共查询到18条相似文献,搜索用时 125 毫秒
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《机械工程学报》2017,(15)
通过在MK9025A型曲线磨床上开展微晶玻璃陶瓷磨削试验,研究可加工陶瓷表面成形机制和表面粗糙度。结果表明,可加工陶瓷材料磨削时其材料去除具有延性去除、延脆性去除、脆性去除三种模式,以硬脆材料相关系数Mr改进可加工陶瓷未变形切屑厚度模型,提出延性域系数η0、延脆性域系数η1,用以构建延性-延脆性和延脆性-脆性两个临界磨削深度模型。根据可加工微晶玻璃陶瓷单因素磨削试验,提出了复合磨削因子Q,基于以上未变形切屑厚度模型和两个临界磨削深度模型建立表面粗糙度模型,得到了表面粗糙度与复合磨削因子之间的关系,利用标准差检验模型精度。正交试验验证结果表明,可加工微晶玻璃陶瓷表面粗糙度试验值与所建立的表面粗糙度模型理论值吻合度较高。 相似文献
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硬脆材料微磨削表面形成机理试验研究 总被引:9,自引:0,他引:9
微磨削作为微尺度硬脆材料元器件的一种重要加工方法越来越受到重视,分析硬脆材料微磨削材料去除机理、提出其应为脆性去除与延性去除的综合作用,并就硬脆材料微磨削中材料去除过程与传统磨削方式的不同建立微磨削表面形成模型。为揭示硬脆材料微磨削过程的表面形成机理,验证所提出的微磨削未变形切屑厚度hm与微磨削表面粗糙度Ra计算模型的科学性和准确性,针对钠钙玻璃这一典型硬脆材料设计了正交微磨削试验,就试验结果进行硬脆材料微磨削表面形貌分析,讨论硬脆材料微磨削表面影响因素以及影响规律。基于试验数据结果对所建立微磨削模型的科学性进行了验证,并通过试验获得了微磨削后表面粗糙度Ra从78 nm至0.98 μm的一系列表面,为硬脆材料微磨削表面形成机理研究提供了理论参考与试验依据。 相似文献
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《机械工程学报》2017,(7)
针对微晶玻璃超精密磨削加工不可避免的表面/亚表面损伤问题,通过微晶玻璃磨削试验研究500#、1 500#、2 000#和5 000#金刚石砂轮磨削微晶玻璃的表面形貌、表面/亚表面损伤特征及其材料去除机理,揭示微晶玻璃脆性域磨削和塑性域磨削的表面/亚表面损伤特征,提出依次采用500#金刚石砂轮粗磨和5 000#金刚石砂轮精磨的微晶玻璃高效低损伤磨削工艺。结果表明,500#和1 500#金刚石砂轮磨削表面的材料去除方式为脆性断裂去除,2 000#金刚石砂轮磨削表面的材料去除方式同时包括脆性断裂去除和塑性流动去除,5 000#金刚石砂轮磨削表面的材料去除方式为塑性流动去除;脆性域磨削微晶玻璃的表面损伤形式为凹坑、微裂纹、深划痕,亚表面损伤形式为微裂纹;塑性域磨削微晶玻璃的表面损伤形式为微磨痕,亚表面损伤形式为靠近磨削表面的材料的塑性流动。 相似文献
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构建了单颗磨粒划擦各向同性硬脆材料的弹性应力场解析模型,并以此为基础提出单颗磨粒划擦各向同性硬脆材料表面的裂纹失稳扩展临界函数,临界函数包含原始表面应变速率、磨削液等因素对裂纹扩展造成的影响。将石英玻璃作为研究对象,深入分析了表面微裂纹损伤的可控磨削机理。在进行石英玻璃的磨削试验中,材料的磨削机理随单颗磨粒磨削深度的增加而变化,依次是塑性域去除、低载半脆性域去除、全脆性域去除和高载半脆性域去除。在1 mm/min的工件进给速度下,可以对石英玻璃进行塑性域磨削,从而获得无裂纹损伤的光滑磨削表面,然而其磨削效率较低,在实际生产中不能发挥理想的作用。对石英玻璃开展全脆性域磨削时,材料去除率较高、加工表面表面质量好、微裂纹损伤深度较小,砂轮自锐性良好,是一种优良的精密磨削工艺。 相似文献
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硬脆材料高效精密磨粒加工技术 总被引:1,自引:0,他引:1
分析了硬脆材料加工特点,研究了硬脆材料超高速磨粒加工、延性域磨粒加工、高效率端面磨削加工、高效率自由磨粒加工和砂带磨削等高效率加工硬脆材料材料去除机制,分析了其关键技术以及国内外研究现状,为硬脆材料的高效率加工提供合理的技术方案. 相似文献
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通过对硬脆材料 (玻璃 )的切削试验 ,建立了硬脆材料的磨削模型 ,讨论了硬脆材料在磨粒作用下的塑性变形和断裂行为 相似文献
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J. Cheng Y. D. Gong 《The International Journal of Advanced Manufacturing Technology》2013,69(1-4):147-160
This paper proposes a model to predict the material removal mode in soda-lime glass micro-grinding. This model defines material removal process to three stages which conclude ductile type, ductile-brittle type and brittle type by the quantization of undeformed chip thickness h m . The model for computing undeformed chip thickness in micro-grinding has been built considering tool topography, grit distribution and size effect in this paper. Micro-grinding experiments with different cutting depth on soda-lime glass have been designed and conducted. From experiment results, it was found that the edge crack length tends to have a wide range with different h m . Three types of chip have been investigated in results, and coolant has been verified to be an important factor to soda-lime glass ductile-regime micro-grinding. Critical depths of soda-lime glass micro-grinding have been found to be 2 and 5 nm, grinding forces in experiment provide the proof to predictive model proposed by this paper. 相似文献
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The current research of micro-grinding mainly focuses on the optimal processing technology for different materials. However, the material removal mechanism in micro-grinding is the base of achieving high quality processing surface. Therefore, a novel method for predicting surface roughness in micro-grinding of hard brittle materials considering micro-grinding tool grains protrusion topography is proposed in this paper. The differences of material removal mechanism between convention grinding process and micro-grinding process are analyzed. Topography characterization has been done on micro-grinding tools