---
title: Does Calibration Light The Way To The Sieving Holy Grail
description: Sieves, Sieve Calibration, and Certification are what this is about. Sieve cleaning often distorts sieve mesh. The result is an invalid certification.
---

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# [Does Calibration Light The Way To The Sieving Holy Grail](https://www.cscscientific.com/csc-scientific-blog/is-sieve-calibration-really-the-holy-grail-part-iii)

 Written by [Art Gatenby](https://www.cscscientific.com/csc-scientific-blog/author/art-gatenby) | Aug 19, 2020 8:00:00 PM

# All about sieve Calibration

We continue to search for answers to the question "**Is Sieve Calibration Really the Holy Grail?**"  **Pequeño,** y**ou may remember him as *a very small* (150-micron) *particle who has many similar-sized family members.* They are determined to defeat Brad and his Sieve Certification. **

## Foiling A Sieve Test

**In the first episode, he and his family were on the way to a sieve analysis. *They had the objective of foiling the sieve test results by passing through sieves with certified openings of less than 150 microns.***

**Later we described ****Pequeño**** & Co.’s**** experiences in an actual sieve test wherein he and family member got past the 150-micron sieve. Many even transited the 125-micron sieve, which is 16% smaller. The 106-micron sieve finally stopped most of them.**

## **After TheSieve Shaker Stopped**

**We now rejoin the story after the violent shaking stopped. The testers removed the sieves from the stack and emptied the contents onto a balance to obtain a retained-weight distribution for each one. *When they came to the 106-micron sieve*, ****Pequeño *****and** **couple of his siblings did not drop to the balance, because they were wedged into some of the openings. ***

**When the analysis was completed, a tech used a brush to remove any residual material in the 106-micron sieve. Most everything was cleaned out, but ****Pequeño ****was among the particles that were still wedged into openings. ****The tech saw them on a visual check and ****gently pushed them through.**

**This unfortunately caused the mesh to spread, creating 150-micron openings in this 106-micron sieve -- much greater than the largest allowable opening of 141 that Brad (the Professional Sieve Certifier from the first episode) certified.**

## The Next Test For The Pequeño Family

## **The next time, ****Pequeño ****and his 150-micron siblings are used in a stack that includes the following sieves:**

- **#80 - 180 Micron**
- **#100 - 100 Microns**
- **#120 - 125 Microns**
- **#140 - 106 microns**

***It is likely that many of them will find their way through the 106-micron sieve and fall on to the next-smallest-size sieve screen***. This additional transit, is a result of the cleaning process. Most would assume, given that it is certified, that the 125-micron sieve would catch all of the150-micron particles. Not so. Worse still, a number of these will now pass through this 106-micron certified sieve, which has nominal openings 30% smaller than **Pequeño****.**

## When Harry Started To Question

**Harry, the QC Manager ** has always relied on the *certification process* to insure that his sieves would perform to high standards. He never evaluated the process from the view of a small particle with the mindset: “*I want to get through everything and do not care how much error I create*.”

**Onl****y when repeated tests indicated result anomalies would Harry suspect a problem with sieve performance. After he experienced ****Pequeño ****and his siblings’ onslaught, ****Harry began to consider better methods of predicting and checking real-world sieve performance than certification.**

**Until the next time, I continue to find new things in the world of material testing that baffle me.**

**Again we hope to be entertaining and helpful.**

**Check out the next article in the series here: [Sieve Calibration is the Holy Grail!](https://www.cscscientific.com/csc-scientific-blog/sieve-calibration-is-the-holy-grail)**

**Art**

**P.S. If these musings on lab test equipment are engaging, please consider forwarding them to associates and subscribing.**

P.P.S. Click on the button to learn more about  **Sieve Calibration.**

 

 

 

 

[View full post](https://www.cscscientific.com/csc-scientific-blog/is-sieve-calibration-really-the-holy-grail-part-iii)

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