激光清洁去除塑料模具表面残余物的工艺研究

Research on Process of Laser Cleaning to Remove Surface Residues of Plastic Molds

塑料模具经过多次使用后表面黏附的塑料等残余物会影响加工精度,必须进行清洁,但现有清洁方式存在一定缺陷。采用激光清洁技术对塑料模具表面残余物进行清洁,考察了不同激光功率和脉冲频率的影响。利用场发射扫描电子显微镜、X射线能谱、显微硬度、电化学极化曲线表征了塑料模具表面清洁的效果。结果表明:激光清洁能够显著降低模具材料表面氧含量,并起到去除塑料模具表面残余物的作用。同一激光功率下,随着脉冲频率的提升,模具材料表面氧含量呈上升趋势,而模具表面显微硬度呈先降低后增大趋势。该现象可能是激光高温引起了模具材料表面二次氧化和局部淬火作用所导致。综合考虑,在200 W激光功率、100 kHz脉冲频率的激光清洁条件下,塑料模具表面氧含量、硬度、腐蚀电位和腐蚀电流密度最接近对照样,达到了最佳综合清洁效果。

The plastic adhesion on the surface of the plastic mold after multiple uses seriously affects the processing accuracy and must be cleaned;however,the existing cleaning methods have certain defects.Laser cleaning technology was used to remove residues on the surface of plastic molds,and the effects of different laser powers and pulse frequencies were investigated.Field emission scanning electron microscopy,X-ray energy spectroscopy,microhardness,and electrochemical polarization curves were used to jointly characterize the cleaning effects of residues on the surface of plastic molds.The results show that laser cleaning can significantly reduce the oxygen content on the mold surface material and significantly remove residues on the surface of plastic molds.Under the same laser power,with the increase of pulse frequency,the oxygen content on the surface of plastic molds gradually increases,while the hardness of the surface of plastic molds first decreases and then increases.The phenomenon may be due to the secondary oxidation and local quenching of the surface of the mold material caused by the high temperature of the laser.Considering comprehensively,under the laser cleaning condition of 200 W laser power and 100 kHz pulse frequency,the surface oxygen content,hardness,corrosion potential,and corrosion current density of the plastic mold are the closest to the control sample,achieving the best comprehensive cleaning effect.