ISO 8295 pdf download

ISO 8295 pdf download.Plastics – Film and sheeting – Determination of the coefficients of friction 1 Scope 1.1 This International Standard specifies a method for determining the coefficients of starting and sliding friction of plastic film and sheeting when sliding over itself or other substances. The method is intended to be used for non-sticky plastic film and sheeting (in the following text, referred to simply as “film”) of up to approximately 0,5 mm thickness. 1.2 This test method serves primarily for quality control. It does not give a comprehensive assessment of the machinability on packaging or processing ma- chines since other effects, e.g. electrostatic charges, air cushion, local rise of temperature and abrasion are, as a rule, involved. 1.3 The static frictional force increases as a rule, with the time the surfaces are in contact. Therefore, to get comparable results, this time span is specified. 1.4 Slip properties are sometimes generated by ad- ditives in the plastic material. The additives have varying degrees of compatibility with the film matrix. They may bloom or exude to the surface and change the slip properties, Since these effects are time- dependent, measurements on such films have to be related to the age of the film. 2 Normative reference The follovwing standard contains provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publi- cation, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most re- cent edition of the standard indicated below. Mem- bers of IEC and IS0 maintain registers of currently valid International Standards. IS0 291: 1977, Plastics – Standard atmospheres for conditioning and testing. 3 Definitions For the purposes of this International Standard, the following definitions apply. 3.1 friction: The resistance that two surfaces lying in contact with each other build up against sliding. A distinction is made between static friction and dynamic friction. 3.1.1 static friction: Friction which has to be over- come as a “threshold value” at the onset of sliding motion. 3.1.2 dynamic friction: Friction which persists dur- ing a sliding motion at a given speed. 3.2 frictional force: The force necessary to over- come friction. A distinction is made between the static frictional force F, and the dynamic frictional force Fo. 3.3 normal force, Fp: The force acting perpendicular to...