ANNALS OF THE UNIVERSITY OF ORADEA FASCICLE OF TEXTILES, LEATHERWORK 93 STUDY REGARDING YARN TENSION DURING KNITTING ON CIRCULAR MACHINE WITH SMALL… [601602]

ANNALS OF THE UNIVERSITY OF ORADEA
FASCICLE OF TEXTILES, LEATHERWORK

93

STUDY REGARDING YARN TENSION DURING KNITTING ON
CIRCULAR MACHINE WITH SMALL DIAMETER

VLAD Dorin1, COLDEA Alina Mihaela1

1 „Lucian Blaga”University of Sibiu, Faculty of Engine ering, Department of Industrial Machinery And Equip ment, Postal
address: 4, Emil Cioran Street, Sibiu, 550025, Român ia, E-mail: [anonimizat] , [anonimizat]

Corresponding author: Vlad, Dorin, E-mail: [anonimizat]

Abstract: If yarn tension is controlled properly during knitt ing, it gives an improved and uniform fabric
appearance. The main objective of knitters is to fe ed yarn to the knitting point at a low and uniform tension.
To ensure that the stress do not affect yarn proper ties, literature recommends that the yarn tension s hall be so
adjusted that it fits in the field elastic. The val ue of the yarn stress influences not only quality o f knitted product,
but also the value of the knitting machine producti on, by the frequency rupture of yarns. This is infl uenced
directly by the yarn stress and yarn quality.
The value of this tension is influenced by a comple x of factors, such as: technological diagram of the routing of
the yarn from coils up to the knitting area, the st ructure and characteristics of the raw materials, t he typo of
knitting, type supply, etc.
In the present article, using practical method, we test some ecological yarns used to make sock, like cotton,
organic cotton, bambooviscose, Tencel, according to 6 different fabric geometry: single jersey, plated single
jersey, ribb 4:2, plated ribb 4:2, purl, plated pur l. Was enregistered and discussed the values of yar n tension.

Key words: cellulose yarns, socks, yarn tension, single jerse y, purl, ribb

1. INTRODUCTION

The yarn feeding tension in knitting means axial force in the yarn in the moment of its
transformation into a loop [1], [2].
In the knitting industry maximum production speed is restricted to a certain limit such as
300m/min. on circular knitting machine. This limit is generally caused by yarn tension, wich breaks
the yarn and create several process troubles. Yarn tension is one of the important factors in the knit ting
industry, not only to make high quality knitted pro ducts but also to prevent process faults. Hence,
tension control should be properly maintained durin g knitting process [3].
Establish the yarn tension can be accomplished by practical methods (direct measurement with
appropriate devices) and through theoretical method s (calculation of the tension at different points o f
the route travelled characteristic of yarn) [1], [2 ].
In circular weft knitting, the monitoring of ththe faults and at the same time controlled inside
tight limits to prevent machine’s premature stop du e to yarn break [4].
Apart from the existing means of yarn tension contr ol such as positive feed devices, yarn
accumulating devices, yarn tension meter etc., inno vative ways of monitoring and controlling yarn
tension during knitting are always explored by scie ntists and researchers which benefits the
manufacturer by lower costs and introduce a new con cept on knitting machines, by using a full
integrated information system with all sensing devi ces inter-connected [5].

2. METHOD AND APPARATUS

The "Matec Silver 1L" (fig. 1) is an automatic and computerized machine with two cylinder
and two operating systems. These machine is for the production of socks from cotton and cotton type
yarns, for children, women and men, in the structur e jersey, rib and purl, with heal and top of produc t
in swing motion.

94

Fig. 1: Small cylinder knitting machine
„SILVER 1L” [6] Fig. 2 : Mecanical tensiometer ZF2 – 10, model
Schmidt
Specifications of the knitting machine used to obta in samples [7]:
– Gauge: 14 E
– Diameter of cylinders: 3¾ " (95, 25 mm)
– Number of neadles: 168
– Neadles tickness: 0,7 mm
– Number of cam systems: 2;
– Knitting speed: 300 rot/min. (circular motion), 1 80pend/min. (pendular motion)
Mecanical tensiometer ZF2 – 10, model Schmidt – fig ure 2 – was used for measure yarn feed
tension in different point of yarn.

