Breakage Analysis - Fractography
Broken samples and cracks tell stories and leave behind clues. By applying optical and scanning electron microscopy we determine the origin and propagation of glass breakage. Clear evidence of the root cause can be drawn and the applied force that lead to the failure can be determined.

Fracture surface of a broken syringe showing the fracture origin and specific markings such as the fracture mirror, Wallner lines, fine hackles, and coarse hackles

Contamination in the vicinity of the fracture origin, analyzed by SEM/EDX, explains cause of breakage
Strength Testing
The strength of products made of glass is not a materialproperty, but rather depends on the individual quality of the surface. Strength testing allows the prediction of fracture probabilities of glass containers and form the basis of a risk assessment for a given container system.
Samples of different manufacturers and different lots can be compared and evaluated, and the influence of processing steps can be analyzed. Burst pressure testing reveals the weakest spot of a container, while specific tests target critical areas like the flange or cone. The testing is carried out via customized testing methods together with comprehensive statistical evaluations.

Broken vial after burst pressure test

Probability for flange breakage in auto injector as function of equivalent force (deducted from actual force profile)
Stress Analysis
It is said that glass as a brittle material does not forget. Any mechanical impact like glass to glass contact that it experiences as a finished product will be saved as surface defects. It does not heal. Consequently the accumulated damages enhance the probability of breakage.
Additional risks come from stress that is introduced during processing steps like lyophilization or that is not completely relieved after hot-forming. Advanced analytical methods can reveal the inherent stress in order to determine weak spots.

Stress distribution in vial that not was completely relieved after hot-forming

Simulation: stress distribution in flexural loading of the syringe cone