PET bottle manufacturing process involves blow moulding procedure. During which the bottle is first blown into a preform structure. This is done for testing purpose and see if the final product will be manufactured as per company production requirements or not. The preform structure are subjected to many quality tests but the most common among them is the stress analysis. During heating, cooling blowing of PET material, there are chances of stress or strain generation on the PET preform surface. These strains are so minute that it can’t be inspected with naked eyes. Thus, the need of a suitable test equipment arises.
However, it is important to choose the right machinery or else a poor quality equipment may not lead you to the exact issues and as a manufacturer you may fail to detect the reason and end up producing faulty or low quality bottles.
Polariscope for stress analysis is a high-tech testing equipment. It is used by various industries to inspect the quality and transparency level of PET preforms. Uses dual intensity light source, Monochromatic light and Sodium Lamp. Deliver a sharp and crystal clear flaw detection. Equipped with a standard test template of inspecting preform at an angle of 45 and 90 degrees. Has a large viewing area to allow detection for numerous shape and sized specimen. The inspection area is 260 x 240 mm in dimensions. A standardized pictorial chart containing all possible strain and stress defect patterns is given along with the equipment. User can compare the viewed defect with the chart and asses the reason.
Polariscope for stress analysis works on the principle of refractive index. As per the theory if the Preform has any amount of stress or strain distribution in the body it will modify the directions of refracted light and show a multicolour pattern. User can detect molecular birefringent flow lines and black isoclinic lines.
Read our article on Polariscope – Features and Uses for more information.