The document discusses apron slippage in ring frames and its effect on yarn quality. It reports on test results that show apron slippage increases when roving is present and higher slippage leads to poorer yarn quality, with more neps, diameter variability, and breaks. Using an anti-slip apron reduces slippage to zero and improves yarn quality. The document also examines the impact of higher machine speeds and draft ratios on apron and front roller cot speeds. It concludes that controlling apron slippage through the use of anti-slip aprons improves yarn quality.

1. Apron Slippages
S.M. Ishtiaque

2. Apron Slippage
S.M. Ishtiaque

3. Apron Slippage at Ring Frame
Type of
Material
Spindle
Number
Speed of
Bottom
apron
without
roving
(mm)
Speed of
Top apron
without
roving
(mm)
Apron
Slippage
without
roving (%)
Speed of
Bottom
apron
with
roving
(mm)
Speed of
Top apron
with
roving
(mm)
Apron
Slippage
with
roving (%)
40 Ne
Cotton
1 25.43 24.97 1.80 25.14 24.40 2.94
2 25.56 25.02 2.10 25.16 24.29 3.46
3 25.49 25.13 1.41 25.14 24.20 3.74
30 Ne
Cotton
1 32.10 31.40 2.18 31.69 30.58 3.50
2 32.01 31.27 2.31 31.50 30.31 3.78
3 31.79 31.07 2.26 31.41 30.23 3.76
30 Ne P/V
(65/35)
1
2
3
47.99
48.42
48.49
46.81
47.15
47.32
2.46
2.62
2.41
47.92
47.49
47.92
45.58
45.26
45.90
4.88
4.70
4.22

4. Effect of apron slippage on yarn quality
Type of
Yarn
Apron
Slippage
(%)
U% Diameter
CV%
Thin
Places
(-50%)
Thick
Places
(+50%)
Neps
(200%)
Tenacity
(cN/tex)
Elongati
on (%)
Hairines
s Index
(HI)
24 Ne
Cotton
3.48 14.64 14.2 74 788 542 11.83 5.86 682
4.50 15.14 15.7 112 881 625 11.48 5.99 694
8.64 17.31 17.2 342 1658 862 10.51 6.02 689
24 Ne
P/V
65/35
2.87 10.58 9.8 8 104 257 15.44 7.56 312
4.72 11.55 11.3 14 189 375 14.19 7.68 307
7.96 12.93 12.7 38 266 543 13.32 7.44 322

5. Apron Slippage with normal and anti-slip aprons
Type of
Yarn
Type of
Apron
Speed of
bottom
apron
without
roving
(mm/s)
Speed of
top apron
without
roving
(mm/s)
Apron to
apron
slippage
without
roving (%)
Speed of
bottom
apron
with
roving
(mm/s)
Speed of
top apron
with
roving
(mm/s)
Apron to
apron
slippage
with
roving (%)
20 Ne
Cotton
Normal 17.96 17.79 0.95 17.71 17.19 2.94
Anti-slip 17.82 17.82 0 17.54 17.54 0
20 Ne P/V
(65/35)
Normal 23.43 23.12 1.32 23.07 22.09 4.25
Anti-slip 23.26 23.26 o 22.73 22.73 0

6. Effect of type of apron on yarn properties
Type of
yarn
Type of
Apron
Mass
irregul
arity
(Um %)
Diamet
er
irregul
arity
(Ud %)
Thin
places
(-50%)
Thick
places
(+50%)
Neps
(200%)
Tenacit
y
(cN/tex)
CV% of
tenacit
y
Breakin
g
elongat
ion (%)
CV% of
breakin
g
elongat
ion
Hairine
ss
Index
(HI)
20 Ne
Cotton
Normal 14.54 15.80 69 758 785 10.80 12.49 3.72 13.27 817
Anti-
slip
14.10 14.80 66 389 436 12.32 8.06 3.70 9.47 837
20 Ne
P/V
(65/35)
Normal 10.58 13.60 0 100 187 15.87 10.39 8.44 10.64 504
Anti-
slip
10.02 10.50 0 60 134 17.53 9.00 9.54 8.96 593

7. Impact on cots and apron on high speed
drafting and high draft ratio
Parameters Existing
parameters
High speed
drafting
High draft
ratio
High speed
drafting with
high draft
ratio
Front roller delivery speed
(m/min)
12.46 16 12.46 16
Feed hank (Ne) 2.8 2.8 2.0 2.0
Delivered hank (Ne) 100 100 100 100
Surface velocity of apron
(m/min)
0.396 0.506 0.283 0.396
Surface velocity of front roller
cot (m/min)
12.46 16 12.46 16

8. CONCLUSIONS
Control of Apron Slippages
certainly improves the yarn
quality.
Pay attention to
avoid apron slip