Thread Consumption Calculation is quite a common process in the apparel industry. It is very important that the Merchandiser must calculate thread consumption very carefully because it will save a lot of money. It is particularly important in cost. There are many ways to calculate thread consumption.
In this article, we will learn 3 methods of consumption calculation.
Method Number 1: Measuring Actual Thread Consumed
- In this process, the sewing thread is carefully removed from different seams with specific lengths.
- Then the factor is calculated by the total length of the thread divided by the specific length. With this ratio of thread consumed is calculated.
- Then seam length is measured and the factor is multiplied by total seam length, with this total thread consumption is calculated for a particular seam.
Example:
- Stitch class is 401 = 2-Thread Chainstitch
- Length of seam taken = 100 Centimeter
- Length of the seam for which thread is removed = 10 Centimeter
- Needle Thread removed = 13 cm Needle Thread factor = 13/10 = 1.3
- Looper Thread removed = 40 cm Looper Thread factor = 40/10 = 4
- Total Needle Thread = 100 cm x 1.3 = 130 cm
- Total Looper Thread = 100 cm x 4.1 = 400 cm
- Total thread = 130 + 400 = 530 cm
- 15% wastage is generally added to for various reasons like rework, thread break, machine problem, etc.
- 540 cm x 1.15 = 609.5 cm or 6.09 meters of thread per seam including wastage.
With these steps, one can calculate thread consumption.
Method Number 2: Using Thread Consumption Ratios
One of the simple and effective methods is to use a thread consumption ratio. The below table explains the constant or ratio that can be used in thread consumption calculation. If we know stitch type and stitch class and seam length one can easily calculate the thread consumption with these ratios.
| Stitch Class | Stitch Type | Thread Usage (cm per cm of the seam) | Number of Needle | Percentage of Needle Thread | Percentage of Looper Thread |
|---|---|---|---|---|---|
| 301 | Lockstitch | 2.5 | 1 | 50 | 50 |
| 101 | 1- Thread Chainstitch | 4 | 1 | 100 | 0 |
| 401 | 2-Thread Chainstitch | 5.5 | 1 | 25 | 75 |
| 304 | Zig-Zag Lockstitch | 7 | 1 | 50 | 50 |
| 503 | 2-Thread Overedge stitch | 12 | 1 | 55 | 45 |
| 504 | 3-Thread Overedge stitch | 14 | 1 | 20 | 80 |
| 512 | 4-Thread Mock-safety stitch | 18 | 2 | 25 | 75 |
| 516 | 5-Thread Safety stitch | 20 | 2 | 20 | 80 |
| 406 | 3-Thread Covering stitch | 18 | 2 | 30 | 70 |
| 602 | 4-Thread Covering stitch | 25 | 2 | 20 | 80 |
| 605 | 5-Thread Covering stitch | 28 | 3 | 30 | 70 |
Note: These ratios are applicable for 18 Stitches per inch. The ratio may change if SPI changes.
Example:
- Length of seam = 100 Centimeter
- Stitch class 504 = 3-Thread Overedge stitch
- Thread Consumption ratio = 14 (taken from the table)
- Total thread consumption = 100 cm x 14 = 1400 cm
- Estimated Needle Thread (20 %) = 1400 x 0.20 = 280 cm
- Estimated Looper Thread (80%) = 1400 x 0.80 = 1120 cm
- Add 15% wastage = 1400 cm + 15% = 1610 cm = 16.10 meters of thread per seam
Thread consumption for an average-sized knitted t-shirt
| Stitch Class | Stitch Type | Seam Length (m) | Thread ratio | Total Thread Consumption (m) | Needle Thread | Looper Thread |
|---|---|---|---|---|---|---|
| 301 | Lockstitch | 5 | 2.5 | 12.5 | 6.25 | 6.25 |
| 401 | 2-Thread Chainstitch | 2 | 5.5 | 11 | 1.3 | 4.1 |
| 101 | 1-Thread Chainstitch | 1 | 4.0 | 4 | 4 | 0 |
| 503 | 2-Thread Overedge stitch | 0.50 | 12 | 6 | 3.3 | 2.7 |
| Total (m) | 33.5 | 14.85 | 13.05 | |||
| Wastage (15%) | 5.02 | 2.2 | 2.0 | |||
| Total Thread Consumption (m) | 38.5 | 17.1 | 15.0 |
Method 3: By Using Average Thread Consumption
The following table contains the average thread consumption of thread lengths for different types of apparel. These figures arrived with consideration of 5% wastage
| Item | Consumption | Item | Consumption |
|---|---|---|---|
| Blouses | 100 | Men’s shirt | 120 |
| Boiler suit (chain stitch) | 420 | Boys Shirt | 75 |
| Bras | 45 | Trousers: Men’s | 270 |
| Cap | 75 – 90 | Skirt | 100 |
| Gloves | 25 | Waistcoats | 50 |
| Ladies Swimwear | 45 | Polo T-Shirt | 100 |
| Raincoat | 285 | Ties | 7 |
| Umbrellas | 20 | Under Pants | 50 |
One can directly take the consumption as per the product.
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