How to calculate the cost price of knitted fabrics in the textile industry

For your reference:
1、 Basic formula
GM/㎡=G(gm)÷S(㎡)
WIDTH=CUTS÷WPI 
OZ/YD=WIDTH × GM/㎡ × zero point zero zero zero eight two
MAX REPTAT OF FEED=FEEDERS÷CPI
GM/㎡=(CPI × WPI × 50C)÷S/1 × zero point zero one eight three six seven
S/1=840yds÷1lb=0.00059 × L(mm)÷G(gm)
[note]
G - weight
S - area
L - length
GM / ㎡ - gram weight per square meter of fabric
CPI - number of coil rows of fabric within 1 inch
WPI - the number of longitudinal rows of fabric coils within 1 inch
50c - total length of 50 coils (unit: mm)
S / 1 - yarn count (Imperial System)
Oz / yd - ounce weight per yard of fabric
Cuts - total number of stitches of the machine
Feeders - total number of paths of the machine (number of looping systems)
2、 Theoretical derivation
1. Yarn count is used to describe the density (diameter or fineness) of yarn, which is the ratio of weight to length. The yarn count systems we usually use include British system (s / 1), metric system (nm) and denier (d), and their relationship is as follows:
S/1=0.591Nm
S/1=5319D
For example: 150D ≈ 35.46s/1
48Nm≈28.4S/1 
Generally speaking, British thread is used for cotton yarn (such as cotton, cotton / wool, cotton / poly, cotton / line); Common thread is used for wool yarn (such as 100% wool, acrylic / wool, acrylic); Denier is used for filaments (such as filamentpoly, filamen nylon, cyarl, silk, Lurex).
According to the definition of British branch, S / 1 = 840yd ÷ lb, we can get the formula s / 1 = 0.00059 × L (mm) ÷ g (GM) to measure the yarn count of the customer's sample.
For example, if we measure that the total weight of 12 172mm cotton yarns is 0.062gm, we can calculate that the yarn count is 12 × one hundred and seventy-two × 0.00059÷0.062=19.6S/1-20S/1 
2. GM / ㎡ is the total weight of fabric per square meter and the total weight of each coil woven into this fabric. Therefore, if we know the number of coils per square meter of fabric and the weight of each coil, we can calculate the gram weight of fabric per square meter, that is, the total number of coils × Unit coil weight. Since we know the CPI and WPI of the fabric, we can calculate the total number of coils in square meters, that is, CPI × WPI × thirty-nine point three seven × 39.37。 Similarly, according to the definition of yarn count and the length of unit coil, or to calculate the weight of each coil, that is:
Coil length ÷ yarn count = (50C ÷ 50000) × (453.6÷S/1÷840÷0.9114) 
So the gram weight per square meter is:
CPI × WPI × thirty-nine point three seven × thirty-nine point three seven × 50C÷50000 × 453.6÷S/1÷840÷0.9114 × one point zero one eight three six seven
For example: 40s / 1 × 2 Cotton Piece Dye Solid Jersey 20G × 30” 9.75OZ/56-58” 205GM/㎡， CPI=45，WPI=31， 50C=160MM。 According to the above formula, the gram weight is 45 × thirty-one × 160÷40 × two × 0.018367=204.975(gm/㎡)。 In the standard, because the parameters used in the formula are artificially determined, there will be a corresponding deviation between the calculated weight and the standard weight, which is generally within 5%.
3. Knitted fabrics form a vertical line with each needle, so the total number of needles of the machine divided by the fabric WPI is the door width of the fabric.
4, the first mock exam of each die can form a horizontal row, so the modulus of the machine is divided into CPI FEED REPEAT.
3、 Formula application example
1. Impact on sample analysis:
1) If the customer has enough samples (1 door width and at least 1 yard or more), we can directly weigh the yard weight and gram weight, measure the door width, calculate CPI and WPI, measure the yarn count, and count the total number of stitches, so as to know the gauge for the production of the fabric. It can also test other relevant parameters, such as fabric shrinkage, pilling, wet crocking, etc.
2) If the customer's sample is not enough for one door width, but can be engraved with large circle or small circle, then we can weigh the gram of large circle or small circle, measure CPI and WPI, and calculate the producible door width according to the formula: width = cuts ÷ WPI; According to the formula: oz / yd = width × GM/㎡ × 0.00082, calculate the corresponding code weight. However, it is not known that it originally produced the fabric model gauge.
