Research On Quality Characterization Method Of Micro-injection Products Based On Cavity Pressure

In the context of rapid economic development,injection molding products are more widely used in various industries,and products tend to be miniaturized.Micro injection molding products have a very broad application prospect due to their large demand.However,since the appearance size of micro-injection molded products is mostly micron or even nanometers,and the weight of the products is mostly milligrams,the required accuracy is high,so slight changes in process parameters during the injection molding process will have an important impact on product quality,Its injection molding process control becomes more challenging.Traditional injection molding methods cannot meet the needs of micro injection molding.Based on the cavity pressure monitoring technology,this paper monitors the cavity pressure in real time,introduces the peak cavity pressure and the projection area of the cavity pressure curve,takes the weight of the product as the characterization object,and monitors the quality of micro-injection molded products online by changing the process parameters And characterization,optimize the design and manufacture of micro-injection molds,and improve the quality of micro-polymer products.The main work content and results are as follows:First,the experimental platform is built.Adopt BOY-XS type miniature injection molding machine,install Kistler pressure sensor inside the cavity,and connect the computer to collect the cavity pressure information,and the temperature of the mold is controlled,and the experimental sample is obtained and then weighed with a high-precision electronic balance.Secondly,use the self-built experimental platform to carry out the cavity pressure experiment.Change the process parameters such as V/P switching point position,mold temperature,melt temperature,holding pressure,injection rate,and analyze the influence of process parameters on product weight.Using the peak value of the cavity pressure and the projected area of the cavity pressure curve as the characterization means of the product quality,the mechanism of the two effects on the product weight is analyzed.Through orthogonal experiments,the main effect of the process parameters is analyzed,and the characterization effect of the projected area of the cavity pressure curve and the peak pressure of the cavity is analyzed.The experimental results show:(1)Too early V/P switching value will cause the short shot defect of the experimental spline.Too early V/P switching will increase the weight of the experimental spline and obtain qualified injection molded products;and mold temperature,melt temperature and injection Although the increase of the speed will cause the weight of the experimental spline to increase,the increase issmaller,indicating that the three have less influence on the weight of the experimental spline.(2)Analyzing the pressure curve of the experimental spline obtained when the V/P switching position is 10 mm,it is concluded that a higher cavity pressure peak usually corresponds to a larger product weight,and the characterization effect of the cavity pressure peak is better than the cavity pressure curve projection area.(3)The analysis of orthogonal experiment results shows that the projected area of the cavity pressure curve can better characterize the weight of the product.The main reason for this difference is the influence of the holding pressure.The peak pressure of the cavity cannot indicate the holding stage of the filling process,and the peak pressure only indicates The maximum value of the cavity pressure during the entire filling process,and the process after the completion of the product filling is ignored.