In recent years, high-efficiency technology has been widely used across the country. It has played a positive role in greatly increasing the production capacity of pre-spinning equipment, saving electricity and energy consumption, and improving product quality. However, its shortcomings are also obvious. The hairiness of the yarn increases and the strength decreases. Is there an economical and practical solution that can not only make up for the shortcomings of efficient processes? After more than two years of research and exploration, we believe that combining high-efficiency technology with siro spinning technology is a technological innovation that offers the best of both worlds.
01 Defects of high-efficiency processes
The key to the high-quality and high-efficiency technology lies in the adoption of certain technical measures in the rear area of the spinning area to strengthen friction control and greatly improve the drafting capacity of the spinning machine. The total drafting is increased from 10 to 50 times the original Stretch to 50-100 times. Some data show that it can even reach about 120 times without deteriorating the quality, which can greatly increase the ration of pre-spun rovings, slivers and cotton laps. Due to the weight increase, the theoretical output of a single machine in each pre-spinning process can be increased by 1.6-2.0 times, which brings very considerable economic benefits. It can save a lot of pre-spinning equipment and save pre-spinning operating costs. The benefits are obvious. However, due to the adoption of roving weight and large draft of spun yarn, yarn hairiness becomes more serious and strength loss increases due to the following reasons:
(1) Increase in roving weight The width of the strands fed into the drafting part is increased, and the edge fibers are easily lost during the drafting process;
(2) The larger draft in the rear area makes the strands enter the front area It tends to be more twistless, and the strands are easy to diverge;
(3) The larger front draft of the spun yarn makes the strands diverge more obviously.
(4) The twisting triangle area of the high-efficiency process is larger than that of the traditional process, and the transmission of twist is affected. The fibers at the edge of the twisting triangle area are not easily twisted into the yarn body.
The general response to the above problems in actual production is to strengthen the control of the slivers in the areas before and after the spinning yarn drafting, and use a more sophisticated cotton collector in the front area of the spinning yarn. The winding machine can reasonably control the increment of hairiness, etc., but the implementation effect is not very satisfactory. Some factories use compact spinning to make up for the shortcomings of efficient technology, with better results. Since the compact spinning technology achieves the aggregation of fibers by shrinking the width of the sliver in the drafting output area of the spinning frame and eliminating the twisting triangle area, it strengthens the lateral control of the fibers and effectively reduces the hairiness of the yarn, which is just right. Make up for the shortcomings of efficient processes.
However, since the investment cost and operating cost of compact spinning are relatively large, which affects the economic benefits, we have combined high-efficiency technology with siro spinning technology. Practice has proved that the combined application of two new spinning technologies can achieve satisfactory results with little or no increase in investment costs.
02 Mechanism analysis of siro spinning to improve hairiness and strength
Siro spinning is a new spinning process. Since two rovings are fed and merged in the drafting area, the hairiness is significantly reduced and the strength is significantly increased. The improvement of hairiness is due to the fact that in the spinning triangle area, the single yarn is first slightly twisted, and then combined and twisted. The sliver has become a cylinder at the main twisting point, which is conducive to the entanglement of the fiber ends into the yarn body. The increase in strength is due to the fact that the whiskers have a triangular twisting area at the output of the front roller. The whiskers are twisted together under the action of tension to form a double-center yarn strip similar to a strand. When the force is applied, the two whiskers squeeze each other. Pressure makes it difficult for fibers to slip off, has low hairiness and high fiber utilization, so it is strong.
03 Siro spinning high-efficiency process production practice
3.1 The necessity of equipment condition analysis
Efficient technology is essentially based on modern textile equipment, fully tapping the potential capabilities of the equipment to draft parts and equipment The technological progress promotes the development of technology, realizes the weighting of the whole process of pre-spinning, and the third generation of large draft of spun yarn, thereby achieving high efficiency and high profitability of cotton spinning engineering. Therefore, the condition of the equipment and the quality of the equipment configuration will directly affect the implementation of efficient technology, especially the drafting capacity of the spinning frame, which is a key factor in determining efficient technology. The drafting capacity of the spinning frame is insufficient, and forcing high-efficiency technology will be counterproductive. Therefore, before implementing high-efficiency technology, it is necessary to analyze the equipment status and evaluate the drafting capacity of each equipment to formulate a specific high-efficiency process route. “The process follows the equipment”, blindly applying efficient processes without considering specific equipment conditions is extremely detrimental to the promotion of efficient processes.
