高速干切滚齿工艺系统切削热全过程传递模型

高速干切滚齿工艺消除了切削油/液的使用,是一种绿色高效的齿轮制造工艺。切削热伴随着高速干切滚齿工艺全过程且区别于传统湿式滚切工艺,是造成干切滚刀磨损和机床热变形的重要因素,直接影响制造成本和加工精度。根据干切滚刀周期性断续传热特性,综合考虑切削热在切屑、工件、干切滚刀、冷却介质以及滚齿机床加工空间的传递规律,提出将高速干切滚齿工艺系统切削热的发生与传递全过程划分为三个阶段的研究思想,从关系模型和热传递方程两个层面建立了高速干切滚齿工艺系统切削热全过程传热模型,包括切削接触界面热传递、切削区域热传递和机床加工空间热传递三个阶段的模型,然后基于工艺仿真试验对所建模型进行了应用研究,揭示了高速干切滚齿工艺系统的切削热在工件、干切滚刀、切屑中的动态变化规律,最后通过试验验证了模型的有效性。     

齿轮高速干切滚刀寿命预估模型与优化方法

由于齿轮高速干式滚切工艺切削速度高且缺少切削油的冷却润滑,为满足高速干切滚刀的抗磨损、耐高温等性能要求,高速干切滚刀基体材料和涂层的制备工艺均较为复杂,且价格昂贵,因而需要优化高速干切工艺以延长高速干切滚刀使用寿命,进而降低工件制造成本,提高效益。结合生产实践和理论分析,研究了齿轮高速干切滚刀的失效形式和失效原理,提出了以单个刀齿切削长度为高速干切滚刀寿命评价指标并建立相应计算模型的方法,基于此开展了高速干切滚刀寿命试验,建立了高速干切滚刀寿命多元线性回归模型,采用MATLAB求解得到该试验条件下的高速干切滚刀寿命经验公式。最后基于此提出了通过优化滚切工艺参数以及采用新型窜刀方式等来延长高速干切滚刀寿命的方法。     

圆柱齿轮滚切多刃断续切削空间成形模型及应用

滚切加工作为当前圆柱齿轮制造应用最为广泛的工艺具有高效但成形过程复杂的特点。基于展成原理,由规则分布在滚刀基本蜗杆螺旋面上的一系列切削刃相继从圆柱齿坯上切除材料,最终包络形成渐开线齿面。研究其成形原理可以为提升该工艺性能提供有效指导。针对齿轮滚切工艺过程多刃切削成形特征,建立圆柱齿轮滚切的空间成形模型。基于滚刀几何结构参数的理论约束关系,建立滚刀切削刃序列的参数方程;根据滚刀和工件的几何参数以及切削参数确定滚切过程中滚刀与工件的空间位置和运动关系,并基于空间运动学方法推导求得滚刀刀刃序列形成的空间成形曲面参数模型;采用离散数值方法获得滚切过程中的切屑几何形态及切屑厚度,并根据切屑几何计算各刀刃去除材料时的瞬时主切削力。该模型可以为滚切工艺参数优化、滚刀几何设计等研究提供支撑。     

基于有限元分析的滚齿SLD构建

针对稳定性耳垂线图(SLD)应用于滚齿颤振预测时存在动力学参数获取困难、切削深度难以确定等问题,建立了考虑滚刀刀杆柔性的三维滚齿系统动力学模型,通过滚刀极限切屑厚度与轴向进给量的关系计算滚齿系统动力学参数,并在此基础上绘制出滚齿SLD。设计了滚齿颤振实验方案,通过采集的实验数据分析平稳切削与颤振切削振动的特征量,确定颤振频率及颤振主体,证实了所建立的动力学模型及SLD的有效性。所提方法为滚齿工艺颤振预测、切削参数选取提供了一种新手段。     

A 3D chip geometry driven predictive method for heat-loading performance of hob tooth in high-speed dry hobbing

