齿轮轴承座零件的加工工艺和粗镗、半精镗、精镗φ52的工装夹具设计参考素材
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夹具设计的综述1 前言 机械加工工艺及夹具设计是全面综合运用有关专业课程的理论和实践知识进行加工工艺及夹具设计的一次重要实践。机床夹具是在机床上装夹工件的一种装置,其作用是使工件相对于机床和刀具有一个正确的位置,并且在加工过程中保持这个位置不变。夹具不仅能保证工件的加工精度、提高加工效率,还能减轻工人的劳动强度、降低产品的制造成本、扩大机床的使用范围。制造技术已经是生产、国际经济竞争、产品革新的一种重要手段,所有国家都在寻求、获得、开发和利用它。它正被看作是现代国家经济上获得成功的关键因素。机械加工工艺规程是规定产品或零部件机械加工工艺过程和操作方法等的工艺文件,是一切有关工生产人员都应严格执行、认真贯彻的纪律性文件。生产规模的大小、工艺水平的高低以及解决各种工艺问题的方法和手段都要通过机械加工工艺规程来体现。而机床夹具是在机床上用以装夹工件的一种装置,其作用是使工件相对于机床或刀具有个正确的位置,并在加工过程中保持这个位置不变。它们的研究对机械工业有着很重要的意义。2 机械加工工艺及夹具设计的发展21 发展历史 从1949年以来,我国机械工业有了很大的发展,已经成为工业中产品门类比较齐全、具有相当规模和一定技术基础的产业部门之一,其机械加工和夹具也有很大的发展,但是与工业发达国家相比,我们这方面的水平还存在着阶段性的差距,主要表现在机械产品质量和水平不够高,加工工艺过程不合理,夹具应用也比较少,使其加工工人劳动强度大,加工出来的产品也不理想。22发展现状 现在,各工业化国家都把制造技术视为当代科技发展为活跃的领域和国际间科技竞争的主战场,制定了一系列振兴计划、建立世界级制造技术中心,纷纷把先进制造技术列为国家关键技术和优先发展领域。 机械加工工艺及夹具随着制造技术的发展也突飞猛进。机械加工工艺以各个工厂的具体情况不同,其加工的规程也有很大的不同。突破已往的死模式。使其随着情况的不同具有更加合理的工艺过程。也使产品的质量大大提高。制定加工工艺虽可按情况合理制定,但也要满足其基本要求:在保证产品质量的前提下,尽可能提高劳动生产率和降低加工成本。并在充分利用本工厂现有生产条件的基础上,尽可能采用国内、外先进工艺技术和经验。还应保证操作者良好的劳动条件。但我国现阶段还是主要依赖工艺人员的经验来编制工艺,多半不规定工步和切削用量,工时定额也凭经验来确定,十分粗略,缺乏科学依据,难以进行合理的经济核算。机床夹具最早出现在18世纪后期。随着科学技术的不断进步,夹具已从一种辅助工具发展成为门类齐全的工艺装备。国际生产研究协会的统计表明,目前中、小批多品种生产的工件品种已占工件种类总数的85左右。现代生产要求企业所制造的产品品种经常更新换代,以适应市场的需求与竞争。然而,一般企业都仍习惯于大量采用传统的专用夹具,一般在具有中等生产能力的工厂里,约拥有数千甚至近万套专用夹具;另一方面,在多品种生产的企业中,每隔34年就要更新5080左右专用夹具,而夹具的实际磨损量仅为1020左右。特别是近年来,数控机床、加工中心、成组技术、柔性制造系统(FMS)等新加工技术的应用,对机床夹具提出了如下新的要求:1)能迅速而方便地装备新产品的投产,以缩短生产准备周期,降低生产成本;2)能装夹一组具有相似性特征的工件;3)能适用于精密加工的高精度机床夹具;4)能适用于各种现代化制造技术的新型机床夹具;5)采用以液压站等为动力源的高效夹紧装置,以进一步减轻劳动强度和提高劳动生产率;6)提高机床夹具的标准化程度。23发展趋势长期以来,加工工艺编制是由工艺人员凭经验进行的。如果由几位工艺员各自编制同一个零件的工艺规程,其方案一般各不相同,而且很可能都不是最佳方案。这是因为工艺设计涉及的因素多,因果关系错综复杂。CAPP将是机械加工工艺的发展趋势,它不仅提高了工艺设计的质量,而且使工艺人员从繁琐重复的工作中摆脱出来,集中精力去考虑提高工艺水平和产品质量问题。231夹具的发展趋势现代机床夹具的发展趋势主要表现为标准化、高效化、精密化和柔性化等四个方面。(1)标准化 机床夹具的目的就在于提高生产效率,这样也就必使其具有标准化和通用化,而机床夹具的标准化与通用化是相互联系的两个方面。目前我国已有夹具零件及部件的国家标准:GB/T2148T225991以及各类通用夹具、组合夹具标准等。机床夹具的标准化,有利于夹具的商品化生产,有利于缩短生产准备周期,降低生产总成本。(2)高效化 高效化夹具主要用来减少工件加工的基本时间和辅助时间,以提高劳动生产率,减轻工人的劳动强度。常见的高效化夹具有自动化夹具、高速化夹具和具有夹紧力装置的夹具等。例如,在铣床上使用电动虎钳装夹工件,效率可提高5倍左右;在车床上使用高速三爪自定心卡盘,可保证卡爪在试验转速为9000r/min的条件下仍能牢固地夹紧工件,从而使切削速度大幅度提高。目前,除了在生产流水线、自动线配置相应的高效、自动化夹具外,在数控机床上,尤其在加工中心上出现了各种自动装夹工件的夹具以及自动更换夹具的装置,充分发挥了数控机床的效率。(3)精密化 机床夹具的精度会直接影响到零件的加工精度,而随着机械产品精度的日益提高,势必相应提高了对夹具的精度要求。精密化夹具的结构类型很多,例如用于精密分度的多齿盘,其分度精度可达0.1;用于精密车削的高精度三爪自定心卡盘,其定心精度为5m。这些精密化的夹具为以后零件加工的精度提供了保证。(4)柔性化 机床夹具的柔性化与机床的柔性化相似,它是指机床夹具通过调整、组合等方式,以适应工艺可变因素的能力。工艺的可变因素主要有:工序特征、生产批量、工件的形状和尺寸等。具有柔性化特征的新型夹具种类主要有:组合夹具、通用可调夹具、成组夹具、模块化夹具、数控夹具等。为适应现代机械工业多品种、中小批量生产的需要,扩大夹具的柔性化程度,改变专用夹具的不可拆结构为可拆结构,发展可调夹具结构,将是当前夹具发展的主要方向。231机械加工制造技术的发展趋势(1)特种加工 它是指一些物理的、化学的加工方法,如电火花加工、电解加工、超声波加工、激光加工、离子束加工等。特种加工方法的主要对象是难加工材料的加工,如金刚石、陶瓷等超硬材料的加工,其加工精度可达分子级加工单位或原子级加工单位,所以它又常常是精密加工和超精密加工的重要手段。特种加工与传统加工相结合的复合加工有较大的发展前途。(2)快速成形 利用离散、堆积成形概念,可将一个三维实体分解为若干二维实体制造出来,再经堆积而构成三维实体。(3)精密工程 它包括精密加工的超精密加工技术、微细加工和超微细加工技术、微型机械和纳米技术等方面。当前,以纳米技术为代表的超精密加工技术和以微细加工为手段的微型机械技术有重要意义,它们代表了这一时期精密工程的方向。(4)传统加工工艺的改造和革新 这一方面的技术潜力很大,如高速切削、超高速切削、强力磨削、超硬材料磨具的出现都对加工理论的发展、加工质量和效率的提高有重要意义。另一方面,旧设备的改造和挖潜,如普通机床改造成数控机床等,对机械工业的发展和提高是不容忽视的。3 简单的评述综上,机械加工艺及夹具随着科技的发展都使计算机技术、数控技术、控制论及系统工程与制造技术的结合为制造系统,形成现代制造工程学。而物料流、能量流、信息流是组成制造系统的三个基本要素。现代加工都为集成化的系统加工,这虽减轻了工人的劳动强度,但同时对工人的知识水平要求较高。这需要我们全方位的认知现代科技知识。因此,在以后的学习中需要我们全方位的学习其各个相关领域的知识,不能只注重一点,为将来的人才战略提出了新的要求。