小直径PCD麻花钻头电火花磨削加工系统的研制

基于数控电火花磨削加工机床,研制了用于加工小直径PCD麻花钻头的数控螺旋伺服进给加工系统,介绍了系统的加工原理、机械系统和伺服控制系统的设计方法。     

颗粒电荷测定在纸机生产中的应用

介绍了轻型印刷纸生产过程中,颗粒电荷测定在调整化工助剂用量、改善纸机抄造环境中的应用。     

Meso-scale mechanical testing methods for diamond composite materials

Diamond composite materials prepared as thin layers on tungsten carbide substrates for applications such as rock cutting present characterisation challenges. As a consequence of the production route, the availability of only small pieces of diamond composite material has required some ingenuity in devising testing methods which are appropriate but which also yield accurate data to enable differences between grades of material to be characterised. A number of additional problems associated with their hardness and stiffness, coupled with difficulties of accurate machining, have to be overcome. This paper reports some of the techniques attempted to measure flexural strength, fracture toughness, elastic modulus, fatigue behaviour and edge chip resistance, and assesses their success.     

PDS中PCD文件及材料商品编码的自动创建

介绍在HLMS材料管理系统中,根据系统中已经建立的管道材料等级数据库,自动由计算机生成相应的PDS三维设计软件需要的等级文件,同时在PCD文件中自动生成每一个元件的材料商品代码,以满足后续的采购及施工方面的项目管理要求。     

Effect of controllable decomposition of MAX phase (Ti3SiC2) on mechanical properties of rapidly sintered polycrystalline diamond by HPHT

Sintered polycrystalline diamond (PCD) was prepared via high temperature and high pressure (HTHP) process using Ti₃SiC₂ and Si as the binder. The effect of decomposition of Ti₃SiC₂ on comprehensive properties of PCD was investigated at different temperatures. Results show that Si formed liquid phase infiltrated diamond surface at high temperatures to inhibit diamond graphitization and to reduce defects significantly. In addition, strong covalent bond of Si-diamond was generated, which increased the strength of PCD. At suitable temperature, Ti₃SiC₂ would partially decompose to TiC and SiC with high activity. Strong covalent bond of TiC and SiC also increased relative density and hardness of PCD, and residual Ti₃SiC₂ enhanced the toughness of PCD. At 1500 °C, the hardness and toughness of PCD reached 54.35 GPa and 8.6 MPa m^1/2, respectively, which are 19% and 82%, respectively, higher than PCD sintered at 1350 °C.     

从国际工业金刚石会议看有关工业金刚石的最新应用研究

为应对全球经济危机，我国超硬行业有必要透过国际工业金刚石会议分析研究国际超硬材料应用的发展趋势，从中获得启迪，发展自主创新的高新技术。文章只涉及某些超硬材料的最新应用研究即纳米微晶金刚石在尖端技术中的应用研究以及PCD在石油天然气钻井和汽车制造行业的最新应用研究。     

The Role of Additive Manufacturing and Physiomimetic Computational Design for Digital Construction

The recent adoption of the term additive manufacturing (AM) to describe a broad range of digital ‘layer by layer’ fabrication techniques comes 20 years since its inception and more than 10 years since architectural practices engaged with the technology for making prototypes and models. Soon this technology will join existing CNC subtractive and formative processes within the volume and mass-market sectors, where design complexity and increased functionality result in competitive advantage. It is also about a decade since researchers proposed additive manufacturing for construction. Rupert Soar and David Andreen introduce here the different construction-scale additive manufacturing systems currently in development. If linked to physiomimetic computational design strategies, these technologies provide novel possibilities for addressing architecture's manufacturing challenges in the face of energy expenditure, material resources and environmental impact. Copyright © 2012 John Wiley & Sons, Ltd.     

金刚石刀具材料粒度、磨削砂轮粒度与刃口质量的关系

聚晶金刚石(PCD)刀具由于其自身的高硬度、高耐磨性的特征,使得刃磨加工极易出现崩刃——呈锯齿状刃口的典型缺陷,因此其机械磨削加工较其它刀具材料来看难度更大。本文针对金刚石刀具常用的加工方式——金刚石砂轮机械刃磨展开试验,主要针对金刚石刀片自身材料颗粒度与磨削砂轮粒度这两方面进行研究。通过收集数据,分析对比,研究金刚石材料颗粒度、磨削砂轮粒度对刀具最终刃口质量的影响。     

聚晶金刚石复合片的电火花线切割精密加工试验

为了提高聚晶金刚石(PCD)刀具的生产效率,改进加工表面质量并减少刃磨余量,利用慢走丝电火花线切割机床(WEDM)对PCD复合片进行了加工工艺试验.对PCD复合片进行了5次切割,并分别测量了每次加工后的表面粗糙度、富钴界面层凹槽深度及宽度和PCD层刃口加工质量.试验结果表明:PCD复合片经慢走丝线切割多次加工,能够得到较好的表面质量,在众多影响因素中金刚石颗粒大小对加工质量影响较大;其中CTH025型号和CTB010型号的最终表面粗糙度分别为Ra=0.85 μm和Ra=0.57 μm,富钴界面层凹槽的深度分别为16.3 μm和5.7 μm,刃口处切口缺陷的尺寸也与金刚石颗粒的尺寸相当.经WEDM加工后的PCD复合片的刃磨余量可控制在4～15 μm左右.     

Machining behavior of AA6351–SiC–B4C hybrid composites fabricated by stir casting method

ABSTRACT

This study presents an effective approach to assess the machinability of 6351 aluminum alloy matrix, reinforced with 5 wt.% silicon carbide (SiC) and (0, 5, and 10 wt.%) boron carbide (B₄C) particles. The turning tests are carried out with a polycrystalline diamond (PCD) tool to identify the effect of the B₄C particles addition to the composite, with an objective to improve the material removal rate (MRR) and to reduce the surface roughness (Ra) and power consumption (P). The significant level of each factor, which contributes to affect the output response, is found through analysis of variance (ANOVA). The results show that the inclusion of B₄C particles in the hybrid composite significantly affects the machinability, with a contribution to the surface roughness by 7.87% and P by 6.36%. The increase in MRR affects the quality of the material, irrespective of the composites.