英語(yǔ)翻譯
The reason for these results is the 950-bar packing pressure.This high pressure was the cause of higher melting temperature and increased cooling time for plastic part.Because of this,determination of optimal melt temperature is necessary to obtain acceptable part quality.Similar variation behavior was observed from the error of roundness of molded parts.The error of roundness is a kind of warpage defects.Hence,the temperature of the part is high because of the high value of temperature inside the mold,but after the ejection process,the hot part cools sharply in the room temperature and this sharp temperature change increases the error of roundness of parts.Although variation direction is opposite of shrinkage and error of roundness,the second considerable result from this study is that similar inclination behavior can be observed from the measurements of cavity pressure (Fig.13).Yet,when the melt temperature was increased,the mold temperature also increases.The relationship between the melt temperature and mold temperature can be inevitable,though description of the behavior of the cavity pressure in this case is not easy because in plastic injection molding,there are so many parameters which may influence cavity conditions or quality of parts.However,on the other perspective,these results show that the cavity pressure has a dominant effect on the amount of shrinkage and error of roundness that occurs.