熔接结构与工艺对PMMA双色注塑熔接状态的影响

利用具有不同末端熔接夹角的聚甲基丙烯酸甲酯(PMMA)双色注塑拉伸试样模具,通过实时监测成型过程中第二次注塑的末端熔体温度、末端熔体压力、末端模具温度等重要注塑工艺参数,分别分析了末端熔接夹角、末端熔体温度、末端熔体压力、末端模具温度对PMMA双色注塑试样熔接状态的影响。结果表明,在末端熔接夹角为70°、末端模具温度不低于80℃的工艺条件下,提高注塑温度,确保第二次注塑的末端熔体温度不低于250℃,或者末端熔体压力控制在63 MPa左右,此时PMMA双色注塑试样熔接强度处于较佳状态,而且可以避免PMMA双色注塑试样熔接处溶剂应力开裂的风险。

Effects of Fusion Structure and Injection Parameters on PMMA Fusion Status of Bi-color Injection

Bi-color injection tensile sample mould with different end fusion angles were used to compare the fusion status of PMMA bi-color injection sample under different process conditions.During the process,the important injection parameters such as end melt temperature,end melt pressure and end mould temperature of the second injection were monitored in real time.The influences of the end fusion angle,end melt temperature,end melt pressure and end mould temperature on the fusion status of the PMMA bi-color injection sample were analyzed separately.From the results,it can be concluded that the end fusion angle should be 70°and the mould temperature should be more than 80℃,at the same time,the injection temperature is increased to ensure that the end melt temperature of the second injection is more than 250℃or the end melt pressure is controlled around 63 MPa,the fusion status of the PMMA sample is better and the risk of solvent stress cracking at the fusion position of the PMMA sample can be avoided effectively.