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DIFFERENT SPLICING SYSTEMS USED IN WINDING

DIFFERENT SPLICING SYSTEMS USED IN WINDING


     1.    Introduction
A high degree of yarn quality is impossible through knot, as the knot itself is objectionable due to its physical dimension, appearance and problems during downstream processes. The knots are responsible for 30 to 60% of stoppages in weaving.

Splicing is the ultimate method to eliminate yarn faults and problems of knots and piecing. It is universally acceptable and functionally reliable. This is in spite of the fact that the tensile strength of the yarn with knot is superior to that of yarn with splice. Splicing is techniques of joining two yarn ends by inter mingling the constituent fibres so that the joint is not significantly different in appearance and mechanical properties with respect to the parent yarn. The effectiveness of splicing is primarily dependent on the tensile strength and physical appearance.

Splicing satisfies the demand for knot free yarn joining: no thickening of the thread or only slight increase in its normal diameter, no great mass variation, and visibly unobjectionable, no mechanical obstruction, high breaking strength close to that of the basic yarn under both static and dynamic loading, almost equal elasticity in the joint and basic yarn. No extraneous material is used and hence the dye affinity is unchanged at the joint. In addition, splicing enables a higher degree of yarn clearing to be obtained on the electronic yarn clearer.

 Splicing technology has grown so rapidly in the recent past that automatic knotters on modern high speed winding machine are a thing of the past. Many techniques for splicing have been developed such as Electrostatic splicing, Mechanical splicing and Pneumatic splicing. Among them, pneumatic splicing is the most popular. Other methods have inherent drawbacks like limited fields of application, high cost of manufacturing, maintenance and operations, improper structure and properties of yarn produced.

2. Different types of splicing Systems
The basic pneumatic principle of the system allows it to be optimally adapted to the requirements of any desired application with only slight modifications. With only few movements of the hand and few additional components, the Standard Splicer can be converted into Thermo splicer, Injection-Splicer or Elasto splicer. All these variants are based on the principle of air splicing and their functionality is adapted to suit the specific requirements of the material to be spliced. Therefore, the operation is simple and, as regards the main splicing parameters, uniform. 

3. Principle of Pneumatic Splicing
The splicing consists of untwisting and later re-twisting two yarn ends using air blast, i.e., first the yarn is opened, the fibres intermingled and later twisted in the same direction as that of the parent yarn. Splicing proceeds in two stages with two different air blasts of different intensity. The first air blast untwists and causes opening of the free ends. The untwisted fibres are then intermingled and twisted in the same direction as that of parent yarn by another air blast.

3.1. Twisting
The two yarn ends comprising the splice are twisted around the body of the yarn, each yarn strand twists on the body of the yarn on either side of the middle of the splice. The cross-section of this region distinctly shows the fibres of the two yarn strands separately without any intermingling of the fibres.

3.2. Tucking / Intermingling
The middle portion of the splice is a region (2-5 mm) with no distinct order. The fibres from each yarn end intermingle in this splice zone just by tucking. The studies on quantitative contribution of splice elements showed that intermingling/tucking contributes the most to the strength of splice (52%), followed by twisting (33%) and wrapping (about 15%). The lower strength of the splice is attributed to the lower packing coefficient of the splice zone. Spliced yarn has a lower breaking elongation than normal yarn. Breaking elongation is mainly affected by intermingling. Wrapping and twisting provides mainly transverse forces. The absence of fibre migration gives lower breaking elongation to splice.

4. Universal Splicing Procedure
The Autoconer splicing process consists of the partial processes: Positioning of the yarns (1), Sucking up of the yarn ends (2), Loosening and opening of the yarn ends (3), Pulling the yarn back into the prism (4), Intermingling and twist insertion (5). 

5. Mechanical splice achieving procedure
Step – 1:
Suction arm (1) and suction pipe (2) transport the yarn ends to be spliced. The suction pipe shutter (3) guides both, lower and upper yarn end. The suction pipe shutter (3) pushes the upper end brought down by the suction arm (1) into the channel of the splicer prism (4). 


Step – 2:
Yarn clamps (5 and 6) close, separately clamping upper and lower end. Opening valve (=A3+C1-Y81) releases compressed air for yarn end opening. Both, shears (7 and 8) close. Feeder (9) and lid (10) begin their motion, shifting to the right.


Step – 3:
Shears (7) cut the lower end; shears (8) cut the upper end. The cut-off surplus ends are evacuated through suction arm and suction pipe. Retainer tubes (11 and 12) inhale upper and lower end and open both yarn ends in preparation for splicing. The feeder pulls the opened yarn ends out of their retainer tubes (11 and 12).

