Microbial contamination of cutting fluids and associated hazards

In this paper, an experimental investigation into the microbial contamination of cutting fluids is presented. The paper confirms the laboratory based results of the fluid biocontamination by culture and identification of the micro-organisms, and their ability to survive in the workshop fluid systems. Direct and/or indirect associations of the identified micro-organisms with the potential health hazards are pointed out.     

Water based cutting fluids and human health

The question of whether machining operations and exposure to water-base cutting fluids constitutes a human health problem is complex. The literature on the subject is hard to find; it is difficult to create study groups of workers large enough to develop statistically significant information; there is often a lag phase of several years between exposure to cutting fluids and the appearance of a medical problem; public attitudes restrain research on the subject; the identity of the chemicals involved is not completely known and animal studies involving cutting fluids are not adequate at present. Until adequate information is available, efforts should be directed towards minimizing exposure and controlling the microbial loads found in these products.     

MQL加工中切削液的作用及性能

MQL加工是可持续发展战略在机械加工中的微观体现,微量切削液的使用可以达到甚至好于传统浇注切削液的加工效果,同时降低成本,减少环境污染。简述了生态效应对MQL切削液的要求,给出了具有生态效应的几种切削液基油和添加剂,并对其生态性能和切削性能进行了比较。为正确制定和实施MQL机械加工工艺提供了理论和工程依据。     

金属切削刀具的工作角度及其影响因素的研究

从刀具标注角度与工作角度的概念出发,较系统地分析影响金属切削刀具实际几何角度的主要因素,提出合理选择刀具几何角度的方法。对合理地设计、制造刀具,保证零件加工质量,提高加工效率,延长刀具寿命,降低生产成本具有重要意义。     

Effects of cutting fluids on drilling aluminium casting alloy 390

The primary objective of this research project was to compare the tool wear resulting when a semi-synthetic cutting fluid was used, to that from use of a premium soluble oil. The secondary objective was to determine the effects of cutting speed, drill diameter, and fluid concentration, on tool wear. The experiments contained two key elements: (1) cast aluminium alloy 390 was used as the workpiece material and (2) deep-hole drilling to a depth greater than two diameters was performed. Numerous drilling tests were performed with each cutting fluid using a flood application. To meet the primary objective, an experiment was designed for each cutting fluid and the wear on the lands of twist drills was measured. The secondary objective utilized a statistically-designed 2³ factorial experiment which evaluated the effects that moderate and relatively high cutting speeds, two drill diameters, and two levels of fluid concentration, had on tool wear. After analysis of the test results, it was concluded that concentration had the most significant effect on land wear when the experimentally-formulated semi-synthetic cutting fluid was used. Cutting speed was the most significant factor when drilling with the commercially-available premium soluble oil. Tool wear while using the semi-synthetic fluid was slightly less than that for the premium soluble oil.     

Development of novel sustainable neat-oil metal working fluids for stainless steel and titanium alloy machining. Part 1. Formulation development

This paper introduces and describes the development and application of methodologies for the formulation of novel sustainable neat-oil metal removal fluids. A further paper will describe the methodologies being employed and the results of the performance benchmarking of the final fluid formulations for stainless steel and aerospace-grade titanium alloy materials. In this paper, a stepwise approach to the development of novel sustainable neat-oil metal removal formulations is described with a detailed discussion and analysis of the approach taken and the methodologies developed and applied. Two target applications were identified for cutting stainless steel and aerospace-grade titanium alloys. The key required properties of the fluids for these applications were combined with targets identified for cost, low temperature properties, kinetic viscosity (KV) and oxidative stability. Samples of base oils were obtained and characterised. The oils ranged from commodity commercial and specialist natural vegetable oils to chemically modified vegetable-oil-derived fatty acid esters and polyols. The selected oils were used to create blends which were screened for their key properties. From this work, four blends of base oils were identified for being taken forwards to the formulation screening stage. These blends represented a range of natural and modified oils blended in such a way as to achieve all of the required key properties of cost, KV, melt/pour points and oxidative stability. To determine if the oils were likely to also perform well as metal cutting fluids, they were subjected to a range of tests with and without the addition of certain additives, and their performances were benchmarked against a range of mineral oil and polyol-ester-based commercial fluids currently supplied to the target applications areas. The tests employed were: SRV, microtap and oxidation stability. The issues involved in the extrapolation of results from tribological testing to the prediction of fluid cutting performance are highlighted and discussed. From this work, one base oil blend for each of the two target applications was identified and the best performing mineral and polyol ester benchmark fluids were selected. Full-scale drilling and rigid torque tapping tests were used to refine formulations and to screen other additives identified in parallel microtap tests. The durability, oxidation stability, machine tool compatibility and misting potentials of the final formulations were also benchmarked using a range of standard and novel methodologies—this work will be described in a later paper.     

