(1) Conductor Consumption Calculation Formula

In wire and cable production, the calculation of conductor consumption is crucial. The calculation formula is as follows:

Conductor consumption (Kg/Km) = d^2 * 0.785 * G * N * K1 * K2 * C.

Each parameter in this formula has a clear meaning:

• "d" represents the conductor diameter, usually in millimeters (mm). It directly determines the thickness of the conductor and is one of the basic parameters for calculating consumption.

• "G" represents the conductor specific gravity. We have also introduced the specific gravities of common conductor materials before. For example, the specific gravity of copper is about 8.89g/cm³, and that of aluminum is about 2.7g/cm³. The specific gravity parameter is used to determine the weight of the conductor per unit length in combination with other data such as the diameter.

• "N" refers to the number of strands, that is, the number of conductors included in the cable. For example, in a multi-core cable, there will be multiple conductors, and the number of strands will affect the calculation result of the overall conductor consumption.

• "K1" is the conductor lay ratio, which reflects the increase ratio of the conductor length during the stranding process. Because stranding will cause the actual length of the conductor to change compared with the theoretical straight length.

• "K2" represents the core wire lay ratio, which is also related to the influence of the stranding process on the length, but focuses on the core wire stranding process.

• "C" represents the number of insulated core wires, which reflects the number of insulated core wires in the cable and plays an important role in calculating the overall conductor consumption.

Let's take a look at how to use this formula for calculation through a practical example. Suppose there is a copper-core cable with a conductor diameter d of 2 mm, the number of strands N is 3, the conductor lay ratio K1 is 1.05, the core wire lay ratio K2 is 1.03, and the number of insulated core wires C is 3. The specific gravity G of copper is known to be 8.89g/cm³. First, convert the units uniformly. 2 mm is converted to 0.2 cm. Then substitute the values into the formula for calculation: Conductor consumption (Kg/Km) = (0.2)^2 × 0.785 × 8.89 × 3 × 1.05 × 1.03 × 3 ≈ 2.87 (Kg/Km). Through such calculations, the conductor consumption per kilometer of this cable can be accurately obtained, providing accurate data support for production and procurement.

(2) Insulation Consumption Calculation Formula

The insulation consumption calculation formula is: Insulation consumption (Kg/Km) = (D^2 - d^2) * 0.7854 * G * C * K2.

The meanings of the parameters are as follows:

• "D" represents the insulation outer diameter, which refers to the outer diameter of the insulation layer wrapped around the conductor. The unit is usually millimeters (mm), and it reflects the overall outer size of the insulation layer.

• "d" is still the conductor outer diameter, that is, the outer diameter of the conductor itself wrapped by the insulation layer. The calculation of insulation consumption needs to be based on the difference between the conductor outer diameter and the insulation outer diameter.

• "G" represents the insulation specific gravity. Different insulation materials have different specific gravity values. For example, the specific gravity of rigid PVC (polyvinyl chloride) is usually about 1.4, and that of soft PVC is generally about 1.2. Through the insulation specific gravity, the volume and other data can be converted into weight to calculate the consumption.

• "C" represents the number of insulated core wires, which is similar to the meaning in the conductor consumption calculation formula and is a factor that needs to be considered when calculating the overall insulation consumption.

• "K2" is the core wire lay ratio. In the calculation of the insulation consumption of stranded core wires, the lay ratio is essential for accurately calculating the actual consumption.

Let's illustrate its application with an example. For example, there is a cable with an insulation outer diameter D of 5 mm, a conductor outer diameter d of 2 mm, the number of insulated core wires C is 3, the core wire lay ratio K2 is 1.03, and the insulation material used is rigid PVC with a specific gravity G calculated as 1.4. First, convert the units uniformly. 5 mm is converted to 0.5 cm, and 2 mm is converted to 0.2 cm. Substitute the values into the formula to get: Insulation consumption (Kg/Km) = ((0.5)^2 - (0.2)^2) × 0.7854 × 1.4 × 3 × 1.03 ≈ 0.73 (Kg/Km). In this way, the insulation material consumption per kilometer of this cable is obtained, which is convenient for reasonably preparing insulation materials in production.

(3) Sheath Consumption Calculation Formula

The sheath consumption calculation formula is: Sheath consumption (Kg/Km) = (D1^2 - D^2) * 0.7854 * G.

The meanings of the parameters are as follows:

• "D1" represents the finished outer diameter, which refers to the final outer diameter of the cable after adding the sheath. This parameter reflects the overall outer size of the finished cable, and the unit is usually millimeters (mm).