英文翻译:Overview of the fixture design1 IntroductionMachining process and fixture design is a comprehensive process and fixture design is an important practical use of theoretical and practical knowledge of the relevant professional courses. Machine tool fixture is a device for clamping the workpiece on the machine, its role is so that the workpiece to have a correct position relative to the machine and tool, and to maintain this position unchanged in theprocess. The fixture can not only guarantee the accuracy of the workpiece processing, improve processing efficiency, but also reduce the labor intensity of workers, reducing the manufacturing costs of products, expanding the use of the machine. Manufacturing technology production, international economic competition, an important means of product innovation, all countries seeking to acquire, develop and exploit it. It is being seen as a key factor in the success of the modern state economy.Mechanical process planning is the process of the specified products or components machining process and methods of operation and other documents, all relevant work production personnel should be strictly enforced, conscientiously implement the disciplinary file. The size of the production scale, technology level of a variety of process issues, methods and means to go through the machining process specification to reflect. Machine tool fixture is a device used for clamping the workpiece on the machine, and its role is to enable the workpiece relative to the correct location of the machine or tool, and in the process to maintain this position. Their research on the machinery industry has very important significance.The development of the two machining process and fixture design 2.1 history of the development Since 1949, Chinas machinery industry has been greatly developed and has become a relatively complete industrial products, with one of the considerable size and some technology-based sectors, machining and fixture also has a great development, but industrial developed countries, the level of our stage gap, mainly in the quality and level of mechanical products is not high enough, the machining process is unreasonable, fixture applications is relatively small, its processing workers in labor-intensive, processing out of the product is not satisfactory. 2.2 Development of Now, industrialized countries have manufacturing technology as the development of modern science and technology to the main battlefield of the active area and in the international technology competition to develop a series of revitalization plan, the establishment of the center of world-class manufacturing technology, have advanced manufacturing technology as a key national technologies and priority areas of development. Machining process and fixture with the development of manufacturing technology is also advancing rapidly. Machining process to the specific circumstances of each plant, the processing procedures are very different. Breakthrough in previous years, the death mode. It as the situation different with a more reasonable process. Also greatly improve the quality of the product. Development of processing technology, although according to reasonable development, but also to meet their basic requirements: the premise of ensuring product quality, maximize productivity and reduce processing costs. Domestic and foreign advanced technology and experience and, as far as possible on the basis of full use of the existing production conditions of the factory. It should also ensure good working conditions for the operator. Present stage still mainly rely on the experience of the craft workers to the preparation process, most do not require working steps and cutting, fixed working hours rule of thumb to determine, very rough, the lack of scientific basis, it is difficult to make reasonable economic accounting. The machine tool fixtures first appeared in the late 18th century. With the continuous progress of science and technology, the fixture has evolved from a tool developed into a complete range of process equipment. Association for the Study of international production statistics show that now, about 85 percent of the workpiece varieties of small batch production of many varieties accounted for the total number of workpiece types. The