Case Study: How FTIR Failure Analysis Uncovered the Cause of Valve Failure During Shipping
All product manufacturers have rigorous quality control processes that aim to ensure all products are properly functioning before sending them off to customers. However, some quality issues may not present themselves until they’re exposed to different conditions. At least, that’s what one of our customers figured out.
After our customer’s air pumps had tested 100% functional prior to shipping, once they arrived at their destination in New Zealand, the failure rate was a whopping 80% due to sticking valves. We were brought in to determine the cause of the sticking valves.
Upon examination of both “good” valves and failed valves, we found that a white material was present in the valves that had stuck. The control valves did not have the white material present, but instead had a clear oily-like material present. To analyze both materials, Fourier transform infrared spectroscopy (FTIR) analysis was our failure analysis tool of choice.
The oily material in the control valve was a silicone lubricant that had been put into the valves. In addition to the silicone, FTIR analysis found small amounts of a hydrocarbon wax and dimethyldithiocarbamate present as well. The hydrocarbon wax was from the surface of the o-rings and dimethyldithiocarbamate was a fungicide used in the o-rings. The white material in the stuck valves showed mainly dimethyldithiocarbamate and smaller amounts of silicone and hydrocarbon wax.
Why the Valves Failed
Based on the chemical makeup of the materials analyzed, we were able to determine the high heat seen in the shipping containers was causing the fungicide to bloom to the surface of the o-rings and causing the valves to stick. When o-rings that did not contain the fungicide were used, the pumps could be exposed to high heat and no stuck valves occurred.
Need to Troubleshoot a Product Failure?
Then contact us. We have more than two decades of experience as a materials testing lab and we’re ready to help. In addition, you can find more examples of FTIR, failure analysis and a variety of other analytical techniques in action by vising our Case Studies page.
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