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Jingwei Textile Machinery Co., Ltd. has been developing and developing the ring gauze long machine with the collective doffer for more than ten years. It has taken a series of effective measures to improve the reliability and stability of the equipment, so that the F1518J type collectively falls. The yarn spinning machine has become mature and stable, and has been mass-produced. It is the spinning machine with the highest degree of automation and technical content in China. In the following, from several aspects, some shallow and shallow analysis and research on the reliability, stability and market of the collective doffing yarn long machine are made.
1 Comparison of domestic and foreign ring spinning machines
At present, the most technologically advanced ring spinning machines in the world are: 350 spinning machine from Zinser, Germany; G30 spinning machine from RIETER, Switzerland; Fiomax1000 spinning frame from Suessen, Germany; RX240 spinning machine from TOYOTA, Japan ; NSF4 spinning frame from Marzoli, Italy.
l: J_k spinning machine from the overall analysis, its advanced nature is mainly reflected in:
(1) High-speed, high-efficiency, energy-saving, mechatronics and automation technologies have matured. The spinning machine has a maximum spindle speed of 25,000 r/min and a spindle count of up to 1488 spindles.
(2) High-speed, semi-automatic and automatic spinning machines are available in various forms and have excellent performance, which can meet the needs of users at different levels and have been commercialized.
(3) The reliability and stability of the collective doffer are high, and the doffing time is less than 3 min.
The domestic spinning frame has been improved in adapting to the high speed and suitable spinning range, and the products have begun to enter the cotton spinning factory for production and use. However, the development of technology is slow, and there is an urgent need to further improve the quality of spinning, high speed, high efficiency, automation, reliability and stability. At present, the representative spinning machines in China are: F1518J spinning frame of Jingwei Textile Machinery Co., Ltd. Yuci Branch; EJMl28JL spinning frame of Shanghai Second Textile Machinery Co., Ltd.
The main institutional forms of the above-mentioned domestic and foreign spinning frames are shown in Table 1.
2. The importance of reliability design
Reliability refers to the ability of a product to perform a specified function under specified conditions and time, or when the product can maintain its function. It comprehensively reflects the durability, trouble-free, maintainability, usability and economics of a product.
With the development of cotton textile industry technology, the spinning frame is developing towards high speed, high efficiency, energy saving, automation and intelligence. It adopts long machine and is equipped with collective doffing device, PLC control technology, AC servo system, etc. Machines and systems become large and complex, and the number of components and components is increasing, which increases the chances of failure. In order to ensure the reliability of the whole machine and system does not decrease, it is necessary to improve the reliability level of zero and components, and at the same time guarantee the design. "The reliability of the product is designed, produced, and managed." This is the conclusion made by Comrade Qian Xuesen at a defense system reliability work conference. The reliability of the product is first designed. According to Japan's investigation and analysis of the causes of product failures, failures due to poor design accounted for 50%, components and materials accounted for 37%, and manufacturing defects accounted for 13%. 3 Several main factors determining the reliability and stability of the collective doffing yarn
3.1 The straightness of the longitudinal direction of the spindle and the cumulative error of the spindle distance
The degree of linearity in the longitudinal direction of the spindle directly affects the centering of the gripper and the spindle on the creel. The length of the super-long spinning machine is more than twice that of the ordinary short machine. The spindles and the ribs of the long-distance machine at home and abroad are matched with tolerances. After assembly, the center of the spindle will not move, effectively controlling the straightness of the longitudinal center of the spindle, eliminating the need to normally knock the spindle, the same steel ring and spindle. Axial guarantee is achieved by adjusting the steel collar.
The cumulative error of the spindle distance is mainly reflected in the connection and manufacturing precision of the dragon rib. If the dragon ribs are connected according to the FA506 type spinning machine, the length of each dragon rib is 2520±0.1mm, the tolerance of the spindle hole to the first hole is ±0.2mm, and the tolerance of the first hole to the end of the rib is ±0.1mm, then 1008 Ingot spindles require 14 dragon ribs on one side. In theory, the maximum long-direction cumulative tolerance is ±1.7mm (504 spindles are ±1.0mm). It is necessary to control the long-direction cumulative error of the long machine to the same level of the short machine, and it is bound to increase the tolerance of the long rib length of 2520 mm to ±0.05 mm, which is difficult to realize in milling manufacturing.
The F1518 series of spinning frames adopts the fastening method of the hinge pin connection, which makes full use of the manufacturing advantages of the machining center, improves the manufacturing precision to ensure the installation accuracy, and strictly controls the spindle tolerance and the cumulative error of the long direction of the dragon tendon. Achieving the level of the short machine is an improvement in the manufacture of domestic spinning frames, creating conditions for the group doffing machine. This connection method eliminates the work of pre-arranged rack assignment, and has strong interchangeability and high work efficiency.
3.2 Pipe grabber for pulling and inserting the bobbin
The pipe grabber is directly related to the reliable guarantee of the performance index of the inserted and removed bobbin in the process of collective doffing. The flexibility of the gripper head in and out, the tightness of the seal and the guiding of the bobbin play a decisive role in reliable plugging.
