Combing Process in Spinning: The Ultimate Short Fiber Remover

Combing Process: The Ultimate Short Fiber Remover

Textile Engineering | Lap Preparation | Noil Control | Exam Guide

18 min read

1. What is Combing in Spinning?

Combing is an optional but highly critical process used when producing premium, fine-count yarns (typically above 40s Ne for cotton). While carding separates fibers, it leaves behind short fibers, neps, and impurities. The combing machine acts as a rigorous filter, actively removing short fibers (below a set length), neps, and remaining trash, leaving only the longest, strongest, and cleanest fibers to be spun into yarn.

  EXAM DEFINITION: Combing is a mechanical process that removes short fibers, neps, and impurities from a parallelized sliver or lap, further parallelizing the remaining long fibers to produce a superior quality combed sliver for high-count yarn manufacturing.

2. Objectives of Combing

• Short Fiber Removal (Noil Extraction): The primary goal. Removing fibers shorter than a specific cutoff length (e.g., 16mm) drastically improves yarn strength and evenness.
• Nep Elimination: Removes neps that survived carding. Combed yarn has almost zero visible neps.
• Maximum Parallelization: Fibers are combed straight, resulting in yarns with a smooth, lustrous surface.
• Blending: Additional mixing occurs as multiple laps are fed into the comber simultaneously.

3. Lap Preparation (The Pre-Combing Sequence)

You cannot feed standard drawn sliver directly into a comber. It lacks the density and cohesion required to withstand the harsh combing action. It must be prepared into a "mini-lap" through a specific sequence:

Lap Preparation Flow: Draw Frame Sliver → Sliver Lap Machine (makes a soft lap) → Ribbon Lap Machine (makes a dense, uniform mini-lap) → Comber

Modern mills often use a single "Unilap" machine (like Rieter UNIlap) that combines both processes, taking up to 24-28 drawn slivers and converting them directly into a compact comber lap in one step.

4. How the Comber Works (The Nip Cycle)

The comber operates on a cyclic basis. A single head (combing station) goes through these steps every second or so:

The 5-Step Combing Cycle

• 1. Feeding & Clamping: The lap is fed forward by a specific length (feed length/nip). A top and bottom clamp hold the fiber bundle tightly.
• 2. Combing: A rotating cylinder covered with fine saw-tooth wire penetrates the unclamped fringe of fibers. Long fibers are combed straight; short fibers and trash are left behind on the cylinder wire.
• 3. Detaching & Piecing: The detached rollers move backward, gripping the newly combed long fibers and pulling them away. As they pull, they overlap (piece) them with the previous combing cycle's fiber bundle to form a continuous web.
• 4. Cleaning the Cylinder: A brush or air blast strips the short fibers (noil) and trash off the combing cylinder.
• 5. Top Comb Action: A stationary comb (top comb) descends into the fiber fringe from above to catch any neps or short fibers the cylinder missed.

5. Combed vs. Carded Yarn: The Real Difference

Feature	Carded Yarn	Combed Yarn
Short Fiber Content	High (15-20%)	Very Low (4-6%)
Yarn Strength	Lower	10-15% Higher
Evenness (U%)	Higher U% (more variation)	Lower U% (smoother)
Surface Appearance	Hairy, dull	Smooth, lustrous, clean
End-breakages in Spinning	Higher	Significantly Lower
Production Cost	Lower (fewer processes)	Higher (8-12% extra waste + machinery)
Typical Use	T-shirts, denims, towels (20s-40s Ne)	Shirts, fine fabrics (60s-120s Ne)

6. Real Combing Machines

Rieter E 86 SWITZERLAND

• Heads: Up to 8 heads per machine.
• Speed: Up to 500 nips/min.
• Features: Integrated web cleaner, automatic piecing monitoring, touch-screen CAN system.
• Observation: The E 86 is known for incredibly gentle fiber handling, minimizing long fiber breakage during the harsh combing action.

LMW LC 300 INDIA

• Heads: 6 or 8 heads.
• Speed: Up to 400 nips/min.
• Features: Touch panel, servomotor drives, auto-doffing.
• Observation: Highly popular in Indian mills for 40s-80s combed yarn. Cost-effective and rugged.

7. Essential Formulas

Noil % = [(Weight of Lap Fed - Weight of Sliver Produced) / Weight of Lap Fed] × 100

Example: Fed 1000 kg of lap, produced 840 kg of sliver. Noil = (160/1000)*100 = 16%. (Standard noil is 14-20% depending on cotton quality).

Combing Efficiency % = (Noil Extracted / Total Noil Present in Feed) × 100

8. Frequently Asked Questions

Why is noil percentage kept between 14-20%?

If you extract less than 14%, you are leaving too many short fibers, which defeats the purpose of combing. If you extract more than 20%, you are cutting perfectly good long fibers, wasting money and reducing yarn realization. 16-18% is the sweet spot for medium-staple Indian cotton like Shankar-6.

What is "piecing" in combing?

Because the comber detaches fibers in discrete tufts (once per nip), these tufts must be joined together to form a continuous sliver. This joining process is called piecing. The detaching rollers overlap the new tuft with the tail end of the previous tuft by several millimeters to ensure strength.

Continue Learning

• Drawing Frame: Drafting, Doubling & Autolevelling
• Roving Frame Technology & Flyer Design (Coming Soon)

Written by Arnab Chakraborty

Textile engineer specializing in spinning technology and process optimization. Sharing real-world mill knowledge through Textile Engineering Academy.

Textile Engineering Combing Spinning Technology