组合机床文献综述

文献综述

1.前言

钻、镗两用组合机床是以系列化、标准化的通用部件为基础，配以少量的专用部件组成的专用机床。它适宜于在大批、大量生产中对一种或几种类似零件的一道或几道工序进行加工。这种机床既有专用机床的结构简单、生产率和自动程度较高的特点，又具有一定的重新调整能力，以适应工件变化的需要。［1］钻、镗两用组合机床广泛应用于大批量生产的行业，如；汽车、拖拉机、电动机、内燃机、阀门、缝纫机等制造业。［2］

2. 钻、镗两用组合机床发展历史

1908年，美国福持汽车公司率先制造出第一台组合机床，用于汽车零件的加工。1928年，前苏联开始生产钻、镗两用组合机床。我国的钻、镗两用组合机床制造技术是从“一五”计划期间，“—汽”、‘洛拖’’引进钻、镗两用组合机床开始的。1956年3月，当时的第一机械工业部第二机器管理局批准成立了第一专业设计处(即现大连钻、镗两用组合机床研究所的前身)，全面引进了前苏联的钻、镗两用组合机床通用部件和设计指导资料，开始了我国组合机床的创业阶段。并于同年在大连机床厂制造出我国的第一台钻、镗两用组合机床、1961年，又制造出我国第一条钻、镗两用组合机床自动线。钻、镗两用组合机床设计制造从“一所一厂”起步已发展到如今—个独立的配套齐全的行业。［3］我国钻、镗两用组合机床制造技术的发展大体经历／以下四个阶段:

(1).引进消化，开创我国组合机床技术标准体系

(2).普及钻、镗两用组合机床技术，发展形成行业

(3).组织科技攻关，努力担高组合机床技术水平

(4).柔性制造技术的发展，推动了组合机床传统制造技术的转变

3. 钻、镗两用组合机床的发展现状和发展趋势

近十多年来，组机床及其自动线在高效、高生产率，柔性化以及采用并行(同步)工程制订更为合理、更为节省的方案方面取得了不小的进展。尤其是汽车工业，为了提高汽车的性能，对零件的加工精度提出了一些新的要求，因此对机床性能的要求也更高了。［4］近年来随着数控技术、电子技术、计算机技术等的发展，钻、镗两用组合机床的机械结构和控制系统也发生了巨大变化。［5］钻、镗两用组合机床有了以下的发展：1、数控化。数控组合机床的出现，不仅完全改变了过去那种由继电器电路组成的组合机床的控制系统，而目．也使组合机床机械结构乃至通用部件标准发生了或正在发生着巨大的变化。2、模块化。数控加1二模块化极大地丰富了组合机床的通用件，它必将引起组合机床通用件发生根本性变化。3、高速化。由于高速加工可大大降低零件表面粗糙度及切削力，大大减小切削温度，提高生产效率，故机床的高速化研究方兴未艾，特别是数控机床的主运动和进给运动速度已达到了惊人高速。如美国生产的加工中心，主轴转速可达15 000—60 000r／min，工作台快进速度高达90—120m／min 。顺应机床高速化的潮流，组合机床的速度也

越来越高。例如德国大众汽车厂在加工铝金缸盖燃烧室侧面时，采用PCD铣刀，

铣削速度高达3 075m／min，进给速度达3 600mm／min，而采用安装有CBN刀片的新颖镗刀加工灰铸铁时，切削速度达800m／min，进给速度达I 500 mm／min。［6］4、精密化。由于机床实现了数控化，因而机床的加工精度越来越高，使一些过去看来难以达到的加工精度今天也已经实现了。5、全防护化。全封闭是现在机床的一大特点，不论是单机还是机床生产线，均采用全封闭的

外罩，电器、液压全部采用空中走线。全封闭防护，不但使机床及其生产线外形美观，而且也提高了安全性、可靠性和维修的便利性。

4.结语

钻、镗两用组合机床装备的发展思路必须是以提高组合机床加工精度、组合机床柔性、组合机床工作可靠性和组合机床技术的成套性为主攻方向。一方面，加强数控技术的应用，

提高组合机床产品数控化率；另一方面，进一步发展新型部件，尤其是多坐标部件，使其模块化、柔性化，适应可调可变、多品种加工的市场需求。

参考文献

［1］黄奇葵、钟华珍、张福润.《机械制造基础》

［2］李庆余、张佳.《机械制造装备设计》.机械工业出版

［3］佟璞玮. 中国组合机床市场.《1999中国机电产品市场展望》.