3.2 Analysis of workshop equipment status and formulation of efficient process flow
3.2.1 The main equipment modifications
Mainly include the use of some new spinning equipment, new card clothings for steel wires, and the addition of fixed points on some machines. Comb elements; combing uses dense cylinder, double-row top comb and other combing elements to increase the combing capacity. Spinning is the key process in the transformation, mainly including the transformation of the cradle, the roller, the top pin, and the use of low hardness untreated rubber rollers.
3.2.2 Development of efficient process flow
From the above analysis of equipment conditions, the equipment in our workshop is basically A-prefixed equipment, and the equipment is relatively old. Especially the blowroom equipment is basically equipment from the 1950s, which is difficult to adapt to the requirements of efficient process spinning. Although the A186 carding machine uses new card clothing and its carding capacity has been improved, the cylinder speedThe improvement of � is greatly limited. If the high-efficiency process of heavy weight is adopted, the carding degree of the fiber will be affected to a certain extent. Production practice has proved that the increase in card sliver quantity must ensure the necessary fiber carding degree and knot removal rate, because they are closely related to the quality of the yarn. In the sliver roughening process, due to the advantages of the pressure rod drafting of the draw frame and the double apron drafting of the roving frame, they are suitable for semi-finished slivers with a wide drafting range and heavy input and output quantities.
Due to the use of new carding components in the combing process, the carding capacity of the equipment has been greatly improved, and the necessary carding degree can basically be ensured for carding heavy cotton layers. . Although the equipment of the spinning frame except FA506 is old, the cradle has been basically modified and the rollers have been basically replaced with mechanical rollers, especially the use of new top pins, which provides strong equipment support for the implementation of efficient technology. Based on the analysis of the equipment status of our company and the research on the efficient process of the system, we believe that there are obviously some shortcomings in implementing efficient processes in the entire spinning system. Therefore, we focus on the combined coarse and fine process of carding and the pre-combing process of combing. The comprehensive implementation of weighted spinning not only fully utilizes the potential of the equipment, improves the quality of the product, but also saves equipment investment, especially labor and electricity costs.
3.3 Determination of the quantification of each channel
Whether the quantitative configuration of cotton laps is appropriate or not mainly affects the opening efficiency and impurity removal efficiency of the cleaning process. The opening degree of cotton laps is the basis of carding machine carding.
When increasing the sliver quantity, the necessary fiber carding degree and knot removal rate must be ensured. Otherwise, if the carding degree is insufficient, the separation of semi-finished products will be affected, resulting in thick knots. Deterioration of dryness. Therefore, the carding capacity of the equipment must be considered when increasing the card sliver quantity.
Quantitative feeding of roll weight is beneficial to increasing the output of the combing machine, but it is limited by the pressure of the top roller. Therefore, the quantitative configuration should not be too heavy, generally no more than 50g/m.
When the combing machine feeds a heavy cotton layer, the matching of the carding machinery should be carefully selected and the ability of the nipper to clamp the cotton layer should be increased.
04 Issues that need to be paid attention to when implementing high-efficiency siro spinning technology
4.1 Select the appropriate distance between double bell mouths
4.2 Pay attention to the selection of roving twist coefficient.
Due to the double-feeding of siro spinning, the drafting capacity of the spun yarn is subject to certain limitations. Therefore, when applying high-efficiency technology, the roving basis weight cannot be increased to a large value like that of a single yarn. The large cohesion theory of efficient process application is difficult to realize. Therefore, great attention must be paid to the selection of roving twist coefficient.
4.3 The implementation of high-efficiency processes must be combined with the status of the own equipment, and the process should follow the equipment to formulate an appropriate high-efficiency process route.
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