The figures are differential counts, and the NAS class is usually reported as a single figure >5µm. >15µm. >25µm. >50µm. >µm. Size code. A. B. C. D. E. F. 76 SAE AS rev E Table Particle Contamination Level by Class. The SAE aerospace standard (AS) ASD defines cleanliness classes for particulate contamination of hydraulic fluids and includes methods of reporting. From this basic distribution, a series of 14 classes was created covering very clean SAE A6 Aerospace panel developed AS for aircraft hydraulic systems. . instance NAS Class 6, can be swapped to AS Class 6B through F.

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The reasoning behind this is not entirely clear, but thought to be to separate old and new APC data.


About the Author Mike Day. Equally, sizes that are not critical can be omitted. It also gave the overseeing-ISO committee the opportunity to obtain traceability for the particle size distribution PSD of the calibration material. This concept gives AS much more flexibility than was possible with NAS because it is often the control of the cleanliness level that specifiers require rather than a sae as 4059 class 6b-f distribution; for ax, they can specify improved control sae as 4059 class 6b-f critical sizes or relax controls over those that are not.

Many are specified for analyzing oil samples and presenting data to NAS format for existing designs. From this basic distribution, a series of 14 classes was created covering very clean to very dirty levels, where the interval between each class is double the contamination level.


Students Click Here Join Us! The accuracy, sae as 4059 class 6b-f and speed of analysis allowed it to be used extensively for research into the effects of dirt on components and systems.

One aspect of the change, which may be a little unclear, is that of component cleanliness – the scope of the original NAS document.

What Happened to NAS ?

Is NAS dead? This distribution was based on particle contamination inside delivered aircraft hydraulic components in the s. Red Flag This Post Please let us know here why this post is inappropriate. Promoting, selling, recruiting, coursework and thesis posting is forbidden.

SAE ASD | Particle Sizing Systems

Machine Oil Case Study: Toggle navigation Az search. Click Here to sae as 4059 class 6b-f Eng-Tips and talk with other members! Download Now Digital transformation may be the most frequently misunderstood and misused term in business discourse today. The reason for this is not entirely clear but it is thought to be the need to separate old and new APC data.

Trending these sizes was fraught with problems and inaccuracies.

The size distribution was derived in using the optical microscope, so in effect, the APC was set-up to record identical numbers of ACFTD particles as the microscope. As products get more complex, so do the supply networks that build them.

Resources Product innovation is speeding up. It converts the particle counts at various size ranges into convenient broad-base classes. Because this situation could cause an uproar within the industry when companies would have to change specifications, the ISO committee decided sae as 4059 class 6b-f take the road of least resistance and selected new size descriptors that would give the same particle counts while retaining integer sizes.


The most significant changes are:.

What Happened to NAS 1638?

The particle numbers can range from single particles to many millions; therefore, a power series is used to cover the number range sae as 4059 class 6b-f a convenient number of classes.

This is in spite of cleanliness specifications being written around them. Click here to see Table 3. NAS saw widespread acceptance in the s and s by industries where reliability was a prerequisite, in areas such as offshore oil production, iron and steel industries, etc.

Product innovation is speeding up. Thank you for helping keep Eng-Tips Forums free from inappropriate posts. Specifying cleanliness over the complete size range – AS 6A through F.

Are you an Engineering professional? Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework. It was also embarrassing for laboratories involved with contamination testing which often had flass explain why there was no traceability and control over the dust.

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