Creating the Right Lab Environment for ISO 16232 Analysis

Q: Is my existing quality lab and equipment suitable for ISO 16232 contamination analysis?

A: Manufacturing cleanliness is a metric that must be considered far beyond the lab inspection reports for any given component or assembly. When a new product is required to meet a minimum level of “clean” on a consistent basis, your existing quality lab environment may not be sufficient in its current state.

Even if you currently perform contamination testing in some fashion, there are several key points your quality team should consider before moving forward with new cleanliness requirements that might be impossible to reach with your current lab process and equipment.

Specifications/cleanliness requirements

The first and more important point to consider is the new cleanliness requirement(s) to be analyzed by your lab. Assuming your lab already has the capability to prepare a cleanliness test filter sample, you should confirm the ability to achieve the proper “blank” value with your equipment according to the ISO 16232 standard method. If your facility has already produced similar components with similar requirements, it would be reasonable to assume you can meet those requirements in terms of blank values on your test equipment. However, if the new component has a much stricter requirement, the first step in qualifying your lab is to prove ability to meet blank levels consistently.

A blank test will analyze the cleanliness of your test equipment and environment alone, without the presence of a test part. Refer to ISO 16232:2018, Chapter 6. The amount of contamination present on your rinsing and handling equipment should not contribute significantly to your component test; the blank test will confirm that.

If you are starting a new test lab from scratch, consult with equipment manufacturers and industry experts to ensure you are procuring the right equipment to meet the requirements you have. A majority of cleanliness requirements can be analyzed with the same set of tools with only minor adjustments.

Trained staff

When new cleanliness specifications are implemented, the staff in charge of performing the tests must fully understand and be trained in the methods for preparing and analyzing the samples. If the new requirements are put in place by an outside customer or OEM, the customer should offer support to explain how the test should be done in order to match the process at the OEM. The only way to ensure the test is done repeatably is to coordinate the materials and equipment so the process can be matched as close as possible. General ISO 16232 training as well as supplemental training from your lab equipment manufacturers can be helpful to understand new specifications.

Layout

The layout and workflow of your test lab can have a large impact on your results (especially blank tests). Cleanliness testing results do not need to be an expression of how clean your entire lab room is (unless absolutely necessary). It is important that your test process is isolated from the open-air environment of the plant as much as possible. Foot traffic should be kept to a minimum to avoid unnecessary dust and fibers from collecting in the area. The test equipment should be kept far away from metallurgical saws and machining tools. A regular dusting and cleaning routine for all surfaces is critical.

When possible, the testing area should have a positive air pressure by forcing filtered air into the room and enabling the air to flow toward the floor and out beneath/through the doorway or other exhaust vents on the floor. This is the ideal way to control excess dust and fibers from collecting on your test equipment. If you discover that you cannot pass a blank-value test because of fibers or small dust particles, consider the location of your equipment and the airflow in that space.

Refer to VDA 19.2 standard for more information on environmental analysis and tips for proper “clean lab” layouts.

Measurement equipment

Most cleanliness requirements can be reliably measured with the same types of equipment. The most prevalent being the glassware that is often used to rinse, collect and filter the particles that are extracted from the test component. It is important to have the proper glassware (beakers, vacuum flask, filtration funnels, fritted-glass filter holder and so on) that fits the size and number of components you need to analyze. This also holds true for any rinsing trays or cabinets; the component to be tested must fit easily and safely inside to capture the contaminants that are rinsed off. Large parts may require fixtures to hold the component at certain angles to rinse the necessary areas for analysis. You might also need a much larger flask to hold the amount of fluid necessary for each test.

For the actual particle measurement process, you must confirm that your microscope is capable of reporting the particle size and count requirements for the new specification. For example, if your lab has followed the ISO 4406 particle counting standard in the past, this does not necessarily mean that your microscope is appropriate for the ISO 16232 standard. Contact your microscope manufacturer to discuss your specific needs.