The Quest To Make A Single “Weaveable” Yarn

The journey continues, pushing the boundaries of textile engineering, innovation and discovery to find a better way in producing single ‘weaveable” yarn which avoids sizing process, writes S. Murugan

“Can you make this kind of yarn?”

Kato-San, the Technical Director, asked, holding up a new magazine article, his eyes gleaming with curiosity.

It was the year 1990, and we were gathered at a technical meeting led by Kato-San. He used to visit our mills twice a year, bringing invaluable feedback and insights gathered from his travels to textile factories across the world.

As he unfolded the paper, I tried to catch a glimpse of the image, though it was closer to the Factory Manager. Moments later, the FM passed it to me.

The bold title read: “Siro Spun Process.”

Back then, in the early ’90s, neither compact spinning nor Siro spun was familiar to most technicians. Confusion clouded our faces rather than an eager acceptance of the challenge ahead.

Kato-San smiled knowingly and began his explanation.

“The Siro spun process was developed by CSIRO—Commonwealth Scientific and Industrial Research Organisation—back in the 1970s. This revolutionary spinning method integrates spinning and doubling into a single step, enhancing yarn strength and weaving efficiency.”

I furrowed my brows in disbelief. “Twenty years ago? Why haven’t we adapted it into our machinery yet?”

He gestured towards the article. “Look at the description below the image,” he said.

As I examined the details, I realized something crucial—the process was designed for worsted spinning.

Kato-San continued, delving deeper into the history.

“Though the technology was pioneered by Dieter Plate and his colleagues at CSIRO’s Textile and Fibre Technology division in the 1970s, it wasn’t commercially released until 1980. Before this breakthrough, worsted yarns had to be doubled before weaving. Single yarns lacked the tightly bound surface fibres needed to withstand abrasive forces, making them unsuitable for weaving. Since worsted yarns were not ‘sized’ with starch like cotton yarns, weavers relied only on two-fold yarns.”

Intrigued, I leaned forward. “Can you explain the concept, sir?”

He nodded. “Siro spun utilizes the torque and friction forces during twist insertion to bind two drafted roving strands together initially and then applies additional twist to form a two-fold structure. That’s why, at the yarn delivery point, you can observe the clear characteristic ‘Y’ shape of the yarn strands.”

“Has any spinner tried using this for cotton spinning, sir?” the Factory Manager asked Kato-San.

He nodded thoughtfully. “Yes, I’ve seen it in a few mills in China. They were working with Sea Island cotton. That got me thinking—why don’t we try it with our Suvin cotton?”

His eyes scanned the room, searching for a spark of inspiration.

We all nodded in agreement, confidently saying, “Yes, sir, we can do it!” Yet, in truth, none of us knew the challenges waiting for us in this ambitious experiment.

With the materials at hand, we modified 24 spindles on a ring frame to accommodate the SIRO process. Additional bobbin holders were installed at the creel, leaving the remaining spindles idle. Once everything was set, we began the process, eager to demonstrate our expertise.

But reality hit hard.

To our astonishment, even the most skilled operator struggled to mend the frequent yarn breaks on the SIRO spindles. Lowering the speed didn’t help—we still couldn’t run the machine effectively.

Kato-San observed carefully, measuring critical aspects—particularly the distance between the two rovings.

“The gap between the rovings is currently 10 mm. Reduce it to 6 mm,” he instructed.

The results were remarkable.

With the adjusted spacing, performance improved drastically. The Suvin yarn showed enhanced quality, reducing hairiness, IPI, and increasing strength and elongation by more than 10%.

Kato then provided a crucial insight: “Keep in mind that, while SIRO replaced the doubling process in worsted spinning, it is still considered a single yarn when it comes to cotton spinning. This process cannot replace traditional doubling or TFO methods. The key difference lies in the twist direction—SIRO maintains the same twist for individual strands and the overall yarn, whereas TFO creates a distinct texture and lustre by reversing the twist.”

Buoyed by our success with Suvin, we expanded our trials to other fibres.

What we discovered was fascinating—the ideal rovings gap depended on fibre length!

• 4 mm for fibres around 30 mm in length.
• 5 mm for fibres approximately 33 mm long.

However, the performance of 30 mm fibres was poor. Further reducing the gap caused the rovings to almost merge, eliminating the SIRO effect entirely.

A fine balance had to be maintained. The larger the gap, the more pronounced the SIRO effect—but at the cost of performance. Conversely, a smaller gap improved spinning efficiency but weakened the SIRO characteristics.

Fast Forward to Today…

With the arrival of compact spinning systems, which naturally increase yarn strength by about 15%, SIRO technology can now be successfully applied to even 30 mm fibres.

However, compact systems operate with a fixed distance between the slots for rovings, posing a new challenge: how to adapt the process for fibres of varying lengths?

Still, these yarns need sizing before weaving, however in a small quantity compared to non-compact/non-SIRO yarns.

The journey continues, pushing the boundaries of textile engineering, innovation and discovery to find a better way in producing single ‘weaveable” yarn which avoids sizing process.