Study on blade parameter optimization analysis of broccoli cuts based on minimum slice stress

Abstract: In order to explore the effect of the broccoli cutter working parameters on cutting characteristics of broccoli branch stalk as well as to optimize the working parameters of the cutting blade, the cutting tests of broccoli branch stalk were performed with electronic universal material testing machine cutting test-bed. The samples were the outer branch stalk of broccoli with same diameter. The main test equipment included the electronic universal material testing machine, blades and cutting stand, a digital camera and its image processing and analysis software ImageJ, scorpion, meter ruler, vernier caliper, protractor and marker pen. The test method and scheme were designed based on the measurement and control system of the universal material testing machine, the data measured by the pressure sensor on the universal material testing machine automatically displayed, relation curve of cutting force and time of cutting blade could be get. The maximum cutting force obtained during the cutting process was taken as the maximum cutting force FMS of broccoli branch stalk. Some researchers considered that it is more reasonable to use unit cutting force as the research target. therefore, in order to eliminate the influence of the diameter difference of broccoli branch stalk on the experimental results, the maximum cutting force per unit area was taken as the target value. The influence of the cutting blade working parameters on the maximum cutting force were studied, the cutting blade working parameters include blade structure, blade angle, cutting angle and cutting position on the branch stalk. The cutting tests were grouped into the single factor tests, multi-factor orthogonal test. The testing factors were cutting position(ranging from 30-50 mm), cutting blades (cone blade、straight blade、spherical blade), blade angle (5(-17(), cutting angle (45(-90(). Multi-factor orthogonal method was a three-factor three-level testing scheme. The multi-factor orthogonal method used to optimize the working parameters of broccoli cutter. The multi-factor test results showed that the change trends of the objective values (the maximum cutting force per unit cutting area) with the changes of the testing factors were basically consistent with the results of the single factor tests. Single factor test results show that the dicing performance is best when the cutting position is 40 mm, the straight blade, the cutting angle is 60(, and the blade edge angle is 5(-10(. The results of multi-factor test showed that the position of the cutting, the structure of the blade, the blade angle and the cutting angle of the cutting tests were the primary and secondary factors that affect the cutting performance, the cutting position was 40 mm, the blade structure was spherical blade, blade edge angle was 8( and the cutting angle is 90(. According to the experimental optimization results, the broccoli cutter was designed, and the cutting test was carried out on the prototype. The cutting effect was good and the cutting success rate reached 91%, the mean value of cutting force was 18.32kPa, which is basically close to the theoretical value of 17.45kPa, it verified the rationality of tool parameter setting. The study results provided theoretical support for the development of subsequent broccoli cutting machine and cutting blade parameters.