Md. Rubel Miah
Department of Textile engineering
World University of Bangladesh
Email: rubel099@gmail.com
Sequence of combing operation:
The combing operation is carried out in order to improve the quality of the sliver coming out of the card. The process eliminates short fibers, it achieves better parallelization of fibers, it straightens curls, and it removes neps and residue impurities. Combing operation is done by comber machine. It is clear from these functions that the combing process is essentially aimed at obtaining excellent quality yarns and to fulfill this objective raw materials with above average physical and mechanical features must be used from the very beginning of the spinning process.
Objectives:
To remove fibers shorter than a predetermined length so as to enable spinner to produce finer yarn than that can be spun from the same carded sliver.
To remove neps and impurities.
To produce uniform sliver of required wt/unit length.
To make the fiber straight and parallel so that yarn becomes even and lustrous.
Working principle:
1. Lap feeding by feed roller:
The feed roller(A) move the sheet/Lap (B) (4 to 6.5) forward while the nipper C/D are held open (feed).
Fig: Lap feeding by feed roller
2. Lap nipping by nipper:
The top nipper (C) is lowered onto the bottom nipper (B). So that the fiber are clamped between them (nipper).
Fig: Lap nipping by nipper
3. Combing by cylinder:
The combing segment (E) mountain on rotating cylinder (F) swaps its needle or show teeth through the fiber & carries away anything not held by nipper.
Fig: Combing by cylinder
4. Nipper opening & forwarding:
The nipper open again 7 move towards the detaching rollers (G).
Fig: Nipper opening & forwarding
5. Detaching roller backward movement:
Mean while the detaching roller (G) have returning part of the previous drawn off slack by moves of a reverse rotation. So that the web produce as from the back of the detaching rollers.
Fig: Detaching roller backward movement
6. Piccing of web:
In the course of the forward movement of the nipper the projecting fiber is place upon the returned web.
Fig: Piccing of web
7. Combing by top comb:
Before the short of the detaching operation, the top comb (H) has thrust its single raw of the needle into the fiber. As the fibers are pulled through the needle of the top comb (H) during detaching, the tailing part of the top combed. Thus making up for the inability of the cylinder combs to reach this part of the fiber & thus performs combing.
Fig: Combing by top comb
8. Detaching roller forward movement:
The detaching roller being to rotate in the forward direction again and drawn the clamped fiber out of the sheet held first by the feed rollers.
Fig: Detaching roller forward movement
9. Preparation for next combing cycle:
As the nipper assembly is retracted, the nippers up for the next feeding step the top comb is withdrawn. As new combing cycle beings.
Fig: Preparation for next combing cycle
10. Waste extraction by the brush:
The combing cylinder rotates continuously and the combing segment is therefore attached with same impurities and short fiber. There are a rapidly brush (I) mounted below the combing cylinder. Thus the impurities & attached fiber.
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
