Matching yarn storage capacity with tension on a two-for-one twisting machine requires consideration of yarn linear density, breaking force, target twist, spindle speed, and storage device design. A mismatch between yarn delivery speed and storage release speed, or an unsuitable tension setting, can cause slack yarn, tension fluctuations, or yarn breakage.
The adjustment process should begin with the yarn and machine specifications. The target yarn delivery speed and initial tension can then be established and verified through trials at different storage levels.
Confirm the yarn and machine parameters
Yarn specifications
Linear density is an important reference when setting initial yarn tension. Examples of yarn linear density in the source text range from 14.8 tex to 97.2 tex. The yarn's breaking force, elongation at break, and required twist must also be confirmed. When available, use the test data provided in the yarn manufacturer's inspection report.
For example, the source text gives a minimum breaking force of 180 cN for 18.2 tex pure cotton yarn. For denim yarn, it gives a target twist range of 80 to 120 turns per 10 cm. Actual production settings should follow the requirements for the specific yarn and application.
Two-for-one twisting machine specifications
Machine parameters should include the rated spindle speed, storage device type, and relevant dimensions. The source text gives a reference spindle speed range of 8,000 to 12,000 r/min.
Storage devices should be identified as disc type or cylindrical type. For a disc type device, confirm the storage disc diameter D and its rotational speed. For a cylindrical device, confirm the effective storage capacity and the operating parameters of the feed rollers.
The draft ratio must also be selected according to the yarn type and machine design. The source text gives a reference range of 1.02 to 1.05 for filament yarn processed on a two-for-one twisting machine. These values should be checked against the machine manufacturer's technical documentation before use.
Calculate yarn delivery speed and storage release speed
Yarn delivery speed must correspond to the spindle speed and target twist. Let n represent spindle speed in r/min, T represent actual twist in turns per metre, and V represent yarn delivery speed in m/min.
For a two-for-one twisting machine, the relationship between twist and spindle speed is:
T=\frac{2n}{V}
The yarn delivery speed can therefore be calculated as:
V=\frac{2n}{T}
Use consistent units when applying this formula. If the twist specification is given in turns per 10 cm, convert it to turns per metre before performing the calculation.
Disc type storage device
If the machine design allows the peripheral speed of the storage disc to approximate the relevant yarn release speed, use the following formula:
V_{\text{storage}}=\frac{\pi D n_{\text{storage}}}{1000}
Here, D is the storage disc diameter in mm, and (n_{\text{storage}}) is the disc speed in r/min. The calculated speed is in m/min.
Compare the storage release speed with the target yarn delivery speed. The source text gives an initial matching target of keeping the relative difference within ±3%. Whether the disc's peripheral speed can be used directly for this comparison depends on the storage mechanism, yarn path, and calculation method specified by the machine manufacturer.
Cylindrical storage device
For cylindrical storage, calculate or adjust the release speed using the feed roller speed and the machine's specified transmission relationship. The target is to match the resulting release speed to the required yarn delivery speed.
The disc type formula should not be applied directly to a cylindrical storage mechanism. After the initial adjustment, check the machine under operating conditions for slack yarn, excessive stretching, and tension fluctuations.
Set initial tension and adjust it for different storage levels
Set initial tension according to yarn linear density
The source text provides the following initial tension ranges:
| Yarn linear density | Reference initial tension |
|---|---|
| Below 10 tex | 5 to 10 cN |
| 10 to 30 tex | 10 to 20 cN |
| Above 30 tex | 20 to 30 cN |
These values can serve as initial trial settings. They are not universal specifications for every fiber type, yarn count, or two-for-one twisting machine. Measure the actual running tension with a tension meter and check whether the yarn runs consistently.
Adjust tension according to storage level
The source text proposes the following initial adjustments:
Full storage: reduce the initial tension by 5% to 8%.
Storage approaching empty: increase the initial tension by 3% to 5%.
Half-full storage: maintain the initial tension.
These adjustments can be tested during commissioning, but storage level should not be assumed to have a fixed percentage relationship with yarn tension. Actual tension also depends on spindle speed, winding speed, feed package dimensions, and the yarn path. Recheck the measured tension at each storage level and adjust it according to the machine requirements.
Check working tension against yarn breaking force
The source text recommends keeping working tension within 10% to 15% of the yarn's breaking force. This should be treated as a reference from the original material, not as a universal safety limit for all yarns.
The actual setting must account for breaking force, elongation at break, production speed, and machine requirements. Excessive tension can cause yarn breakage, while insufficient tension can result in slack yarn or unstable delivery.
Dynamic calibration and production verification
Calculations provide initial settings. The final match between storage release speed and yarn tension must be verified while the machine is running.
Test different storage levels
Run trials with the storage device empty, half full, and full. Record the corresponding storage release speed, actual tension, and yarn breakage. Use the measurements to adjust the storage drive or tensioning device.
Check finished yarn quality
The source text proposes running 1,000 m of finished yarn and checking the following indicators:
Twist deviation within ±2%.
End-break rate no greater than 0.5% per minute.
These are test targets provided in the source text. Production teams should also define the calculation method for the end-break rate and confirm acceptance criteria against the product specifications and machine documentation.
Make adjustments based on the results
If twist deviation or yarn breakage exceeds the target, identify the source of the problem before changing the settings. Adjust the storage release speed or tensioning device as required. Measure and record the results after each adjustment, repeating the process until yarn operation and finished product quality meet the applicable requirements.
Safety requirements: Stop the machine before adjusting the storage disc, spindle, or related transmission components. Never touch rotating components. These operations must be carried out by qualified maintenance personnel holding the required certification.
Custom precision machining for industrial components
In addition to components for two-for-one twisting machines, we provide custom precision machining based on customer supplied drawings. We support single piece and small batch production. Hansheng Automation also manufactures custom components for tobacco packaging machinery, filling machinery, yacht equipment, and radio controlled racing cars.
The manufacturing approach is determined by the component drawings, structural features, and specific technical requirements.
