PET bottle manufacturing is one of the widest packaging industry in the world. Due to its durability and quality to barrier water, moisture and gases makes it perfect for storing and transporting. Also, PET packaging is suitable for materials with different properties like solid, powder, liquid, semi-solid, etc. To make packaging and storage suitable for wide range of materials there are certain tests to assure the quality of packaging.
Hot wire bottle cutting. In this test, a sampled bottle is cut into sections using a hot wire bottle cutter. Every section is tested individually to check the uniformity in neck, walls, and bottom sectional weight. If there is a discrepancy in any of the section, it would lead to balancing issue in the bottle. Every section is assessed individually and reports are logged manually.
Buckling load testing. Also called top load test, it is performed to determine the minimum pressure that a bottle can bear from the top without getting deformed. The maximum strength that bottle yield is called buckling strength. The results are displayed on the pressure gauge or on the digital display. This test is like the compression stress test. The only difference is that it also tells the weak area where buckling can be seen. If every sample has same buckling spots for the entire line, this means there is a defect in the manufacturing line and need reconsideration.
Strain viewer testing. This test determines the flaws in the preforms of PET bottles using optical test, results are based on visual observation. It is based on the change in refractive index of light when passes through the sample. Performing this test is important as it will help in avoiding product failure. This test helps in quality management and quality control.
Drop testing. In this test, the sample is made to fall free from a height to see how it would behave if handled inappropriately. The height is chosen as per the industry standards. This test serves multiple purposes, it tests the resistance against free fall and impact also. However, impact test is way different from drop test but later one can be skipped if drop test has been performed.
Wall thickness testing. This test determines the unevenness in the walls of the bottles. Apart from this, this test can be performed to check the minimum wall thickness that can withstand the subjected conditions. The most appropriate technique used is “Hall Effect” which is NDT. In this test, a magnetic target ball is placed inside the body of the sample. A probe creates a magnetic field along with the target ball. The distance in between the ball and the probe is measured, processed and displayed on the screen of the instrument. Saved readings can be transferred to a USB drive or a PC via RS232 port. The files are compatible with Excel or txt.
Tests performed by hot wire bottle cutter, top load tester, drop tester are destructive tests, whereas wall thickness test is a non-destructive test.