基于预胶化多糖结合剂磨具的单晶蓝宝石加工试验研究

Machining experiment of single crystal sapphire based on pre-gelatinized polysaccharide bonded abrasive tool

针对单晶蓝宝石加工用磨具所使用树脂结合剂环境友好性差的问题,提出使用预胶化多糖材料作为结合剂的单晶蓝宝石绿色加工磨具。分析了纤维素增强相对预胶化多糖凝胶特性的影响。设计了预胶化多糖结合剂磨具配方与制作工艺,制作了磨具试样并分析了其机械特性。基于所制作磨具进行了单晶蓝宝石研磨片的表面加工试验。试验结果表明:纤维素可实现预胶化多糖凝胶的物理增强。使用“常温干燥+置换干燥+热风干燥”混合干燥工艺的磨具试样具有最佳的机械特性。随着砂结比增大,磨具机械强度整体呈现先增大、后减小的趋势。砂结比为4∶1的磨具具有最高的单位载荷工件温升,有利于固相反应的进行,表现出相对最优的加工特性:经过10 min加工,单晶蓝宝石表面粗糙度Rq值下降了84.25%,材料去除率为0.1μm/min。

Aiming to substitute the environmental-unfriendly resin binder used by current abrasive tool for single crystal sapphire machining,a novel abrasive tool for green machining of single crystal sapphire adopting pre-gelatinized polysaccharide as binder was proposed.Influence of cellulose as reinforcing phase on the gelation property of pre-gelatinized polysaccharide was analyzed.Prescription and manufacturing process of pre-gelatinized polysaccharide bonded abrasive tool was designed.Samples of abrasive tool were made and their mechanical properties were tested.Surface machining experiment of pre-lapped single crystal sapphire wafer was carried out.It is found that physical reinforcement of pre-gelatinized polysaccharide gel can be realized by cellulose.Abrasive tool samples dried by“natural drying+displacement drying+hot-air drying”mode presented the best mechanical properties.The mechanical strength of abrasive tool samples increased first then decreased with abrasive to binder ratio increasing.Abrasive tool with abrasive to binder ratio of 4∶1 had the highest temperature rise of workpiece per machining load unit,which is beneficial to the solid-solid reaction and leads to the relatively best machining performance:after 10 minutes’machining,Rq value of single crystal sapphire decreased by 84.25%,and the material removal rate was 0.1μm/min.