What is auto levelling in carding?
For regular delivery or regular output of material changing draft according to the change of input material is called auto levelling.
Let the card mat wt. 550gm/m and required sliver wt. 70 gr/yd.
In the spinning mill, carding machine is the effective start of the spinning process since the sliver is produced here. A relatively high degree of evenness is required in this product. For various reason, carding machine cannot always operate absolutely evenly, for example owing to uneven material feed. Spinning mills are therefore forced to use auto levelling equipment under highly varying circumstances. Adjusting the feed roller speed usually performs auto levelling. Auto levelling serves to keep the sliver count constant. Measuring is performed by the sensor in the card’s sliver trumpet at the sliver delivery. The card control unit analyses and processes the incoming signals which is produced in the sensor unit and accordingly adjust the speed of the feed roller to adapt to the delivered sliver via electronic regulating devices
Draft = card mat weight per unit length/card sliver weight per unit length
Normally if sliver wt. is high (above 70gr/yd) then less card mat will be fed (less than 550gm/m) by the help of feed roller to keep the sliver wt. constant. If sliver wt. is low (less than 70gr/yd) then more card mat will be fed (more than 550gm/m) by the help of feed roller to keep the sliver wt. constant.
How auto levelling is performed in a carding machine?
Auto levelling in a carding machine is a process of automatically adjusting the carding process to maintain a consistent sliver weight or thickness. This is achieved by monitoring the sliver weight or thickness at the delivery end of the carding machine and adjusting the speed of the feed roller accordingly.
There are two main types of auto levelling systems:
Open-loop systems: In open-loop systems, the sensor measures the sliver weight or thickness and sends a signal to the actuator. The actuator then adjusts the speed of the feed roller based on the signal from the sensor.
Closed-loop systems: In closed-loop systems, the sensor measures the sliver weight or thickness and sends a signal to the controller. The controller then compares the signal from the sensor to the set point and adjusts the speed of the feed roller accordingly.
Here are the steps involved in auto levelling in a carding machine:
The sliver is fed into the carding machine.
The sliver is carded and the fibers are disentangled and aligned.
The sliver is delivered to the delivery roller.
The sensor measures the sliver weight or thickness.
The signal from the sensor is sent to the actuator or controller.
The actuator or controller adjusts the speed of the feed roller.
The sliver weight or thickness is adjusted accordingly.
The process is repeated.
Auto levelling is an important part of the carding process because it helps to improve the quality of the yarn. By maintaining a consistent sliver weight or thickness, auto levelling can help to reduce the number of imperfections in the yarn. This can lead to a stronger yarn that is more resistant to breakage.
Implementation of Auto Levelling Systems
Auto levelling systems are an essential component of modern carding machines, playing a crucial role in ensuring yarn quality and production efficiency. By automatically regulating the fiber flow during carding, these systems can significantly improve yarn uniformity and reduce waste. In this section, we will discuss the factors to consider when implementing auto levelling systems, their integration into existing carding machines, and their overall performance in terms of yarn quality, efficiency, and cost-effectiveness.
Factors to Consider When Implementing Auto Levelling Systems
When implementing auto levelling systems, several factors need to be carefully considered to ensure optimal performance. These factors include:
Type of carding machine: Different carding machines may have varying requirements for auto levelling systems. For instance, high-speed carding machines may require more sophisticated levelling systems than slower machines.
Fiber type and characteristics: The type of fiber being carded can also influence the choice of auto levelling system. For example, synthetic fibers may require different levelling settings than natural fibers.
Yarn quality requirements: The desired yarn quality level is a critical factor in selecting an auto levelling system. For high-quality yarns, more precise levelling systems may be necessary.
Production capacity: The production capacity of the carding machine should be matched to the capabilities of the auto levelling system. Overloading the system can lead to performance issues.
Integrating auto levelling systems into existing carding machines typically involves the following steps:
Compatibility Assessment: Ensure that the chosen auto levelling system is compatible with the existing carding machine’s design and specifications.
Sensor Installation: Install the leveller sensor at a strategic location on the carding machine, where it can effectively detect variations in fiber density.
Actuator Integration: Connect the actuator to the carding machine’s drive system to enable adjustments in fiber flow based on sensor signals.
System Calibration: Calibrate the auto levelling system to ensure accurate measurements and optimal performance.
Testing and Evaluation: Conduct thorough testing and evaluation of the integrated auto levelling system to verify its effectiveness.
Performance/Benefits of Auto Levelling in Carding
Improved Yarn Quality: Auto levelling significantly reduces variations in sliver thickness, leading to a more uniform and consistent yarn. This, in turn, enhances the overall quality of the fabric produced from the yarn.
Reduced Waste and Increased Production Efficiency: Auto levelling minimizes the occurrence of thick and thin spots in the sliver, which would otherwise result in imperfections or breaks in the yarn. This reduces waste and improves production efficiency by minimizing downtime due to yarn defects.
Enhanced Carding Machine Productivity: Auto levelling allows for a more consistent and efficient carding process, enabling the carding machines to operate at their optimal capacity. This translates into increased productivity and throughput.
Reduced waste: By maintaining consistent fiber flow, auto levelling systems minimize fiber loss and reduce waste generation during carding.
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