浅谈机械设计加工中应注意的几个问题

在社会的发展下,为了满足生产活动的需求,机械产品类型越来越多,精度越来越高,影响机械加工精度的因素很多,包括机床几何误差、加工运动误差、近似刀具导致的误差、机床磨损、刀具与夹具误差、磨损误差、工艺系统受热误差等等,为了保障机械设计与加工的精度,必须要需要做好材料选择工作,综合各方面的因素来选择加工设备、机床、刀具、润滑剂。本文主要分析机械设计加工中应该注意的几个问题。     

慢走丝电火花线切割加工钨钢刀具实验研究

在慢走丝机床加工平台上搭建了由伺服控制系统控制的主轴系统,进行了刀具的制作研究.通过实验研究了三种不同加工路径、加工路径不同分段进给速度对刀具制作效率的影响,研究不同平移距离对刀具球头形状的影响,通过实验研究刀具削边加工路径对球头直径的影响并分析了原因.分析了加工过程中效率和精度优化的原因.通过本文的研究所搭建的加工平台和加工策略为加工微小型刀具提供了一种方法,加工效率和加工精度的改善为此类刀具制造提供了方法借鉴.     

影响不锈钢螺纹加工质量的因素分析和改进对策

通过机床加工切削螺纹是目前螺纹成型的主要方式之一,在机床上加工不锈钢螺纹时其相对普通碳素钢材料的螺纹较难切削、精度较难控制,加工时影响螺纹质量的因素较多。在实际生产中受材料特性、刀具性能和工艺系统等方面因素的影响,不锈钢材料的螺纹易出现粗糙度不佳、牙型角与尺寸精度存在误差、刀具容易磨损等方面的问题,螺纹质量难以把控。针对不锈钢材料螺纹加工中易出现的问题,对其影响因素进行分析,在材料调质、刀具参数、刀具安装、工艺系统、切削参数、加工方法和冷却润滑等方面进行调整改进,通过对策可以解决加工时所出现影响螺纹质量的诸多问题,提高螺纹加工质量和效率,促进产品的整体质量提升。     

机械模具加工精度控制技术研究

在机械加工机床中,机床及机械模具的精度直接影响加工零件的精度。为确保加工零件的加工精度,机床及机械模具的精度应当与所加工零件要求的精度相适应。机械模具的加工精度受夹具、刀具、量具选择的差异性,加工过程中会使机械加工精度受到不同程度的影响。加强对影响机械模具加工精度的因素的控制,就可以有效的提高机械模具加工的进度。本文介绍了机械模具高精度加工的要求,分析了影响机械模具加工精度的主要因素。在此基础上探讨了机械模具加工精度控制策略。旨在为机械模具高精度加工制造提供一些参考。     

试论机械数控加工过程中刀具的合理使用控制

机床在加工精度、生产效率和加工产品的稳定性等方面具有普通机床无法比拟的生产加工优势。数控加工具有越来越广泛的应用前景。然而,在机床数控加工中,刀具的使用直接影响产品生产的质量,也在一定程度上影响机床运行的稳定性。因此,在机械数控机床的加工中,有必要对刀具的使用进行科学合理的控制。本文研究了数控加工过程中刀具的合理使用控制。分析了钻井原理、工具的特点和工具的控制技术在加工中的应用,并讨论了数控加工过程中刀具的控制技术和措施,从而大大提高数控加工的工作效率。     

专用电火花磨削机床磨削工艺参数的优势因素分析

针对金刚石木工刀具专用电火花磨削机床进行现场测试实验,并对磨削工艺参数进行优势因素分析,确定了影响加工精度的主要因素.     

镗、铣加工中刀具产生径向跳动的原因分析与对策

刀具产生径向跳动是镗、铣削加工生产中比较常见的问题.如果对其不加以有效防止,则不仅会影响到工件的加工精度（特别是镗削内孔表面时的加工精度）、表面质量,同时也会影响到刀具的寿命和生产率.因此,我们必须对刀具产生径向跳动的原因加以分析、研究,进而采取有效措施加以防范.通过对机械加工生产企业镗、铣削加工中所采用的具体加工工艺方法、切削工艺参数和所使用的机床、夹具、刀具等方面的观察、了解和分析研究,我们找到了刀具产生径向跳动的主要原因,并且为操作者提供了解决问题的具体办法与措施,从而有效解决了这个普遍感到棘手和伤脑筋的问题.     

