Aluminum caps for injection bottles require testing and control of their mechanical properties, opening force, and other properties to ensure product quality. Aluminum covers come in two types (B-type), three types (C-type), flowering aluminum covers, and tear open aluminum covers (D-type). The fracture force and fully open force of the bridge joints are tested and analyzed separately.
Mechanical properties of aluminum material: Take an appropriate amount of aluminum sheet from the same batch number, use a tool with a width (b) of 12.5mm, an original gauge length (L0) of 50mm, a parallel length (Lc) of 75mm, and a transition arc radius (r) of at least 20mm to cut the specified sample, and conduct the test on a tensile device at a test speed of 10mm/min ± 2mm/min. Tensile strength refers to the tensile load borne per unit initial transverse plane during a tensile test until fracture. Elongation refers to the ratio of the increase in distance between markings at the time of fracture in a tensile test to the initial gauge length, expressed as a percentage.
Opening force: Take an appropriate amount of aluminum cover, drill two holes in the same radial plane of the aluminum cover, fix one end of the aluminum cover, and connect the other end to a load cell. Conduct the test at a speed of (100 ± 10) mm/min, measure and record the following two parameters: a. Bridge fracture force (the maximum force required for the first bridge fracture); b. Fully open force (the maximum force required to completely tear open along the engraved line). During the experiment, it should be torn off along the engraved line on the aluminum cover.