Shock Parameters Optimization Of High Frequency Shake-out Machine

The casting shake-out is an important part of the casting process,for the shake-out of the cavity of the complex castings are mostly used high frequency shake-out machine.The shock parameters of shake-out is a key factor in the shake-out quality of castings.The shock parameters include the air hammer impulse amplitude,impulse width,impulse frequency and the impulse points position and number.The appropriate shock parameters of shake-out can ensure the shake-out quality of castings and improve the shake-out efficiency.It can be seen that it is important to determine the appropriate shock parameters of shake-out for the casting to achieve high quality of shake-out.Therefore,proposes to optimize the shock parameters of high frequency shake-out machine.Currently,the shock parameters of shake-out are chosen mainly based on experience by using trial and error method shocking the casting repeatedly.For the foundry of casting,the shock parameters of shake-out of different type of casting be chosen mainly rely on the shake-out machine manufacturers which through repeatedly shock the casting,then to determine the shock parameters of shake-out by observe the effect of the shake-out.After each time of experiment also need to cut the casting to observe the quality of shake-out,this method not only waste time but also waste energy,and trial and error experiment lack scientific guidance,it is difficult to determine the best shock-out parameters.So it is necessary to provide a convenient and reliable way to choose the appropriate shock parameters,not only make quality of shake-out more reliable,but also improve production efficiency.On the basis of summarizing the current research status of the shock parameters of shake-out machine both at home and abroad,we propose a method to optimize the selection of shock parameters by dynamic analysis method and the shock parameters of shake-out are optimized.The main works accomplished are as follows:(1)The development status of shake-out technology is expounded,it is time-consuming and laborious,low efficiency and low reliability for the current selection of shock parameters of shake-out,this paper puts forward the research on the optimization of the shock parameters of high frequency shake-out machine.The working principle of high frequency shake-out machine are introduced,the main factors influencing the effect of shake-out are analyzed.The pulse amplitude of air hammer,the pulse frequency,the pulse width and the shock position and numbers of the air hammer are determined as the main optimized parameters.(2)Based on the Fourier transform theory,the spectrum analysis of pulse sequence of shake-out shock force is carried out.The relationship between the time domain parameters and the frequency domain parameters of the impulse pulse sequence is obtained.According to the theory of shock,the process of air hammer shock casting is analyzed theoretically,and establish shake-out model of the air hammer shock the casting.Meanwhile the pulse width of the air hammer shock the casting is estimated and prepared for optimal selection of pulse width.So that we narrow down the select range of pulse width and improve the efficiency of parameter optimization.(3)A three-dimensional model of the casting is established in the SolidWorks by using the block modeling method.The elasticity of the casting is imposed by the method of coordinate connection.Then we divide the grid and establish the finite element model of the complex casting.The natural frequencies and modes of the casting are obtained through the modal analysis.The results of the harmonic response analysis show that the maximal response peak frequency of the casting adhering sand interface.In combination with modal analysis,we determine the selection range of pulse frequency.Which further narrow down the selection range of the pulse frequency and improve the parameter optimization efficiency.(4)The experimental design analysis of shock parameters is carried out,therefore the shock parameters are optimized.Firstly,the experimental design analysis of single pulse shock casting is carried out,obtain the excellent scheme is four shock points are evenly arranged A2B1C3 parameter combination.The scheme shows that the influence order of each factor on shear stress,tensile stress and acceleration of castings adhering sand interface is the pulse amplitude,followed by the pulse width,the last is the position of the action point.The study also found that the larger of pulse width,the smaller effect of the pulse position on the shake-out index.The narrower of pulse width,the larger of obtained shake-out index value with the position of the pulse is close to the lower support of the casting.Keep other factors unchanged,by changing the pulse width,we find that the narrower of the pulse width,the greater of the shake-out index value.Through the experimental design analysis of two and more pulse shock casting is carried out,obtain the excellent scheme is four shock points are evenly arranged A2C1B2 parameter combination.The scheme shows that the influence order of each factor on shear stress,tensile stress and acceleration of castings adhering sand interface is the pulse amplitude,followed by the pulse frequency,and finally is the pulse width.The fundamental frequency of pulse sequence,fifth times fundamental frequency,sixth times fundamental frequency are corresponding to the casting’s first frequency,seventh frequency,tenth natural frequency.The pulse width is equal to half of the pulse cycle.Through the experimental design analysis,the optimized scheme of shock parameter of shake-out is obtained and the shock parameters are optimized.Which overcomes the shortcomings of time-consuming,inefficient,low reliability and other shortcomings in selecting the shock parameter of shake-out based on experience traditionally.(5)Based on the principal component analysis method,the comprehensive evaluation equation of shake-out index is constructed.The principal component analysis is carried out on the shake-out index.According to the principal component analysis,the comprehensive evaluation equation of shake-out index is constructed,and the comprehensive evaluation equation of the shake-out index is verified.We can obtained: the greater of the comprehensive evaluation value,the better of the corresponding impact parameters scheme.The comprehensive evaluation value of the optimization scheme obtained by the experimental design analysis is the largest.The comprehensive evaluation equation of the shake-out index can realize the comprehensive evaluation of the shake-out index.And then can determine the optimal combination of shock parameters based on the size of the comprehensive evaluation.Which overcomes the influence of subjective factors on the comprehensive evaluation of the shake-out index.(6)Air hammer and vibratory motor will shock the shake-out machine and absorber.Easy to damage the isolator and affect work performance of the shake-out machine,so that affect the efficiency of shake-out.The influence of the shock parameters and the vibratory motor to the vibration response of shake-out machine is studies by Adams.As the pulse width varies from small to large,the vibration response parameters of the isolator increases first and then decreases.The pulse amplitude has a greater effect on the vibration response parameter than the pulse width,the pulse amplitude is the most influential factor.When the pulse frequency changes,the vibration response parameters are generally proportional to the frequency for the isolator.The vibratory motor is most damaging to the isolator,mainly due to the shock of the vibratory motor on the isolator.It is possible to consider increasing the torsional stiffness of the isolator or replacing the isolator with stronger torsional resistance.The study of the vibration response analysis of high frequency shake-out machine has great significance to reduce the shock damage to the isolator,so that obtain good work performance of high frequency shake-out machine and realizes shake-out more reliable and high efficiency.