牙釉质表面高速铣削机理研究  

Research on the Mechanism of the High Speed Milling of Enamel Surface

作　　者：吴世雄[1,2] 倪湧潜 王成勇[1,2] 李苏洋[1,2] WU Shingxiong;NI Yongqian;WANG Chengyong;LI Suyang(Mechanical and Electrical Engineering Institute,Guangdong University of Technology,Guangdong 510006;National Engineering Research Center for Healthcare Devices United Engineering Laboratory of Operation Instruments Manufacturing for Orthopedic and Dental,Guangdong University of Technology,Guangdong 510006)

机构地区：[1]广东工业大学机电工程学院,广东510006 [2]广东工业大学国家医疗保健器具工程技术研究中心骨科手术器具及牙科设备制造联合工程实验室,广东510006

出　　处：《机械工程学报》2021年第11期78-92,共15页Journal of Mechanical Engineering

基　　金：佛山仙湖实验室开放基金重点(XHT2020-010);国家自然科学基金(51735003);广东省自然科学基金(2018A0303130107)资助项目。

摘　　要：牙釉质表面高速切削是牙科修复手术的一个关键过程,切削中可能出现较大切削力、低表面质量以及表面损伤等问题,因此有必要开展相关科学研究。针对活体牙的咬合面和颊舌面,设计硬质合金刀具高速铣削牙釉质表面试验方案,获得关键加工特征,并进一步讨论材料断裂和表面形成机理。结果表明,逆铣加工形成高摩擦和挤压,诱发非稳态材料断裂,切削力、表面粗糙度和表面损伤均因此明显增大。口腔修复手术牙釉质表面切削应优先选择顺铣加工方式。切削中材料断裂及表面生成主要有三类方式:产生层片状相对稳态切屑的相对稳态材料断裂方式、产生断裂切屑的非稳态材料断裂方式、通过脆化效应和熨压机制形成光滑塑性表面方式。顺铣方式下咬合面和颊舌面切削可获得一些亚微米厚层片状稳态切屑,内有褶皱和裂口,反映出高应变速率下的材料脆化及位错作用。与咬合面的垂直相交切削方式不同,颊舌面切削时切削刃斜交牙釉柱。此方式下材料更难断裂,从而导致非稳态块状或撕裂切屑更容易出现,切削力和表面损伤更大。顺铣方式下得到的良好塑性表面与切入-切出尾段圆弧直接相关。尾段圆弧满足产生塑性加工表面条件,加工结果由脆化效应和熨压机制所主导。High-speed cutting of tooth enamel surface is a key procedure for dental restoration surgeries, with problems such as large cutting force, low surface quality and surface damage in the cutting process. Therefore, related scientific research is required. For the occlusal and buccal/lingual surfaces of the human teeth, an experimental plan for the high-speed enamel surface milling with carbide cutters is designed for key processing characteristics, and the material fracture and surface formation mechanisms are further discussed. The results show that the up-milling process produces high friction and extrusion, further resulting in unsteady material fracture. In addition, the cutting force, surface roughness and surface damage are all significantly increased accordingly. And down-milling mode is preferred for the enamel surface cutting in dental restoration surgeries. There are three main types of material fracture and surface formation in cutting: the relatively steady material fracture which produces lamellar chips, the non-steady material fracture which produces fractured chips, and the smooth plastic surface formation by embrittlement effect and ironing mechanism. For occlusal and the buccal/lingual surfaces cutting under down-milling mode, some sub-micron thick layers of stable chips with folds and cracks can be cut to obtain, reflecting the material embrittlement and dislocation at high strain rate. Different from the perpendicular intersection cutting of the occlusal surface, the cutting edge crosses the enamel rod obliquely during buccal/lingual cutting. In this way, the material is more difficult to fracture, resulting in more unstable blocks or tearing chips, more cutting force and surface damage. Good plastic surfaces can be obtained with the down milling mode, which is directly related to the tail section of the cut-in-cut-out arc. The tail section arc satisfies the conditions for producing plastic surface, and the processing results are dominated by embrittlement and ironing mechanisms.

关 键 词：牙釉质 高速铣削 硬质合金铣刀 材料断裂 表面形成 

分 类 号：R318[医药卫生—生物医学工程]