淬硬模具钢高速加工中切削温度的研究

本文应用常规的自然热电偶和标准热电偶方法对高速铣削过程中切削温度的动态变化规律进行试验研究,给出了淬硬钢瑞士S136高速铣削过程中存在的临界切削速度关键数据及切削温度随切削速度的变化规律,其结论有助于指导淬硬模具钢高速铣削加工、优化高速切削工艺及建立高速切削数据库。     

刀具与切削加工技术的发展现状与趋势

经济的不断发展与科技的日益进步,使社会生产过程中遇到的难以加工的生产材料越来越多,现代加工技术所需要的多个功能复合型加工刀具以及高效高速加工刀具、智能加工刀具也渐渐成为了机械加工机床生产中不可或缺的中坚力量。伴随着工业的发展,加工刀具材料的使用上和加工刀具的使用结构上也产生了更多的变化和发展。本文针对切削技术以及切削的刀具的制作工艺、刀具结构等方面进行详实的分析和阐述,并对未来的发展前景进行研究探讨。     

高速切削加工技术应用于车辆覆盖件模具

汽车产业是一个国家的支柱性产业之一,庞大的汽车需求需要成体系的加工制造产业,车辆覆盖件模具是车辆制造中的关键一环,通过车辆覆盖件模具可以完成车辆覆盖件的一次成型冲压,提高车辆覆盖件的制造效率。车辆覆盖件的冲压质量与车辆覆盖件模具的机械加工质量密切相关,由于车辆覆盖件模具的尺寸大、形状复杂、表面精度要求高,为完成车辆覆盖件模具的高精度加工现今多采用高速切削加工技术。利用高速切削加工技术可以在车辆覆盖件模具表面形成良好的加工精度。文章将在分析高速切削加工技术特点的基础上对其在车辆覆盖件模具加工中的应用进行分析介绍。     

基于Deform-3D的AISI1045钢切削温度场仿真研究

建立基于Deform-3D有限元软件的AISI1045钢切削加工物理仿真模型,运算获取切削温度场分布数据。通过单一变量因素的切削加工仿真试验,分析切削用量参数对切削温度的影响。仿真结果表明,切削速度、进给量、背吃刀量都与切削温度呈正相关关系。研究对实际生产中控制工件受热变形、延长刀具寿命,合理选择切削加工参数具有积极意义。     

数控高速切削加工的关键技术探讨

在数控加工中,高速切削加工技术是重要的组成部分,应用该技术不仅可以使数控机床的工作水平和工作效率得到提高,同时也能够进行资源的有效节约。以高强度钢的注射模零件的加工为例,对数控高速切削加工的关键技术展开探讨,从而为关注这一话题的人们提供参考。     

超硬刀具现代切削加工中的重要手段

代表现代机械加工主流方向的高速切削加工，因顺应了21世纪机械加工高效率、高精度、柔性与绿色化的要求而迅速发展，这一技术主要应用于车削和铣削。高速干切削能消除切削液所带来的污染环境、危害工人健康的负面影响，是符合可持续发展要求的先进制造技术。精磨是轴承精加工中最常用的加工工艺，随着PCBN刀具的出现及数控机床等加工设备精度的提高，以硬态切削代替磨削来完成零件的最终加工已成为硬轴承钢的一个新的精加工途径。后继工序有超精加工或精度磨削要求时，硬态切削是最好的选择。要实现高速切削、干切削、硬态切削，精密和超精密切削，刀具材料是关键。而PCD、PCBN刀具为上述切削技术的实现提供了最基本的前提条件。     

用立方氮化硼刀具在卧式加工中心上高速精镗深孔

从零件加工的工艺要点分析,论述了在具备高速切削能力的M-H5B-S三菱卧式加工中心上,用具有高硬度、高热硬性和化学稳定性的CBN刀具,采用高速切削的工艺方法,满足了零件高的尺寸精度、形状精度和表面质量的要求.由于高速切削单位时间材料切除率高,并且取消了后道工序,因而大大地提高了该零件的生产效率.     

