I

I

Yarn Preparation For Weaving And Knitting

De fin ition Yam preparation involves those processes that improve the yam’s weaveability or knittability.

I Preltlara 8 ‘on R t or a in Yarn warpyarns

Yams must be aligned properly Yam strength must be increased Yam hairiness must be decreased Yam smoothness must be increased Yam elongation and flexibility must be sustained

Yarn must be wound properly and on a suitable package for high speed unwinding

FillingYarns

I P h Weft Knitting -’++.

Yam friction must be decreased Fiber shedding must be decreased Yam smoothness must be increased

Yam friction must be decreased Fiber shedding must be decreased Yam smoothness must be increased Yarns must be properly aligned for introduction to knitting needles

warp Knitting

6-2 Yam Prepordon For Weavbrg And Warp Knlfflng

I

Yarn Preparation For Weaving And Knitting

Winding + Winding Q I I

Quilling lwsrping (Shuttle Loom only) I

I Slashing

Drawing-In or

Tying-In

WOVen Fabric

Knitting

Weft A Knit Warppit

winding 0 waxing

Winding 0 waxing

Fl Fabric - I El Fabric

Yam Reparatbn For Weuvhg And Warp Knmhg 8-3

I

Winding

Materials Processed Input - Yam (spinning bobbins) Output - Yarn (large cones, tubes, etc.)

Obiectives of the Process Inspect the yam

Clearing of defects

Lubricate the yam

Package the yam

6-4 Yam Preparation For Weavlng And Walp Knlfflng

Doffing

Package

Cylinder

/- +- Slub Catcher N n m rl*"W\\A . Stopped Motion Feeler

YarnGuide - Tension Dtvicc Y

[ A QLU L r w l U a J

Elements of Winding

Yam withdrawal

0 Yamtensioning

0 Yamclearing --

Stopmotion

Takeup

2,

L

Y

Figure 8-1 Open W

ind Coner

/ Tenskrr%

Knock-O

n I

I I

--

8-6 Yam P

reparatkn For We

am

And Warp K

nlfflng

D”

I

Yarn Preparation for Weaving

I. Waning k An operation where yarn is transferred from single packages of

yam to an even sheet of yam representing hundreds of ends and then wound onto a warp beam.

II, P L k The packages in the warper creel must be uniform in density,

size, and wind configuration.

B. Tension applied in warping must be uniform throughout. * C. Contact surfaces which the yam passes must be smooth and

must not impede the progress of the yam.

D. The speed of the warper must not exceed that at which the yam can be withdrawn from supply packages without undue strain.

E. Warp winding speed must be controlled and maintained at a constant rate throughout.

I& Direct Versus Indirect Warning

A. Direct Warping 1. Warp is wound directly onto section beams. 2. Used predominantly in preparing yam for warp knitting

and weaving.

B. Indirect Warping 1. Warp is wound in bands onto pattem drum and then

2. Used for fancy pattem warps or where creel capacity transferred onto a beam in a separate operation.

is limited.

Yarn Preparation For Weavlng And Warp KnltHng 8-7

Figure 8-2 Single End Creels

6-6 Yam Preparation For Weavhg And Warp Knlfflng

Figure 8-3 Traveling Package Creel

New packages placed on inside while the packages on the outside arc being unwound

Yam Reparallon For Weaving And Warp Knrmng 6-9

Figure 8-4 Indirect Warping: Drum Warper

8-10 Yarn Preparation For Weaving And Warp KnHttng

I

Slashing

13 Obiectives k Strengthen the yam

B. Make outer surface of yam smoother

C. Lubricate the yarn

D. Have no effect on subsequent processes or resulting fabric

II. Whv Warp Yarns Need To Be Strendhened k To overcome tension levels in the warp

1. Constant average tension determined by: a. rate of take-up of cloth and let-off of warp b. contraction of warp due to crimp e. stretch of warp due to tension

a. due to shedding b. due to beat-up c. higher level in dense fabric d. highest tension in cycle is where a weak yam will break

3. Random variations in tension a. due to large, badly shaped knot b. yam and fiber entanglements c. knot tails entangling

2. Cycling variations in tension

B. To overcome weaknesses in the yam created by: 1. Yam damage caused by the machine 2. Weak places in the yam supplied 3. Inadequate distribution of load over all warp ends 4. Inadequate knotting or joining --

Yam Preparation For Weavlng And Warp Knlfflng 8-1 1

I

III. Sections Of The SZasher k Beamcreel

B. Sizebox

C. Dryingunit

D. Warp separation

E. Headstock

a Size Add-on

_. V. Factors Affecting Size Add-on

k Yam characteristics

B. Number of ends and tension of warp

C. Squeeze roll control and conditions

D. Residence time of yarn in size box

E. Viscosity of mix

- VI. ImDortant Inpredients In A Size Mix k Adhesives

B. Lubricants

C. Additives

D. Water or solvent

8-12 Yam Preparation For Weaving And Warp Knmhg

VILParameters ControZZed In The Size Box

A. Level of size solution

B. Temperature

C. Concentration of size liquor

D. Squeeze roller pressure

E. Yamspeed

VIILNew Sizing Technwues

A. High pressure squeezing

B. Hot melt sizing

C. Foam sizing

Ix. SZashing Calculations

Yam Prepaaatlon For Weaving And Warp Knlfflng 8-13

Figure 8-5 Slashing - Preparatory To Weaving

Loom Beam

8-14 Yarn Preparatlon For Weavlng And Warp K M h Q

I

Requirements For A Quality Warp Beam

Objective: To Make A 'More Perfect Warm Beam" Ends wound straight and parallel to one another from beginning of beam to the end with each end holding its relative position in the warp with no "Rolled, "Crossed", 'Stuck, or "Lost Ends".

Tension uniform on all ends.

Density of the warp is uniform from beginning of beam until fizll beam.

. Selvage ends flat with the rest of the warp.

Size added is uniformly applied on all ends and improves warp weaveability.

Yam Preparatlon For Weavlng And Warp Knlfflng 8-15

Warp Preparation

Drawing-In Provides each warp yam with its drop wire, heddle, and reed dent.

Tying- In When mass producing the same fabric by simply typing each end of a new beam to its corresponding end of the old beam

8-16 Yarn Preparatkn For Weavlng And Warp Knrmng

Yam Preparallon For Weaving And Warp Wfflng 6-17