Views: 1000 Author: Site Editor Publish Time: 2021-08-11 Origin: Site
The raw materials of dyed products mainly refer to grey fabrics and dyestuffs. Regardless of the batch size, the requirement of consistent quality of raw materials before and after is an important condition to ensure that the LOT color is overcome. Even if the quality of the raw materials is different objectively, they must be aware of the differences in handling, and strictly control the LOT color to the minimum amount.
The specific approach is as follows:
1.1 For grey fabrics of the same color number, the purchasing department is required to purchase grey fabrics with cotton from the same cotton weaving factory and from the same batch of origin.
1.2 If the intermediary supplies blanks, the products of different cotton weaving factories must be distinguished. If there are grey fabrics from two factories, they must be put into production according to the batch number when they are put into production. When necessary, the pre-treatment and dyeing process materials should be adjusted appropriately to overcome the intra-batch color difference of the batch of products.
1.3 For some special products, such as flax, flax cotton and other semi-bleached blanks, although pre-processing, it is still difficult to control the LOT color change of sensitive colors. The control method can be to sample 1 meter from each roll, make a record of the number of each roll and sample, and try to dye more sensitive colors; then, according to the result of the LOT color of the sample, put each roll into production in batches. Adjust in batches during dyeing to reduce the production of LOT colors.
1.4 For products of the same color number, when the raw materials change (including the origin of grey fabrics, dyes, finishing agents), the supply department must notify the technical department, stack them separately, and strictly compare and test, so that the process and technology can be adjusted reasonably. Change.
1.5 Dyeing and chemical materials should be prepared in sufficient quantities according to the batch requirements. For a color, regardless of size, the first requirement is the same origin, the same batch, the same shade, and the same concentration of dyes. It is best to use a full inspection method for the dye, and if it is found to be different, use it separately and re-sample to avoid the LOT color due to the difference in shade and intensity of the dye.
1.6 Don't ignore the influence of softeners and other finishing agents on shade, shade and edge color. For a large batch of colors, in the soft finishing process, it is best to use the same batch of products to produce on the same machine; at the same time, it is also necessary to cut the sample to track the color, otherwise it is difficult to control the LOT color and edge color within the batch.
1.7 Whether the dye selection is correct is another key to controlling LOT color and edge color. Many companies submit samples to the laboratory after receiving samples from customers, and the compatibility of dyes is determined by the samplers. The problem is that some samplers lack practical experience in production. They just align the sample with the customer's sample, but it is difficult to grasp the degree of dye uptake, the speed of the color change, the stability of the compatibility, and the size of the metamerism of different color samples. Samples are often sent to customers for confirmation, and the problem is discovered during production. At this time, the dye compatibility is changed, and it is restricted by the color light and the change of the lamp, which makes it very passive.
To this end, computer color matching is used. According to the dye combination selected at ordinary times, the most ideal combination of DE value is selected, and the combination of six is selected. Then the dyeing supervisor is sent to the dyeing supervisor according to the good quality and strong stability (the dyeing curve is roughly the same), The principle of low cost is to select one group of compatibility; then send it to the test laboratory for proofing, such a sample not only meets the customer's requirements, but also ensures that the color difference can be controlled to the most stable during production.
1.8 Although there are thousands of changes in the three primary colors, the three primary colors are not omnipotent. Practice has proved that you can’t rely on the combination of the three primary colors. For any color, the best way is to choose a similar color dye as the main color, and then fine-tune other dyes according to the shade; at the same time, the compatibility of the dyes should be adhered to. The better principle.