Glass Expert Performs Bottle Failure Analysis

A glass failure expert witness performs a failure analysis on a failed cosmetic bottle. As received, the top of the bottle had broken off. Upper left is a photograph of 'as receceived' failed bottle. Approximately one half of the bottle finish had broken off. Read Consulting performed a glass failure analysis to determine if this failure was a manufacturing defect, or it failed as a result of shipping damage. The upper right photomicrograph is 30X view of the failure origin. The failure initiated at a bruise (small impact damage) on the top of the finish. Three of nine bottles from the same molding cavity also had damage to the top of the finish. In this shipping lot there were over thirty five bottles from other cavities, and none of these showed damage. Thus, the glass failure analysis expert witness believes that this product defect occured during manufacturing. However, both the shipping methods and the manufacturing proceedures will be reviewed for product liability improvement.

Glass Fracture Due to Liquid Pressure

Glass failure analysis expert witness performs a failure analysis on a hollow glass tube that failed due to internal pressure. The glass fracture initiated at a small bruise on the outer surface of the glass tube. The upper left 25X photomicrograph gives an overview of the failure. One can see that the glass fracture analysis determined that the failure initiated at a small bruise. The upper right 100X photomicrograph gives more detail of the origin. This was a manufacturing defect because the bruise was created during manufacturing.

Glass Fracture Due to Liquid Pressure

GLass Expert Discusses Chill Cracks

Glass failure analysis expert witness discusses a common glass bottle manufacturing defect. After the bottle has been formed it is removed hot from the clam shell tool. If it encounters any localized cooling at this stage, it can form a manufacturing defect called a "chill crack". Thermal shock cause the cooled area to shrink, and this causes localized tensile stresses. This event can create a small crack that can cause later failure of the bottle. Above are two photos of the same chill crack. Upper left is a 20X photomicrograph, and upper right is a 40X photomicrograph. To start, this crack is less than 0.1" long, and it has grown to be approximately 0.7" long. The bottling line has had numerous failures from this lot of bottles, and the cause has been traced back to this type of chill crack.

Cosmetic Bottle Failure Analysis

Glass failure analysis expert witness performs failure analysis on a broken small cosmetic bottle. This bottle failure occured when it was being capped on the line. The objective of the analysis was to determine the cause of the failure and to advise the bottle manufacturer. The bottle broke into two pieces, and these are shown in the upper left photograph. Upper right is a 20X photomicrograph of the failure origin. This failure originated as a result of a "chill crack" which is a manufacturing defect formed when, exiting the clam shell tool, the hot bottle touched an unprotected metal tool. The cold spot created a chill crack that eventually caused the bottle failure. The manufacturer is presently correcting the manufacturing problem. In the meantime, only bottles from another supplier are being used.