Research On Key Technology For Automatic Feeding Of Flexible Strips With Large Length-diameter Ratio

Automatic feeding is the basis of automatic packaging and assembly operations. However, with characteristics of slender soft, the geometry of the flexible material with large length-diameter can not be determined. Soft material is difficult to separate and pick up, so this kind of packing operation still stays in the semi automation system. With the case of disposable venous blood taking needle, the existing machines adopted a combination of artificial feeding and machine packing. This increased the labor costs and intensity, and sanitary conditions can not be guaranteed. At the same time, it is difficult to meet the needs of large-scale and automated packaging.In order to solve this problem, in this paper, analyzed present situation on automatic feeding of flexible object at home and abroad, meanwhile, and Considered characteristics of the material, studied on two key technologies, including automatic picking and sorting, then designed an automatic feeding device for large length-diameter ratio flexible material, and completed the machine manufacture and test research. The main work of this paper is as follows:1) Through the analysis of the typical characteristics of the flexible material with large length-diameter ratio, selected representative medical venous blood collection needle as specific implementation object, measured parameter and characteristic, including diameter, length, weight and state of aggregation.2) According to the geometrical shape and deformation characteristics of soft material, put forward two methods of material picking mechanism, adsorption type and rubbing type, made a mechanical and dynamics analysis of rubbing type pick-up mechanism, calculated that optimum pit angle was 60 degrees, and the minimum clamping force was 0.02 N, which ensured the reliability and stability of the rubbing type. To adsorption type picking mechanism, the dynamic analysis of the material during the adsorption process was mainly carried out, which showed that it can ensure the reliable adsorption while the minimum adsorption force is 0.2N and minimum suction cavity section is 2.86mm2, which were important design parameters.3) Study on the feed mechanism through experiment. Design of rubbing type and adsorption type experiment platform. The results indicated that ratio of the two efficiency was 80%: 86%; the best parameter combination of rubbing type was determined by orthogonal test, which were as follows: depth of insertion was 30 mm, initial rod distance was 4mm and clamping force was 1.0N.4) Designed physical platform of collating device, the goal was to shorten the station waiting time of collating device, a variety of arrangement scheme design and comparison, put forward two arrangement methods, Even to Odd method and split step method. From efficient point of view, determined split step method as the final order method, which finished picking and arrange task up to five steps.5) Based on adsorption type, designed the feeding device of automatic feeding, including three main functional modules: reclaiming, spinning, straight. Based on PLC, the sensing technology, the servo control technology, the hardware and software of the system was design and build, a platform was assembled and debugged, feeding efficiency was 80000 times / day, and the data of the test platform basically meet the design requirements.