A case study on how tramp oil affects the painting process

Effect of tramp oil on surface coating or painting of surfaces – let us start with an example, consider you decide to buy a car and imagine a hypothetical scenario wherein you walk into a car showroom and find a vehicle with dull paintwork, rusty exteriors, and bad ergonomics. No matter how perfectly the car performance meets the customer specification, or how well the company marketed their creation, or how excellent the salesperson is, you will not even take a glance at it, it might also be a case that you might not even consider taking the vehicle home if offered free!

Now consider a case prior to the above on the shopfloor where the quality department in a vehicle manufacturing company rejects a finished job at the last minute due to bad paintwork. You will be surprised how often this happens despite all the latest paint technology. Bear in mind, the cost of re-painting a finished product is a financial burden for a company. It involves pumping added resources in terms of manpower, time, and money in rectifying the mistake, analyzing the root cause of why it happened and the opportunity cost. The whole methodology of six sigma is based on minimizing or eliminating this cost.

Back in 2013, I experienced a similar case with one of our reputed customers. They are a two-wheeler and three-wheeler making company and they were facing huge challenges in terms of re-painting their finished vehicles. The engineering team launched a six sigma project and to test one of their hypotheses of ‘whether the vehicle surface is prepared well before painting’ they performed the water break test. To everyone’s surprise, a high percentage of vehicle surfaces failed the water break test, confirming that the surface had oil, grease, and other contaminants that should have been removed during the pre-degrease and de-grease process of the 11-tank surface preparation process.

 Armed with this data, they started monitoring the tramp oil level in their pre-degrease and de-grease tanks at regular intervals. As the numbers started pouring in, they could see a rising trend in the oil levels during the degreasing process. This was when they realized that they had to take immediate action to arrest this increase in oil level and hence reached out to us for a solution.

At first, we looked at this data and found out whether there was any mechanism at all during the whole paint process to remove the tramp oil. Surprisingly, the company which had installed the paint line which had a tramp oil separation system in place. It was evident that the existing system was ineffective. Moreover, the engineering team realized that there was a significant loss of degreasing chemical because of this system.

Convinced with our approach and the solution, the company agreed to install our tramp oil separation system based on the coalescence principle. Please find below the results that we could achieve.

Data Interpretation-

1. The oil level in pre-degrease and degrease tanks was increasing despite the ‘existing’ oil separation system
2. The oil level in both the tanks started decreasing after Jan 2013 i.e. when the IFS system was installed
3. The oil level in the tanks did not increase even though the production volume increased

This reduction in the oil quantity had the desired effect and the percentage of vehicles failing the water break test decreased over time and come down to zero eventually. Not only did the company save money by avoiding re-painting but our solution also ensured increased the bath life and significantly reduced the wastage of degreasing chemical.

This case study proves that when it comes to coating/painting any surface, nothing is more important than surface preparation. With proper investigation and systems in place, companies can not only reduce the re-painting costs but also improve the overall aesthetics of their products which can make selling easier!

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