MACHINE FOR TESTING EXTENSIBLE PLASTIC FILMS FOR PACKAGING

摘要

A testing machine (1) to perform a plurality of measurements and/or tests on a film (100) made of plastics in order to determine mechanical and physical properties of the film (100), comprises a basic structure (2) provided with a supporting plane (8); an unwinding station (3) provided with an unwinding roller (31) driven and/or controlled in rotation about a respective longitudinal axis by first driving means (32) and arranged to support a reel (101) of the film (100); a pre- stretching station (4) arranged to unwind the film (100) from the reel (101) with a preset unwinding speed and to pre-stretch the film (100) of a preset percentage, the pre-stretching station (4) comprises a couple of pre- stretching rollers (41; 42) driven in rotation about respective longitudinal axes by second driving means (43, 44) and a plurality of return rollers (45, 46; 47) to deviate and wrap the film (100) on the pre- stretching rollers (41, 42) according to a predetermined pre-stretching path; the pre-stretching rollers (41, 42) and return rollers (45, 46, 47) are interchangeable and adjustably positionable to change the pre-stretching path; the testing machine (1) further comprises a wrapping station (5) provided with a testing drum (51) driven and/or controlled in rotation about a respective longitudinal axis by third driving means (52) and arranged to be wrapped at least partially by the film (100) coming out from the pre- stretching station (4); a plurality of guiding rollers (21-24) to lead the film (100) along an unwinding path from the unwinding station (3) to the pre-stretching station (4) and from the latter to the wrapping station (5), the guiding rollers (21-24) being interchangeable and reversibly and adjustably mountable to the supporting plane (8) to change the unwinding path; a plurality of measuring groups (11-16) to perform a plurality of respective measurements at least of dimensional and/or physical parameters of the reel (101) and of the film (100) and reversibly and adjustably mountable to the supporting plane (8) depending on the unwinding path; a plurality of testing groups (17-20) provided with respective means to interact with the film and perform respective tests and measurements on the film (100) in order to determine mechanical and physical properties of the latter.