Part manufacturing flaws

In chemical handling processes, parts are exposed to mechanical forces and chemicals. Fluoropolymer parts can fail for three reasons mechanical, chemical, and physical changes, or their combinations. Failure often initiates at the location of fabrication flaws that arise from problems during manufacturing of the fluoroplastic part. These flaws often shorten the useful life of the part in service or form a starting point that can evolve into the failure point of the part. 

Equipment, if necessary, should be disassembled in a suitably equipped facility and inspected for excessive wear, cracks, flaws, or deformation. Corrections should be made in accordance with the recommendations of the manufacturer. Before inspection, all foreign material, such as dirt, paint, grease, oil, scale, etc., should be removed from the inspected areas by a suitable method. The equipment should be disassembled as much as necessary to permit inspection of all load bearing parts, and the inspection should be made by trained, competent personnel. 

Yencho then constructed the initial version of the machine and explored the parameters necessary to successfully form flaw-free parts. A key finding concerned the effects of trapped moisture. Despite the generally hydrophobic nature of PEEK, it was found that small amounts of moisture absorbed by the Gr/PEEK laminates subsequent to their manufacture converted into steam during the forming operation and caused extensive delamination. This was in... 

Elsewhere, the industrial use of radioisotopes rests on the fact that radiation loses energy as it passes through substances. Manufacturers have consequently been able to develop gauges to measure the thickness and density of products and, using radioisotopes as imaging devices, to check finished products for flaws and other sources of weakness. For their part, the fossil fuel industries involved both in mining and oil and gas exploration are using radioactive waves that measure... 

For the past 20 years it has been a goal in the ceramics community to use NDE techniques to predict lifetimes and to remove severely flawed ceramic parts. Several advantages will accrue from successful routine NDE of ceramics. It is difficult to sell products that have been broken, so destructive testing reduces production yields. With NDE, on the other hand, each component manufactured can be tested. It is also useful for a manufacturer to be able to guarantee his product for a given lifetime. NDE allows components that are likely to fail (i.e., components with large flaws) to be removed from the product stream. In research and development... 

Using the fracture mechanics approach automatically accounts for the occasional non-ideal part. The assumption that a flaw will exist enables the ability to determine if the flaw will propagate or simply remain at its current size. A joint that can tolerate occasional unintentional defects will be far easier to manufacture and result in fewer field failures. 

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