Analysis of two kinds of defects in seamless underwear nylon dyeing and preventive measures

Update:19 Jul 2019
Summary:

1. Cylinder and cylinder color difference cylinder diff […]

1. Cylinder and cylinder color difference cylinder difference is the main indicator of the quality of dyeing products. The main reasons for cylinder difference are:
(1) Inconsistency in dyeing process control.
(2) Instability of dyeing chemicals.
(3) The instability of the product batch difference.
(4) The professionalism and accountability of dyeing technicians and operators.
Precaution
(1) Improve dyeing equipment. For example, switch to external heating or bottom plus circulation pump to ensure uniform heating around.
(2) Speed up the operation of the blades to accelerate the heat transfer up and down.
(3) When the product is put into the cylinder, the uniformity of the left and right intermediate quantities should be ensured.
(4) The feeding can be changed to the automatic feeding system.
(5) Strictly control the dyeing process to ensure the consistency of the process between cylinders.
(6) It is preferred to dye and auxiliaries, and do a good job in testing batches of dyes and auxiliaries to ensure the accuracy of dyeing prescriptions.
(7) Strengthen the management of the product blank, ensure the accuracy of the weight of the cylinder, do not confuse the batch of the product, and do not mix the product number.
(8) Strengthen the quality education of employees and improve their literacy and professionalism.
2. Causes of color spots and stains
(1) The yarn is impure, and impurities or color yarns are mixed in, which cannot be eliminated after dyeing.
(2) Color flying hair is mixed in the weaving production process.
(3) The white billet stacking time is too long to produce mildew and yellow spots.
(4) During the dyeing process, the dye fly to the color forming point on the product.
(5) In some parts of the product, some kind of auxiliary liquid is encountered during pretreatment or dyeing, which affects the dyeing of the dye, thereby producing white spots or light spots.
(6) When color matching with some dyes with particularly low solubility, the dye is not added to the dyeing tank, and the dye that is not completely dissolved is stained on the product to produce a color point.
Precaution
(1) Strengthen the quality inspection and control when entering raw materials to prevent the entry of impure yarns.
(2) Strengthen the on-site management of weaving, do a good job of isolation of yarn-dyed products, and clean the machine and the site.
(3) The blanking time should not be too long and placed in a dry and ventilated place.
(4) Do a good job of isolating dyes and products. Powdered dyes must not enter the workshop. Strictly in accordance with the chemical materials, feeding operation procedures, the use of additives should be protected, the additives should be diluted and added to the dyeing tank.
(5) Strengthen workshop management and do a good job in cleaning and sanitation.