The Anatomy Of An End Break: How Yarn Fails In Spinning

The deeper I delved into the mechanics of end breakage, the more I realized how much was yet to be understood. This wasn’t the end—it was just the beginning of a fascinating unravelling, writes Murugan Santhanam

During a spinning technology workshop, our technical trainer threw a deceptively simple question at the group: “What is an end break in spinning?”

We looked at each other, puzzled. The term “break” seemed straightforward—it implies a discontinuation, doesn’t it?

After a brief silence, one attendee ventured a response: “Sir, it is the rupture of yarn that makes the yarn get separated and lose its continuity.”

His answer felt like something lifted straight out of a dictionary—but it sparked a follow-up from the trainer. “Great! But what do you mean by rupture?”

The same attendee thought for a moment. “It’s a yarn cut, sir—like a fracture.”

The trainer smiled and challenged us again: “So you’re saying all the fibres across the yarn cross-section break completely, as if cut by a pair of scissors?”

None of us could confidently say yes—we’d never really analyzed broken ends in all our years on the shop floor.

Then another participant chimed in, albeit hesitantly: “Sir, in a yarn end break, the fibres don’t actually break—they slip or slough off, losing the grip between them.”

The trainer nodded and posed a new question: “How many of you think an end break means the yarn is cut, and how many think it’s fibre slippage?”

Hands shot up. The room was split almost 50–50.

Three Faces of a Break
The trainer then unveiled research findings from strength testing of broken yarn ends.

“Now, I will explain our findings on the analysis of the broken ends of the yarn after strength testing. These breaks can be broadly categorised into three types. One has sharp broken ends (as if cut by a pair of scissors). The second one is a tapered end (Here, some fibres would break, and the rest would slip). The third category is a fully slipped end. Here, you won’t find any broken fibres. However, the chance of an end break to have 100% slippage of fibres is only 7%. For the first category of breakage, it is around 50% and for the second one, it is around 43%.”

He paused for a moment and continued, “One thing we have to understand is that as the count becomes coarser and at the same TM level, the percentage of sharp broken ends will be decreasing. In the meantime, if the TM is increased for the same count, the percentage of sharp broken ends increases. Do you know why?”

“It may be due to the compactness of the yarn!” somebody responded.

“Exactly!” he said. Even if TM is held constant, coarser yarns have a larger cross-section. The same TPI (turns per inch) isn’t sufficient to fully bind the greater number of fibres, so slippage becomes more prevalent.

The Hidden Weakness in Spinning Zone
Curious, I raised a hand. “Are the breaks during spinning different from those at the strength tester?”

“Absolutely,” he replied. “The mechanism of end breakage at spinning is entirely different from that at tensile testing. In spinning, an end breaks when the tension imposed on the yarn exceeds the weakest yarn strength. In all the research, it has been observed that almost all the breaks are occurring just after the delivery from the front nip. That is between the front roller nip and the thread guide, which we call the spinning zone. An interesting fact here is that all the breaks are slippage-dominated. So far, no evidence has been found for the fibre breakage.”

“Normally, the spinning tension will be between 25 to 60 grams! But why a yarn, say 60s Ne, with a tested strength of 180 gms, still break at the ring frame, sir?” I interrupted the trainer.

The trainer chuckled and dropped a striking insight: “The interesting fact here is that at the spinning zone, the yarn strength is significantly less than the yarn strength measured at the tensile tester. This strength has been calculated as one-third of the mean strength of the yarn measured by the tensile tester.”

I leaned forward. “Can you elaborate, sir?”

“Supposing if the yarn’s breaking force, say for 60s, is 180 gms, the actual strength at the spinning zone is only 60 gms! The mean yarn strength at the spinning zone is 60 gms. This strength follows a normal distribution curve. In reality, the weakest portions can have strength as low as 60 minus five times the standard deviation. Also, it has been observed in several studies that in every traveller rotation, there are five peak tensions, some exceeding 60 grams. That’s how end breaks happen, despite the apparent strength.”

As the session drew to a close, the room settled—but my mind didn’t. The unfolding mystery of peak tensions and hidden weak spots in yarn left me with more questions than answers. One thing was certain: we had only scratched the surface. The deeper I delved into the mechanics of end breakage, the more I realized how much was yet to be understood. This wasn’t the end—it was just the beginning of a fascinating unravelling.

(Murugan Santhanam is Managing Director of Texdoc Online Solution Pvt. Ltd.)