Forensic Engineering
We investigate the causes of failures in an industrial process or commercial product and propose customized solutions to resolve them.
Problem
The client has a problem with the appearance of defects in plastic samples. The defect appears after painting the last finishing coat at the end of the production process. These defects cause cosmetic failure and parts must be reworked or disposed of outright.
Objective
Know the possible origin or cause of the defect in the plastic samples.
ATRIA Solution
Different tests were carried out to characterize the surface and the inner layers of the samples and to know if there are differences between them. Using a FIBSEM test, the paint layers of the sample were analyzed. In the superficial analysis, it was observed that the composition in the areas with defects and areas without defects was the same, so the defect was covered by a layer of paint.
However, in the areas of the inner layers, embedded materials such as those shown in the photo were observed. In the analysis of said materials, both silicon and aluminum were observed. These elements are usually present in polishing agents.The plastic pieces that were analyzed did not undergo any polishing stage, but the washing stage, before painting, is carried out together with other pieces that do have this stage in their process.
Polishing agents can become embedded and later loosen in the tank, damaging or sticking to other parts.
In addition, if ultrasound also comes into play in the washing tanks, the parts are more likely to collide with each other and be damaged.