3. EXPERIMENTAL PART

To avoid obtaining knitted fabric with shades (diff erent heights of loops in different rows),
due to uneven usage cams from the two systems, were used only 1 knitting system for made samples.
For the purpose to establish the yarn feeding tensi on we’ve chosen practical method, using
mechanically with Tensionmeter ZF2 – 10, model Schm idt.
In figure 3, we have represented the route of yarn, from the bobbin up into the area of
unloading to the knitting needles.
The circles … represent points in which we have measured the te nsion. In the table 1
were describe the steps from figure 3 and we showed the contact points of the yarn with the machine
parts
…
[8].

Table 1: Yarn contact points [8]
Contact point Description
1 Yarn bobbin unwinding
2 Tensioning device with plates + photocell for autom atic stop if detect
broken yarn
3 Yarn guide + automatic stopping device if detect small yarn tension
4 Contact with a metal part
5 Yarn guide + tensioning device with plates
6 Antenna for yarn recovery (negative feeding with yarn) + yarn guide
7 Final yarn guide.

ANNALS OF THE UNIVERSITY OF ORADEA
FASCICLE OF TEXTILES, LEATHERWORK

95

For study were chosed the samples knitted
from 5 types of carded yarns, coded: 1MDX
(100% cotton, 34/1 Nm), 2MDX (100% cotton,
40/1 Nm), 1DC (100% organic cotton, 34/1 Nm),
9DC (Tencel, 34/1 Nm), 10DC (Bambooviscose,
34/1 Nm). The plated yarn is polyamide 6, 44/12×2
dtex.

Fig. 3: The route of yarn in feeding
system [8]

964. RESULTS
The cumulated value of yarn tension (cN) is those m easureated in the F point. Tests resultes
are showed in tables 2 – 6.

Table 2. Yarn tension for variant 1MDX (Fond = cotton, 34/1Nm + Plating = Polyamide)

Checkpoint
for
measured
tension Knitted fabric geometry
Single
jersey Plated
single
jersey Ribb
4:2 Plated rib
4:2 Purl Plated purl
F F P F F P F F P
A 1.1 1.2 1.1 1.1 1.2 1.1 1.2 1.3 1.2
B 2.4 2.8 1.8 2.2 2.4 1.7 2.6 2.8 2.4
C 2.6 2.2 2.2 2.3 2.5 2.2 2.6 2.8 2.5
D 2.6 2.5 2.2 2.3 2.5 2.2 2.8 2.8 2.4
E 2.8 2.6 2.4 2.6 2.5 2.4 2.8 3.2 2.6
F 8.5
cN 8.2
cN 10.2
cN 9.5
cN 9.5
cN 10.4
cN 9.8
cN 8.2
cN 10.2
cN

Table 3. Yarn tension for variant 2MDX (Fond = cotton, 40/1Nm + Plating = Polyamide)

Checkpoint
for
measured
tension Knitted fabric geometry
Single
jersey Plated
single
jersey Ribb
4:2 Plated rib
4:2 Purl Plated purl
F F P F F P F F P
A 1.1 1.2 1.1 1.1 1.2 1.1 1.2 1.3 1.2
B 2.1 2.1 1.8 1.8 2.2 1.7 2.2 2.2 2.6
C 1.8 1.8 2.2 1.6 1.8 2.2 2.2 2.0 2.4
D 2.1 1.8 2.0 1.7 1.8 1.8 2.5 2.0 2.4
E 2.4 2.0 2.2 1.8 1.8 2.0 2.5 2.2 2.6
F 6.5
cN 7.5
cN 10.1
cN 6.2
cN 6.7
cN 10.3
cN 8.5
cN 8.2
cN 10.2
cN

Table 4. Yarn tension for variant 1DC (Fond = organic cotton, 34/1Nm + Plating = Polyamide)

