Energy saving and emission reduction, reducing consumption and protecting the environment are the sustainable development strategies of the textile industry. The printing and dyeing link is the top priority for the entire textile industry to achieve energy saving and emission reduction. 80% of the water consumption in the textile industry is in the printing and dyeing link, and 60% Wastewater discharge originates from the printing and dyeing industry. “Dyeing is successful the first time” is the most direct and effective energy-saving and emission-reduction measure. It is the core of the dyeing factory’s profits. It is also a systematic project to improve product quality and product grade.
Improving the first-time success rate of dyeing is the common expectation of dyeing factories and is a research and exploration topic across the country and even the world. Hotspot is an exploratory research topic with no end point. The analysis of knitted fabric dyeing benefits is shown in Table 1. The value of dyeing and finishing engineers is reflected in process design, and the results are reflected in high quality and low consumption. Implementing quality standards, “standardizing production management, standardizing process technology” from thinking power to decision-making power and then strong on-site execution ability, the three work together to ensure the realization of “dying success the first time”. “Dyeing is a success the first time” refers to the one-time success of the finished product that meets the established quality standards after the dyeing and finishing process of qualified gray fabrics.
1 Rough statistics are based on one dyeing and are for reference only. Each enterprise can calculate its own results based on the practices of each factory. More accurate data consistent with this unit;
2 Every time the success rate of dyeing is increased by 1%, the production cost can be reduced by 1%;
3 For every 1% increase in the first-time dyeing success rate, the revenue per kilogram of dyed fabric produced can increase by approximately 10%.
Production management and testing standards
Production management and process technology are The basic work to improve the first-time success rate of dyeing must be carried out in an orderly manner with the goal of high quality and low consumption, in a more rapid, efficient and space-saving manner.
Quality control points:
Appearance quality: the cloth surface is plump and smooth, with uniform color; body cloth and accessories (ribs, collars, The cuffs should be in the same color and pleasing to the eye; the weft and warp skew should be correct.
Intrinsic quality: color fastness (sun resistance, water resistance, sweat resistance, friction resistance, saliva resistance), gram weight deviation, width deviation, shrinkage, etc.
Environmental quality: formaldehyde content, pH value, odor, banned substances, pesticides, heavy metals and other organic hazards.
Since the dyeing factory cannot be directly responsible for the textile raw materials and dyeing materials, the supplier needs to ensure the quality of the supplied raw materials and must produce a certificate or qualified test report. If there are any errors, the supplier shall be responsible. , Dyeing and finishing companies must keep this in mind and always pay attention to the ever-escalating customer requirements and standards.
Comprehensive consideration of the whole process of dyeing and finishing
Production process and technology The process design must be scientific, thorough, well-executed and constantly maintained and protected, so that decision-makers can spend more time and energy studying tomorrow instead of getting stuck in today and yesterday.
Among them, the business department must record the customer’s quality requirements in detail when receiving orders. Generally include:
The full name and specifications of the gray fabric; the structure, fiber composition and proportion of the gray fabric; dyed fiber; final sales region and grade; environmental protection requirements; dyeing color fastness requirements; plain color , color matching (especially white sportswear); opposite color side (front, back); color matching light source; shaping method, such as door width (full width, needle in, pulp trimming), gram mass (square meter gram mass, Mick quality, yard quality), shrinkage (number of washes, vertical and horizontal directions); and brushing, polarizing, sanding, polishing, etc. These requirements must be clarified, otherwise proofing will not be possible, let alone blind production.
Control and requirements of the dyeing and finishing process
Achieve first-time success in dyeing The key to dyeing and finishing is the control of the dyeing and finishing process, and the key to dyeing and finishing is the process. It is necessary to grasp the overall goal and develop a reasonable and effective process.
1 Attention points and requirements in the dyeing and finishing process
First of all, here are 5 equally important reminders: The selection of dyes and auxiliaries is equally important, pre-dyeing treatment is equally important as dyeing, dyeing and post-dyeing treatment are equally important, dyeing and finishing are equally important, and dyeing and finishing process design and execution process are equally important.
