and that the time necessary to reach temperature equilibrium throughout the sample is greater. The barrel-bore diameters of commercially available rheometers lie in the range between 6.35 mm and 25 mm.
5.1.3 Capillary dies (method A)
5.1.3.1 The entire length of the capillary die wall shall be machined to an accuracy of ±0,007 mm for the diameter (D) and ±0,025 mm for the length (L) (see Figure 1).
The capillary shall be manufactured using techniques and materials that produce a Vickers hardness preferably of at least 800 liv 30 (see ISO 6507-i and Note ito 5.1.2) and a surface roughness of less than
= 0,25 pm (average arithmetic discrepancy, see ISO 4287).
The capillary opening shall show no visible machining marks nor perceptible eccentricity.
NOTE 1 Diameters of capillary dies typically used lie in the range between 0,5 mm and 2 mm, with various lengths to obtain the desired LID ratios. For testing of filled materials, larger diameters might be required.
NOTE 2 Hardened steel, tungsten carbide, stellite, and hardened stainless steel are the most common die materials.
NOTE 3 The precision with which capillary dimensions can be measured is dependent upon both the capillary radius and the capillary length. With capillaries of diameter smaller than 1.25 mm. the specified precision (±0,007 mm) is difficult to obtain. Due to the extreme sensitivity of flow data to capillary dimensions, it is important that the capillary dimensions, and the precision with which the dimensions are measured, are known and reported. This also applies to the dimensions (thickness, width, and length) of slit dies (see £14).ISO 11443 pdf download.