提高数控车床螺纹加工精度的研究

数控车床被广泛地应用在机械生产中,本文研究了积屑瘤、机床和刀具等因素对数控车床螺纹加工精度产生的影响,通过实践经验,总结了提高数控车床车削螺纹精度的一些方法,从而提高数控车床螺纹零件的加工精度。     

数控车床刀尖半径调整方法

1引言 在数控曲面车削加工中,影响曲面精度的主要有机床精度(定位精度、重复定位精度、主轴跳动等)、机床数控系统精度、刀具的制造和安装精度等因素.     

机械加工影响表面粗糙度的因素及改善措施

机械加工工件时加工精度与机床的精度及包括刀具、夹具、工件在内的整个系统有直接的关系,影响机械加工精度的因素很多,如机床制造零件的误差和安装误差以及加工过程中的有关操作,需要掌握机械加工中各种工艺对加工零件表面质量影响的规律,以便运用这些规律来控制零件加工的表面粗糙度,最终改善零件的表面质量、提高产品使用性能、减少机械设备的损坏、降低生产成本、提高经济效益。本文探讨了机械加工影响零件表面粗糙度的因素及改善措施。     

数控机床加工精度的影响因素及优化策略

先进的数控机床被应用在制造业中,不仅能够提高制造效率,还能保证制造质量。虽然从整体发展情况来看,数控机床得到了良好的应用,但是在具体的应用过程中仍然存在一些问题。数控机床的作用能否充分发挥出来在很大程度上受加工精度的影响,目前部分被应用在制造业中的数控机床存在较为严重的加工精度问题,如果不对现存问题进行科学有效的解决,将会严重影响制造业的稳定发展。本文在具体的研究过程中从数控机床的概述入手,分析了影响数控机床精度的因素,并且根据影响因素提出了切实可行的解决策略。     

Robust regenerative chatter stability in machine tools

The expeditious nature of manufacturing markets inspires advancements in the effectiveness, efficiency and precision of machining processes. Often, an unstable machining phenomenon, called regenerative chatter, limits the productivity and accuracies in machining operations. Since the 1950s, a substantial amount of research has been conducted on the prevention of chatter vibration in machining operations. In order to prevent regenerative chatter vibrations, the dynamics between the machine tool and workpiece are critical. Conventional regenerative chatter theories have been established based on the assumption that the system parameters in machining are constant. However, the dynamics and system parameters change due to high spindle speeds, tool geometries, orientation of the tool with respect to the rest of the machine, tool wear and non-uniform workpiece material properties. This paper provides a novel method, based on the robust stability theorem, to predict chatter-free regions for machining processes, by taking in account the unknown uncertainties and changing dynamics for machining. The effects of time-variant parameters on the stability are analyzed using the robust stability theorem. The experimental tests are performed to verify the stability of SDOF and MDOF milling systems. The uncertainties and changing dynamics are taken into account in order to accommodate the optimal selection of machining parameters, and the stability region is determined to achieve high productivity and accuracy through applications of the robust stability theorem.     

Process parameter definition with respect to the behaviour of complex kinematic machine tools

The definition of machining processes with respect to complex kinematic machine tool behaviour involves the control of machine accuracy and kinematic performances. The aim is to propose process settings and tool paths which guarantee the required machining quality while maximizing productivity. This article presents an experimental protocol which enables the determination of machine tool structure behaviours which have an influence on machining quality. In parallel, an experimental analysis of the different kinds of settings which can improve machining quality is carried out. Two kinds of settings appear: the first class of settings improves machining quality or machining time, and the second class has an antagonistic influence on machining quality and machining time. Thus, the definition of the second class of settings arises from an optimisation between first-order defects, second-order defects and machining time. The developed method is illustrated on a parallel kinematic machine tool, the Tripteor X7. Note that this study is a first step towards controlling machine tool behaviour during machining.     