For example, a customer's sample is 40s / 1 cotton piece dye solid double face (rib M / C). We measured that its gram weight is 219gm / ㎡, WPI = 37.5, CPI = 88. If it is produced by 18G 34 "(1920 cuts), its door width is 1920 ÷ 37.5 = 51.2", estimated to be 50-52 ", and its code weight is 52" × two hundred and nineteen × 0.00082=9.34(OZ/YD)。
3) If the incoming sample is too small to carve a large circle or a small circle to weigh it, we can only weigh the weight of the whole cloth and measure its area. According to the formula GM / ㎡ = weight (g) ÷ area (s), calculate the gram weight. The same method as 2) can be used to calculate the door width and yard weight, but the measured data is very inaccurate.
For example, the sample from a customer is 2cm × 2cm, its gram weight is 0.08g, and its square meter gram weight is 0.08gm ÷ 0.02M ÷ 0.05m = 200gm / ㎡.
Note:
Among them, 2) and 3) because the shrinkage of the sample cannot be measured, the shrinkage is required to be good in the formal production. The actual fabric door width and weight may differ greatly from the analysis results.
2. Estimation of door width:
A: Direct calculation method:
Fabric door width = total stitches of producible machines ÷ WPI
For example: 20s / 1 CTN s / K Jersey PD solid 18g × 30" WPI=29 
It can be seen from the model table that 18g × The total number of stitches of 30 "is 1680, and the door width of the above cloth types can be calculated:
Width = 1680 ÷ 29 = 58 ". Therefore, the door width is 56-58".
This method is mostly used for fabric sample analysis.
Note: here is the total number of needles of the machine that can be produced. For example, a machine with too fine machine number cannot be used for thick yarn count, and a machine with too thick machine number cannot be used for spinning count. At the same time, the cloth type shall be consistent with the model. For example:
RIB SOLID/FEED M/C： 
15G × 34，1596 × 2 CUTS 
18G × 34，1592 × 2 CUTS 
14G × 34，1416 × 2 CTUS 
INTERLOCK SOLID/FEED： 
18G × 30，1728 × 2 CUTS 
22G × 30，2088 × 2 CUTS 
24G × 30，2304 × 2 CUTS 
28G × 30，2664 × 2 CITS 
INTERLOCK AUTO： 
18G × 30，1680 × 2 CUTS 
22G × 30，2064 × 2 CUTS 
24G × 30/22G × 30，2256 × 2 CUTS 
24G × 33，2496 × 2 CUTS 
B: Comparative calculation method (change gauge)
If the door width and weight of the fabric are known, the following formula can be used to calculate the remaining door widths that can be produced when the weight and shrinkage remain unchanged:
Producible door width = total needles of producible machines ÷ total needles of existing machines × Existing door width
For example, 20s / 1 CTN s / K Jersey PD solid 18G is known × 30 "181gm 56-58", if 20g × 30 "machine to do, what is the door width?
Look up table 18g × The total number of stitches at 30 "is 1680, 20g × The total number of stitches of 30 "is 1860. According to the formula, width = 1860 / 1680 × 58 "= 64.2, calculated from this, e.g. 20g × The door width that can be produced by 30 "machine is 62-64".
Note: the precautions are the same as method a.
3. Max: Calculation of feed repeat.
The basic calculation formula is: Max repeat of feed (B / W) = modulus of producible machine ÷ CPI
The key point here is to find out the module of the production machine. For example, the rib machine is 70F, the interlock machine is 84F, and the ordinary machine is 96F. For detailed machine types, refer to the actual models of each company.
For example:
1)20S/1 COTTON DK 1 × 1 RIB FEED 259 GM/㎡ 15G × 34" 64-66" 14.0OZ/YD CPI=36。 Because the modulus of rib machine is 70F, the Max: repeat of feed of the above cloth is: modulus ÷ CPI = 70 ÷ 36 = 1.94“
2)32S/1 COTTON YD INTERLOCK FEED 223GM/㎡ 18G × 30" 50-52" CPI=75。 Because the modulus of interlock machine is 84F, the Max: repeat of feed of the above cloth is: modulus ÷ CPI = 84 ÷ 75 = 1.12 "(B / W).
3)20S/1 COTTON YD S/K PIQUE FEED 20G × 30" 14.0OZ/YD 80-82" 208GM/㎡ CPI=64。 Because the modulus of ordinary machine is 96F, the Max: repeat of feed of the above cloth is: modulus ÷ CPI ÷ 2 = 96 ÷ 31 ÷ 2 = 1.5 "(B / W).