Secondly, to improve the first-time success rate of dyeing, two centers must be grasped: one center is in the laboratory (prototype proofing, resampling before dyeing); the other center is in the dyeing workshop . On the premise that the dyeing and finishing process design and prescription are accurate according to the quality target, the five aspects of measurement, liquor ratio, temperature, time, and pH value must be accurate during production. Especially for laboratory colorimetric technicians, they must keep in mind that the scale from small samples to large-scale production samples is tens of thousands to hundreds of thousands times, and they must pay attention to the measurement. The higher the measurement precision, the better.
2 Control of dyeing and finishing processes
2.1 Dyes and Standardization and control of auxiliaries: Strictly regulate the application of dyes and auxiliaries according to requirements, and check whether they are implemented according to regulations when sampling in the laboratory. The general specifications are as follows:
a. Full name, strength and supplier of dye;
b. Full name of additive, active ingredient (content), supplier;
c. Dye combinations (pay attention to compatibility) are divided into light three primary color combinations, medium three primary color combinations and deep and extra dark three primary color combinations, as well as dye combinations such as bright red, bright red, black, sapphire blue, navy blue, lake blue, turquoise blue, etc., and then choose another set of dyeing prisonVery high-quality dyes are used to dye combination color combinations, especially white combinations.
2.2 Control of standard samples: First of all, it must be clear that there is only one standard sample, which is the customer confirmation sample; secondly, It is necessary to carry out re-sampling before dyeing (also called on-site re-sampling). Take large-scale production cloth and the batch number of dyeing materials currently used in the workshop for re-sampling. You must never fail to make duplicate samples and do them carefully, otherwise you will not be able to put them into production.
Comprehensive control of production quality
1 Quality of each production process Control and design the production process according to the dyeing and finishing process
Establish clear responsibility goals and quality standards for each process – quality is broken down into each process. The production process is as follows:
Assemble a vat → Arrange, turn and seam → Pre-process → Dye → Soap, restore and clean → Dehydrate → Arrange and wet expand → Dry → Inspect the fabric → Sectioning → Softening →Shaping→Packaging.
Product quality is determined by manufacturing, not by testing. Inspection is only a means of quality control. In order to ensure that the final product meets the quality standards set by the company, quality requirements for each dyeing and finishing process are formulated as the management basis for quality control of each process at the knitted fabric dyeing and finishing production site. Implement a layer-by-level control system for each process. Each process should regard the next process as its own “customer”, and itself is the “customer” of the previous process. It can refuse unqualified products from flowing to its own process. Each process They have all checked carefully and met the quality requirements one by one. The quality of the final product naturally meets the quality requirements smoothly.
Consider each process as a section in the production chain. Each section must operate well. If there is a quality accident in any section, it should be repaired and then run again. Otherwise, continue Blind operation does ineffective work and wastes resources.
2 Production site control
The supervisor of the production technology department must constantly Research and pay close attention to the production site, it is necessary to effectively control the factors affecting hue changes, and understand the causes of hue changes, so as to find the source of the problem according to the specific situation.
3 Production execution control
Perfect dyeing and finishing process design must Only with strong on-site execution ability can you achieve “first-time success in dyeing”. Each process must strictly control the following aspects:
a. Fake measurement: Measuring tools do not correct errors, precision is poor, additives are not weighed, etc.
b． False temperature: The actual dye bath temperature is inconsistent with the instrument temperature indication.
C． Fake bath ratio: The bath ratio is not determined according to regulations, and the operator estimates the bath ratio based on experience.
d． False proof: the proof is not dried or overheated, the proof is not soaped, and the proof is not restored and washed.
e. Fake workmanship: The operator does not operate according to the process specifications or the execution of the process is not strict.
4 Employee training
Regular training is combined with on-site training. Product quality is achieved by on-site workers, and improving the technical level of operators is an indispensable intellectual investment for “first-time success in dyeing”.
“Dyeing successfully the first time” requires great efforts from the perspective of total quality management, guided by process principles, and controlled by systematic methods, in order to achieve the ultimate goal.