The Design Of Rolling Centering Test Bed And Study On Centering Process Parameters Of Lotus Kernel

Lotus kernel centering is an important step to removing core,the centering accuracy decided product quality.As the lotus different size and irregular shape,it is difficult to ensure that the lotus axis and twist drill axis coaxial,thus drilling deviation in the production.Because of drilling deviation not only can not reach the purpose of removing the core,but also increase the losses of lotus kernel.In order to improve the processing quality of lotus kernel and explore the process parameters which affect the accuracy of centering,in this thesis,developed a lotus kernel rolling centering test bed to research lotus kernel process parameters based on rolling centering method.The main work of this thesis are as follows:1.The characteristic parameters of the irregular shape of lotus kernel are analyzed statistically.With the Hunan lotus as the sample,the roundness error,diameter,length,static friction coefficient and recovery coefficient of lotus kernel were tested.The shape parameters such as diameter and roundness error were extracted from the geometric parameters as the main feature parameter.2.The numerical simulation of the rolling centering process was carried out.The influence of the rotation speed,diameter and the center distance of the roller on the centering accuracy of the lotus were obtained by simulating the rolling process of the lotus kernel by using the discrete element simulation and analysis software EDEM.3.Developed rolling centering test bed of lotus kernel.In order to research the influence of geometric parameters,the centering process parameters and the process parameters on the centering precision and processing quality of lotus kernel,the lotus rolling centering test bed was designed and manufactured.Selected and calculated the key parts of test bed.Builded 3D model of test bed by UG software.Based on Siemens PLC completed the development of test bed control system.Which established material conditions for research centering rule of lotus kernel.4.Experimental study on the centering process parameters of lotus kernel was carried out.Based on the lotus kernel rolling centering test bed,the single factor test was carried out on the centering rotate speed,center diameter,center distance of the centering roller.The optimum process parameters of lotus roll centering were obtained by orthogonal test are: centering roller speed 210 r / min,diameter 35 mm,center distance 40mm;Using the optimal centering process parameters to the lotus kernel removing core test,to detect the actual centering accuracy.The experimental results show that the precision value is located in 0.3mm ~ 0.45 mm of the largest,accounting for 32% of the total sample,removing core of the better rate of 83.5% accuracy,drilling exactly rate of 95.6%.From the test results,the optimal centering process parameters can meet the lotus precision machining requirements.The optimal technological parameters of lotus kernel rolling centering in this thesis are of great significance to the research and development of high quality and efficient lotus kernel removing core and splitting equipment.