High-speed dry hobbing is an emerging green technique for gear hobbing owing to its high productivity and environmental friendliness. However, severe friction occurs and heat instantaneously accumulates in the cutting region due to the adoption of high cutting speed and the lack of metalworking fluids, which causes serious hob wear. This investigation is concerned with the thermal performance and heat-loading quantitative method of hob cutter in high-speed dry hobbing. According to the multiple-edge and intermittent cutting behavior, the temporal dynamic characteristics of hob cutter are analyzed. Based on the complex 3D chip geometry produced in high-speed dry hobbing, the calculation method for heat-production (the amount of generated cutting heat) of hob tooth is proposed. Considering the coupling effects of heat conduction, heat convection, and heat radiation, the prediction model for heat-loading quantity (the bearing capacity of cutting heat) of hob tooth is developed. With the help of the developed method, the interrelation between the thermal performance of hob cutter and material removal volume, cutting conditions, coating material, respectively, are investigated. The predictive method developed in this work provides a methodology for process parameter optimization and hob cutter manufacturing of high-speed dry hobbing.     

An investigation of cutting edge failure due to chip crush in carbide dry hobbing using the finite element method

The aim of this research is to investigate a type of failure of dry carbide hobbing that occurs when the generated chips are pinched and crushed between the hob cutting edge and the work gear tooth flank by utilizing the finite element method. This problem is of great importance because gear hobbing is extensively used in the manufacturing industry. Many machine tool manufacturers have so far developed dry hobbing techniques using carbide hobs as there is a growing acknowledgment that it is necessary to employ carbide hobbing for higher productivity and pollution free gear cutting. To meet the increasing needs of cost reduction and environmentally friendly methods, dry hobbing being employed for gear mass production has completely eliminated the need of tool cooling. However, carbide hobbing has not come into wide use due to the high cost of carbide hobs, and mainly due to the unexpected chipping of the brittle carbide material, making it difficult to control the tool service life. Dry hobbing often causes problems such as chipping of the carbide hob tooth and/or damage of the surface finishing when the generated chips are pinched and crushed between the hob cutting edge and the work gear tooth flank. A manufacturing case of helical gears is taken as a case study, and it was simulated using a coupled thermomechanical rigid viscoplastic FEM analysis. Simulations have successfully identified a chip crush between four adjacent generating positions and thus, a definite mechanism that cause chip crush is revealed. Furthermore, valuable insights during chip formation, i.e., stress, strain, strain rate, temperature gradients, etc., are also provided.     

高速干切滚齿工艺切屑形变规律及其对刀具的损伤行为

针对高速干切滚齿过程中切屑的形变规律及切屑挤压行为,基于DEFORM-3D建立了高速干切滚齿工艺仿真实验模型,通过对不同工艺参数下高速干切滚齿工艺实验仿真,实现了高速干切滚齿过程中齿轮材料去除过程的可视化,获得了高速干切滚齿过程中切屑的形变规律以及干切滚刀的磨损状态。结合实际高速干切滚齿加工实验,对比切屑形貌及干切滚刀损伤情况,进一步验证了切屑在生成及流动过程中的形变规律以及切屑对干切滚刀的挤压损伤行为。研究结果可为高速干切滚齿工艺参数优化以及高速干切滚刀的寿命延长和性能控制提供参考。     

高速干切滚齿工艺参数的多目标优化与决策方法

为降低高速干切滚齿加工能耗、提高滚齿加工质量,提出一种基于改进多目标灰狼优化（MOGWO）算法和逼近理想解排序法（TOPSIS）的高速干切滚齿工艺参数多目标优化与决策方法。分析了滚齿工艺参数,将切削参数和滚刀参数作为优化变量,构建了面向最小加工能耗和最优加工质量的多目标优化模型,采用改进MOGWO算法对所建的模型进行迭代寻优,利用TOPSIS对优化的工艺参数解进行多属性决策。实验结果验证了所提方法的有效性。      