which are fabricated by electroplating. Models of grain density generation and grain interval are built, and new predicting model of micro-grinding surface roughness is developed. In order to verify the precision and application effect of the surface roughness prediction model proposed, a micro-grinding orthogonally experiment on soda-lime glass is designed and conducted. A series of micro-machining surfaces which are 78 nm to 0.98 ~tm roughness of brittle material is achieved. It is found that experimental roughness results and the predicting roughness data have an evident coincidence, and the component variable of describing the size effects in predicting model is calculated to be 1.5x 107 by reverse method based on the experimental results. The proposed model builds a set of distribution to consider grains distribution densities in different protrusion heights. Finally, the characterization of micro-grinding tools which are used in the experiment has been done based on the distribution set. It is concluded that there is a significant coincidence between surface prediction data from the proposed model and measurements from experiment results. Therefore, the effectiveness of the model is demonstrated. This paper proposes a novel method for predicting surface roughness in micro-grinding of hard brittle materials considering micro-grinding tool grains protrusion topography, which would provide significant research theory and experimental reference of material removal mechanism in micro-grinding of soda-lime glass. 相似文献
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针对单晶硅、光学玻璃等硬脆性材料的微结构形状精度难控制的问题,开发出微磨削技术。它是利用金刚石砂轮微细尖端,控制尖端形状及其表面的微磨粒出刃形貌,在硬脆性材料表面加工出微沟槽结构阵列。为了探索其功能特性,微磨削结构表面分别被用于薄膜太阳能电池、单晶硅芯片和石墨叶片的基板表面,然后测试和分析其光伏特性、湿润性和油泵效率。加工结果表明,微磨削技术可以加工出高精度且光滑的微结构表面。应用发现,微透镜结构的薄膜电池可在弱光散光下产生较高的转化效率和填充因子,可以在无太阳照射下发电。当硅晶片表面被加工出微沟槽结构时,较大深度会导致较大的液滴接触角,而且,微沟槽结构梯度表面会产生前后接触角差,可用于控制液滴的微运动。在油泵中,当叶片微结构深度从500 m开始减小到100 m时,油泵的工作效率会逐渐增大,最后大于传统油泵的工作效率。因此,高精度且光滑的微结构表面可以产生更高附加值的功能特性。 相似文献
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The micro-grinding of complex meso/micro-components of hard and brittle materials have attracted much attention in recent years. However, little related knowledge was accumulated, and there is a lack of quantitative evaluation of edge chipping damage, which is a major drawback. A theoretical model was established to further analyze the material removal mechanism under the action of single grain, considering the pressure phase transition, dislocation nucleation, and crack growth. An evaluation factor Fr of edge chipping damage was proposed to provide a reference for evaluating micro-grinding quality. Besides, the theoretical results were verified using the nano-scratch test. The experimental results proved that the proposed evaluation factor was an efficient tool to describe and predict micro-grinding quality. 相似文献
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Micro ultrasonic machining (micro-USM) is an unconventional micromachining technology that has capability to fabricate high aspect ratio micro-holes, intricate shapes and features on various hard and brittle materials. The material removal in USM is based on brittle fracture of work materials. The mechanical properties and fracture behaviour are different for varied hard and brittle materials, which would make a big difference in the processing capability of micro-USM. To study the processing capability of USM and exploit its potential, the material removal of work materials, wear of abrasive particles and wear of machining tools in USM of three typical hard and brittle materials including float glass, alumina, and silicon carbide were investigated in this work. Both smoothed particle hydrodynamics (SPH) simulations and verification experiments were conducted. The material removal rate is found to decrease in the order of glass, alumina, and silicon carbide, which can be well explained by the simulation results that cracking of glass is faster and larger compared to the other materials. Correspondingly, the tool wear rate also dropped significantly thanks to the faster material removal, and a formation of concavity on the tool tip center due to intensive wear was prevented. The SPH model is proved useful for studying USM of different hard and brittle materials, and capable of predicting the machining performance. 相似文献