Step – 4:
The feeder has pulled the yarn ends completely out of the retainer tubes (11 and 12), placing them next to each other with defined overlapping into the splicing prism. The opening valve (=A3+C1-Y81) closes, shutting off the opening air. The splicing valve releases compressed air to the prism. The air jet whirls the two yarn ends together, forming a spliced yarn joint. 


Step – 5:
Lid, clamps, shears, and feeder release the readily spliced yarn and return to neutral position.


Step – 6:
The winding unit starts. Feeder (9) and lid (10) have returned to neutral position. The suction pipe shutter (3) also releases the readily spliced yarn.


Step – 7:
All control parts have returned to neutral position. The clearer tests the spliced joint.


 6. Pneumatic Splicing
The first generation of splicing systems operated with just one stage without proceeding to trimming. The yarn ends were fed into the splicing chamber and pieced together in one operation. Short fibres, highly twisted and fine yarns could not be joined satisfactorily with such method. Latest methods of splicing process consist of two operations. During the first stage, the ends are untwisted, to achieve a near parallel arrangement of fibres. In a second operation the prepared ends are laid and twisted together.
The Standard splicer is the basic type of the modular-design splicer, which has been proving its worth in textile mills for decades. It can be used for all standard applications, producing reproducible spliced joints of high quality. The spliced joints are convincing by their high strength values, very good visual appearance and excellent processing properties. Loosening and opening of the yarn ends and splicing the yarn ends together is achieved by a targeted air jet and entangling the fibres in an air whirl.
Applications:
·         Cotton
·         Cotton Blends
·         PET
·         CV
·         Cotton compact yarns

7. The Injection splicer with dosing valve
            The use of the Injection splicer is recommended for splicing single and plied yarns of vegetable fibres, for example, coarse single and plied cotton yarns, OE-rotor yarns, CO compact yarns or yarns with a strongly marked inhomogeneous structure or very high twist. The standard pneumatic splicing process is optimized in the addition of a small quantity of water through an electro-magnetic dosing valve, which intensifies the effect of the whirling of the fiber ends.

7.1. Requirements for soapy water:
            The water must be de-mineralized


The result is spliced joints with higher strength and smoother appearance. Required quantity of the water be metered and adapted to the characteristics of the yarn spliced. The dosing rates are entered centrally at the Informator. The optimized Injection splicer is made from material that meets the requirements of this special application. The system is completed with an additional blower nozzle for keeping the surroundings of the Injection splicer clean.

Applications:
·         Coarse CO yarns
·         Plied yarns
·         OE-rotor yarns
·         Linen yarns
·         Compact yarns

8. The Elasto splicer
The Elasto splicer is particularly useful for the splicing of elastic Core yarns. Its specific features, including special braking elements, modified clamping and cutting lines and optimized control software, ensure safe and smooth processing of these springy yarns. The Elasto splicer can also be combined with the injection splicing facility. Strength and visual appearance of the spliced joints made with the Elasto splicer are of the excellent quality. Equally important is, that these spliced joints exhibit a high resistance to the alternating stresses to which they are subjected in weaving and that they maintain their characteristic elasticity for knitting.

Applications:
·         CO/EL
·         CV/EL
·         Other blends with elastane.

9. The Thermo splicer
            The Thermo splicer is used for the splicing of wool yarns and blends of these. The pneumatic splicing process is optimized by tuning the splicing air temperature to the specific properties of the yarn spliced. The localized application of heated splicing air allows making optimal use of the thermoplastic properties of the fibres. The result is stable thermo-setting of yarn structure in the zone of the spliced joint and, hence, significantly higher strength of the splice.

9.1. Table of air temperature approximations


The temperatures listed above are those of the air exiting from the prism. “0” should be entered if air heating is not desired. The splice quality is best if in most of the tensile strength
tests the yarn breaks somewhere away from the splice. The air temperature should be selected so that no discoloration or hardening of the yarn in the splice area takes place. If required, perform a dye test on a small amount of yarn containing several splices. During the heating-up period (4 - 10 min.), and when re setting the air temperature by at least 10 % the winding unit is inoperative.
Important Note concerning the use of Thermo splicer:
When splicing with heated air we draw your attention to the possibility that the dye liquor absorption properties of the splices in yarns composed of synthetic fibers, whole or blends, could be different from the properties of the yarn between splices.  These limitations do not apply to woolen yarns, or to other animal fibers.
Applications:
·         WO
·         WO blends
·         Siro yarns
·         WO compact yarns
·         WO/EL

10. References
·         Oerlikon schlafhorst autoconer5 winding broucher.
·         Autoconer 338 Innovation, Know-how, Flexibility broucher.pdf
·         Splicing booklet 2004 by Oerlikon schlafhorst .







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