面向切屑形成过程的瞬时滚削力模型研究

建立滚齿加工的时变滚削力模型是优化滚齿加工工艺参数、减少滚削力波动、提高加工精度的前提,面向滚齿切屑形成过程建立时变滚削力模型是提高建模精度的最直接的物理方法。针对干切滚齿的切屑形成过程,建立滚刀前刀面运动模型,利用MATLAB生成刀齿运动轨迹的动态链接库。基于SolidWorks进行三维布尔运算,提取未变形切屑几何特征,开发切屑几何模型动态链接库。通过C#调用MATLAB和SolidWorks动态链接库,实现三维运动仿真,进而构建多齿瞬时滚削力模型。通过YK3216CNC滚齿机进行样件加工,结合HNC-SSTT软件进行全行程电流检测,间接测量瞬时滚削力。仿真加工的瞬时滚削力与实测滚削力变化趋势基本一致,表明该模型合理、有效。     

CAD-based simulation of the hobbing process for the manufacturing of spur and helical gears

Targeting an accurate and realistic simulation of the gear hobbing process, we present an effective and factual approximation based on three-dimensional computer-aided design. Hobbing kinematics is directly applied in one gear gap. Each generating position formulates a spatial surface path which bounds its penetrating volume into the workpiece. The three-dimensional surface paths generated from the combination of the relative rotations and displacements of hob and work gear are used to split the subjected volume, creating concurrently the chip and the remaining work gear solid geometries. The developed software program HOB3D simulates accurately the manufacturing of spur and helical gears, exploiting the modeling and graphics capabilities of a commercial CAD software package. The resulting three-dimensional solid geometrical data, chips and gears provide the whole geometrical information needed for further research, such as prediction of the cutting forces, tool stresses and wear development as well as the optimization of the gear hobbing process.     

高速干切齿轮滚刀几何设计准则及参数化建模方法

根据高速干式滚齿相对于传统滚齿加工方式的特点,以及高速干式滚齿应实现的目标,进行了高速干切齿轮滚刀应具备的特点分析,提出了高速干切齿轮滚刀几何设计准则。对高速干切齿轮滚刀的参数化建模进行了研究,设计了一种新的高速干切齿轮滚刀计算机辅助设计方案。提出新的滚刀三维建模方法,通过生成二维设计图对高速干切齿轮滚刀的设计进行仿真验证。     

STUDY ON THE CUTTING TEMPERATURE IN GEAR HOBBING

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微小型齿轮的微细滚削加工研究

用自行设计的微小型硬质合金齿轮滚刀进行了模数为0.175mm的微小型齿轮滚削加工研究.首先设计了相应模数的微小型齿轮滚刀,并详细阐述该刀具的设计过程,包括刀具材料的选择、结构形式的设计、齿形设计和刀具局部强度的校核等.简述了该滚刀的制造加工工艺,在微小型数控滚齿机上进行了微小型齿轮的滚削加工试验研究.结果表明,采用范成...     

淬硬齿轮（HRC48～65）高效滚切的研究

本文是淬硬齿轮的加工试验和研究,为提高刀具寿命增加了硬质合金滚刀的齿数并增宽了硬质合金滚刀的切削刃带,为控制切削热,在切削油内加了致冷剂,试验证明可加工出（JB179-837）6级精度的齿轮。     

A method for predicting hobbing tool wear based on CNC real-time monitoring data and deep learning

Intelligent monitoring and diagnosis of tool status are of great significance for improving the manufacturing efficiency and accuracy of the workpiece. It is difficult to quickly and accurately predict the wear state of worm gear hob under different working conditions. This paper proposes a novel approach to predict hob wear status based on CNC real-time monitoring data. Based on the open platform communication unified architecture (OPC UA) technology and orthogonal test, the machine data of motor power, current, etc. related to tool wear are collected online in the worm gear machining process. And then, an improved deep belief network (DBN) is used to generate a tool wear model by training data. A growing DBN with transfer learning is introduced to automatically decide its best model structure, which can accelerate its learning process, improve training efficiency and model performance. The experiment results show that the proposed method can effectively predict hob wear status under multi-cutting conditions. To show the advantages of the proposed approach, the performance of the DBN is compared with the traditional back propagation neural network (BP) method in terms of the mean-squared error (MSE). The compared results show that this tool wear prediction method has better prediction accuracy than the traditional BP method during worm gear hobbing.     

