Lecture 2: The Sizing Machine – Strengthening the Warp for Weaving

We’ve successfully prepared our warp yarns on the warping machine, creating a perfectly parallel and uniformly tensioned warp beam. However, these warp yarns, especially if they are cotton or spun yarns, are still relatively weak and hairy.

They would not withstand the enormous friction and stress they undergo during the weaving process on a loom without significant breakages. This is where the Sizing Machine (also known as the Slashing Machine) becomes indispensable.

I. Introduction: Fortifying the Warp – The Sizing Imperative

The Sizing Machine applies a protective coating, known as size, to the warp yarns. This size material is typically a mixture of starches, synthetic polymers (like PVA), waxes, and other additives. The primary goal is to improve the strength, abrasion resistance, and smoothness of the warp yarns, enabling them to endure the mechanical rigors of the weaving loom.

II. Objectives of the Sizing Process

The main objectives of applying size to warp yarns are:

1. Increase Abrasion Resistance: The most critical objective. The size forms a protective film around the yarn, preventing individual fibers from being rubbed off or damaged by the constant friction with loom parts (healds, reeds, shuttles, other warp ends).
2. Increase Tensile Strength: The size material helps to bind the fibers together, thereby increasing the yarn’s overall breaking strength.
3. Reduce Hairiness: The size lays down protruding fibers onto the yarn surface, making the yarn smoother. This significantly reduces inter-yarn friction and prevents tangling on the loom.
4. Reduce Yarn Breakages: By achieving the above objectives, sizing drastically reduces the number of warp yarn breakages during weaving, leading to higher loom efficiency and productivity.
5. Minimize Lint Shedding: A smoother, stronger yarn sheds less lint onto the loom and in the weaving shed, contributing to a cleaner working environment and less machine maintenance.
6. Impart Smoothness: Creates a smoother yarn surface for better passage through loom elements.

III. Principle of Operation: Immersion, Drying, and Winding

The sizing machine is a long, complex unit that typically consists of several sections:

1. Creel/Beam Stand: Multiple warp beams (usually 8 to 24, depending on the machine and yarn count) from the warping machine are mounted here. The individual warp sheets from these beams are unwound simultaneously and combined into a single, wider warp sheet.
2. Sizing Box (Size Box/Immersion Zone):
   • The combined warp sheet passes through a trough containing the hot size liquor.
   • It is immersed in the size by guide rollers, ensuring that the yarn absorbs the size material thoroughly.
   • Squeeze rollers (nip rollers) then remove excess size, ensuring uniform pick-up (the amount of size absorbed by the yarn). The pick-up percentage is crucial for effective sizing.
3. Drying Zone: This is the longest section of the sizing machine. The wet, sized warp sheet must be dried uniformly and efficiently.
   • Cylinder Dryers (Most Common): The warp sheet passes over a series of heated drying cylinders (steam-heated). The cylinders are often coated (e.g., with Teflon) to prevent sticking. The number and arrangement of cylinders vary.
   • Hot Air Dryers (Less Common for cotton, more for synthetics): Uses hot air to dry the warp.
   • Infrared Dryers: Used in conjunction with other drying methods for quick initial drying.
   • Proper temperature control is vital to prevent over-drying (which can make yarn brittle) or under-drying (which causes sticking).
4. Cooling Zone: After drying, the warp sheet passes over cooling cylinders or through a cooling zone to bring its temperature down before winding.
5. Splitting Zone:
   • Before winding, the sized warp sheet, which might have individual yarns sticking together due to the size, passes over splitting rods or lease rods. These rods separate the individual sized yarns, preventing them from sticking to each other on the final beam. This is crucial for smooth weaving.
6. Headstock/Beam Winder:
   • The now-dry, sized, and split warp sheet is finally wound onto a single weaver’s beam (or loom beam), which is ready to be directly loaded onto the weaving loom.
   • Precise tension control and winding density are maintained during this final winding phase.

IV. Key Features of Modern Sizing Machines

• Integrated Process Control: Advanced PLC-based systems monitor and control all parameters: size liquor temperature, pick-up percentage, drying temperature, yarn tension, and speed.
• Automatic Size Preparation & Feeding: Automated systems for mixing and feeding size liquor, ensuring consistent quality.
• Multi-Motor Drives: Individual motor drives for different sections (creel, squeeze rollers, drying, beaming) allow for precise tension control and synchronization.
• Energy Efficiency: Improved insulation, heat recovery systems, and optimized drying methods to reduce energy consumption.
• Automatic Beam Doffing: Systems to automatically remove full weaver’s beams and load empty ones.
• Data Logging & Analysis: Comprehensive data collection for production analysis, fault diagnosis, and quality control.

V. Advantages of Effective Sizing

• Dramatic Reduction in Warp Breakages: This is the biggest advantage, leading to significantly higher loom efficiency and reduced repair work.
• Improved Fabric Quality: Smoother yarns lead to fewer defects in the fabric and a more even appearance.
• Increased Production: Higher loom efficiency translates directly to more fabric production per unit time.
• Cleaner Weaving Shed: Less lint and fly in the air due to reduced yarn hairiness.
• Enhanced Yarn Aesthetics: Imparts a slight sheen and feel to the yarn.

VI. Limitations and Considerations

• Environmental Impact: Discharge of desizing effluent (after fabric weaving and before dyeing) can be an environmental concern due to starch and synthetic polymer content. Sustainable sizing materials and desizing processes are a focus.
• Cost: Sizing adds a significant cost to yarn preparation (size materials, energy, machinery, labor).
• Skill Requirement: Requires skilled operators to manage the complex process and troubleshoot issues.
• Machine Length: Sizing machines are very long, requiring substantial floor space.

