Cleanliness Testing Using Scanning Electron Microscopes

Technological advances in the automotive manufacturing industry have led to stricter cleanliness standards in fluid systems, such as brakes, hoses, nozzles and pumps. Monitoring the cleanliness of these parts to quickly identify the source of contaminants is a critical concern for manufacturers to reduce warranty costs and failure rates.

Using gravimetric inspection and analysis alone will not produce the level of detail required to analyze individual particle data, where particle size, shape and composition information cannot be sourced. Instead, manufacturers must now use a wider range of tools to comply with the ISO 16232 and VDA 19 cleanliness standards and ensure the safety of their vehicles.

Thermo Fisher Scientific offers a range of instrumentation and software that not only simplifies your cleanliness analysis but also greatly reduces your production time as you bring the quality control process inhouse. By no longer relying on outsourcing for your quality control analysis, you can increase your production cycle times up to ten-fold and gain full control over your test data, creating reports with ease.

In a previous blog post, we explained the principles behind the international ISO 16232 and the German VDA 19 standards.

In this blog post, we examine how Scanning Electron Microscopes (SEMs) and energy dispersive spectroscopy (EDS) can determine the nature of contaminant particles, allowing users to comply with the ISO 16232 and VDA 19 industry standards with ease.

The VDA 19 and ISO 16232 are cleanliness standards for the automotive industry, ensuring the safe manufacture of today’s vehicles. These standards made the measurement and composition analysis of foreign particles and contaminants in compliance with their quality requirements mandatory across the automotive industry.

The ISO 16232:2018 ​ (the latest version of the standard) supplies “requirements for applying and documenting methods for determining particulate contamination on functionally-relevant components and systems (cleanliness inspection) of road vehicles.” The ISO 16232 is based on the more-detailed VDA 19 , which is a standard from The German Association of the Automotive Industry.

There are various methods of technical cleanliness inspection and analysis, including gravimetric inspection and light scattering analysis.

Gravimetric inspection can calculate the total mass of contaminants, effectively inspecting contaminants based on their differences in weight. But it is impossible to investigate the size, size distribution and properties of these minute particles. So, manufacturers cannot obtain detailed, individual particle information to determine the cause of contamination or prevent it from recurring.

As a result, components may pass gravimetric testing, yet still fail to function due to undetected small particles that were missed, such as aluminum oxides.

SEMs and EDS can make all these measurements and address these challenges – determining the nature of contaminant particles, allowing users to comply with the ISO 16232 and VDA 19 industry standards with ease.

Cleanliness goes further than just determining the contamination source; the hardness of the particle determines the damage it can do. Hard materials left in an assembly can cause much more damage than soft materials. Determining these characteristics earlier in the process can save future costs.

This is where an integrated scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDX) system, can help, providing a wealth of cleanliness data for automotive components.

SEM/EDX provides the chemical composition of individual particles from the X-rays that are emitted when the electron beam scans over a sample. This allows manufacturers to set different cleanliness limits for those particles considered most harmful for the component and relax limits for less harmful particles. Almost every SEM is equipped with an EDS system – and at Thermo Fisher Scientific, we have revolutionized this field with our exclusive ChemiSEM Technology.

Historically, there have been issues with training personnel to operate SEM/EDX instruments and this can cause delays in obtaining results. ChemiSEM Technology provides users with an intuitive and fully integrated system.

ChemiSEM Technology colorizes specific elements on your sample’s grayscale image immediately. This allows researchers to see the big picture, revealing elements and particles that may have otherwise gone unnoticed. It provides the most comprehensive micro-scale elemental composition possible – helping you to comply with the ISO 16232 and VDA 19 industry standards.

When examining the elemental composition from a sample, researchers no longer need to move from SEM imaging to EDS analysis for each sample. This not only decreases the amount of time spent developing images but also increases your productivity, as you no longer must switch between different systems. ChemiSEM Technology gives you access to elemental information 2-4 times faster, compared to traditional elemental analysis techniques.

ChemiSEM Technology also makes elemental information available to everyone, increasing the number of researchers who can use your facilities.

To find out more about our ChemiSEM Technology and how it can improve your automotive part cleanliness processes for ISO 16232 and VDA 19 compliance, please click here to contact one of our expert staff today.