【作者】 韩式国；

【导师】 王兆辉；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2005， 硕士

【摘要】 在模具型腔的数控加工研究中,首先考虑的问题之一是刀具和切削参数的自动选择。刀具选择是一个复杂的优化过程,它受到多种因素的影响。国内外现有的CAD/CAM系统仍然需要工艺员手工确定选择刀具和加工参数,才能生成刀具位置源文件(CLSF),再调用后处理模块生成数控加工程序,加工程序的质量依赖于工艺员的技巧和经验,容易造成数控机床的利用效率不高。刀具选择时,所选的刀具不仅要有所需的加工能力,而且应是在一定优化目标下的最优刀具。因此,在零件投入生产前就必须优化刀具组合,可以使没有多少加工经验和技巧的工艺员也能编制高效的加工程序。粗加工是数控加工的重要阶段之一,其任务是快速地切除工件毛坯上的大部分多余材料,只保留用于半精加工和精加工的适当加工余量。事实上,在数控加工复杂的模具和零件时,大约70%的原材料由粗加工阶段切除,大量的加工时间消耗在粗加工中。因此,在型腔加工的粗加工阶段,以基于加工时间的最低加工成本作为优化目标进行刀具组合的选择对于缩短加工时间、提高加工效率、降低生产成本具有重要意义。本文内容首先对CAD/CAM技术进行了分析,进而开发了基于模具型腔数控加工的刀具优选系统,采用求解单源有向无环图的最短路径问题的Di jkstra算法,使得在数控加工前能获取最优刀具组合及相应的工艺参数;获取最低制造成本并在高端CAD/CAM软件--UG平台上进行数控编程、生成NC程序单,利用自主开发的数控加工仿真系统(NCEdit)进行模拟加工。更多还原

【Abstract】 During the investigation of die-pocket NC machining, the issue that appropriate tool sequence selected automatically should be considered first. The selection of cutting tools is a complicated and optimal process, which is affected by many factors. The present CAD/CAM systems still require processors to select tools and cutting parameters manually. Subsequently, the processors produce CLSF files and NC machining programs by using the module of postprocessor. The quality of NC programs depends too much on the user’s technique and experience, which are prone to cause low efficiency. The cutting tools not only need the capacity in metal removal processes, but also are optimal ones under optimized objectives. Accordingly, it is necessary to optimize cutting tools before cutting the parts, which could let processors lack of experience and technique edit high- efficiency NC programs.Rough cut is one of the most important stages in NC machining. Its main function is to remove redundant material from the workpiece in great quantity, and only reserve appropriate part stock which will be removed by semi-rough and fine cuts. In fact, approximately 70% of raw materials will be removed in the step of rough cut when complicated dies/moulds and parts are machined by NC machines, so rough cut consumes plentiful of time.Consequently, during the rough cut of pocket machining, it is significant to select cutting tools aimed at the lowest time-based production cost ,which can shorten processing time ,improve productivity and reduce production cost.In brief, firstly, this paper introduces CAD/CAM technique. Secondly, it develops a cutting tools system based on die/mould pocket NC machining. To attain the shortest-path in the single-source, directed, acyclic graph can be obtained by employing Dijkstra’ algorithm, we can obtain optimal tools combination, corresponding cutting parameters and the minimal machining cost. Lastly, we can develop NC G&M codes byusing high CAD/CAM software------UG, and simulate machining by using NCprocessing emulator system (NCEdit) developed by ourselves.更多还原