VII. Famous Brands of Sizing Machines

• Benninger (Switzerland): A global leader in warp preparation, renowned for its highly advanced and precise sizing machines (e.g., BEN-SIZE TEC, BEN-PROCOM). They are known for energy efficiency and sophisticated control systems.
• Karl Mayer (Germany): Another top-tier manufacturer, offering excellent sizing solutions (e.g., PROSIZE, ISOSIZE) that integrate well with their warping machines. Known for innovation in drying technology and size application.
• Tsudakoma (Japan): Well-known for their high-quality sizing machines, particularly for filament yarns, offering precise tension control and efficient drying.
• Sucker Müller Hacoba (Germany/Now part of A. Monforts Textilmaschinen GmbH & Co. KG): Historically a very strong brand for sizing machines, known for robust construction and reliable performance.
• West Point Foundry and Machine Company (USA): A prominent American manufacturer of warp preparation equipment, including sizing machines, particularly strong in the North American market.
• Lakshmi Machine Works (LMW) (India): A leading Indian textile machinery manufacturer that also produces sizing machines.

VIII. Relevance to Lahore, Pakistan

The Sizing Machine is absolutely critical for the weaving mills in Lahore:

• High-Volume Fabric Production: With a massive fabric manufacturing base, ensuring minimal loom stoppages through effective sizing is paramount for profitability.
• Quality Demands: Pakistani mills supply fabric to international markets with stringent quality standards, which necessitate well-sized warps to prevent defects.
• Energy Efficiency Focus: Given energy costs, mills are increasingly investing in energy-efficient sizing machines with advanced drying and heat recovery systems.
• Environmental Responsibility: As global awareness grows, mills in Lahore are also looking into more sustainable sizing agents and efficient wastewater treatment for desizing effluents.
• Integration with Looms: Optimal sizing directly impacts the performance of the high-speed weaving machines (Picanol, Itema, Dornier, Toyota) commonly found in Lahore’s mills.

Sure, let’s explore some prominent brands and names of sizing machines. You’re looking for the major players in the textile sizing machine market, who are crucial for preparing warp yarns for the rigors of weaving!

Here’s a breakdown of prominent brands and some of their notable characteristics or model series, where available:

1. Karl Mayer (Germany)

• Reputation: A global leader in warp preparation, known for high precision, automation, and innovative sizing technology.
• Key Models/Series:
  • PROSIZE: A highly advanced sizing machine known for its efficiency, precise size application, and gentle yarn treatment. It integrates well with their PRODYE systems for indigo dyeing.
  • ISOSIZE: Another key model, often highlighted for its user-friendly operation and optimal process control. Features like combination size boxes and efficient cylinder dryers are characteristic.
  • FILSIZE: Specific models designed for sizing filament yarns, which require different treatment than staple fibers.

2. Benninger (Switzerland)

• Reputation: A top-tier manufacturer of warp preparation and wet processing machinery, known for robust construction, reliability, and sophisticated control systems.
• Key Models/Series:
  • BEN-SIZE TEC: A prominent model recognized for its excellent sizing results, energy efficiency, and precise control over sizing parameters.
  • BEN-PROCOM: Another advanced sizing machine that emphasizes productivity and quality.
  • Benninger also integrates indigo dyeing with sizing, offering solutions like the BEN-INDIGO for denim production.

3. Tsudakoma (Japan)

• Reputation: Well-regarded for their high-quality textile machinery, including sizing machines, often emphasizing precision, efficient drying, and tension control, particularly for various yarn types, including synthetics.
• While specific model names are less commonly advertised as standalone sizing units, they offer comprehensive preparatory machinery that includes advanced sizing capabilities. Their focus is often on integration within their overall textile machinery offerings.

4. Sucker Müller Hacoba (Germany)

• Reputation: Historically a very strong and reputable brand in sizing machines. While the company’s structure has evolved (parts may now be under other groups like A. Monforts Textilmaschinen), their machines are still widely recognized for their durability and reliable performance.
• Key Models/Characteristics:
  • You’ll often find references to “Sucker Müller Hacoba Sizing Machine” without specific model numbers, indicating their core product. Machines often feature precise size box control, multi-cylinder drying units, and electronic beaming. Older models like Sucker Müller ZT 9 might also be found in used machinery markets.

5. West Point Foundry and Machine Company (USA)

• Reputation: A significant American manufacturer of warp preparation equipment, including robust sizing machines. They are particularly strong in the North American market and are known for durable and high-performing equipment.
• Key Models/Characteristics: Their “Pacesetter” series of sizing machines is well-known, often specified by features like the number of cylinders, size box configuration (e.g., double dip, double nip), and working width. You might see references like “Prashant West Point Sizing Machine” indicating collaborations or licensed manufacturing in regions like India.

6. Lakshmi Machine Works (LMW) (India)

• Reputation: A leading textile machinery manufacturer from India, known for providing comprehensive solutions for spinning and some weaving preparatory processes. They produce sizing machines that cater to the needs of mills in India and other Asian markets.
• While specific model names for their sizing machines are less globally publicized compared to European giants, they offer solutions that integrate with their overall textile machinery portfolio.

These brands are chosen by textile manufacturers worldwide for their reliability, advanced features, and ability to contribute to the efficient and high-quality production of woven fabrics.

In conclusion, the Sizing Machine is a silent workhorse that transforms vulnerable warp yarns into robust, smooth strands capable of withstanding the immense stresses of weaving. Its precise application of size is a cornerstone of efficient and high-quality fabric production.

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This concludes our lecture on Sizing. Our next topic will be the heart of the weaving process: the Weaving Loom itself, exploring its different types and mechanisms.