| The warpage of thin-walled plastic parts is one of the common defects in the injection production,and it has been paid much attention by the manufacturers.The axial fan blade is an important part in automobile HVAC system,and it belongs to the thin-walled plastic parts.The warpage of the fan blade in the injection production not only affects the accuracy,but also may cause the dynamic imbalance,resulting in the vibration and noise of the fan while working,which will affect the performance of the fan.In this paper,the blade of an axial fan produced in an enterprise is taken as the research object.In order to better solve the warpage and prepare qualified fan blades,the injection molding of the blade is simulated by the injection molding CAE technology,and the orthogonal experiment is designed to analyze the influence of the process parameters on the warpage,and the anti-deformation compensation method is used to optimize the design of the die.The main research contents and results of this paper are as follows:(1)Firstly,the model of the warpage analysis for the blade was established by Moldflow.Then taking the warpage of the blade as the index,the orthogonal experiment was designed to analyze the effects of melt temperature,mold temperature,injection time,holding pressure,and packing time on warpage.Through the analysis of range and variance,it was found that the melt temperature and holding pressure have a significant effect on warpage.And the best combination of process parameters for the injection molding of the blade was obtained,that is:the melt temperature is 300~oC,the mold temperature is 90~oC,the injection time is 4s,the packing pressure is 1.4 times of the filling pressure,and the holding time is 14s.After the simulation was performed again based on the obtained optimization parameters,it was found that the warp and deformation of the blade was reduced,and the warpage amount was reduced from 1.908 mm to 1.570 mm.(2)Then,based on the method of anti-deformation design,the warpage of fan blade reverse compensation model with different compensation coefficients was simulated and analyzed,and the best reverse compensation model with a compensation coefficient of 1.1was determined based on the deformation results.Then based on the best model,the optimal design and processing of the die cavity was carried out by pre-compensation.(3)Finally,using the optimized injection mold and process parameters for the blade molding experiments,and the quality of injection molding of the blades were examined.It was found that the warpage of the blade was greatly reduced.The deformation was controlled within 1mm,the maximum warpage was reduced to 0.3mm.A dynamic balance test was performed on the fan blades and it was found that the dynamic unbalance of the blade was within the allowable range.This indicates that the optimized fan blade has a good dynamic balance and the optimized warpage has little effect on it.It can meet the production requirements without checking the dynamic balance.In general,the quality of injection molded blades has been greatly improved after the optimization of the process and the compensation of the mold,which is fully consistent with the requirements of the production,and the production efficiency of the fan blades has been improved,and the economic benefit of the enterprise has been increased. |
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