Influence of cutting fluids on surface finish of holes drilled into aluminium 390

The primary objective of this research was to compare the surface finish resulting when using a semi-synthetic cutting fluid to that of a premium soluble oil. The secondary objective was to determine the effects of drill diameter, cutting speed, and fluid concentration on surface finish. The surface measurements were made on the walls of 6.350 and 9.525 mm lind holes drilled 25.4 mm into aluminium 390. Each cutting fluid was introduced using a flood application. Additional factors in the experimental design for each cutting fluid included two levels of cutting speed and two levels of fluid concentration. Variations in drill diameter, cutting speed, and the interaction between these factors were significant with respect to surface finish for both the semi-synthetic fluid and the soluble oil. Fluid concentration for the semi-synthetic fluid also had a significant effect on the surface finish. The surface finish produced while using the semi-synthetic fluid was approximately the same as that with the soluble oil.     

Effects of blended vegetable‐based cutting fluids with extreme pressure on tool wear and force components in turning of Al 7075‐T6

In this study, performances of four different types of vegetable‐based cutting fluids (VBCFs) over a commercial mineral cutting fluid were evaluated for machinability of Al 7075‐T6. Lubrication properties of VBCFs were improved with additive of extreme pressure. Cutting force and tool wear data were obtained for performance analyses of cutting fluids during longitudinal turning of Al 7075‐T6. Cutting, feed and radial forces indicated 1.70–38.25% improvements for VBCFs over the commercial mineral cutting fluid. The lowest average values of flank and nose wears obtained with blended cutting fluid containing 12% of extreme pressure were 0.09 and 0.10 mm, respectively, whereas these values for the commercial mineral cutting fluid were 0.18 and 0.15 mm. The scanning electron microscope results showed adherence of workpiece material occurred on rake and flank faces, and flank and nose wears were the dominant wear modes. It was found that performances of VBCFs during turning of Al 7075‐T6 were better than that of the commercial mineral cutting fluid. Copyright © 2012 John Wiley & Sons, Ltd.     

材料切削性能的模糊综合评判

介绍了一套材料加工参数智能推理系统的研究。重点讨论了模糊理论在该系统中的运用，采用模糊综合评判、模糊聚类原理，根据用户输入材料的物理机械性能，快速确定材料的切削加工性能。将材料按切削加工性能等级分类可简化材料切削参数推理，有利于新材料切削参数的确定。     

基于热力耦合模型的金属切削过程有限元分析

基于有限元理论和热力耦合模型的研究,通过讨论切削过程中的关键技术,主要包括切削加工有限元方程的建立：构件材料的Johnson-Cook本构模型;切屑分离准则;材料断裂准则;接触摩擦模型;切削热的产生和分布;残余应力的分析和切削力的比较分析等,建立了二位金属切削过程模型,通过采用粘结．滑移摩擦模型,有效地模拟了航空钛合金的切削加工过程,对此类材料加工的切削力、切屑温度以及应力场和应变的分布进行了分析。     

A description of the lubricating action of the tribo-active components of cutting fluids

A multistage mechanism of lubrication layer formation during cutting is described and the necessary conditions for the formation of a lubrication layer are formulated. It is considered that the process of physical adsorption of the tribo-active components of the cutting fluid in the contact zone between tool and chip during metal cutting is one step in a multistage process which occurs in the interface capillary system. A mathematical model describing simultaneous diffusion and adsorption of tribo-active components in a single interface capillary is proposed. Some parameters for a model determining the efficiency of the lubricating action of surface-active additives are also proposed.     

