Type selection, installation and maintenance quality control of roving frame
(1) Equipment selection: at present, there are many roving frame manufacturers in the market, and there are more than ten different models at home and abroad. Each manufacturer's equipment has its advantages and disadvantages. According to the production varieties, product grades and capital status of the manufacturers, you can purchase the equipment model suitable for yourself. Selection must be done: it can meet the needs of production, and does not waste enterprise funds, but also ensure that the operation of the equipment is always in a good state.
(2) Equipment installation: after selection, installation is an important link to ensure the product quality, and also the most basic work. Those who have the ability to install the equipment themselves, and those with poor conditions should ask the equipment manufacturer or the technicians of the same trade with better technology to install and debug. We must find professional personnel to strictly control the installation and debugging, so that in the future production, we can easily carry out various work.
(3) Maintenance quality: to carry out daily maintenance is the most basic daily management, to achieve thorough, comprehensive, no "dead corner", that is to say, to really maintain in place.
(4) Purpose: to keep the equipment in good condition at all times.
Control of roving tension
(1) In order to make the roving winding to the roving tube smoothly, the winding speed of the bobbin must be slightly higher than that of the output sliver of the front roller. Therefore, tension and tension draft will be produced on the sliver between the front roller and the roving tube. It is the key to roving production, which not only affects the roving life, but also directly affects the yarn quality.
(2) According to the requirements of spinning quality, the maximum elongation is generally not more than 3%. The elongation difference between the yarns of the same size, between the front and rear rows and between the same type of machine should be controlled below 1.5%.
(3) The yarn from the front roller to the top of the flyer has a smaller twist and a longer distance due to kinking. At the same time, the flyer vibrates at high speed, which is prone to accidental elongation. According to experience, it should be adjusted as follows: when the small yarn is wound from the starting point to the second layer of the lower part of the bobbin, the sliver may vibrate slightly, but it is better not to start the wave. If the upper yarn is tight, which means that the winding speed is too fast and the elongation is too large, the starting position of the cone pulley belt should be moved to the big end of the upper cone pulley, and no cone pulley should be controlled and adjusted from the frequency converter. The final goal is to achieve a little jitter state consistently. If the yarn is gradually tightened during the spinning process, it means that the movement of the cone pulley belt is too small each time, so the number of tension teeth should be reduced, otherwise, the number of tension teeth should be increased.
(4) The factors influencing roving tension change include roving weight, front roller speed, twist, raw cotton quality, temperature and humidity and mechanical state. Therefore, it is necessary to establish roving quality account in production. The size, difference and unevenness of roving tension will affect the evenness and weight unevenness of roving, which is an important index affecting roving quality, so it should be strictly controlled. Because the fiber in the roving section is much less than that in the sliver, and the twist is lower than that in the spinning yarn, it is easy to produce unexpected elongation after experiencing large tension, which will deteriorate the evenness of roving evenness and increase the breakage.
(5) When the tension difference is large, the weight unevenness of roving increases obviously, which should be controlled within 1.0%. When the roving tension is small, the roving forming is loose and rotten, and it is difficult to store, transport and unwind, which not only affects the quality of roving itself, but also increases the yarn weight unevenness and weight deviation. For example, when spinning pure cotton roving on roving frame with poor false twist effect, the quality index of front row is inferior to that of back row. Under the same spinning conditions, the quality difference will be caused by the different tension between front and back row. Of course, under the condition of good false twist effect, the back spinning tension may be greater than that of the front row. Therefore, in the aspect of roving quality management, we should not only pay attention to the influence of drafting part on quality, but also master the change of roving tension.