Internationally, the form of grasping the tube of the gripper is nothing more than two types - the top grip type and the middle outer grip type. . The top gripping type does not damage the yarn, but the gripper requires a higher degree of median mounting adjustment relative to the spindle. The middle part of the grip type is easy to damage the yarn, but the grip is smoother and the effect on the medium is better. The clamping form is clamped by the cylinder clamp, and the seal has airbag and membrane pad, and the sealing has its own advantages. The bell mouth of the pipe grabber is large, which is beneficial to the guide of the yarn tube, but it should not be too large, so it is easy to ignore and reduce the vertical alignment requirement when the pipe grab is installed. Therefore, it is easy to damage when the yarn tube is inserted and inserted on the spindle. The spindle causes the spindle to oscillate, which affects the quality of the yarn.
After the improved design of the gripper of F1518J spinning frame, the bell mouth is enlarged, the O-ring is changed to the polyurethane film pad, and the appropriate spring diameter is selected to ensure the reliability of the inserted and inserted bobbin.
3.3 The height control of the creel and the consistency control of the entrance and exit
The high and low consistency of the creel and the degree of control of the swing in and out consistency are another important factor affecting the performance index of the pull-in tube of the collective doffing.
In foreign countries, the inner and outer swings of the drive air frame are multi-cylinder control and single-cylinder control. The F1518J spinning frame was originally controlled by multi-cylinder (22 of 1008 spindles). The synchronization was found to be poor during operation. The reason for the analysis was that there was gas loss in the gas path, and the movement of multiple cylinders was not coordinated and not in place. The key point of multi-cylinder control is to solve the problem of loss of gas path, positioning accuracy of cylinder installation and how to alarm when a cylinder fails. The single-cylinder control can achieve the uniformity of the swinging in and out of the air frame.
In the early stage of the collective doffing spinning frame, the lifting and lowering of the creel frame was generally driven by a motor and a chain, which easily caused the height difference of the creel. With the application of new technology, the current spinning frame is controlled by servo system, synchronous toothed belt transmission, and good reliability. The F1518J spinning frame has changed to a single-cylinder control and servo system, and has improved the installation accuracy and running accuracy of the screw drive mechanism that drives the creel, effectively solved the problem of the height difference of the air frame, and makes the lifting smooth and motion-oriented. accurate.
3.4 Stud positioning accuracy of the inserted tube in the bobbin conveying system
The conveying method of the bobbin is a convex disc conveying, a steel belt bolt conveying and a combination of the two.
(1) The convex plate conveying method is provided with an intermediate transition station at the dragon rib, and an intermediate transition action is added between the two positions of the cylinder control, correspondingly an unreliable factor is added, and the doffing time is lengthened. As long as the outer diameter tolerance of the convex disk is controlled and the long-direction cumulative error between the convex plates is eliminated, the positioning accuracy of the convex nails of the convex disk is easy to control, and the positioning surface at the bottom of the convex disk is large, and the vertical direction of the upper tube of the convex nail is applied. Degree control is better. On the other hand, the sprocket transport type can be easily coupled to the winder. The F1518J spinning frame now also has a flat-disc type of doffing machine that meets the needs of users.
(2) The steel pipe bolt conveying method is susceptible to the long-distance cumulative error of the steel strip and the tensile deformation of the steel strip material, resulting in poor positioning accuracy, thus affecting the bolt and the gripper of the pipe plug. Unreliable factors caused by the difference in the middle. The key point of the solution is the problem of tensile deformation of the steel strip. After testing and comparing different steel strips under the same material conditions, the tensile strength of imported steel strips is about twice as large as that of domestic ones. After the F1518J spinning frame was changed to the imported steel belt, the reliability of the equipment was improved and the user's use was satisfied.
3.5 Tight electrical control system and detection device
The collective doffing yarn length machine is a highly automated spinning equipment, which eliminates the traditional manual doffing process and the entire spinning process is unmanned. Therefore, the electrical control system must have a strict set of logic. The program software is guaranteed, and at the same time, it must be implemented with accurate and reliable detection system and advanced control technology.
The F1518J spinning frame has adopted the following measures and means in this respect to ensure the reliability of the product.
(1) The control system adopts the advanced technology results of a PLC control technology and AC servo system control technology, so that the equipment runs smoothly and reliably, the speed can be changed, and the doffing time can be shortened.
(2) After the automation is improved, the complementary detection devices are indispensable. For example, the detection of the remaining tubes on the spindle, the detection of the remaining tubes during the processing of the full bobbin, the detection of the limit during the lifting operation of the air frame and the detection of the overload protection are all effective measures to improve the reliability and stability of the equipment.
(3) Setting the fault display and alarm device can eliminate the fault point and eliminate hidden dangers in time, and guarantee the reliability of the equipment is also an effective means.
3.6 Improve the quality of accessory products
The control of the collective doffing part is mainly done by pneumatic control and electrical control, and plays an important role in the entire doffing operation. In the past, the reliability of domestically produced equipment was not high, and one of the reasons was due to the poor quality of the selected electrical and pneumatic components. With the development of domestic basic industries, the strengthening of international components and components, the selection of international or domestic brand-name products, the reliability of the collective doffing machine has been greatly improved.