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Ductile-regime turning mechanism of single-crystal silicon 总被引:11,自引:0,他引:11
Takayuki Shibata Shigeru Fujii Eiji Makino Masayuki Ikeda 《Precision Engineering》1996,18(2-3):129-137
Diamond turning of single-crystal silicon was carried out along all the crystallographic directions on the (001) and (111) planes at depths of cut of 100 nm and 1 μm, and then the mechanism involved in ductile-regime turning was studied. Pitting damage occurred along certain specific crystallographic orientations. The crystallographic orientation dependence of the surface features also changed with the depth of cut because of the difference in material removal mechanism between plastic deformation and brittle fracture. Transmission electron microscopy characterizations of the (111)(110) slip systems activated by turning revealed that the orientation dependence of the surface features was closely related to the ease with which slip deformation occurred. To predict the surface features turned along each crystallographic orientation, we proposed the slip orientation factor, which was determined from the Schmid factor, and demonstrated that it was useful for turning in the critical regime between ductile and brittle. Our slip model, based on the slip orientation factor, describes the ductile-regime turning mechanism well. 相似文献
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Specific grinding energy as an in-process control variable for ductile-regime grinding 总被引:2,自引:0,他引:2
This article addresses the problem of monitoring the material removal regime (ductile versus brittle) that occurs during the grinding of brittle materials. Often a ductile grinding regime is desired, but currently there is no way to measure the grinding ductility “in process.” A model is developed to describe the dependence of the specific grinding energy on the material removal regime. It is found that the specific grinding energy will remain relatively constant for ductile-regime grinding but will decrease in a power-law relationship with an increasing material removal rate for brittle-regime grinding. Experimental confirmation of the proposed model is presented. The potential for using measurements of specific grinding energy to control the grinding ductility is established, and the benefits of such a closed-loop feedback system in ductile-regime grinding are explained. 相似文献
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《Wear》1996,193(1):105-113
The erosion of a range of brittle materials (soda-lime glass, borosilicate glass, fused silica, boron carbide, partially stabilized zirconia, alumina and silicon carbide) with number of different erodent particle types (silicon, silica, alumina and silicon carbide) has been examined. The mechanisms of erosion depend upon the ratio of particle to target hardness. As this ratio falls towards unity, less damaging mechanisms of erosion dominate. Indentation-induced fracture models for erosion of brittle materials are not valid when this mechanism ceases to operate. The erosion rates decrease rapidly, and the velocity exponents of erosion rate increase, as the ratio of particle to target hardness decreases towards unity. The consequences of this in accelerated erosion testing are addressed. 相似文献