Lecture 1.
Lap former
Combed yarn manufacturing process:
Lap former:
The lap former has the charge of developing the laps that is engaged to feed the comber machine.
The laps are achieved through combining or doubling a definite number of slivers from breaker
drawing passage such as- 16 to 32 doubling or at times even as much as 64 doubling.
Brands of Lap Former
• Trutzschler, Germany.
• Rieter, Switzerland.
• Toyoda, Japan.
• Murata, Japan.
• Lakshmi, India.
Necessity of Lap Former Machine in Textile Industry
It is a process of making flat laps by combining multiple slivers. It is the important process in the
combing process that influences the quality of the combed sliver.
• To ensure straight and parallel fibers fed.
• To reduce strain on combing cylinder and top comb.
• To reduce fiber damage.
• To control the amount of waste.
• To improve the uniformity of material
Functions or Objectives of Lap Former Machine:
1. Doubling
2. Drafting
3. Compressing
4. Lap formation.
Working Principle of Lap Former Machine:
The E 35 OMEGA lap comprises infeed, winding head and delivery sections.
• The infeed section comprises the creel, arranged centrally, the web table with the two
drafting units positioned linearly and without deflection plates, and the web doubling
toward the winding head.
• The winding head accommodates the drive, four calendar rolls, and the belt winding and
tensioning system.
• Draw frame slivers are fed from cans. Individual sliver goes through the guide plate at the
rear of the machine. The material is fed via sliver-preserving guide elements to the two
drafting units, where two webs are formed.
• In normal operation, 12 cans are laid out under each roller-assisted feed table. Altogether,
finally gives a total of 24 doublings.
• slivers are entered into the drafting system of 4 over 4. Because of the draft, the fibers are
sorted, straightened, and paralleled. The draft is about 1.8 and 2.0.
• The calendar roller draws the superimposed webs from the table to lap winding assembly.
The material passes between the four calendar rollers, and strong compression takes place,
compressing the web into a uniform batt.
• Then, finally, the laps are bound on a metallic spool. During winding on the spool,
tremendous pressure is applied to the bobbin so that a long-compressed lap can be
achieved.
• When the appropriate lap length is already rolled to the spool, the Lap Stop Motion stops
the machine immediately.
• The batt is wound onto a tube by means of belt technology. The full lap is then ejected
from the winding head and placed on a lap trolley or conveyor belt.
Figure: Working principle of lap former.
Specification of Super Lap Former/ Technical data:
Production Theoretical: up to 480 kg/h, Effective: up to 350 kg/h
Fibre length 27-38 mm (51 mm)
Sliver count range 3.3-6 ktex
Input weight Maximum 140 ktex
Doublings 24-32,
Drafting unit 4 over 4
Draft 1.36-2.2-fold
Lap Count/ Lap up to 80 ktex, 50–70 g/m
grams per square
meter (GSM)
Lap weight up to 25 kg
Lap width 300 mm
Lap diameter Maximum 650 mm (For E 75 maximum 550 mm)
Delivery speed 70-140 m/min
Technical Specifications of Rieter E35 and E32 Model Lap Former
Sl Parameters E 35 E 32
Up to 520
1 Production Up to 350 kg/hr
kg/hr
Maximum 140
2 Input Weight Maximum 140 ktex
ktex
3 Lap Hank Up to 80 ktex Up to 80 ktex
4 Lap Weight Fixed 25 kg Up to 25 kg
5 Lap Width 300 mm 300 mm
Up to 180
6 Delivery Speed 70-140 m/min
m/min
Additional Features of Super Lap Former Machine:
• Auto weight per unit length adjuster
• Auto doffing for full laps
• Auto stop motion
• Auto Doffing
• Auto lap carrying device
Production problem.
Mathematical problem
Production formula for lap former:
Production Calculation of Lap Former:
PARAMETER:
Delivery Speed : 95 m/min
Lap Weight : 70 gm/m
Efficiency : 85%
Production = (95(m/min)×60(hr)×0.85(Efficiency)×70(gm/m)) / (1000 (kg))
= 339.15 kg (answer)
Problem 1: 70 gr/yd drawing sliver is fed in lap former to form a suitable package for comber, with
draft and doubling of 2.5 and 24 respectively. Calculate the weight of lap?
Problem 2: If production of lap former is 8.424 kg per minute with 25 kg lap, Calculate doffing
time of lap former machine.
Problem 3: Calculate production of a lap former having following parameters: Feed sliver hank=
0.12 Ne, no of doubling = 24 Draft = 1.25, delivery speed = 90 m/min and Efficiency = 85%.
Problem 4: Find out the production of lap former machine in kg/day=? When delivery speed
78/min, feed weight = 160 ktex, draft = 2.5, efficiency = 93% and waste 1%.
Problem 5: Calculate the delivery speed of lap former if production of lap former is 9500 lb per
day with 650 gr/yd lap and efficiency is 80?
Problem 6: Find the no. of lap former required to keep running 10,000 kg per day of combed
sliver, which extracting 16% of comber noil. (Assume all necessary parameters).
References:
Process Management in Spinning by R. Senthil Kumar
Handbook on Cotton Spinning Industry B. Purushothama
