یگدنفابتامدقم - textile.yazd.ac.irtextile.yazd.ac.ir/ms.ahmadi/downloads/textile...
TRANSCRIPT
4/11/2014
1
مقدمات بافندگیWeaving Preparation
271Textile Technology
Textile Technology 272
Spun yarn quality characteristics that are most important for good weaving performance include short- and long-term weight uniformity, imperfections, tensile properties and hairiness.
The cost to repair a yarn failure is much less if it occurs prior to the weaving process.
4/11/2014
2
Textile Technology 273
Textile Technology 274
Winding
Purposes of winding process:A- Building large packages
4/11/2014
3
Textile Technology 275
B- Yarn clearing
Yarn faults
Textile Technology 276
Schematic of winding process
4/11/2014
4
Textile Technology 277
Textile Technology 278
4/11/2014
5
Textile Technology 279
Tension and clearing zone of a modern automatic winding machine
Textile Technology 280
Tension device The tension device maintains a proper tension in the yarn to achieve a uniform package density. It also serves as a detector for excessively weak spots in the yarn that break under the added tension induced by the tension device.
There are three major types of tension devices:
4/11/2014
6
Textile Technology 281
a) Capstan (or multiplicative) tensioner
Textile Technology 282
b) Additive tensioner
4/11/2014
7
Textile Technology 283
c) Combined tensioner
Textile Technology 284
Yarn clearersThe purpose of a yarn detector is to remove thin and thick places.
Yarn detectors are usually two types: mechanical and electronic.
Air splicer
4/11/2014
8
Textile Technology 285
A mechanical clearer may be as simple as two parallel blades. The distance between the plates is adjustable to allow only a predetermined yarn diameter to pass through.
Textile Technology 286
Electronic detectors are mainly two types: capacitive and photo-electric
4/11/2014
9
Textile Technology 287
Stop motionThe purpose of a stop motion is to stop winding when the yarn breaks or runs out.
Winding regionMany types of package configurations can be obtained including cone, tube or cheese, dye tube or spool depending on the next stage of processing.
The basic requirement of winding is uniform tension on the yarn.
Textile Technology 288
4/11/2014
10
Textile Technology 289
Traversing mechanism
a) Grooved drum
a) Traversing guide
Textile Technology 290
Types of packages
4/11/2014
11
Textile Technology 291
Textile Technology 292
Precision WindingIn precision winding, the position of the yarn as it is laid on the package is controlled very precisely to increase the density of the package.
4/11/2014
12
Textile Technology 293
Warping
Textile Technology 294
Direct Warping
4/11/2014
13
Textile Technology 295
Indirect (Section) Warping
Textile Technology 296
4/11/2014
14
Textile Technology 297
Expanding zigzag comb
Textile Technology 298
4/11/2014
15
Textile Technology 299
CreelThere are various types of creels. The most commoncreel types are:
• parallel standard creel with fixed package frame(single end creel)• parallel creel with package trucks• parallel creel with swivelling package framesections (for cotton, viscose, polyester/cotton, wool colored)• parallel creel with reserve packages (magazinecreel, for synthetic filaments)• parallel creel with unrolling draw-off forpolypropylene, monofilaments
Textile Technology 300
• V-creel with reversible frames• V-creel with reversible frames and automatic knotter(for cotton, viscose, polyester/cotton)• V-creel with traveling packages
4/11/2014
16
Textile Technology 301
Schematic top view of warping process (V-creel).
Textile Technology 302
SLASHING (SIZING)
The weaving process requires the warp yarn to be strong, smooth and elastic or extensible to a certain degree. To achieve these properties on the warp yarns, a protective coating of a polymeric film forming agent (size) is applied to the warp yarns prior to weaving.the size materials will be removed from the fabric during the finishing operation, which is called desizing.
4/11/2014
17
Textile Technology 303
The main purposes of slashing are as follows:• to increase the strength of the yarns• to reduce the yarn hairiness that would cause problems in weaving process.• to increase the abrasion resistance of the yarnsagainst other yarns and various weavingmachine elements• to reduce fluff and fly during the weavingprocess for high speed weaving machines.
Textile Technology 304
Tension and abrasion zones in a typical loom
4/11/2014
18
Textile Technology 305
Control of yarn hairiness with sizing, top: unsized; middle: improperly sized; bottom: properly sized
Textile Technology 306
The following terms are used related to sizing:
• Size concentration: the mass of oven dry solidmatter in size paste• Size take-up (size add-on): the mass of pastetaken up in the size box per unit weight ofoven dry unsized yarn• Size percentage: the mass of oven dry size per unit weight of oven dry unsized yarn
4/11/2014
19
Textile Technology 307
Typical relation between size add-on andwarp breakage rate
Textile Technology 308
Sizing machine
The major parts of the slasher are the creel, size box, drying units, beaming and various control devices
4/11/2014
20
Textile Technology 309
Major film forming polymersused in sizing.
Textile Technology 310
DRAWING-IN AND TYING-IN
Schematic of drawing-in
4/11/2014
21
Textile Technology 311
Warp tying machine