Critical Clean Testing in Aerospace Applications

Testing for cleanliness of components is of the highest priority within the aerospace industry. New IEST standards require verification of part cleanliness to multiple levels of restrictions. The most common standard in place today is IEST 1246. There are different criteria of contamination levels associated with this standard, which sets the requirements relative to the amount of particulate counted within size ranges and how many are allowed in each range. For example, IEST 1246 – 100 limits the size of particles to below 100um, thus failing any cleanliness test that produces particles larger than 100um. It also limits amounts of particles it allows to pass below 100um size.

Operators have historically conducted critical cleanliness testing using microscopes to manually scan, size, and count particles on a 42mm diameter filter that captured particles from a rinse cycle. This method was very slow and tedious, and introduced the potential for human error in the results.

Modern methods now provide fully automated filter inspection systems such as the Olympus CIX100 technical cleanliness inspection microscope. These systems are controlled by software that incorporates standards such as IEST 1246. The system scans at a much faster rate than is possible with manual measurements, allowing for greater throughput while also significantly reducing the variability found in manual counts. The added benefit of capturing the particulate data digitally allows for simplified reporting features showing all the data and images. The entire amount of data for every scan is also captured and archived in a database to allow for secure retention of past scans. The traceability and reproducibility of systems such as the Olympus CIX100 provide reassurance that the scan results can be trusted for critical components of aerospace applications.