Fabric specification calculation, for the fabric designer, is the basis of the factory to guide the production of products. For the salesman, it is a means to communicate with customers, quote, control the cost, master this knowledge, no matter for that kind of products, in which kind of occasion can be in the shortest time to calculate the basic cost of the product, do quote accurate, timely, and can master the key to control the cost.

01 Quantitative calculation of raw materials

There are many factors involved in the quantitative calculation of raw materials, among which the calculation of many process shrinkage is very complicated. For ease of mastery, a smaller range of values is listed for reference.

1. Longitude quantification:

Quantitative warp per meter (g/m) = Warp density per centimeter × finished door width (cm) × (1+ process shrinkage) × (1+ weaving shrinkage) × raw material size (D) ÷9000 (or 1/N, 0.59/s)

2. Weft thread quantification:

Quantitative weft per meter (g/m) = door width of finished product (cm) × Density of weft per centimeter × (1+ weft shrinkage) × (1+ process shrinkage) × material size (D) ÷9000

The process shrinkage in the above two formulas refers to the raw material shrinkage rate and twist shrinkage rate

(1) One of the process shrinkage ------- Raw material shrinkage:

Yarn (silk) shrinkage of various properties and different processes, such as:

The shrinkage of mulberry silk soaking process is 1.5%

The shrinkage of silk dyeing and bleaching process is 2.5%

The natural shrinkage of nylon filament is 3%

The natural shrinkage rate of polyester filament is 1.5%

After elastic polyester yarn twisting, the shrinkage rate of high temperature setting is 7% below 100D

After elastic polyester yarn twisting, the shrinkage rate of high temperature setting is 8.5% on 101D~149D

After elastic polyester yarn twisting, the shrinkage rate of high temperature setting is more than 10% for 150D

Cotton, hemp, viscose staple fiber dyeing, bleaching process shrinkage of 2%

The elongation of viscose filament through the slurry is 3%

(2) process shrinkage rate of the second ------ twist rate:

The silk thread will become shorter after twisting. This is because the silk thread will become spiral twisted from straight to short, and the diameter of the silk thread will naturally become thicker. Therefore, when the length is fixed, the size will become thicker, and the twist rate of different sizes and different twists will also be different. The twisting rate can be calculated by the formula, or you can refer to the table of common twisting rate. Generally, 75D filament is added with about 10 twisting per centimeter, and the twisting rate is about 2-3%. 75D filament with 20 twist per centimeter, the twist rate is about 11-12%; 150D filament with about 10 twist per centimeter, the twist rate is about 5-6%; For 150D filament, add about 20 twists per centimeter, and the twist rate is about 13-15%

(3) the third shrinkage of the process ---- meridian shrinkage:

When weaving, warp and weft will form warp of yarn (silk) in the process of interweaving, so that one meter long warp will not form one meter long cloth after interweaving with weft. The ratio between the length of the silk thread and the length of the fabric is the shrinkage rate, which can also be calculated by the formula. The size of shrinkage is related to yarn size, weft density and fabric structure. The coarser the weft (silk), the larger the shrinkage; The larger the weft density, the larger the shrinkage. The smaller the number of tissue cycles, the larger the shrinkage. General products (referring to single fabric, weft density is not particularly thin or particularly dense products) in 3-8% or so. (The specific size can be selected from 3-8% according to the above mentioned thickness, weft density and structure).

02 Fabric weight calculation

The meaning of fabric weight calculation is to understand the approximate weight of the fabric, so as to calculate the cost and price of the fabric.

Weight per meter: refers to the weight in grams per meter of finished fabric. The calculation method is:

Finished product per meter weight (g /m) = (warp quantitative × fold rate + weft quantitative × fold rate) ÷ dyeing and finishing shrinkage rate

(1) Refining yield:

Net weight of yarn (silk) after dyeing and finishing. Different fibers contain different impurities, different processes will make the same raw material folding rate is different. The commonly used raw material smelting rate is as follows:

Mulberry silk: 75~80%

Raw mulberry silk: 95~98%

Floret: 90 ~ 95%

䌷 wire: 88 ~ 93%

Viscose, wool: 97%

Cotton yarn, linen: 95% (mercerized, bleached 92%)

Synthetic fiber: 99%

(2) Dyeing and finishing shrinkage rate:

Dyeing and finishing shrinkage refers to the length ratio of fabric before and after dyeing and finishing

Dyeing and finishing rate = weft density of blank silk ÷ Weft density of finished product = length of finished product ÷ length of blank silk

Weight of square meter silk (g/m2)

Square meter silk weight (g/m2)= per meter silk weight (g) ÷ door width (m)

03 Calculation of raw material content

For fabrics interwoven or blended with two or more materials, the proportion of each material must be calculated as follows:

Content of raw material A = (weight of raw material A × proportion of raw material A × refining rate of raw material A) ÷ (weight of raw material A × refining rate + weight of raw material B × refining rate) ×100%

Example: The warp of a product is 120N/2 silk/flax blended yarn (70% silk, 30% flax), and the weft is 40S/2 light cotton yarn

Finished door width: 140cm plain texture

Finished product warp density: 28 /cm finished product weft density: 24 shuttle /cm blank silk weft density 23 shuttle /cm

Secondly, based on several factors, it is estimated that the shrinkage rate is about 5%, the shrinkage rate of silk process is 2.5%, the zonal shrinkage rate is about 10%, and the shrinkage rate of viscose staple fiber process is 2.0%. Then:

Warp quantification (g/m) = finished product warp density × finished product door width × (1+ process shrinkage) × (1+ weaving shrinkage) × raw material size ÷9000

That's equal to 28 times 140 times (1+5%) times 1/60

=65(g/m)

Weft quantitative (g/m) = finished weft × finished door width × (1+ weft shrinkage) × (1+ process shrinkage) × raw material size ÷9000

=140×24× (1+10%) ×0.59/20=109 (g/m)

Finished products per meter of silk weight (g/m) =(warp quantitative × refining rate + weft quantitative × refining rate)÷ dyeing shrinkage rate

= (109 x 65 x 0.95 + 0.97) present 0.96

=(61.8+105.7 = 167.5 = 168(g/m)

Square meter weight of silk (g/m2)= weight of silk per meter ÷ width =168÷1.4=120(g/m2)

Among them, the content of silk raw material =(including the weight of silk raw material × proportion of silk silk × folding rate of silk refining)÷(including the weight of silk raw material × folding rate of silk refining + weight of human cotton yarn × folding rate)

= (65 * 0.7 * 0.95) present (109 x 70 x 0.95 + 0.97) x 100% = 43.2 present 167.5 x 100% = 26%

Wherein, the content of flax raw material =(weight of flax raw material × proportion of flax × folding rate of flax)÷(weight of flax raw material × folding rate of flax + weight of viscose yarn × folding rate of flax)

= (65 x 3 x 0.95 x 100%) present 65 x 109 x 0.97 = 0.95 + 18.5 * 167.5 = 11% 100% present

Viscose raw material content =(viscose raw material weight × viscose folding rate)÷(warp raw material weight × viscose folding rate + viscose yarn weight × viscose folding rate)

= 109 * 0.97 * (100%), present (109 x 65 x 0.95 + 0.97) = 105.73 * 167.5 = 63% 100% present

Through the above calculation: the product warp raw material quantitative 65g per meter; Weft material quantitative 109g per meter, on this basis according to the product process (white woven, yarn-dyed, sliver, grid) plus a certain proportion of the return rate, combined with the market price of raw materials can be obtained a more accurate cost of raw materials, coupled with weaving, dyeing, is the bottom price of the product.