高速切削刀具在数控加工中的应用

随着科学技术水平的不断提高,作为先进制造技术的重要组成部分高速切削技术在模具加工制造中已得到越来越广泛的应用。文章结合高速切削技术的发展现状,阐述了高速切削技术的应用及其未来趋势。     

复杂曲面多轴加工技术切削稳定性研究

针对复杂曲面多轴加工的条件下,提出了基于实际切削工况的情况下,对切削受力的优化而进行的有效预测。根据被加工复杂曲面的复杂情况进行分级,根据所加工设备的轴数进行分级,根据不同的轴数来配置切削的稳定性进行分级,装夹工况的工艺性系数和刀具加工时与曲面的夹角大小来确定切削受力状况,从而来保证切削的稳定性。从仿真和实验都说明了预测的有效性分析。提出了,优化复杂曲面多轴切削加工的优化因素。为后续的研究,明确了优化方向,具有一定的应用价值。     

切削加工以及切削颤振简述

切削加工作为机械制造行业的传统生产加工工艺,是机械制造的流程中完成零件制作这一中心环节的重要生产技术,文章介绍了切削加工的基本方法,切削加工使用的刀具以及切削过程中产生的切削颤振和相应的控制方法。     

切削参数对竹材切削力影响的研究

研究了竹材切削不同刀具前角、切削量与切削速度对切削力的影响.刀具前角对主切削力的影响较为显著,随刀具前角的增大,所需主切削力明显减小.主切削力与切削量成正相关关系.切削速度对切削力的影响不大.     

干切混凝土时金刚石锯片振动及噪声的研究

干切混凝土时,金刚石锯片在实际工作过程中产生的振动和噪声是非常严重的。文章从理论上分析了混凝土锯切过程中的强振动、高噪音的原因。通过改变锯切速度、进给速度、切深以及通过采用两种不同的基体结构的锯片,研究了不同的切削参数以及锯片的结构对锯片振动和噪声的影响。在不同的锯切工艺参数和锯片结构下,测量了噪声值、噪声功率、噪声电压、振动功率和振动幅值,并对其进行频谱分析。可以从锯片的基体结构、金刚石节块的结构、锯切工艺以及锯机的整体性能等方面来进行改进,从而达到降低噪声与振动的目的。本文在理论分析和实验的基础上提出了一些降低噪声和振动的方法。     

Cutting meat with bone using an ultrahigh pressure abrasive waterjet

An experimental study of abrasive waterjet (AWJ) cutting of beef, pork and lamb meat with and without bone is presented. Salt particles were used as the abrasives. It has been found that an AWJ could significantly increase the depth of cut with much improved cut quality in cutting pure meat as compared to plain (or pure) waterjet cutting, while a plain waterjet was incapable of cutting bone satisfactorily. The study shows that AWJ cutting produced a very narrow kerf of less than 1 mm and hence resulted in mush less meat loss than the traditional cutting processes, and meat can be cut at room temperature to eliminate the freezing or chilling costs. It is shown that a traverses speed of 20 mm/s can be used to cut through 44 mm thick beef rib bones with good cut quality. When slicing pure meat of 150 mm thickness, the traverse speed of 66.67 mm/s can yield very good cut quality. It is suggested that AWJ cutting is a viable technology for meat cutting. Plausible trends for the depth of cut, cutting rate and cut quality with respect to the process variables are discussed. Recommendations are finally made for the selection of the most appropriate process parameters for cutting meat of a given thickness.     

基于数控加工的干式切削与刀具的研究

介绍了干式切削的主要方式及加工过程的特殊性，提出了数控干式切削刀具的基本要求．以及选择原则和应用实例。     

切削参数对人造板切削力影响的研究

通过对中密度纤维板和刨花板的闭式切削实验,研究了不同锯齿前角、切削厚度、切削速度等参数对切削力的影响规律。结果表明:主切削力和法向力皆随前角的增大而呈减小趋势;通常情况下,相同锯齿前角切削时,刨花板的主切削力和法向力皆比中纤板大。切削厚度对切削力的影响显著,主切削力和法向力均随切削厚度增加而增加。切削速度对切削力的影响相对较小,随着切削速度的增加,主切削力和法向力均略有减小。     

