亚干式深孔钻削系统性能的试验研究

以亚干式深孔钻削系统为研究对象,对亚干式深孔钻削系统和传统(湿式)深孔钻削系统加工中的切削力、刀具磨损、钻孔表面质量及断屑排屑等进行对比试验.试验结果表明,亚干式深孔钻削系统加工过程稳定,冷却、润滑、排屑效果良好,可获得较好的刀具耐用度和内孔表面质量,同时极大地减少了切削液的用量并降低环境污染,是一种较为理想的绿色钻削工艺系统.     

亚干式内排屑深孔钻削系统试验与分析

结合亚干式切削和内排屑深孔钻削加工的特点,提出亚干式内排屑深孔加工系统的设计思路。结果表明,该系统具有良好的排屑及冷却效果。同时,通过与湿式(BTA)钻削加工的试验对比及分析,在合理的切削用量下,亚干式钻削的切削性能在排屑及冷却方面要优于湿式(BTA)钻削。     

亚干式深孔钻削系统及其试验分析

将亚干式切削技术与深孔加工技术相结合,在BTA内排屑深孔加工系统的基础上,采用风冷雾化排屑系统代替BTA系统中的切削液排屑系统,形成亚干式深孔加工系统,从而实现风冷雾化切削液对刀具进行冷却润滑和排屑的功能,以减少切削液的使用及环境污染。并在不同的切削用量条件下对亚干式深孔加工与BTA深孔加工的切削力进行了对比试验及分析。试验证明该系统在合理的切削条件下切削力和排屑情况要比BTA系统具有优越性。     

乳化型深孔切削液的切削试验与分析

对切削液的类型和功能进行阐述,比较几种切削液的功能和切削特点,根据内排屑深孔加工的特点和对切削液的要求,选择几种乳化型切削液进行钻削试验。通过对比试验及结果分析,确定出能适应深孔钻削加工的乳化型切削液,可以满足深孔钻削加工中对刀具的冷却润滑和排屑效果,从而可以减少对切削油的使用,降低生产成本及对环境的污染。     

亚干式深孔加工中的低温冷风雾化技术

结合干式切削加工的特点和深孔加工的特性，提出了将干式切削技术应用于深孔加工的设想，制定了运用低温冷风冷却、排屑及切削液雾化润滑刀具的亚干式深孔加工方法，并对其工作原理及在深孔加工中的具体运用进行了系统的分析和探讨，从而使干式切削技术的应用范围更广泛。     

BTA深孔钻削EA4T钢的屑形研究

通过深孔钻床加工同批次空心车轴试验,研究错齿BTA深孔钻在不同切削参数(切削速度、进给量、切削液流量及压力)下的切屑形态对排屑效果的影响。由试验可知:当切削速度为80m/min、刀具进给量为0.2mm/r、切削液压力达到2.8MPa、切削液流量控制在90L/min时,加工后所产生的C形屑是深孔钻削排屑过程中的理想屑形。     

新型外排屑负压抽屑系统

负压抽屑系统已成功地应用到内排屑深孔钻削中,通称DF系统。它是在继承BTA钻(单管内排屑深孔钻)和双管喷吸钻二者优点的基础上研制出来的一种深孔钻削系统。内排屑深孔钻削系统由于其排屑结构上的限制,不适用于小直径深孔(φ10mm以下)加工。对于小直径深孔,一般使用外排屑深孔钻,枪钻即为其代表。由于孔径较小,再加上新材料及难加工材料的出现,排屑就成为一个难题。排屑效果直接影响到孔加工质量和刀具耐用度,排屑不好,产生憋屑,造成钻头扭断和工件损坏,以至于小深孔钻削成为许多厂的卡脖子工序。为了解决这个难题,我们将负压抽吸原理应用到外排屑系统中,研制出了外排屑负压抽     

基于Deform-3D的准干式深孔钻削有限元分析

采用Deform-3D有限元分析软件对准干式BTA单刃内排屑深孔钻钻削做了仿真研究。应用Deform-3D软件设置模拟参数为干式钻削,在不同的切削用量情况下对切削力的大小、刀具磨损以及切削温度场进行了仿真分析,讨论了断屑的发生位置以及分屑的形成过程,为准干式深孔加工的切削参数和刀具参数进一步的优化提供了依据。     

干式深孔加工技术的研究

由于对环保的要求,人们希望实现少或无切削液的绿色切削加工.通过对干式切削技术的理解,提出了将干式切削技术应用于深孔加工的方案,介绍了低温风冷及雾化冷却排屑式的亚干式深孔加工,并对其中的技术难题和关键技术进行了分析探讨.     