Reproducing wear mechanisms in gear hobbing—Evaluation of a single insert milling test

Gear hobbing is a widely used method in industrial gear manufacturing. The most common type of hob is made of homogenous HSS and protected by a PVD coating. In order to increase the reliability and tool life of these milling tools, further developments of the tool surfaces and cutting edges are necessary.A single tooth milling test, using a HSS insert in a conventional milling machine, has been developed with the aim to reproduce the wear mechanisms seen on real HSS gear hobbing teeth. The benefits of such a test, compared to actual gear hobbing tests, are primarily accessibility and reduced costs for both design and production of test specimens (inserts).The main goal of this study was to verify that the wear mechanisms in the developed test correspond with the wear mechanisms obtained in real gear hobbing. Once this was verified, the influence of surfaces roughness on the performance of TiAlN coated HSS inserts was evaluated by using the tool as delivered or after polishing the tool surfaces. Parameters considered were tool wear, cutting forces and the quality of machined surfaces. The polished inserts, yielded less adhered work material and reduced flank wear but no significant difference in cutting forces as compared to the unpolished inserts.     

非圆齿轮滚切最简数学模型及其图形仿真

推导非圆齿轮滚切加工的最简数学模型并作图形仿真验证。以切削点处工件和刀具的切向速度相等 (即滚刀节曲线和非圆齿轮节曲线保持相互纯滚动 )为基本依据 ,推导出坐标轴联动控制的一组方程式。对该组方程式进一步简化便获得滚切加工的最简数学模型 ,它是一个 3坐标联动的结构。根据最简数学模型 ,利用计算机图形仿真的方法 ,动态地演示出齿形的形成过程及结果。利用图形仿真的结果 ,可以初步分析判断所加工齿轮齿形的各种特征 ,从而为设计和制造的顺利进行提供了有力的支持。     

齿轮加工过程中滚齿力矩的试验研究

对齿轮加工过程中产生的切削力矩进行了研究,讨论了滚齿力矩的变化规律、滚削力矩与滚削用量之间的前系。为合理地选择滚削用量和滚刀的几何参烽、延长滚刀的使用寿命、预测滚齿加工过程等提供了参考依据。     

滚齿加工中仿真分析方法应用探讨

滚齿加工由于生产率高/通用性强,在齿轮的制造过程中一直比较受重视。但由于滚齿加工成形过程的复杂性与特殊性,需要建立仿真模型以及方法来辅助分析这一过程。通过CAD几何仿真与有限元仿真研究两个方面进行论述,从切屑、切削力、切削温度和刀具磨损等方面,阐述国内外学者主要研究方法和已取得的成果,分析目前研究中存在的不足,进行总结并展望,为滚齿加工工艺优化、切削刀具寿命和工件表面质量提高等研究提供一定参考和借鉴。     

基于工件材料去除率的滚齿机床能耗模型

开展了滚齿机床能耗建模与参数分析的研究。基于滚刀和工件的几何参数与空间运动分析，进行未变形切屑的数值计算，求取了滚齿加工过程中材料去除率的数值，建立了滚齿机床能耗预测模型，并通过正交试验进行了验证，平均预测准确率超过95%。基于实验结果与所提出的数值模型，对比分析了进给速度、滚刀转速与切削深度对表征能量利用效率的比能耗的影响，结果表明，所提出的模型可以准确预测滚齿加工过程中的机床能耗。