| China is a large country of citrus production and consumption.The planting area and annual output of Citrus rank first in the world.In order to sell out of season,the citrus that needs to be stored in storage every year accounts for about one third of the total citrus output of the whole year.Oranges need to be packed in PE film bags before storage to preserve corrosion and prolong shelf life.At present,citrus storage bagging packaging mainly depends on manual work,which has high labor intensity and low efficiency.Therefore,it is of great practical significance to develop a film packaging machine that can be used for citrus storage.Based on the existing commercial fruit packaging machines at home and abroad,a continuous citrus storage film packaging machine including feeding device,conveying device,heat sealing device(longitudinal sealing,transverse sealing)and auxiliary film feeding device is designed,and the prototype trial production and test are completed.The main research contents of this paper are as follows:(1)Design of the overall scheme of continuous film packaging machine.According to the requirements of functions and technical parameters of Citrus storage film packaging machine,based on the design idea of wrapping citrus with upper and lower films-heat sealing and hot cutting-bag making and packaging,the process flow including feeding,material conveying,film feeding,horizontal sealing and vertical sealing is put forward;The realization mode of each process action is defined,and the structure scheme of the whole machine is determined.(2)Design of key parts of continuous film packaging machine.The feeding device,conveying device,longitudinal sealing device,transverse sealing device and auxiliary film feeding device of film packaging machine are designed and calculated,and the main structure and dimensional parameters of each part are determined;The kinematics and dynamics of the feeding device and the transverse sealing device are analyzed by Adams,and the feeding performance of the feeding device in rows and columns is verified;The static simulation of the transverse sealing device is carried out by using ANSYS,and the maximum stress and deflection of the main components of the transverse sealing device are checked;Aiming at the problem of how to feed the rolled upper and lower films at the same time,the film feeding scheme and structure are designed,and the film feeding speed of the lower film is analyzed to ensure that the film will not interfere with the feeding of Citrus under the condition of continuous film feeding.(3)Determination of main structure and working parameters of heat sealing device of film packaging machine.The experimental research on horizontal seal and vertical seal was carried out,and the influence laws of six parameters on seal strength were clarified: horizontal seal speed,horizontal seal compression,horizontal seal temperature,vertical seal speed,vertical seal blade angle and vertical seal temperature;Through the orthogonal rotation combination test,the regression geometric equation of sealing strength is obtained;The response surface is drawn and analyzed by quadratic regression equation,and the structural and working parameters are optimized.The results are as follows: the sealing speed is 126 / min,the transverse sealing compression is 2.3mm,the transverse sealing temperature is 160 ℃,the longitudinal sealing blade angle is 67 °,and the longitudinal sealing temperature is 166 ℃.Under this parameter,the expected value of sealing strength is 42 N.(4)Design of control system for continuous citrus storage film packaging machine prototype.The control part is based on PLC controller,mainly including hardware selection and software design.According to the working principle and the control requirements of each part,the selection of hardware parts such as PLC controller and sensor is completed;The software part uses Mitsubishi PLC programming tool software to compile the ladder diagram according to the program flow chart.(5)Prototype trial production and prototype performance test.The prototype trial production and test of continuous citrus storage film packaging machine were completed.The parameters of the prototype were set as packaging speed 126 pieces / min,transverse sealing compression amount 2.3mm,transverse sealing temperature 160 ℃,longitudinal sealing temperature 166 ℃.The test results were as follows: the packaging rate was 98.4%;The average transverse seal strength is 40.63N;The average longitudinal seal strength is 41.81 N.The difference between the prototype test results and the expected value of bench test is detected.The test results show that the prototype test meets the expectation. |