钳工操作中深孔的钻削实践分析与改进

在金属切削加工过程中,钻削深孔一直是个难题,尤其是加工精度难以保证。深孔钻削的关键是解决断屑、排屑问题。从教学角度结合实践操作,针对钻削深孔加工存在的问题,设计了一种新型的内排屑深孔钻头。以钻头的结构和刃磨特点为切入点,结合生产实践进行了振动钻削实验,实现了断屑、排屑的流畅,达到了钻头应具备的良好性能。     

Cryogenic minimum quantity lubrication machining: from mechanism to application

Cutting fluid plays a cooling–lubrication role in the cutting of metal materials. However, the substantial usage of cutting fluid in traditional flood machining seriously pollutes the environment and threatens the health of workers. Environmental machining technologies, such as dry cutting, minimum quantity lubrication (MQL), and cryogenic cooling technology, have been used as substitute for flood machining. However, the insufficient cooling capacity of MQL with normal-temperature compressed gas and the lack of lubricating performance of cryogenic cooling technology limit their industrial application. The technical bottleneck of mechanical–thermal damage of difficult-to-cut materials in aerospace and other fields can be solved by combining cryogenic medium and MQL. The latest progress of cryogenic minimum quantity lubrication (CMQL) technology is reviewed in this paper, and the key scientific issues in the research achievements of CMQL are clarified. First, the application forms and process characteristics of CMQL devices in turning, milling, and grinding are systematically summarized from traditional settings to innovative design. Second, the cooling–lubrication mechanism of CMQL and its influence mechanism on material hardness, cutting force, tool wear, and workpiece surface quality in cutting are extensively revealed. The effects of CMQL are systematically analyzed based on its mechanism and application form. Results show that the application effect of CMQL is better than that of cryogenic technology or MQL alone. Finally, the prospect, which provides basis and support for engineering application and development of CMQL technology, is introduced considering the limitations of CMQL.     

Micro-drilling of Ti–6Al–4V alloy: The effects of cooling/lubricating

This paper presents a series of experimental investigations of the effects of various machining conditions [dry, flooded, minimum quantity lubrication (MQL), and cryogenic] and cutting parameters (cutting speed and feed rate) on thrust force, torque, tool wear, burr formation, and surface roughness in micro-drilling of Ti–6Al–4V alloy. A set of uncoated carbide twist drills with a diameter of 700 μm were used for making holes in the workpiece material. Both machining conditions and cutting parameters were found to influence the thrust force and torque. The thrust force and torque are higher in cryogenic cooling. It was found that the MQL condition produced the highest engagement torque amplitude in comparison to the other coolant–lubrication conditions. The maximum average torque value was obtained in the dry drilling process. There was no substantial effect of various coolant–lubrication conditions on burr height. However, it was observed that the burr height was at a minimum level in cryogenic drilling. Increasing feed rate and decreasing spindle speed increased the entry and exit burr height. The minimum surface roughness values were obtained in the flood cooling condition. In the dry drilling process, increased cutting speed resulted in reduced hardness on the subsurface of the drilled hole. This indicates that the surface and subsurface of the drilled hole were subject to softening in the dry micro-drilling process. The softening at the subsurface of drilled holes under different cooling and lubrication conditions is much smaller compared to the dry micro-drilling process.     