modern production requires a variety of products manufactured by the enterprise often replace old ones, in order to meet market demand and competition. However, most enterprises are still accustomed to a large number of traditional special fixture, usually in the factory with medium production capacity, about thousands or even ten thousand sets of special fixtures; the other hand, multi-product production enterprise, every 3 to 4 years is necessary to update 50 to about 80% of special fixtures, fixture wear only about 10 to 20 percent. In recent years, CNC machine tools, machining centers, group technology, flexible manufacturing system (FMS) application of new processing technologies, the machine tool fixture the following new requirements: 1) can quickly and easily equip the commissioning of new products, to shorten the cycle of production preparation, reduce production costs; 2) clamping a workpiece with similar characteristics; 3) high-precision jigs and fixtures for precision machining; 4) can be applied to new jigs and fixtures for a variety of modern manufacturing technology; 5) efficient clamping device, hydraulic station power source in order to further reduce labor intensity and improve labor productivity; 6) Increase the degree of standardization of the machine tool fixture. 2.3 Development Trend of Over the years, the machining process planning is carried out empirically by the craft workers. By several craft their own preparation process specification of the same parts, its programs are generally of the same, and probably not the best option. This is because the process design involves many factors, the complexity of the causal relationship. CAPP will be the development trend of the machining process, it not only improves the quality of the process design and process to extricate itself from a tedious repetitive work, concentrated effort to consider raising the level of technology and product quality issues. 2.3.1 fixture development trends Development trends of the modern machine tool fixture mainly four aspects of standardization, efficiency, precision and flexibility. (1) The purpose of the standardization of machine tool fixture is to improve production efficiency, so that he will make with the standardization and universal standardization and generalization of the machine tool fixture two aspects are interrelated. National standards of China has a fixture parts and components: GB/T2148 T2259-91, and a variety of universal fixture, modular fixture standards. Standardization of jigs and fixtures, commercial production of the fixture, to shorten the production preparation period, reducing the total cost of production. (2) efficient efficient fixture mainly used to reduce the the workpiece basic time and auxiliary time, to improve labor productivity, reduce labor intensity. Efficient common folder with automated fixtures, high-speed jig and fixture clamping force device. For example, the electric vise clamping the workpiece in a milling machine, the efficiency can be increased about five times; on a lathe using high-speed three-jaw self-centering chuck, to ensure that the jaws are still firmly under the conditions of the test speed is 9000r/min to clamp the workpiece, so that the cutting speed is greatly improved. In addition to efficient, automated fixture in the production lines, automatic line configuration on the CNC machine tools, especially in the machining center fixture of a variety of automatic workpiece clamping and automatic replacement of the fixture device, give full play to the CNC machine tools efficiency. (3) the accuracy of precision machine tool fixture will directly affect the machining accuracy, with the increasing accuracy of mechanical products, is bound to a