Tip of the Week — XRF Testing of Turnings: More Representative — But Are You Paying the Price in Accuracy?

Newsletter Tip

XRF Testing of Turnings: More Representative — But Are You Paying the Price in Accuracy?

When it comes to XRF analysis, many professionals face a common dilemma:
Should you test the surface — or take turnings for a more representative sample?

From real-world experience, the answer is clear:
Turnings usually provide a much better representation of the material, especially in cases of segregation or non-uniform surface composition.

However, this comes with a trade-off.

The Challenge with Turnings

Unlike a flat solid surface, turnings introduce several variables:

Irregular geometry and varying X-ray angles
Voids between particles
Local inhomogeneity
These factors can lead to noticeable deviations, particularly when analyzing light elements or complex alloys.

Practical Ways to Improve Accuracy

If you’re working with turnings, here are a few simple steps that can significantly improve your results:

1. Repeat Measurements
Take multiple readings (3–5) and average the results to reduce noise.

2. Improve Sample Consistency

Clean the turnings (remove oils and contaminants)
Aim for uniform particle size
3. Consider Pellet Preparation (Highly Recommended)
Compressing the turnings into a pellet can dramatically improve repeatability and accuracy.

Benefits:

Reduces voids
Creates a uniform surface
Minimizes angle-related effects
Even a simple manual pellet press (10–15 ton) with a standard die can make a big difference.

Bottom Line

Turnings improve representativity — but require better preparation.

If you rely only on loose turnings, you may gain representativity but lose precision.
With proper handling (and ideally pelletizing), you can achieve both.

Real data. Real experience. No fluff.