基于脉冲电源的金属电化学线切割工艺研究

为了提高金属电化学线切割精度,将脉冲电源应用到切割加工中,根据电化学加工原理,并以切割缝宽为切割效果的评价标准,建立了脉冲电源切割理论模型,得出了影响缝宽变化的工艺参数,主要有:电源的电压幅值、脉冲宽度、占空比和进给速度等。并在此基础上对参数进行了优化加工实验。研究结果表明,在保证加工稳定的条件下,通过降低电压、调小脉冲宽度和占空比的方法,加工出的切割缝宽比直流电源加工出的缝宽明显减小,该方法将有望直接用于小尺寸零件的加工。     

Experimental investigations of vegetable based cutting fluids with extreme pressure during turning of AISI 304L

Experimental studies on the performances of both new developed environmental friendly vegetable based cutting fluids (refined sunflower and canola oils) including different percentage of extreme pressure (EP) additive and two commercial cutting fluids (semi-synthetic and mineral cutting fluids) in turning processes were reported in this work. Performances of cutting fluids were compared with respect to surface roughness, cutting and feed forces and tool wear during longitudinal turning of AISI 304L. Experimental results were also compared with dry cutting conditions. The results indicated that 8% of EP included canola based cutting fluid performed better than the rest.     

Development of high water-content cutting fluids with a new concept: Fire prevention and environmental protection

Using water-insoluble cutting fluids, which are good in lubricity but easy to mist, always risks firing and environmental problems. On the other hand, the current water-soluble coolants fail to deliver sufficient lubricity to heavy cutting applications. This study has newly proposed and developed a high water-content cutting fluid, based upon a new concept of having high lubricity despite of its water-soluble nature. As compared to the commercialized water-insoluble cutting fluid, the new cutting fluids shows a better capability of preventing oil mist and is fully applicable into cutting of various metallic materials, particularly effective in cutting of S45C and SUS304. The study also reveals a fact that a sulfur-type extreme pressure agent is the key element to enhance the cutting performance at high temperature.     

基于PMAC的水喷射加工机床开放式数控系统的开发研究

介绍了以PC机为平台、以PMAC为核心的水喷射加工机床开放式数控系统给出了该系统的硬件和软件结构及设计。     

基于Authorware的《金属切削原理》CAI课件的开发

针对多媒体教学中存在的问题和《金属切削原理》课程的特点，该文介绍了利用Authorware软件开发多媒体课件时应注意的问题，包括加强内容间的跳转能力设计，人机交互能力的设计等。该课件开发，对《金属切削原理》教学取到了较好的效果。     

Ecological and health aspects of metalworking fluids' manufacture and use

The manufacture, use, and disposal of metalworking products are reviewed in the light of modern health and environmental considerations, and new stricter legislation, notably in Europe. Some new vegetable oil based formulations, which meet the new criteria, are presented.     

基于TEAMS的系统健康评估方法研究

QSI开发了一种能够应用到大系统、能满足建模和推理系统需求的常用软件框架。依据TEAMS功能．论述了故障从属模型在涵盖决策问题上的重要应用。结果表明,TEAMS的建模和分析对复杂系统的健康评估有很高的应用价值。     

Separation of a sphere from a flat in the presence of couple stress fluids

A mathematical model for couple stress fluid is presented to analyse the separation flow of a fully flooded sphere from a flat under the condition of constant load. Assuming the lubricant between the sphere and the flat to contain additives, the couple stress effect, presented by the characteristic length of the additives, has been considered to account for the non‐Newtonian behaviour. In addition, the effect of the sphere inertia on accelerating the separation process has been considered. Compared with the Newtonian fluid case, the results of the numerical solution indicated that the separation time increases with increasing the characteristic length of the additives. It was also found that the additive characteristic length has negligible effect on the thickness of the lubricant film at the separation point. Copyright © 2007 John Wiley & Sons, Ltd.     

国际标准在教育服务管理中的应用

着重分析了国际标准在教育服务管理中的应用,从分析国际管理标准在教育服务中应用的必要性和可行性开始,提出贯彻质量管理和职业健康安全管理国际标准的主要做法,总结了广西机电职业技术学院贯彻质量管理和职业健康安全管理国际标准取得的效果,同时对贯彻国际管理标准工作提出相应的见解。