1、毕 业 设 计（论 文）外 文 参 考 资 料 及 译 文译文题目： development of automatede fixture planning systems 自动化夹具的规划系统的发展 学生姓名： 学号： 专业： 所在学院： 指导教师： 职称： 20xx年 02 月 25 日Development of Automated Fixture Planning SystemsW. Ma, J. Li and Y. RongDepartment of Mechanical Engineering, Worcester Polytechnic Institute, Worcester,
2、MA, USAFixturing is an important manufacturing activity. The computeraided fixture design technique is being rapidly developed to reduce the lead time involved in manufacturing planning. An automated fixture configuration design system has been developed to select automatically modular fixture compo
3、nents and place them in position with satisfactory assembly relationships.In this paper, an automated fixturing planning system is presented in which fixturing surfaces and points are automatically determined based on workpiece geometry and operational information. Fixturing surface accessibility, f
4、eature accuracy, and fixturing stability are the main concerns in the fixture planning. The system development, the fixture planning decision procedure, and an implementation example are presented in the paper.Keywords: Accuracy; Clamping; Fixture planning; Locating1. Introduction Fixturing is an im
5、portant manufacturing activity in the production cycle. A computer-aided (or automated) fixture design (CAFD) technique has been developed as part of CAD/CAM integration 1. The development of CAFD contributes to the reduction of manufacturing lead time, the optimisation of manufacturing operations,
6、and the verification of manufacturing process designs 2. CAFD plays an important role in flexible manufacturing systems (FMS) and computer-integrated manufacturingsystems (CIMS) 3. Figure 1 outlines the activities for fixture design in manufacturing systems which include three major aspects: set-up
7、planning, fixture planning, and fixture configuration design 4. The objective of set-up planning is to determine the number of setups, the position and orientation of the workpiece in each setup, and also the machining surfaces in each set-up. Fixture planning determines the locating and clamping po
8、ints on workpiece surfaces. The task of fixture configuration design is to select fixture components and place them into a final configuration to fulfil the functions of locating and clamping theworkpiece. An automated modular fixture configuration design system has been developed in which, when fix
9、turing surfaces and points are selected on the workpiece model, fixture units are automatically generated and placed into position with the assistance of fixture component assembly relationships 4,5. This paper deals with fixture planning when the fixturing surfaces and positions on the workpiece ar
10、e selected automatically.Fig. 1. Fixture design in manufacturing systems. Previous papers on fixture design analysis have been published,but a comprehensive fixture planning system which can be used to generate fixture plans for industrial applications hasnot been developed. Previous work includes:
11、a method for the automated determination of fixture location and clamping derived from a mathematical model 6; an algorithm for theselection of locating and clamping positions which provide the maximum mechanical leverage 7; kinematic analysis based fixture planning 8,9; a fixturing grade and depend
12、ency grade based fixturability analysis 10; automated selection of set-ups with consideration of tolerance factors of orientation errors in fixture design 11, and finally a geometric analysis based 2D fixture planning system 12. In our previous research, fixturing features 13, fixturing accuracy 14,
13、15, geometric constraints 16, and fixturing surface accessibility 17 have been studied. A framework has been developed for set-up planning andfixture design 18. In this paper, an automated fixture planning system, Fix-Planning, is presented where fixturing surfaces and points are determined when the
14、 workpiece model and set-up planning information is input to the system.2. Basic Requirements of FixturePlanning In engineering practice, fixture planning is governed by a number of factors, including workpiece geometric information and tolerance; set-up planning information such as machining featur
15、es, the machine tool and cutting tools to be used in each set-up; initial and resulting forms of the workpiece in each set-up; and available fixture components. To ensure that the fixture can hold the workpiece in an acceptable position so that the manufacturing process can be carried out according to the design specifications, the following conditions should be satisfied for a feasible fixture plan. 1. The degrees of freedom (DOF) of the workpiece are totally constrained when the workpiece is located. 2. Machining accuracy specific
