ISO 8307-2018 pdf free.Flexible cellular polymericmaterials —Determination ofresilience by ball rebound.
This document specifies a method for determining the resilience by ball rebound of flexible cellularpolymeric materials.
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references, only the edition cited applies. Forundated references, the latest edition of the referenced document (including any amendments) applies.
The rebound test apparatus (see Figure 1) shall consist of a vertical transparent tube, of inside diameter30 mm to 65 mm.A steel ball of diameter 16 mm±0,5 mm and mass of 16,8g 1,5g is dropped verticallyon the test piece through the tube from a height of 500 mm 0,5 mm using a magnet or other suitabledevice.The steel ball shall be released so that it falls without rotation and is effectively centred.
Measurement errors can arise if the tube is not held in a vertical position, and measurements might beinvalid due to contact of the rebounding ball with the inner surface of the tube. It is therefore importantto use a spirit level or similar device to ensure that the tube is mounted at right angles to the rigidbaseplate, and that the baseplate itself is horizontal.
The scale on the back of the tube shall be graduated directly in per cent as follows: every 5 % (25 mm)a complete circle shall be scribed and at every 1 % a 120° arc shall be scribed on the tube.The completecircles are an essential part of the apparatus, since they are used to eliminate parallax error.
A device capable of determining the rebound height of the steel ball by electronic means can also beused, as long as it has been demonstrated to give the same results as the manual-reading apparatus.The rebound height can be calculated from, for example, the rebound velocity or the time intervalbetween the first and second contacts of the ball with the foam surface (see Annex A). The apparatuscan be equipped with any such device provided it is capable of determining the rebound height to a precision of 1 % of the total drop height (i.e.5 mm). For this type of apparatus, the tube does notrequire graduations.
The test pieces shall consist of the entire product sample or a suitable portion of it, except that inno case shall the thickness be less than 50 mm or the area less than 100 mm.Test pieces lessthan 50 mm thick shall be plied up, without the use of cement, to a minimum of 50 mm. For mouldedproducts, the top skin shall be removed.ISO 8307 pdf download.