Measure Residual Stress of Glass Containers in accordance with ASTM C148.
Residual stress in glass packaging increases the risk of delamination and breaking. To remove the stress and reduce the risk, the glass goes through an annealing process in a lehr oven. Saicheng intelligent polarizing stress tester can be used to detect residual stress after the cooling process in packaging glass with the visually monitored method.
For Vials for example ISO 8362-1:2018(E) states: “The injection vials shall be annealed so that when the vials are viewed in a strain viewer, the maximum residual stress does not produce an optical retardation exceeding 40 nm per millimetre of glass thickness.” The unit of nm/mm refers to the retardation of light in nanometres per millimetre of glass thickness.

YLY-H Intelligent Polarizing Stress Tester is suitable for polarized internal stress testing of glass infusion bottle, glass tube (moulded) medicine bottle, tube (moulded), injection bottle, ampoule bottle, oral liquid bottle, etc. It can also be used for stress testing of glass containers such as beer bottle and liquor bottle.
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