corresponding increase in the precision of the fixture. Precision fixture structure type, for example, the precision of multi-gear, its indexing accuracy up to 0.1; for precision turning, precision jaw self-centering chuck, centering accuracy of 5m These precision fixture to provide a guarantee for the accuracy of the later parts processing. (4) the flexibility of the flexible machine tool fixture and the flexibility of the machine, it refers to the ability to machine fixture by way of adjustment, combined to suit the process variables. Variables of the process are: process characteristics, production volume, the workpiece shape and size. The new fixture types with flexible features: modular fixture, universal adjustable clamp, group fixtures, modular fixtures, CNC jig. In order to meet the needs of the many varieties of modern mechanical industry, small and medium volume production, expand the degree of flexibility of the fixture to change the special fixtures2.3.1 machining manufacturing technology trends(1) special processing it refers to some physical, chemical processing methods, such as electrical discharge machining, electrochemical machining, ultrasonic machining, laser processing, ion beam processing. The main object of the special processing method is the processing of difficult materials, such as diamond, ceramics and other superhard materials processing, and its precision up to molecular level processing units, or atomic-scale processing units, so it is often the precision machining and ultra precision machining an important tool. Special processing and processing a combination of composite processing have a greater future development.(2) rapid prototyping using discrete accumulation of forming the concept of a three-dimensional entities can be decomposed into a number of two-dimensional entity created by the accumulation of a three-dimensional entities.(3) precision engineering, including precision machining of ultra-precision processing technology, micro-machining and ultra-fine processing technology, micro-mechanical and nano-technology. At present, ultra-precision processing technology as the representative of nanotechnology and micro-mechanical technology as a means of micromachining is important, they represent the direction of the precision engineering of this period.(4) the transformation and modernization of the traditional processing technology in this field potential, such as high-speed cutting, ultra-high-speed cutting, strong grinding, abrasive superhard materials processing theory of development, processing, quality and efficiency The increased significance. On the other hand, the transformation of the old equipment and tapping the potential, such as general machine tools transformed into CNC machine tools, the development and improvement of the machinery industry can not be ignored.3 commentsIn summary, the machining process and jig With the development of science and technology, computer technology, CNC technology, control dealt with systems engineering and manufacturing technology combined with manufacturing systems, the formation of the modern manufacturing engineering. Material flow, energy flow, information flow is the three basic elements that make up the manufacturing system. Modern processing for the processing of integrated systems, which reduce the labor intensity, but at the same time require a higher level of knowledge of the workers. This need our full range of cognitive modern scientific and technological knowledge. Therefore, in the future learning needs our full range of learning its various related fields of knowledge, can not focus only on the proposed new requirements for future human resources strategy.15
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