［4］裘愉. 从几个侧面看组合机床的发展动向.《组合机床与自动化加工技术》 1994年第11期.

［5］李明、王合增、张应午 . 组合机床的发展趋势及企业的对策《机械产品与科技》 2002年第1期.

［6］李如松．组合机床和自动线的技术发展．《组合机床与自动化加工技术》，1999．(1)：5～10

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Int J Adv Manuf Technol (2006) 29: 178–183 DOI 10.1007/s00170-004-2493-9
ORIGINAL ARTICLE
Ferda C. C ? etinkaya
Unit sized transfer batch scheduling in an automated two-machine ?ow-line cell with one transport agent
Received: 26 July 2004 / Accepted: 22 November 2004 / Published online: 16 November 2005 ? Springer-Verlag London Limited 2005 Abstract The process of splitting a job lot comprised of several identical units into transfer batches (some portion of the lot), and permitting the transfer of processed transfer batches to downstream machines, allows the operations of a job lot to be overlapped. The essence of this idea is to increase the movement of work in the manufacturing environment. In this paper, the scheduling of multiple job lots with unit sized transfer batches is studied for a two-machine ?ow-line cell in which a single transport agent picks a completed unit from the ?rst machine, delivers it to the second machine, and returns to the ?rst machine. A completed unit on the ?rst machine blocks the machine if the transport agent is in transit. We examine this problem for both unit dependent and independent setups on each machine, and propose an optimal solution procedure similar to Johnson’s rule for solving the basic two-machine ?owshop scheduling problem. Keywords Automated guided vehicle · Lot streaming · Scheduling · Sequencing · Transfer batches entire lot to ?nish its processing on the current machine, while downstream machines may be idle. It should be obvious that processing the entire lot as a single object can lead to large workin-process inventories between the machines, and to an increase in the maximum completion time (makespan), which is the total elapsed time to complete the processing of all job lots. However, the splitting of an entire lot into transfer batches to be moved to downstream machines permits the overlapping of different operations on the same product while work proceeds, to complete the lot on the upstream machine. There are many ways to split a lot: transfer batches may be equal or unequal, with the number of splits ranging from one to the number of units in the job lot. For instance, consider a job lot consisting of 100 identical items to be processed in a three-stage manufacturing environment in which the ?ow of its operations is unidirectional from stage 1 through stage 3. Assume that the unit processing time at stages 1, 2, and 3 are 1, 3, 2 min, respectively. If we do not allow transfer batches, the throughput time is (100)(1+3+2) = 600 min (see Fig. 1a). However, if we create two equal sized transfer batches through all stages, the throughput time decreases to 450 min, a reduction of 25% (see Fig. 1b). It is clear that the throughput time decreases as the number of transfer batches increases. Flowshop problems have been studied extensively and reported in the literature without explicitly considering transfer batches. Johnson [1], in his pioneering work, proposed a polynomial time algorithm for determining the optimal makespan when several jobs are processed on a two-machine (two-stage) ?owshop with unlimited buffer. With three or more machines, the problem has been proven to be NP-hard (Garey et al. [2]). Besides the extension of this problem to the m -stage ?owshop problem, optimal solutions to some variations of the basic two-stage problem have been suggested. Mitten [3] considered arbitrary time lags, and optimal scheduling with setup times separated from processing was developed by Yoshida and Hitomi [4]. Separation of the setup, processing and removal times for each job on each machine was considered by Sule and Huang [5]. On the other hand, ?owshop scheduling problems with transfer batches have been examined by various researchers. Vickson
1 Introduction
Most classical shop scheduling models disregard the fact that products are often produced in lots, each lot (process batch) consisting of identical parts (items) to be produced. The size of a job lot (i.e., the number of items it consists of) typically ranges from a few items to several hundred. In any case, job lots are assumed to be indivisible single entities, although an entire job lot consists of many identical items. That is, partial transfer of completed items in a lot between machines on the processing routing of the job lot is impossible. But it is quite unreasonable to wait for the
F.C. ?etinkaya (u) Department of Industrial Engineering, Eastern Mediterranean University, Gazimagusa-T.R.N.C., Mersin Turkey E-mail: ferda.cetinkaya@https://www.wendangku.net/doc/ee9732804.html,.tr Tel.: +90-392-6301052 Fax: +90-392-3654029