Checkpoint
for
measured
tension Knitted fabric geometry
Single
jersey Plated
single
jersey Ribb
4:2 Plated rib
4:2 Purl Plated purl
F F P F F P F F P
A 1.1 1.2 1.1 1.1 1.2 1.1 1.2 1.3 1.2
B 1.7 1.7 1.7 1.5 1.7 1.8 1.9 2.0 1.8
C 1.6 1.5 2.2 1.3 1.5 2.1 1.7 1.6 2.4
D 1.7 1.5 2.2 1.4 1.5 2.1 1.8 1.6 2.4
E 1.6 1.6 2.5 1.4 1.8 2.4 1.8 1.8 2.6
F 6.5
cN 5.2
cN 10.2
cN 5.2
cN 7.0
cN 10.2
cN 7.2
cN 6.7
cN 10.2
cN

Table 5. Yarn tension for variant 9DC (Fond = Tencel, 34/1Nm + Plating = Polyamide)

Checkpoint
for
measured
tension Knitted fabric geometry
Single
jersey Plated
single
jersey Ribb
4:2 Plated rib
4:2 Purl Plated purl
F F P F F P F F P
A 1.1 1.2 1.1 1.1 1.2 1.1 1.2 1.3 1.2
B 1.8 1.8 1.8 1.8 1.8 2.2 1.8 2.0 1.8
C 1.6 1.5 2.2 1.5 1.5 1.5 1.6 1.6 2.5
D 1.7 1.6 2.2 1.6 1.6 1.6 1.6 1.7 2.6
E 1.8 1.6 2.4 1.6 1.7 1.7 1.6 1.6 2.6
F 5.3
cN 5.2
cN 10.2
cN 5.7
cN 5.2
cN 10.3
cN 5.5
cN 6.0
cN 10.5
cN

ANNALS OF THE UNIVERSITY OF ORADEA
FASCICLE OF TEXTILES, LEATHERWORK

97Table 6. Yarn tension for variant 10 DC (Fond = bamboo viscose, 34/1Nm + Plating = Polyamide)

Checkpoint
for
measured
tension Knitted fabric geometry
Single
jersey Plated
single
jersey Ribb
4:2 Plated rib
4:2 Purl Plated purl
F F P F F P F F P
A 1.1 1.2 1.1 1.1 1.2 1.1 1.2 1.3 1.2
B 2.0 1.8 1.8 1.8 2.0 1.5 2.3 2.2 1.7
C 1.8 1.9 2.2 1.5 2.0 2.2 2.6 2.5 2.4
D 2.0 1.9 2.2 1.7 2.1 2.2 2.7 2.6 2.5
E 2.1 1.8 2.0 1.7 2.1 2.2 2.6 2.5 2.4
F 9.1
cN 9.2
cN 10.1
cN 7.0
cN 7.8
cN 10.5
cN 10.5
cN 10.5
cN 10.5
cN

Fig. 4: Histogram of feeding yarn tension 1 MDX, according to different knitted fabric geometry

Fig. 5: Histogram of feeding yarn tension, accordin g to single jersey fabric geometry,
but different raw materials

Fig. 6: Histogram of feeding yarn tension, accordin g to plating yarn,
polyamide 6 and different fabric geometry

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CONCLUSIONS

In the case of same type of raw material – cotton 1 00 %, for a change of yarn fineness from
34/1 to 40/1 Nm, the yarn feeding tension decreases with 30,76 % (variants of knitted fabric
G1.1MDX and G1.2MDX) – tables 2.- 6., fig. 6.
For the main yarn 1MDX, we find the same values the yarn feeding tension, in the case of
knitted variants GV1 and LV1 – figure 4, 5.
The smallest value of yarn tension for the sample G 1 is in the case of 9DC yarn. The highest is
in the case of 10DC yarn, tables 2 – 6.
The medium yarn feeding tension for polyamide 6 (44 /12x2dtex) is 10,2cN in all the cases,
except the samples LV1 knitted from yarns 9DC and 1 0 DC, small increasing tension, tables 2 – 6, fig.
6.

ACKNOWLEDGMENT

This work was supported by the strategic grant POSD RU/159/1.5/S/133255, Project
ID 133255 (2014), co-financed by the European Socia l Fund within the Sectorial Operational
Program Human Resources Development 2007-2013.

REFERENCES

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