Raw material selection The selection of raw materials n […]
Raw material selection
The selection of raw materials not only affects the quality of the yarn, but is also a necessary guarantee for achieving high speed. In the spinning process, yarn breakage will occur when the dynamic strength of the yarn is less than the dynamic tension. Therefore, maintaining the necessary strength of the yarn is not only a requirement for the subsequent production process, but also a requirement for the normal production of spinning. In terms of raw materials, the length, linear density and strength of cotton fiber have a great influence on the yarn strength.
In recent years, affected by various factors, the quality of cotton in my country has shown a downward trend. The Mark value (Mic) of cotton is getting higher and higher, the fineness of cotton fiber is getting thicker, the length is getting shorter and shorter, and the strength of single fiber is increasing. The lower is: With the gradual promotion and use of machine-picked cotton, the ratio of short fiber and impurity in raw cotton increases, which makes it difficult to mix cotton and directly affects spinning ends.
And the realization of high-speed production should cause concern. On the other hand, affected by the pressure of rising costs, some companies adopt low-quality high-spinning, or use fine-staple cotton instead of long-staple cotton to produce varieties above 9.718tex. Due to the low strength, it is difficult to achieve high-speed production, and overall planning is required.
The choice of different equipment types determines to a certain extent the spinnable speed of spinning in the future production. Equipment is the foundation. Spinning frames designed and produced by different equipment manufacturers have different characteristics. To a certain extent, their structure, processing accuracy and technological performance characteristics will have a decisive influence on the spinning speed.
1. Rack structure
In order to improve the stability of equipment operation, equipment manufacturers continue to optimize the design and improvement of the frame structure, such as the use of steel pipes or section steels instead of cast iron frames, improvement of the rigidity of the wall panels, the elimination of ingots and the use of wheel belt drives, etc. These improvements are even more important. It is conducive to the high-speed operation of the equipment, but the author believes that the processing accuracy of various parts is a guarantee for high-speed. Some people think that imported equipment meets the dimensional accuracy by assembling segments and segments, while the domestic spinning frame is difficult to guarantee accuracy through the assembly of individual parts, which affects the dimensional consistency of the entire frame and affects the level of the frame. This view is open to discussion. . Take Toyota RX240 spinning frame as an example. The equipment is assembled by single parts. A 1200-spindle spinning frame involves 10,729 parts. There has never been a screw hole that has been reprocessed due to positional differences or hole size. This is indeed worth learning from domestic spinning mills. If domestic equipment does not improve the processing accuracy of individual parts, even if assembled in sections, it cannot guarantee that the machine is suitable for high-speed operation.
2. Transmission system
The transmission system must first be designed reasonably, and the force of each component must be uniform. There has been a spinning machine manufactured by a spinning machine factory that directly used the original ordinary ring spinning frame transmission system. As a result, the increase in the force of the system caused the head of the spinning machine. The drive shaft is broken and gear wear is aggravated. Secondly, the material and processing accuracy must be guaranteed, otherwise, high-speed operation will inevitably produce mechanical waves, etc., and even serious local wear problems will cause the equipment to fail to operate normally.
3. Twisting and winding mechanism
The spinning frame adopts servo motors and electronic cams for winding, which can effectively improve the package forming quality and breakage of large, medium and small yarns, and ensure the parallel and level of the dragon ribs and the ring plate. For example, the Toyota spinning frame directly drives the steel through the use of T-shaped screws. The collar plate is raised and lowered to ensure the absolute level of the ring plate and the dragon rib, which is beneficial to the stability of the spinning tension.
4. Collective doffing organization
The collective doffing spinning frame is more conducive to high speed due to the use of aluminum rod spindles. However, if the collective doffing device runs unstable, it will directly damage the spindles, resulting in many broken ends and high hairiness, which will affect the spinning speed, and attention should be paid to the collective doffing. The reliability and stability of the yarn device.
5. Spinning process
The spinning stroke mentioned here refers to the maximum linear distance from the output point of the spinning front roller to the winding start point. The smaller the spinning stroke, the smaller the spinning tension fluctuation and the easier it is to control, which is more conducive to high speed.