covering process principles, parameter Settings, key operation points and quality control, etc., to help optimize the spinning process and improve the quality of the yarn:
I. The Process Principle of the coiling Machine
The main function of the baling machine is to improve the arrangement of fibers through baling and stretching, eliminate the unevenness of short segments, and enhance the uniformity of the strips.
1. Merging effect: Merge 6 to 8 green strips to reduce the weight difference of long segments.
2.2. Stretching effect: Apply stretching force to the fiber bundle to make the fibers parallel and straight, reducing the number of hooks.
3. Uniformity effect: The output bar is detected and adjusted in real time through the self-adjusting uniformity system (for modern models).
Applicable fibers:
Cotton fibers: It is necessary to focus on eliminating short fibers and cotton knots.
Chemical fibers: Pay attention to static electricity control and the straightness of the fibers.
Blending: Ensure that different fibers are evenly mixed (for example, for polyester-cotton blending, 2-3 rounds of blending are required).
Ii. Key Process Parameter Settings
1. Union number
The standard range is 6 to 8 fibers. Too many may increase fiber damage, while too few will affect uniformity.
Basis for adjustment:
When the unevenness rate of the weight of the raw strips is high, increase the combined number.
Chemical fibers (such as polyester) can be reduced to six strands (due to the higher uniformity of the fibers).
2. Elongation ratio
Total elongation multiple: Usually 6 to 8 times, matching the union number (total elongation ≈ union number ×1.05).
Stretching distribution
Posterior zone stretching: 1.2-1.5 times (pre-stretching, reducing anterior zone pressure).
Anterior stretch: The main stretch area, accounting for more than 70% of the total stretch.
Adjustment principle: For long fiber lengths (such as flax), the stretching ratio should be reduced.
For high-count yarns (such as 80S and above), smaller stretching is adopted (to reduce details).
3. Roller spacer
Main stretching zone spacing:
Cotton fiber: 10-12mm (according to the length of the main fiber +2-3mm).
Chemical fibers (such as 1.5D×38mm polyester) : 12-15mm.
Rear zone spacing: 2-4mm larger than the main zone to ensure smooth fiber guidance.
4. Extrusion speed
Conventional range: 200-600m/min.
Low-speed applicable scenarios:
High-impurity raw materials (such as low-grade cotton).
High-count yarn production (reducing breakage).
5. Other parameters
Pressure rod position: Adjust the control force of the fibers and reduce the floating fibers.
Bell mouth diameter: Matching the output weight of the strip (generally 3.5-4.5g/m ³).
Iii. Key Points of Operation
Feeding management
Control of short pile rate of raw strands (short pile rate of cotton fibers < 18%).
The tension of the guide bar frame is uniform to prevent accidental stretching (tension difference < 5%).
Equipment maintenance
Clean the roller and rubber roller twice per shift (to avoid the accumulation of flying flowers).
Check the hardness of the rubber roller (Shore 65-75 degrees) and its surface condition (no dents).
Process adjustment verification
After changing the variety, 3 to 5 strips should be tested to check the weight deviation (within ±1%).
Iv. Common Problems and Solutions
1. Cotton net edge breakage/fracture:
Reasons: The distance between the rollers is too small and the pressure applied by the rollers is insufficient.
2. Measures: Increase the distance by 2mm and check if the air pressure reaches 0.3MPa.
3. Periodic uneven drying:
Cause: Gear wear, roller bending (runout > 0.05mm).
4. Measures: Replace the gears (when the backlash is greater than 0.3mm) and straighten the rollers.
5. Quantitative fluctuation of product issuance:
Cause: Malfunction of the self-tuning sensor or unstable feeding volume.
Measures: Calibrate the sensor and check whether the feeding bar bucket arrangement is aligned.
V. Precautions
Temperature and humidity control: Temperature 25±2℃, humidity 60±5% (Chemical fibers require lower humidity to prevent static electricity).
Blending process: For polyester-cotton blending, it is recommended to use "three parallel strips" for a more uniform blend.
Equipment upgrade: The new type of merging machine (such as Trutzler TD-10) can be equipped with online monitoring to adjust the process in real time.
By setting parameters reasonably and strictly monitoring quality indicators, the yarn strength can be significantly enhanced (by approximately 10%-15%) and the breakage rate can be reduced. It is recommended to conduct a full-process process optimization test once every quarter and benchmark against the industry level in combination with the data from the Uster Bulletin.