注射速度对高透光性PMMA制件光学性能的影响

摘要

By single factor experiment,the effect of injection velocity on the stress birefringence,haze and light transmittance of high transmittance parts was studied,considering poly(methyl methacrylate)(PMMA) flat shell instrument panel mould as an example.The results show that at the same point of the parts,with the injection velocity (screw speed)gradually increasing from 25 mm / s to 55 mm / s,the stress birefringence show a gradual downward trend and close to quasi-linear,the haze appears inverted "V"change trends,and reaches a maximum value when the injection velocity is 30 mm/s.The change trend of the light transmittance is opposite to the haze,it reaches the minimum when the injection velocity is 30 mm/s.Under certain conditions of the injection velocity,with the distance between measuring point and the gate position increasing,stress birefringence will appear a peak in front of the gate,and with the peak as the center showing a downward trend,the haze gradually increase,light transmittance show a downward trend.%以某平板类仪表板模具为例,以聚甲基丙烯酸甲酯(PMMA)为实验材料,通过单因子实验研究了注射速度对高透光性制件的应力双折射、雾度和透光率的影响.结果表明,随着注射速度(螺杆速度)由25 mm/s至55 mm/s逐步提高,相同点位处制品的应力双折射率呈准线型逐渐下降的趋势,雾度呈倒“V”趋势变化,且在注射速度为30 mm/s时达到极大值,而透光率则与雾度变化趋势相反,同样在注射速度为30 mm/s时达极小值.在注射速度一定的条件下,随着测量点距离进浇位置的增大,应力双折射率会在浇口前方出现一个峰值,并以该峰值为中心呈下降趋势,雾度逐渐升高,透光率总体呈下降趋势.