Case Studies

Here are a number of Case Studies of problems Edotek has solved for clients.

Case Study #1; Our client was a chemical engineering company which had started to use a new supplier to do electro-machining of thin sheet metal parts. As delivered, the parts looked to be very well made, but when put in to service at high-temperature, they develop a blue coloration which had never been seen on comparable parts from other suppliers.

Edotek performed tests which proved that the problem was inadequate cleaning of the parts after machining. A very strong alkaline cleaner was being used to remove the machining chemicals. It was found that the cleaner itself needed very thorough rinsing in clean water to remove it. This had not been done and the result was enhanced oxidation of the metal resulting in a blue ‘temper film’. Since the long-term effects of this behaviour could not be determined, the blued parts were scrapped and a more effective cleaning process adopted.

 

Case Study #2; Our client manufactured critical components for defence systems. When all work on component parts was completed, each part was washed in ultra-pure solvent which was then tested in a particle counting machine. To be acceptable for use, the number of particles (typically, microscopic metal fragments) found in the solvent wash had fall within certain limits, thereby demonstrating adequate cleanliness of the part. One particular group of components repeatedly failed to pass this test despite the most careful and thorough cleaning.

Edotek investigated the problem and found that the “particles” which were being observed were not metallic but were actually microscopic globules of silicone grease. These particular components has been subject to a re-work having been installed once already. To assist installation, they had been lubricated with silicone grease. Subsequently, the client thought that he had removed the grease by cleaning the parts in an ultrasonic bath but this process had proved unsuitable. Edotek recommended vapour phase degreasing and this solved the problem.

 

Case Study #3; Our client developed electronic sensors for aviation applications. They needed to have a junction box in some long cable runs which would be exposed to temperatures of 600-700°C and wanted to fill the junction box with a suitable potting compound. This was sourced from an industry-leading supplier who confirmed that it was fine for use at those temperatures. After some initial trials, it was found that the wires in the junction box were very badly oxidiser, almost to the point of destruction. The supplier of the potting compound (a cement type material) refuted any suggestion that this was related to his material and said it must be due to other causes.

Edotek carried out some experiments which showed conclusively that when the potting compound reached temperatures of 600°C, it started to give off fumes, which condensed to produce droplets of concentrated phosphoric acid. It was this acid which damaged the conductors and the problem was solved by going to another supplier of potting compounds.

 

 

 

 

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