陶瓷坯体加工中的材料分离机理及加工参数影响
发布时间：2018-10-16 13:25
【摘要】：陶瓷材料的强度大、硬度高、耐热性能好、耐腐蚀能力强,在航天航空、医疗、微机械等领域中逐渐得到广泛应用。其中,氧化铝陶瓷以其优良的物理化学性能及较高的强度成为应用最广泛的陶瓷材料之一。对陶瓷生坯的直接加工容易导致边缘破损及表面精度降低,而完全烧结后的陶瓷坯体强度大大提高,加工难度增加。因此采用对陶瓷生坯进行低温热处理即预烧结的工艺,不仅可以提高其机械强度,而且加工获得的结构表面质量较好。本文通过在氧化铝陶瓷坯体上铣削不同深度的微长槽研究了陶瓷坯体在铣削过程中的分离机理及加工参数的影响,并在陶瓷表面进行微孔钻削,从而获得最佳的加工条件。通过单向加压的方法制备陶瓷生坯,并对其进行预烧结来提高坯体强度,利用三点抗弯强度测试实验测试了不同压力成型下材料的抗弯强度。实验数据表明,陶瓷材料的抗弯强度随着压力的增加呈线性增长。由于陶瓷生坯铣削加工中材料呈颗粒状剥离,导致加工后的结构出现加工间隙,与金属加工存在很大的不同,另一方面,加工产生的絮状切屑从坯体与刀具之间的间隙流出时会对结构边缘产生挤压导致表面精度降低。基于这些特点,通过在陶瓷坯体上加工不同深度的长槽确定了加工过程中的三种材料分离机理,并研究了不同加工参数对材料分离机理的影响。分析了不同转速下刀具上吸附切屑的情况,结果表明刀具上吸附切屑的数量随着主轴转速的增加而减少。通过线电极电火花磨削(WEDG)技术在线制备微细刀具,之后在预烧结陶瓷坯体上进行微孔钻削,探讨了各种工艺参数及切屑对加工结果的影响。实验结果显示,当采用D形截面刀具进行微通孔钴削时,预烧结温度应选择800℃,且加工过程中加入切削液(水)。同时,加工过程中加入的切削液会对坯体产生一定的作用力,减弱了坯体加工过程中的应力集中现象,使孔出口处的边缘破损程度降低并减少出口处的切屑堆积。最后研究了切削液对微孔加工间隙的影响,取得了加工间隙明显降低的良好效果。
[Abstract]:Ceramic materials with high strength, high hardness, good heat resistance and corrosion resistance have been widely used in aerospace, medical, micro-machinery and other fields. Among them, alumina ceramic has become one of the most widely used ceramic materials because of its excellent physical and chemical properties and high strength. The direct machining of raw ceramic billet can easily lead to edge damage and surface precision decrease, while the strength of ceramic billet after sintering is greatly improved, and the processing difficulty is increased. Therefore, the low temperature heat treatment of raw ceramic billet, that is, pre-sintering process, can not only improve its mechanical strength, but also the structure surface quality obtained by processing is better. In this paper, the separation mechanism of ceramic billet and the influence of machining parameters during milling process were studied by milling micro-long grooves with different depths on alumina ceramic billet, and microhole drilling was carried out on ceramic surface to obtain the best processing conditions. Ceramic billets were prepared by unidirectional compression and pre-sintered to improve the strength of the billets. The bending strength of the materials under different pressure forming was tested by three point bending strength test. The experimental data show that the bending strength of ceramic materials increases linearly with the increase of pressure. Because the material is peeled off in the milling process of ceramic billet, the structure after processing appears machining gap, which is very different from metal processing, on the other hand, When the flocculating chip flows out from the gap between the blank and the cutting tool, it will squeeze the edge of the structure and reduce the surface precision. Based on these characteristics, three kinds of material separation mechanisms were determined by machining long grooves of different depths on ceramic billets, and the effects of different processing parameters on material separation mechanism were studied. The results show that the amount of chip adsorbed on the cutting tool decreases with the increase of spindle speed. Micro cutting tools were prepared by wire electrode electrical discharge grinding (WEDG) technique on line and then drilled on pre-sintered ceramic billets. The effects of various technological parameters and chips on the machining results were discussed. The experimental results show that the pre-sintering temperature should be chosen at 800 鈩，
本文编号：2274499
[Abstract]:Ceramic materials with high strength, high hardness, good heat resistance and corrosion resistance have been widely used in aerospace, medical, micro-machinery and other fields. Among them, alumina ceramic has become one of the most widely used ceramic materials because of its excellent physical and chemical properties and high strength. The direct machining of raw ceramic billet can easily lead to edge damage and surface precision decrease, while the strength of ceramic billet after sintering is greatly improved, and the processing difficulty is increased. Therefore, the low temperature heat treatment of raw ceramic billet, that is, pre-sintering process, can not only improve its mechanical strength, but also the structure surface quality obtained by processing is better. In this paper, the separation mechanism of ceramic billet and the influence of machining parameters during milling process were studied by milling micro-long grooves with different depths on alumina ceramic billet, and microhole drilling was carried out on ceramic surface to obtain the best processing conditions. Ceramic billets were prepared by unidirectional compression and pre-sintered to improve the strength of the billets. The bending strength of the materials under different pressure forming was tested by three point bending strength test. The experimental data show that the bending strength of ceramic materials increases linearly with the increase of pressure. Because the material is peeled off in the milling process of ceramic billet, the structure after processing appears machining gap, which is very different from metal processing, on the other hand, When the flocculating chip flows out from the gap between the blank and the cutting tool, it will squeeze the edge of the structure and reduce the surface precision. Based on these characteristics, three kinds of material separation mechanisms were determined by machining long grooves of different depths on ceramic billets, and the effects of different processing parameters on material separation mechanism were studied. The results show that the amount of chip adsorbed on the cutting tool decreases with the increase of spindle speed. Micro cutting tools were prepared by wire electrode electrical discharge grinding (WEDG) technique on line and then drilled on pre-sintered ceramic billets. The effects of various technological parameters and chips on the machining results were discussed. The experimental results show that the pre-sintering temperature should be chosen at 800 鈩，
本文编号：2274499
本文链接：https://www.wllwen.com/kejilunwen/huagong/2274499.html
