After twisting, raw white polyester sewing thread, embroidery thread and bonded nylon 66 sewing threads will be experienced precision winding to dye tube, prepare for tube dyeing. Compared to hank dyeing, tube dyeing (cone dyeing or package dyeing) offers advantages such as shorter processes, lower energy consumption, reduced waste, higher product quality, and fewer yarn breakages. With its promising prospects, tube dyeing has become the preferred choice for dyeing process.
However, many factors affect the quality of tube dyeing, and even minor oversights can lead to defects such as color differences, uneven dyeing, or poor dye penetration. Precision winding is one of the critical processes influencing tube dyeing outcomes. Regardless of the winding form, yarns to be dyed must undergo precision winding according to the specifications set by dye house, this is the first production step in tube dyeing. The purpose of precision winding is to convert tightly wound yarns into dyeing tube packages with density, weight, and shape that meet dyeing requirements. The quality of dyeing tube packages plays a decisive role in the final dyeing quality.
1. Impact of Precision Winding Quality on Dyeing
1.1 Winding Density
Thread winding density on dye tube is a key factor affecting dyeing quality. During dyeing, the resistance encountered by the dye liquor circulation is directly related to the density and uniformity of the Dyeing tube winding. Excessive density prevents the dye liquor from penetrating the yarn layers evenly, causing uneven coloration ("color spotting"). Conversely, overly low density can lead to "short-circuiting" of the dye liquor, resulting in uneven dyeing, fiber fuzzing, or yarn breakage.
Typical density requirements are:
* Non-mercerized cotton yarn: 0.40–0.42 g/cm³
* Mercerized cotton yarn: 0.38–0.40 g/cm³
* Polyester/cotton blends: 0.30–0.40 g/cm³
* Heat-set synthetic fibers: 0.32–0.34 g/cm³
* Viscose fibers: 0.32–0.34 g/cm³
Higher yarn counts require lower winding densities.
Additionally, density must be uniform both within each tube and across tubes in the same batch, significant density variations between tubes can lead to color differences between tubes.
1.2 Dyeing Tube Package Weight
As yarn winding weight increases, the yarn layer thickens. Thicker layers amplify differences in winding diameter between inner and outer layers, prolonging dye penetration time and exacerbating color gradient differences between layers. Excessive thickness can also cause overly tight contact between yarns inside the dye vat, leading to undyed patches. Thus, dyeing tube package weight must be controlled within a specific range. Uniform weight across tubes is crucial - uneven weights create variations in yarn layer thickness, causing uneven dye liquor flow and color differences across tubes.
1.3 Yarn Layer Length
The yarn layer must fully cover the perforations on the dyeing tube to prevent dye liquor from bypassing the yarn and spraying directly through the holes. Improper winding positions or insufficient traverse distances can cause "exposed holes," leading to dye liquor short-circuiting, fuzzing of tube ends, and uneven dyeing. However, excessively long yarn layers may result in incomplete dye penetration.
1.4 Winding Shape
A well-formed dyeing tube package meets shape requirements without defects such as collapsed edges, belt-like layers, or cobweb patterns. In practice, mechanical issues or operator errors often produce irregularly shaped tubes with uneven internal densities, leading to uneven dyeing.
1.5 Dyeing Tube Package Geometry
Cylindrical cheeses are widely used due to their reliable dyeing results and high productivity. However, for fast-dyeing or smooth-surfaced yarns (e.g., mercerized or synthetic fibers), cylindrical shapes may cause slippage during dyeing. Spool-shaped cheeses are preferable for such yarns, as they reduce undyed areas and edge loosening.
2. Factors Affecting Precision Winding Quality
Dye tube package winding requires precise coordination of tension, arm pressure, speed, overfeed, winding angle, and ambient conditions (temperature/humidity) to control dyeing package weight, density, and shape.
2.1 Winding Tension
In practical production, winding tension is a critical factor affecting the density and formation of dyeing packages and should be maintained within an appropriate range. The control of dyeing package density is primarily achieved by adjusting the winding tension. Winding tension control involves three aspects: First, the magnitude of the winding tension must be suitable - excessive tension leads to higher package density, while insufficient tension results in lower density. Second, the winding tension must be consistent across all spindles; inconsistencies will cause variations in density between dyeing packages. Third, the winding tension must remain uniform throughout the winding process for each spindle. Fluctuations in tension during winding can lead to uneven internal density and poor formation of the dyeing package.
2.2 Arm Pressure
Arm pressure settings depend on yarn count and process conditions. Incorrect pressure leads to uncontrolled density, affecting efficiency and quality. Two adjustment methods are:
Trial winding: Pre-production tests on selected spindles to determine parameters (arm pressure, tension, speed). Suitable for new or coarse yarns.
Historical data: Using records from previous productions to save time. Ideal for frequently processed yarns.
2.3 Winding Speed
The winding linear speed itself has no significant direct impact on the density or formation of dye packages; it primarily influences winding quality by affecting the winding tension. Theoretically, the winding linear speed can be arbitrarily selected, and higher speeds generally increase production efficiency. However, the linear speed of yarn winding varies with the changing radius of the dye package. Fluctuations in linear speed directly cause variations in winding tension, thereby affecting the formation quality of the yarn. Higher winding linear speeds make it more challenging to control the external shape of the dye package. If tension fluctuates excessively during winding, differences in yarn elongation caused by uneven tension can lead to inconsistent yarn density. To avoid compromising the mechanical and physical properties of the yarn or the density and formation of the package, production processes require minimizing both winding tension and its variability during winding. It is recommended to maintain the winding linear speed within a range of 800 m/min to 1000 m/min for optimal results.
2.4 Overfeed
Overfeed releases residual tension. Insufficient overfeed increases density and causes edge swelling, while excessive overfeed raises breakage risks. Optimal overfeed: ~25%, adjusted via controlled motor settings.
2.5 Winding Angle
The winding angle refers to the acute angle formed between the tangent direction of the yarn at a specific point on the package surface and the circumferential velocity direction of that point. A larger winding angle results in a lower yarn winding density. Typically, the winding angle ranges between 30° and 55°. For dye packages used in high-pressure dyeing, a winding angle of approximately 55° is recommended. This configuration creates larger inter-yarn pores, reduces winding density, and minimizes resistance to dye liquor flow. Consequently, increased dye liquor velocity enhances yarn dyeing efficiency.
2.6 Temperature and Humidity
Precision winding has stringent requirements for temperature and humidity, particularly humidity. When humidity is high, friction during the yarn winding process increases, leading to higher winding tension and greater density of the yarn tubes. If the humidity in the production environment fluctuates significantly, it can result in uneven internal density of the yarn tubes and issues such as poor formation. In practical production, humidity is generally controlled at around 70%.
3. Conclusion
Precision winding significantly impacts tube dyeing quality. Defects caused by poor winding (e.g., uneven density or shape) are difficult to rectify through post-dyeing corrections. High-quality precision winding ensures half the success of premium dyeing outcomes. Controlling winding parameters not only reduces costs but also enhances efficiency, achieving optimal results with minimal effort.
#Soft cone precision winding #Dye package #Tube dyeing cone dyeing #Raw white on dye tube
#Polyester sewing thread #Bonded nylon 6.6 sewing thread #Trilobal polyester embroidery thread