Comber

Comber:

Combing is a process by which the quantity of short fibers and remnant fragments of impurities present in a carded or drawn sliver are minimized to give a clean sliver.

The process used to remove the short fiber and remnant impurities from fiber strand is called combing.

Principle of combing operation/Combing cycle:

Operation flow:

a.     Lap feeding by feed roller

b.     Lap nipping by the nippers

c.      Combing by the cylinder

d.     Nippers opening and forwarding

e.     Detaching roller backward movement

f.       Piecing

g.     Detaching roller forward movement

h.     Combing by the top comb

i.        Starting a new cycle

j.       Cleaning of cylinder comb

(a) Lap feed by feed rollers:

Feed rollers (S) move lap sheet (W) forward by a small amount (4.3 - 6.7 mm), while nippers (Zo/Zu) are held open (feed).

(b) Lap nipping by nippers:

Upper nipper plate Zo is lowered onto cushion plate (Zu) so that the fibers are 

clamped between them (nipping).

(c) Combing by the cylinder:

Combing segment (K), mounted on rotating cylinder (Z), sweeps saw-teeth through fiber fringe (B) and carries away anything not held by the nippers (rotary combing).

(d) Nippers opening and forwarding:

The nippers open again and move toward detaching rollers (A)
(nippers forward).

(e) Detaching roller backward movement:

Meanwhile detaching rollers (A) have returned part of the previously
drawn-off stock (web V) by means of a (partial) reverse rotation,
so that the web protrudes from the back of the detaching device
(web return).

(f) Piecing:

In the course of the forward movement of the nippers the projecting
fiber fringe (B) is placed on the returned web (V) (piecing).

(g) Detaching roller forward movement:

The detaching rollers begin to rotate in the forward direction again
and draw the clamped fibers out of web (W) held fast by feed rollers
(S) (inside the nippers) (detaching).

(h) Combing by the top comb:

Before the start of the detaching operation, top comb (F) has thrust its
single row of teeth into the fiber fringe. As the fibers are pulled through
the teeth of the top comb during detaching, the trailing part of the
fringe is combed.

(i) Starting a new cycle:

As the nipper assembly is retracted, the nippers open for the next
feeding step. The top comb is withdrawn. A new combing cycle begins.

(j) Cleaning of cylinder comb:

Contrary to the movements of the other parts, the combing cylinder
rotates continuously. During this rotation and at a certain instant the
combing segment is brought into the vicinity of a rapidly revolving
brush mounted below the combing cylinder. This brush removes the
imperfections, etc., from the combing segment, and ejects them into
an extractor that carries the noil away to a collecting filter system.

References:

1.     Manual of Short Staple Spinning by Mohammed Farhad Mahmud Chowdhury

2.     The Rieter Manual of Spinning by Werner Klein

 

Written by

Ahmed Saber Shravan

Lecturer, Department of Textile Engineering,

Primeasia University; Bangladesh