3.7 Improve the assembly process level and strengthen the management of users
In addition to the reasonable design of the equipment, improving the assembly process level is also a very important factor to improve reliability. Whether the assembly process is perfect and reasonable, and whether the assembly work is in place directly affects the use status of the product. Good assembly quality can make up for the shortcomings in the processing of parts. Improving the assembly process, controlling the assembly quality and improving the quality of the assembly workers will be effective measures to improve reliability.
On the other hand, with the improvement of the automation degree of cotton spinning equipment and the sublimation of technical content, new requirements have been put forward on the level of management of users, and the requirements for vehicle handlers and maintenance workers are getting higher and higher. The manufacturer should do a good job in after-sales service and strengthen the training of users. The use of the factory should strengthen and refine the management work, strictly follow the training requirements, correct some unreasonable operating habits, and summarize the effective measures in practice. These will be the prerequisites for ensuring the normal and stable operation of the equipment. .
Thanks to the unremitting efforts and improvement of the F1518J spinning frame, the reliability and stability of the product can be guaranteed and improved, and the pulling and intubation rate of the collective doffer is increased from 96% to over 99%. The rate of retention has increased from 70% to more than 96%.
4 Market Analysis
4.1 Advantages of the spun yarn machine
(1) The main difference between the long machine and the short machine is that the length of the car is increased. The front and rear of the car are basically the same. Only a set of synchronous drafting drive is added at the rear of the car. The power of the main drive and the suction motor is large. Roughly the same. Therefore, the price per spindle of the long machine is low.
(2) The number of spindles per long machine is equivalent to two short machines. When the spinning mill is installed and arranged, the floor space of one car, the front and the rear of the car can be reduced, and the investment in plant construction is also reduced. In other words, the number of spindles increased by 96 spindles under the same floor area, effectively increasing production and increasing productivity. In short, the investment in the long-term development of the new plant or the old plant can be reduced.
(3) The long machine is more demanding than the general short machine in design and manufacturing precision. Therefore, there are fewer failures during operation and use, less wear and tear on the parts, and fewer breaks. As a result, operational maintenance and maintenance work can be reduced, correspondingly reducing daily operating expenses and reducing spinning costs.
4.2 Benefits of a collective doffer
(1) Reduce labor intensity and reduce labor
Most of the textile enterprises use manual doffing. Each of the doffing workers has a large amount of work for daily insertion and unloading, and the labor intensity is relatively large. Generally, the doffing workers are served by young and good women workers. The use of the collective doffer can not only greatly reduce the doffing work, but also greatly reduce the labor intensity. It has been verified by practice that the F1518J type collective doffing yarn long machine can reduce the number of employees by 10,000 spindles and reduce the cost by 70,000 yuan per year. With the further improvement of the reliability and stability of the equipment, the management level of the spinning mill will be higher, and the economic and social benefits of the enterprise will be more impressive.
(2) Improve labor productivity
Due to the high degree of automation of the collective doffing machine, the operation can be completed fully automatically during the entire spinning process, which can shorten the doffing time, save the finishing work of the empty bobbin and the finishing equipment, and the quality of the bobbin Improvement, which increases labor productivity.
(3) Improve the level of automation and continuity
On the basis of automation of the spinning frame, continuous production of thickness and fine mesh can be realized. The meticulous combination not only directly connects the two processes of cotton spinning factory with the most people and the labor intensity, realizes automatic and continuous production, improves product quality and labor productivity, and solves the spinning process that has been difficult to solve in the world for a long time. The contradiction between the spinning package and the speed is developed from a medium-speed large package to a high-speed small package, thereby greatly increasing the spindle speed of the spinning frame and improving labor productivity.
4.3 Market demand
It is an inevitable trend to use a long machine and a flat doffer with a spinning frame. The textile industry is a traditional industry in China and will continue to play its role as a pillar industry of the national economy in the 21st century. Under the control of the national policy of ingots, most of the old equipment has been eliminated, and the textile industry has gradually stepped out of the predicament. After entering the WTO, the textile industry must improve labor productivity, reduce staff and increase efficiency, and further improve the quality of textile products. In particular, the spinning machine with high degree of automation, stable yarn quality, high spindle speed and power saving will be favored by users. In recent years, some joint ventures and developed regions in China have been equipped with advanced foreign doffing yarns and long-term equipment, and have begun to use domestically produced equipment. The demand for users is increasing.
Analysis on the reliability of collective doffing yarn long machine
The ring spinning machine is a large-volume equipment in the cotton spinning production process, which plays a vital role in the quality of the yarn. It is also a concentration point of the spinning mill's labor force and labor intensity. The spinning machine of the ring spinning machine with the collective doffer is an important part of the cotton spinning enterprise to improve the labor productivity. Among the internationally advanced cotton spinning enterprises, enterprises that can reduce the employment of 10,000 spindles to less than 50 people almost all use the spun yarn. The long machine is equipped with collective doffing and fine wire connection as the main means. To achieve the fine connection, the first is the single machine automation of the spinning frame, the key is to ensure the reliability and stability of the collective doffing machine.