Textile sizing is called the heart of weaving. During weaving the warp sheet have to go through subsequent stress and friction.
Appropriate textile sizing and yarn strength play the vital role to withstand on that stress and friction. This article discusses the way of doing effective sizing by making sure proper control and combination between Man, Machine & Material- the 3M’s method.
Currently, some latest air jet loom developed that can run in 1000 -1100 RPM. To run a fabric in this high speed loom it is mandatory to have quality sizing and good yarn strength as well. Correct sizing can avoid ball formation during weaving, reduce warp breakage in the loom and consequently lead loom efficiency and make sure elite quality fabric. Sizing put an impact on yarn properties by increasing strength, abrasion resistance, stiffness, frictional resistance, yarn weight, and diameter. On the other hand, it decreases yarn hairiness, irregularity, flexibility, elongation and static electricity formation.
Once in warp yarn improper sizing is done, there is nothing to do with the warp set but put into junk as there is no reprocess or corrective chance further on. So on or before sizing all precaution and corrective measure should be taken.
3M’s functionalities mean the function of man, machine, and materials on sizing.
The function of sizer or sizing technician:
- The main responsibility of a sizing technician is to select proper sizing recipe, machine, machine route and operate the machine properly.
- Cocking size recipe with maintaining correct cocking procedure ( mixing first synthetic adhesive in cold water then modified starch in cold water then raise temperature 900 C cock 30 minutes and agitate liquor properly then mix acrylic binder and softener and cocking whole ingredient 5-10 minutes in temp 900C )
- Keep size box temperature 850C and maintain regular liquor viscosity, reflection. Also, adjust squeezing pressure, machine speed, warp immerse time in order to maintain a regular and standard pick up of 10-12%.
- Keep no of warper beam as low as possible, adjust beam alignment parallel, also zonal tension setting i.e. creel tension, and roller, dryer cylinder speed, leasing rod orientation, table tension or winding tension, headstock beam pressure roller pressure in order to synchronize warp tension regular and thus keep yarn elongation and loss of yarn elasticity minimum. Standard elasticity loss is 1.5%
- Yarn must contain 7-8% moisture during sizing. No of dryer cylinder, cylinder temperature setting base on yarn fineness and Take care of proper yarn drying as over dry make the size film brittle and under dry create sticky sizing. For course and dense yarn cylinder temperature required 1300 C to 1400C and machine speed would be lower. For fine and low dense yarn, cylinder temperature required 1200 C to 1300 C and machine speed would be higher.
- Sizing technician should be attentive all the time during size beam preparation. S/He must cut off and clear lapper as swiftest as possible. Also, adjust headstock V reed to ensure parallel and even winding on beam. Take care on flange side overlapping or entanglement problem.
The function of the machine:
- Sizing machine and machine specification play a vital role for quality sizing
- A machine with double and larger size box length with double-dip double nip immersion roller can make good sizing quality for high dense higher total ends fabric. In double dip double nip process immersion time is higher and so more penetration occurs, also the more spread the warp sheet is the more chance of having a coating with size film. Covering % by a warp sheet in a particular size box should be below 65%.
- PLC control machinery with automatic zonal tension synchronizes system can keep a regular tension through the full
- The machine should have moisture control unit (like Pleva) which can control uniform and standard moisture (7-8%) in yarn. The machine should have sufficient drying cylinder 12 to 16 pieces, the more no of drying cylinder the more possible to run the machine with high speed and high-speed increase pick up% and lead higher productivity.
- Squeezing roller has to be uniform and if required need to grind or rubberizing properly, also the hardness of squeezing roller need to be below 600 shour. It’s required to control uniform pick up%.
The function of raw materials or sizing chemical:
- Selection of sizing recipe mainly depends on yarn count, blend, type (kW/CW/ac), total no of ends etc.
- Primary sizing ingredient is the starch which acts as adhesive. Its function is to increase strength by penetrating a portion in the yarn and coating the yarn to make yarn surface sooth and reduce hairiness. Previously native starch use but currently modified starch of maize, potato used combined with synthetic adhesive polyvinyl alcohol, acrylic co polymer.
- Softener/ lubricant is the next primary ingredient which mainly is used to reduce the stiffness of yarn and make yarn flexible. Oil, wax etc. are used as softener/ lubricant
- Secondary ingredient for sizing is the antiseptics, wetting agent, an antifoaming agent, brightening agent etc. All these are applied based on requirement. Nowadays combined ingredient name as ‘one short chemical’ found in the market which mainly is a combination of these entire ingredients.
- Corse yarn/AC yarn( 10-20 Ne count) require less viscosity (16-17) and less pick up 8-10% normal sizing and fine (30-50 Ne) yarn require medium sizing i.e. pick up 11-12% whereas CVC /PC / high ends pick fine count fabric to require heavy sizing i.e. pick up 15-16%. For dyed yarn require less sizing i.e. pick up 8-9%. All these are a general guideline, although all these things i.e.- viscosity, reflection, add-on and overall all sizing depends on sizing ingredient properties and quality.