• "D" represents the outer diameter of the previous process, that is, the outer diameter of the cable before wrapping the sheath. The calculation of the sheath consumption is based on the volume difference determined by the finished outer diameter and the outer diameter of the previous process, and then combined with the specific gravity of the sheath material to calculate the consumption.

• "G" represents the insulation specific gravity. Although it is called the insulation specific gravity here, it is actually the specific gravity of the sheath material itself. For example, for some rubber sheath materials and plastic sheath materials, they all have corresponding specific gravity values for calculating the weight.

Let's look at a practical example. Suppose there is a cable with a finished outer diameter D1 of 8 mm and an outer diameter of the previous process D of 6 mm. The sheath material used is HDPE (high-density polyethylene) with a specific gravity G of 0.96g/cm³. First, convert the units. 8 mm is converted to 0.8 cm, and 6 mm is converted to 0.6 cm. Substitute these data into the formula for calculation: Sheath consumption (Kg/Km) = ((0.8)^2 - (0.6)^2) × 0.7854 × 0.96 ≈ 0.23 (Kg/Km). Through such calculations, the sheath material consumption per kilometer of the cable can be known, which is helpful for reasonably arranging the procurement and use of the sheath material.

(4) Taping Consumption Calculation Formula

The taping consumption calculation formula is: Taping consumption (Kg/Km) = D^2 * 0.7854 * t * G * Z.

The parameters represent the following contents:

• "D" represents the outer diameter of the previous process, that is, the outer diameter of the part to be taped when the tape is wrapped. The unit is usually millimeters (mm), and it determines the basic wrapping range of the tape.

• "t" represents the tape thickness, and the unit is also millimeters (mm). Different tape thicknesses will result in different consumptions, and it is one of the key parameters for calculating the tape volume and then the consumption.

• "G" represents the tape specific gravity. Different materials of the tape have different specific gravities. For example, the specific gravity of common cotton tape is about 0.55. According to the specific gravity, the volume data of the tape can be converted into weight data to determine the consumption.

• "Z" represents the overlap ratio (1/4Lap = 1.25). During the tape wrapping process, there is often an overlap situation, and the overlap ratio is used to measure the degree of this overlap and has a great impact on accurately calculating the actual tape consumption.

The following is a calculation example using this formula. For example, there is a cable with an outer diameter D of 4 mm during the tape wrapping process, the tape thickness t is 0.2 mm, the tape specific gravity G is 0.55g/cm³, and the overlap ratio Z is calculated as 1.25. First, convert the units to centimeters. 4 mm is converted to 0.4 cm, and 0.2 mm is converted to 0.02 cm. Substitute the data into the formula to get: Taping consumption (Kg/Km) = (0.4)^2 × 0.7854 × 0.02 × 0.55 × 1.25 ≈ 0.0017 (Kg/Km). In this way, the taping consumption per kilometer of this cable is calculated, which is convenient for controlling the use amount of the taping material in production.

(5) Jacket Consumption Calculation Formula

The jacket consumption calculation formula involves parameters such as the circumferences before and after extruding the jacket.

Specifically:

The jacket thickness can be calculated by the formula "Jacket thickness = (Circumference after extruding the jacket - Circumference before extruding the jacket) / 2π" or "Jacket thickness = (Circumference after extruding the jacket - Circumference before extruding the jacket) × 0.1592". The circumferences before and after extruding the jacket are the key parameters. The circumference before extruding the jacket reflects the external size of the cable before wrapping the jacket, and the circumference after extruding the jacket reflects the external size of the finished cable after adding the jacket. The thickness of the jacket is determined by the difference between the two, and then combined with other factors to calculate the consumption.

Let's explain the actual calculation operation of this formula with an example. Suppose there is a cable with a measured circumference of 30 cm before extruding the jacket and a circumference of 40 cm after extruding the jacket. According to the formula "Jacket thickness = (Circumference after extruding the jacket - Circumference before extruding the jacket) / 2π", first calculate the difference as 40 - 30 = 10 cm. Then the jacket thickness = 10 / (2 × 3.14) ≈ 1.59 cm (here, the approximate value is taken for convenience in the example). After knowing the thickness and other relevant parameters, combined with the specific gravity of the jacket material and other data, the consumption of the jacket material can be further calculated. For example, if the specific gravity of the jacket material is 1.2g/cm³ (assumed), the weight consumption of the jacket material per kilometer of the cable can be calculated through the relationship between the volume (related to the thickness, etc.) and the specific gravity, providing an accurate basis for the preparation of the jacket material in production.