负压式生鲜食品包装机关键部件设计与试验研究

发布时间：2018-08-24 18:54

【摘要】：本文在分析研究国内外大量生鲜食品包装机械研究和应用现状的基础上,提出了适应中国市场的负压式生鲜食品包装机包装工艺及整机方案,重点研究生鲜食品包装机的输送装置、切断机构和横封装置的工作原理和技术,实现生鲜食品的高速、高质量包装。主要研究内容及结论如下:(1)根据我国生鲜食品包装机械现状,提出了负压式生鲜食品包装机的设计要求以及技术参数,并对包装工艺进行了分析。确定了负压式生鲜食品包装机整机结构以及工作原理,根据生鲜食品包装机的传动要求,对包装机的传动系统进行了设计研究,并对各个机构传动的关键参数进行了计算。(2)对包装机输送装置进行了仿真与试验研究,通过压缩试验和ANSYS有限元仿真分析了输送装置对包装盒压缩变形的过程及机理,分析了包装盒的易损伤位置及原因。并通过正交试验,确定最佳参数组合,在包装盒及生鲜食品不压缩受损的同时,保证PET包装盒和输送装置有较好的输送同步性。(3)研制了基于凸轮连杆式的包装机切断机构,应用ADAMS建立了切断机构的参数化模型,对其进行运动学分析和仿真模拟,得到该机构主要参数变化对机构运动的影响规律。通过二次规划算法优化分析计算,得出一组最优参数组合,此参数条件下切刀的加速度最大值为7971 mm/s2,切割距离为20.4 mm,满足切断机构工艺需求。利用此参数组合的运动学仿真分析表明,下切刀的加速度最大值为7971 mm/s2,切割距离为20.4mm。试验样机对多种厚度的PVC保鲜膜切断率都在98%以上,切断机构满足生鲜食品包装机作业要求。(4)设计了一种基于负压原理的生鲜食品包装机横封装置,横封装置采用负压吸膜方式实现横封作业,装置主要由前吸风盒、切断器、后吸风盒和辊子输送机为主要部分组成。对横封装置裹膜过程中的动力学特性进行了分析,应用FLUENT进行后吸风盒流场研究。通过样机正交旋转组合试验进行影响因素的回归方程显著性分析,并通过MATLAB优化得出装置最佳的结构和工作参数,横封率为99.5%,回归方程式可较好的分析和预测横封装置的性能。(5)通过负压式生鲜食品包装机样机试制以及试验研究,样机对于生鲜食品的包装速度为49.4包/min,包装率为99.4%,鼓包率为5%,基于负压式原理的负压式生鲜食品包装机,达到了设计要求和预期目标。
[Abstract]:On the basis of analyzing and studying the research and application status of a large number of fresh food packaging machinery at home and abroad, this paper puts forward the packaging technology and the whole machine scheme of the negative pressure fresh food packaging machine adapted to the Chinese market. The working principle and technology of the conveying device, cutting off mechanism and transverse sealing device of fresh food packaging machine are studied in order to realize the high speed and high quality packaging of fresh food. The main contents and conclusions are as follows: (1) according to the present situation of fresh food packaging machinery in China, the design requirements and technical parameters of negative pressure fresh food packaging machine are put forward, and the packaging technology is analyzed. The structure and working principle of the negative pressure fresh food packaging machine are determined. According to the transmission requirements of the fresh food packaging machine, the transmission system of the packaging machine is designed and studied. The key parameters of the transmission of each mechanism are calculated. (2) the simulation and experimental research on the conveying device of the packaging machine are carried out. The process and mechanism of the compression deformation of the packaging box are analyzed by compression test and ANSYS finite element simulation. The easily damaged position and reason of packing box are analyzed. Through orthogonal test, the best parameter combination is determined, while the packing box and fresh food are not compressed and damaged, the PET packing box and conveying device are guaranteed to have good transport synchronism. (3) the cutting mechanism of packaging machine based on cam connecting rod is developed. The parameterized model of the cutting mechanism is established by using ADAMS. The kinematics analysis and simulation are carried out, and the influence of the main parameters of the mechanism on the motion of the mechanism is obtained. Through the optimization analysis and calculation of quadratic programming algorithm, a group of optimal parameter combinations are obtained. The maximum acceleration of the cutter is 7971 mm/s2, and the cutting distance is 20.4 mm, under this parameter condition, which meets the technological requirements of the cutting mechanism. The kinematics simulation results show that the maximum acceleration of the cutter is 7971 mm/s2, and the cutting distance is 20.4mm. The cutting rate of PVC film with various thickness is above 98%, and the cutting mechanism can meet the requirements of fresh food packaging machine. (4) A kind of transverse sealing device of fresh food packaging machine based on negative pressure principle is designed. The transverse sealing device adopts the negative pressure suction film method to realize the transverse sealing operation. The device is mainly composed of the front suction box, the cut-off device, the rear suction box and the roller conveyor. The dynamic characteristics of the transverse sealing device during the process of film wrapping were analyzed and the flow field of the rear suction box was studied by using FLUENT. The regression equation of the influencing factors was analyzed by orthogonal rotating combination test of prototype, and the optimal structure and working parameters of the device were obtained by MATLAB optimization. The horizontal sealing ratio is 99.5, and the regression equation can better analyze and predict the performance of the transverse sealing device. (5) the prototype of the negative pressure fresh food packaging machine is trial-produced and the experimental research is carried out. The packaging speed of the prototype for fresh food is 49.4 / min, the packing rate is 99.44.The packing rate of drum is 5. The negative pressure type fresh food packaging machine based on the principle of negative pressure has achieved the design requirements and expected objectives.
【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TS206.5

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