صفحه اصلی در باره ما راهنما تعرفه/پرداخت ثبت‌نام نمایندگی ها نمایشگاه های نساجی کتاب و کاتالوگ اخبار تماس باما

محصولات نساجی خدمات نساجی ماشین آلات نساجی-قطعات استخدام نساجی

بازگشته به لیست اطلاع رسانی
جزئیات خبر

تاريخ ثبت : ۷ دي ۱۴۰۴ ساعت ۱۴ و ۲۶ دقيقه

تعداد بازدید : ۶۰ بار

Common Dyeing Defects and Practical Solutions

Dyeing is one of the most critical and technically sensitive processes in the textile industry. Achieving an exact shade match between the pre-production sample and the buyer-approved standard is a complex task that requires precise control of process parameters. Any deviation in conditions may result in shade variation, sometimes making re-dyeing of the entire batch unavoidable. In addition to shade mismatch, various dyeing defects may occur during processing. The most common dyeing faults, along with their causes and remedies, are discussed below.

Uneven Dyeing
Uneven dyeing mainly occurs due to improper pretreatment, rapid addition of dyes and chemicals, or insufficient control over dyeing parameters. This defect can be minimized by ensuring gradual and uniform addition of dyes and auxiliaries, carrying out proper pretreatment, monitoring rope turnover time, and performing thorough washing after dyeing.

Running Shade
Running shade is generally caused by excessive machine loading, low nozzle pressure, or high bath draining temperature. To prevent this issue, the dyeing cycle time should be properly maintained, nozzle pressure accurately adjusted, and the bath drained at a moderate temperature.

Crease Mark
Crease marks may develop due to overloading of fabric, sudden temperature changes during cooling, or lack of synchronization between winch speed and pump pressure. Maintaining a controlled temperature gradient throughout the dyeing cycle, loading fabric according to loop length, and ensuring proper coordination between winch speed and pump pressure can effectively reduce this problem.

Pin Hole
Pin holes are often caused by the presence of iron or copper ions in the process bath, soda dosing at high temperatures in the presence of oxygen, or insufficient stabilizer during hydrogen peroxide bleaching. Using hardness-free water and carrying out soda dosing at temperatures not exceeding 60°C can help prevent pin hole formation.

Dye Spot
Dye spots usually result from improper dissolution and mixing of dyestuffs or from hardness in the dye bath water. Proper mixing and complete dissolution of dyes before dosing, along with the use of softened water, are essential to avoid this defect.

Soda Spot
Soda spots may occur if soaping is started before proper washing, if calcium or magnesium carbonates are present in the soaping bath, or due to rapid soda dosing. Ensuring complete dissolution of soda particles and proper neutralization after pretreatment and dyeing can minimize soda spot formation.

Fly Dye Stains
Fly dye stains are caused by airborne dust particles coming into contact with dissolved dyestuffs, especially when dyes are mixed on a dirty dyeing floor. This problem can be avoided by dissolving dyes in a separate drum and maintaining a clean and well-organized dyeing area.

Trim Shade Does Not Match Body Fabric
Shade mismatch between trims and body fabric may occur due to the use of different yarn types, different dye lots, or improper recipe selection. Using the same yarn type, dye lot, recipe, nozzle pressure, and ensuring uniform dye distribution for both fabric and trims can help achieve consistent shade matching.

Softener Marks
Softener marks are mainly caused by improper pH control, poor emulsification of the softener, or the use of inferior-quality softeners. Uniform dissolution of the softener, correct application procedures, and maintaining the recommended pH level are essential for preventing this defect.

Barré
Barré appears due to high yarn tension, yarn count variation, or mixing yarns from different lots. Maintaining uniform yarn tension across all feeders and using yarn from the same lot during knitting can effectively reduce barré defects.

Metamerism
Metamerism occurs when different dye classes or dye lots are used for various components of the same garment, such as the body fabric and collar or cuff. Selecting dyes from the same class that provide consistent appearance under different light sources is essential to overcome this issue.

Hand Feel Problems
Hand feel issues arise from the use of harsh metallic chemicals or insufficient softener application during processing. Demineralization of the fabric and proper application of suitable softeners can significantly improve fabric handle.