Performance profiling of minimum quantity lubrication in machining

This study develops the analytical understanding of mechanical and environmental effects of minimum quantity lubrication (MQL) in machining and profiles the MQL performance as functions of machining and fluid application parameters. Physics-based predictive models are formulated to quantitatively describe the resulting contact stress and temperature distributions under completely dry, MQL (under boundary lubrication), and flood cooling conditions in cylindrical turning. On that basis, the air quality effects in terms of cutting fluid aerosol emission rate and droplet size distribution have been derived through the modeling of evaporation, runaway aerosol atomization, and dissipation processes. Additionally, the abrasion, adhesion, and diffusion wear mechanisms under time-evolving cutter geometry have been quantitatively evaluated for the development of a tool wear and tool life relationship with the fluid application condition. Experimental measurements of force, temperature, aerosol concentration, and tool flank wear rate in dry, MQL, and fluid cooling cases has also been pursued to calibrate and validate the predictive models. The MQL performance profile is assessed through the sensitive analysis of tool utilization, power consumption, and air quality with respect to MQL application parameters; and it serves as a basis to support the overall optimization of machining process by incorporating both mechanical and environmental considerations.     

Deformation behaviour of sintered silicon–copper steel preforms of various aspect ratios during cold upsetting

This paper presents the optimization of the face milling process of 7075 aluminum alloy by using the gray relational analysis for both cooling techniques of conventional cooling and minimum quantity lubrication (MQL), considering the performance characteristics such as surface roughness and material removal rate. Experiments were performed under different cutting conditions, such as spindle speed, feed rate, cooling technique, and cutting tool material. The cutting fluid in MQL machining was supplied to the interface of work piece and cutting tool as pulverize. An orthogonal array was used for the experimental design. Optimum machining parameters were determined by the gray relational grade obtained from the gray relational analysis.     

微量润滑复合增效技术及其应用研究进展

微量润滑技术具有切削液用量少、润滑效率高等优点,但在特定工况下仍存在冷却性不足以及润滑不充分等问题.微量润滑复合增效技术,如低温冷风、液态CO2等,综合了良好冷却和润滑优势,可有效解决难加工材料清洁切削加工难题.综述了各类微量润滑复合增效技术原理、关键装置及其工艺应用最新研究进展,详细剖析了各类装置性能及其参数调控特性...     

EFFECTS OF COOLANT SUPPLY METHODS AND CUTTING CONDITIONS ON TOOL LIFE IN END MILLING TITANIUM ALLOY

Titanium machining poses a great challenge to cutting tools due to its severe negative influence on tool life primarily due to high temperature generated and strong adhesion in the cutting area. Thus, various coolant supply methods are widely used to improve the machining process. On account of this, tool life and cutting force are investigated based on dry cutting, flood cooling, and minimum quantity lubrication (MQL) techniques. The experimental results show that MQL machining can remarkably and reliably improve tool life, and reduce cutting force due to the better lubrication and cooling effect.     

最小量润滑在振动钻削中的应用

为了有效地发挥最小量润滑(Minimum quantity lubrication,MQL)在钻削加工中的冷却和润滑性能,把MQL和振动钻削技术结合起来,对MQL在钻削加工(尤其是振动钻削)中的作用效果进行理论分析和试验研究,并对加工中的最大轴向力和表面粗糙度进行测量.研究结果表明,与普通钻削相比,振动钻削能够有效改善MQL的作用效果,通过合理选择参数,能使最大轴向力明显减小,表面粗糙度显著改善;增大振幅是提高MQL作用效果的有效途径,能够降低表面粗糙度,提高加工质量.     

EFFECTS OF COOLANT SUPPLY METHODS AND CUTTING CONDITIONS ON TOOL LIFE IN END MILLING TITANIUM ALLOY

Titanium machining poses a great challenge to cutting tools due to its severe negative influence on tool life primarily due to high temperature generated and strong adhesion in the cutting area. Thus, various coolant supply methods are widely used to improve the machining process. On account of this, tool life and cutting force are investigated based on dry cutting, flood cooling, and minimum quantity lubrication (MQL) techniques. The experimental results show that MQL machining can remarkably and reliably improve tool life, and reduce cutting force due to the better lubrication and cooling effect.