| Textile industry occupies an important position in the national economy in our country. It is the important pillar industry and people’s livelihood industry of the national economy. Spinning machine is a key step of yarn, there are a lot of old spinning machines in our country, most of them adopt artificial doffing method, and its efficiency is very low. It is difficult to employ workers in domestic spinning mill at the same time, and labor costs has increased, so the old spinning machines needs to be reformed in order to replace the artificial doffing, According to the situation of China, the automatic doffing car becomes the inevitable choice of reforming the old spinning machine. A series of automatic doffing cars have been launched at home and abroad, but they all exist many problems, and can’t meet the needs of spinning enterprise, so a kind of automatic doffing car with high efficiency, low failure, stable and reliable performance is needed eagerly in domestic.In this paper, a unique automatic doffing car is designed through the study of a large number of articles and objects, and combined with advanced PLC technology. Automatic doffing car’s type of motion is go and stop, it will stop when it goes every ten distances of bobbins, and does extubation operation and intubation operation at the same time. Its extubation method is different from other doffing cars’airbag extubation method. It uses manipulator to extubate tube from the bottom of the tube. This way makes spinning longer, production efficiency becomes higher, and it doesn’t need to change the airbag frequently, reduces reconstruction funds of the enterprise. It is more suitable for winding process. Intubation method is also different from other doffing car. It uses stepper motor to organize hollow tubes into the tube vault, and places hollow tubes on the bobbins with gas claw on the same time. It uses photoelectric detection device to detect whether there is a full tube in order to determine whether grabbing hollow tube or not. The car becomes more intelligent.In this paper, the automatic doffing car uses S7-200 SMART PLC of Germany’s Siemens Company as the main control unit. This PLC has compact structure, flexible configuration, powerful function, strong anti-interference ability. It’s stable and reliable. It forms a perfect automatic control and a human-computer interaction platform using Smart 700 IE touch screen matched with this PLC. The S7-200 SMART PLC provides three roads with high speed pulse output, one road is used to control A5 series servo motor of Panasonic Company in order to realize the precise location, and another road is used to control stepping motor in order to realize the order of hollow tubes. PLC’s outputs control the solenoid valves’ open or close through the intermediate relays. The solenoid valves control the movement of the gas cylinder or claw so as to realize the basic action of the doffing car. The proximity switch and the limit switch input signals to PLC, PLC rely on them to judge whether a cylinder moves in place. The Smart 700 IE touch screen realizes the real-time display of the motion parameters, one step operation and alarm window’s display.The automatic doffing car is easy to operate and has friendly interface. It achieves a higher rate of intubation, extubation and end break after repeated experiments and tests. It is very suitable for the domestic transformation of the existing old spinning machines. The doffing car will advance intelligence and automation of spinning machine in our country, and enhance the competitiveness of textile enterprises. The textile enterprises will be able to reduce labor, and save the labor money. It will improve the quality of yarn and meet the needs of people’s high quality textiles. |
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