基于DEFORM-3D的不锈钢切削力有限元仿真

为更好地研究金属材料的切削加工过程,以DEFORM-3D软件为平台,利用有限元方法对0Cr18Ni9不锈钢的切削过程进行了建模与仿真,分析0Cr18Ni9不锈钢的切削力变化规律以及切削速度和进给量对其切削力的影响,并同理论计算结果进行对比验证。研究表明,DEFORM-3D软件所得仿真数据与理论计算结果吻合度较高,说明仿真结果具有较高的可信度,为系统地研究金属的切削过程提供了一种新的途径。     

Impact of Excitation and Material Parameters on the Efficiency of Ultrasonic Cutting of Bakery Products

ABSTRACT: Cutting with tools excited by ultrasound is increasingly applied in the food industry, especially for cheese, confectionary, and bakery products. Due to the lack of a thorough understanding of the separation process, most of the ultrasonic cutting systems are designed and applied on the basis of empirical knowledge. The aim of the study was to elaborate the impact of ultrasonic parameters, that is, amplitude and frequency, on the cutting process, and special emphasis was placed on resulting effects in the close vicinity of the cutting edge, which are reflected by the separation forces. To allow a direct investigation of the mechanical separation without artifacts due to secondary effects such as melting and cavitation, the crumb of different bakery products (for example, dark and white bread, yeast dumplings, and cake) were analyzed. The results show that the influence of ultrasonic amplitude and frequency can be expressed by the maximum vibration speed on the cutting edge. For each product, an increasing maximum vibration speed results in a particular reduction of the cutting force and an increased quality of the cut. The magnitude of the cutting force reduction is inversely related to a material-specific parameter c_x, which was calculated from the mechanical properties according to the speed-of-sound concept. Therefore, the determination of c_x allows a specific adjustment of ultrasonic amplitude and frequency to achieve optimum cutting quality.     

Effects of technological settings on yield,curd, whey,and cheese composition during the cheese-making process from raw sheep milk in small rural dairies: Emphasis on cutting and cooking conditions

The technological conditions of cheese-making affect cheese yield and compound losses in the whey, especially the processes of cutting and cooking. Although significant compositional and functional differences have been reported among animal species, there is a lack of studies on the effects of cheese-making technology on cheese yield and losses for sheep milk. Thus, we examined the cheese-making settings in 8 small rural dairies working with raw sheep milk and their effects on cheese yield and compound losses in whey during the cheese-production season. Actual cheese yield varied in 2 to 3 kg of cheese/100 kg of milk among dairies due to the cheese-making conditions, particularly the duration of cutting and cooking and the final cooking temperature. The combination of the conditions used during cutting and cooking, especially, determined fat losses in the whey. Fat losses were increased with high-speed and short cutting time settings together with high stirring speed and long duration of cooking. Additionally, cheese-makers should adapt the cutting and cooking conditions to the seasonal variations of milk composition, especially during early summer, when fat losses in the whey are higher. Our results suggest that it could be useful to use approximately 10 to 15 min of cutting time and moderate cooking speed and duration. The data reported in this study may assist the improvement of the cheese-making process in small rural dairies using sheep milk, where facilities are limited and the role of the cheese-maker is crucial.     

数控服装裁剪机裁刀切割机构的设计及平衡校核

针对目前国产数控服装裁剪机裁刀切割机构震动噪声很大,为了提高服装裁剪机的切割精度和速度,设计一种将高速旋转运动转变为高频直线切割运动的裁刀切割机构裁剪布匹。文中提出了裁刀切割机构的具体设计方案,并对机构的平衡做了校核和分析。样机的实际测试结果表明,振动电机在高速运转的情况下,切割机构震动噪音较小,能够满足实际工作要求。     

超高压纯水射流切割羊胴体试验

目的:减少机械切割羊肉损耗。方法:采用龙门式超高压纯水射流切割平台，针对羊胴体的不同部位，选取不同的参数进行试验。对比切割效果、找出合适的切割参数并分析切割损耗。结果:针对常温羊肉、冷冻羊肉、羊排、羊脊柱、羊腿、羊颈部、剔骨取肉等几个方面进行了试验，明确了羊酮体不同部位、不同试验参数对切割效果的影响。结论:纯水射流切割对冷冻羊酮体的不同部位适应性不同，但均可以获得良好的效果而且损耗很小，对常温羊肉、羊腿、羊颈部等部位的切割效果不佳。