Influence of the phase composition and microstructure of plasma cladding Fe-Cr-Ni-C alloy coating on residual stress and crack formation

Tool path generation is one of the key challenges in multi-axis sculptured surface machining. Besides geometry accuracy, machining processes have been considered in tool path generation in order to improve machining quality and efficiency as far as possible. However, so far, the machine tool accuracies have not been yet fully taken into account during tool path generation. Contour accuracy is one of the most important precision indexes to guarantee the machining quality of sculptured surfaces. One of the major reasons causing contour error is the dynamic mismatch between feed axes of machine tools. In this study, the mathematic relationship between the cutting direction, dynamic mismatch of feed axes and contour error is theoretically established. The mathematic relationship can be used to calculate the optimal cutting directions which minimize the contour error caused by dynamic mismatch between feed axes during machining a sculptured surface by a three-axis machine tool. A machining experiment is carried out to verify the mathematic relationship. In the experiment, the tool paths are generated along the optimal cutting direction and other cutting directions for comparison. The results show that the contour error under the case of the optimal cutting direction is much smaller than that under the other cases.     

改进精密镗床加工精度的方法应用

针对高精度孔在镗削加工中出现的孔表面质量不稳定和孔的圆柱度波动大的实际问题,通过对镗杆和机床丝杠的改进,使镗床的加工精度及其所加工内孔的重要指标精度均有了显著提高.     

微细孔超声加工关键技术

为提高微细孔超声加工的微细程度和精度,研究微细孔超声加工的关键技术,包括高精度的机床本体、超声加工单元、微细工具的制备技术、微细工具几何参数的选择等。对微细工具的动态压杆稳定性进行分析,结果表明微细工具的压杆稳定性不仅与静压力有关,还与超声振幅有关。导出判别动态压杆稳定性的Mathieu方程,并经简化给出工具临界压力和临界长度的计算判据,解决因工具长度、静压力(压应力)大小和超声振幅选择不当而导致的加工中出现工具轴弯曲、折断、破坏孔的形状精度的问题。对工件振动方式的微细孔超声加工进行的试验表明,微细工具的磨损率随着进给速度和超声振幅的增大而增加。在所研制的微细超声加工系统上可加工出直径13 μm的微细孔。     

Study on symmetrical machining technology

In order to promote machining efficiency of large symmetrical freeform surfaces, a new concept of symmetrical machining is put forward. In addition, problems of collision among cutters or headstocks and machining residue in symmetrical machining are studied in this paper. Through an example of a twin-skeg ship model surface, the design principles of 4-axis symmetrical machine tool are proposed and tool path planning of symmetrical machining is investigated. Based on the above research work, a 4-axis symmetrical machine tool for a ship model surface has been developed. The machining efficiency of the symmetrical machine tool is 85% higher than that of traditional machine tool with a single cutter. Furthermore, the overall cost of the symmetrical machine tool is reduced by saving one set of servo drive system.     

基于综合评价体系的五轴数控机床加工性能评价和误差溯源方法

五轴数控机床的加工性能在制造行业一直是研究的热点,基于检验试件切削是常见的测评方法,然而试件和机床之间的映射关系难以确定,出现误差后如何调整精度成为难点。为了科学对其评价,通过仿真平台建立了机床控制系统参数与五轴机床检验试件——S试件加工误差之间的映射关系,引入机床各轴分类评价的隶属度,此基础上开发了误差溯源的综合评价体系,由三坐标测量机得到的S件轮廓误差数据反求出机床的加工性能等级和较差的轴类控制参数,并制订了基于S试件的机床加工精度测评规范,最后通过某五轴AB摆数控机床的切削试验,验证了方法的有效性。该成果有助于解决我国高端制造业长期缺乏机床性能测评的共性技术问题,具有重要的应用前景和经济价值。     

新型双闭环高精度数控机床

针对制造工业对高精度数控机床的需求,研究开发出新型双闭环高精度数控机床系列产品。其特点是,采用转角—线位移双闭环位置控制和信息化精度创成技术,既具有高档全闭环机床的加工精度,又具有半闭环机床的稳定性和环境适应性,并且其造价与普及型数控机床相当。实际应用证明,双闭环机床在复杂精密零件加工方面具有良好效果     

数控机床的经济化高精度控制

为实现低成本高精度自动化加工,提出了数控机床的经济化高精度控制方法和基于该方法的闭环驱动控制系统。由此构成的新型数控机床,其成本与普通经济型数控机床相当,但却具有高档全闭环数控机床的加工精度。数十例实际应用证明,这种新型机床在复杂精密零件加工方面具有良好效果。