Household Electric Drill Optimization Design Based On CAE And DOE

With the further application of computer technology in the field of mold design,the product development cycle and cost are reducing.As one of the most important components of electric drills,the shell is generated from engineering plastic injection molding,its structure design not only affects the quality of injection molding process,but also the operational reliability of products.On the other hand,electric drills also have higher quality requirement on the operational reliability,life time,property level.So,the simulation analysis for these limiting cases is very necessary.This paper focuses on the J1Z-FM-13 electric drill,the main work and research results are summarized as follows:(1)Based on the general design of electric drill shell,analyzing its complex structure characteristics.From the method that Moldflow analysis CAE technology is taken advantage to simulate the filling time,pressure at the end of fill,weld lines,temperature at flow front and warping deformation.Finally the result shows the filling time is short with no short shot and retention,the pressure at the end fill is balanced and symmetrical,there are fewer air traps,the highest temperature at flow front is in the range of the usage temperature,the total deformation of the shell is not obvious.(2)Based on the combination CAE with DOE technology and the simulation data of moldflow to design different experiment for the different purposes.Select the melt temperature,mold temperature,injection time,holding pressure,holding time,cooling time as the experiment factors of full factorial experiment method and select the shrinkage and warpage as for the research target.Finally,it is confirmed the melt temperature,mold temperature,holding time,holding pressure are significant factors for the shrinkage and warpage,meanwhile,the interactions of each experiment factors are confirmed through the full factorial experiment.According to DOE experiment scheme of Moldflow,the optimal process parameters combination is determined.(3)After the shell is analyzed and optimized by Moldflow,combined with the reliability test requirements,the boundary condition and loading are discussed to establish five kinds of finite element analysis models about thermal deformation,random vibration,drop impact,noise analysis and strength check for the key parts.On the aspect of thermal deformation,the shell’s strain and deformation in extreme temperatures are studied and then the maximum stress is far less than the allowable stress.On the term of the random vibration,after seek inherent frequency and vibration type of the electric drill through modal analysis,realize that 3 Sigma response stress and deformation are both very little;In the drop impact,we research plastic products of the maximum strain during the instant impact,involving the bottom,side,45° and find the biggest stress on the side of three directions is still less than the yield strength.Noise analysis results show that under the first-order sound pressure,sound pressure value is far less than the national standard regulations.In the strength check of key parts,mainly considering the meshing between rotor spindle pinion and output system of big gear.Results show that the maximum stress occurs in the rotor tooth surface contact part,less than corresponding to the yield strength of material.Finally,using the surface response method,further explore on electric drill shell design to confirm the influence of the deformation and the overall stress.To sum up,with the strong acknowledge of engineering application,this paper has two aspects of the injection molding and reliability experiment,combined with the optimization theory to study how to apply CAE technology to guide for structure optimization.And the optimum design of household electric products can provide certain theoretical basis.