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SFI Channel
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LabPack
Surface Index SFI
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1 Requirements of the Yarn2 Yarn surface structure
4.1 SFI/D-Reference
4.2 Limit values in percent (+/-)
4.3 Surface variation of a yarn
4.4 Off Standard bobbins
4 Quality control with SFI/D
Summary
3.2 SFI
3 Definition
5 Quality data collection with SFI
3.1 SFI/D
6 SFI Experience
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The scope of a spinner is:
permanently supply customers with the required quality
Requirements of the Yarn
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Yarn surface structure
The surface of the yarn is characterized by:
Irregularities (thick-thin)
Hairiness, neps
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Periodic faults: - cluster channel
Detection of off-standard bobbins
Yarn Count: - count channel
- Neps
- Shorts- Longs
Surface Index: - Hairiness
- Neps
- Irregularities
Yarn Clearing with YarnMaster SpectraRare yarn faults (classical
yarn faults)
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Definitions Surface Index SFI/DYarn core diameter 100%
Sum signal SFI/D
100%
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Surface variation of a yarn
Bobbin tip
Drawing system
(output)
Bobbin base
SFI/D +/-10%
Investigations have shown that
the surface index can
vary within a bobbin (basis/peak)
by up to +/-10%.
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Surface variation of a yarn
3 Bobbin tip
1
Drawing
system
(output)
2 Bobbin base
= SFI/D deviation 10 %
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Hairiness
Bobbin tip
Bobbin base
Surface variation of a yarn
= SFI/D deviation 10 %
SFI/D deviation 10 %
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DefinitionsSurface Index SFIThe yarn core diameter is hiddenSum
signal SFI
Measured length 1cm
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Yarn Clearingwith SFI/D
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SFI/D-Reference
Settings:
Constant
fixed reference value
yarn clearing immediately active
Float
window length of 40 km per spindle (about 30min. of winding)
yarn clearing is activated after winding 10% of the window
length(= 4 km per spindle)
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Limit values in percent (+/-)
+ Limit: 20%
+ Limit: 20%
- Limit: 25%
- Limit: 25%
SFI/D-Reference
SFI/D-Reference
Limit is exceeded Yarn length 80m Cut / blocked Spindle
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SFI/D Clearer Limits (+/-) Limit exceeded observation length 80m
cut / alarm
Reference SFI/D (10%)
+ limit
20% (+2.0%)
-limit
25% (-2.5%)
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Example: Periodic fault
+40% SFI/D-Deviation
Effects the quality parameters: IPI, CVm, H
Cause: Drawing system
Off Standard bobbins
Spectrogram of the mass
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Fault: IPI, CVm
Normal yarn Example:+48% SFI/D deviation
Presentation in knitwear
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Quality Data Collection with SFISFI Comparison / Hairiness
measurement (H)
Correlation ( r = 0.91)
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Ring yarn, combed (100% CO)
Measuring Length : 80m
Limit +/- : 20%
Deviation +/- : 10%
ExamplesFault pattern : Periodical Faults (Moir)
SFI/D-Deviation : +20% to +34%
Caused by : Ringframe: Drafting system (Top Roller
defective)
Fault pattern : Imperfections (Neps)
SFI/D-Deviation : +30%
Caused by : Ringframe: Ring-Traveler system (Travelers
defective)
Regular yarn (good Quality)
SFI Experience
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Compact yarn (100% CO)SFI Experience
Regularyarn (good Quality)Measuring Length : 80m
Limit +/- : 25%
Deviation +/- : 15%
ExamplesFault pattern : Periodical Faults (Moire)
SFI/D-Deviation : +40%
Caused by : Ringframe: Drafting system (Bottom section
defective)
Fault pattern : Imperfections, Irregularities, Hairiness
SFI/D-Deviation : +42%
Caused by : Ringframe: Drafting system (Compact area dirty)
Fault pattern : Imperfections, Irregularities
SFI/D-Deviation : +27%
Caused by : Ringframe: Drafting system (Compact section
defective)
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