【作者】 徐造坤；

【导师】 吴昌林；

【作者基本信息】 华中科技大学 ， 机械设计及理论， 2013， 博士

【摘要】 不锈钢薄壁材料小家电广泛应用于人们的日常生活中,比如电热水壶、咖啡壶、电热锅、电热杯等,具有极其广阔的市场空间。抛光是这些器具加工中最重要的一道工序,要求工件表面材料去除均匀,粗糙度值较低。不锈钢薄壁材料工件在抛光中具有工件表面易烧伤、变形、难以夹持等特点,属于难抛光材料。目前国内研究机构对不锈钢薄壁材料小家电自动化抛光技术的研究较少,且现有的少数设备具有限制性,还不能普遍应用于小家电抛光行业。国内生产企业主要还是采用手工抛光方式,存在抛光质量和生产效率低、污染严重、劳动力短缺等问题,严重制约了该生产行业的发展。在不锈钢薄壁材料小家电中,电热水壶因其形状相对复杂,具有典型性,因此,本文主要以电热水壶抛光为研究对象,结合电热水壶工业实际生产背景,针对现有设备的不足,研究了一套适合不锈钢薄壁材料工件抛光的高效自动化机械抛光技术,并研发出了相应的机械抛光机床和自动化控制系统。这一研究对改善我国不锈钢薄壁材料小家电抛光及同类型家用器具产品行业普遍依赖手工方式的现状具有重要意义。第一,针对不锈钢工件建立表面材料去除率理论模型及工件表面粗糙度模型,为自动化机械抛光工艺提供了理论依据。(1)、运用弹塑性力学和磨粒磨削等理论建立了工件表面材料去除率模型,从微观角度揭示了磨粒和相关工艺参数与材料去除率之间的关系。模型表明,材料去除率与磨具旋转的切线速度、工件圆周线速度、工件进给速度和法向抛光压力等参数成正比,和磨具粒度大小、组织号等成非线性关系。(2)、基于回归分析和正交试验的方法建立了工件表面粗糙度和抛光工艺参数之间的关系模型,模型表明：加工表面粗糙度随法向抛光压力、工件圆周线速度和进给速度的增大而增大,随磨具旋转切线速度的增大而减小。运用数学仿真和试验验证的方法进行研究分析,仿真和试验有良好的一致性,证明了这两种建模方法的正确性,对自动化机械抛光工艺的合理规划具有指导意义。第二,为满足高效抛光的要求,提出了一种多工位多磨具自动化机械抛光技术,能够分别对工件外表面和内表而进行抛光,关键技术包括多工位多磨具抛光机床的结构设计、多工位姿态同步调整装置设计、工件夹具设计,并基于这一技术设计了相应的多工位多磨具机械抛光机床的自动化控制系统。根据实际生产加工中磨具需要自适应工件形状,提出了一种基于示教法的抛光刀位数据生成方法,用于自动化抛光系统中。第三、结合现行抛光工艺,提出了一套适合于不锈钢薄壁材料小家电自动化机械抛光的工艺方法。针对工件表面形状特征进行分片规划,设计了自动化机械抛光方案,采用螺旋式抛光路径作为抛光刀具的轨迹,并研究了刀具轨迹数据计算方法。通过一系列试验,并结合现行抛光经验,提出了一套适合小家电自动化机械抛光的粗抛、半精抛、精抛的工艺流程。第四、在保证工件抛光质量的前提下,尽可能提高加工效率,对自动化机械抛光工艺参数进行优化实验研究。用正交试验的方法,分别以材料去除率和表面粗糙度值为目标,得到了在给定实验条件下的最优工艺参数组合。实验表明工件表面材料去除率与法向抛光压力、磨具切线速度、工件圆周线速度和工件进给速度成正比,表面粗糙度与法向抛光压力、工件圆周线速度和进给速度成正比,与磨具切线速度成反比。第五、基于以上的研究,利用选取的最佳工艺参数组合,在多工位多磨具机械抛光机床上对电热水壶进行批量抛磨实验,实验表明,抛光后的工件表面抛光质量均匀,粗糙度值较低,达到企业质量要求,生产过程环保无污染,加工效率较手工提高3倍,证实了多工位多磨具自动化机械抛光方法的正确性和优越性。更多还原

【Abstract】 Stainless steel thin-wall household appliances are widely used in our daily life, like electric kettle, dripolator, electric food warmer, and service plate, etc., which have a broad market prospect. Polishing is the most important procedure when processing the appliances. It’s necessary for the surface material to be removed evenly with low roughness level, workpieces of stainless steel thin-wall materials are tend to burn, to transform, and hard to clamp during polishing. It’s not easy for the material to be polished. So far, automatic polishing technique for home appliances of stainless steel thin-wall materials are lack of further study in the research institutes in China, and more over, there are some limitations in the few present equipments, which are not available for the wide use of home appliance polishing industry. At present, manual polishing is still mainly applied in home industry, which not only results in such problems as poor quality, low efficiency,.serious pollution and being short of hands, but also severely restricts the development of such industry.Among stainless steel household appliances, electric kettle is typical for its relatively complex shape. So, this thesis mainly focuses on electric kettle polishing:in connection with the real productive background of the electric kettle of stainless steel, and in frference to the lack of equipment, this thesis studies a set of high-efficient automatic mechanic polishing technique fit for stainless steel electric kettle polishing as well as develops a corresponding mechanical polishing machine tool and automatic control system. This research is important for improving the present manual method which is widely used in our electric kettle polishing and the same type of other household appliances industry.Firstly, for stainless steel parts, setting up a theoretical module of surface material removal rate and a module of surface roughness of workpiece supplies a theory basis for automatic mechanical polishing technique.(1). applying theories of elastic mechanics and abrasive grinding in setting up a module of surface material removal rate proclaims, from the microscopic point of view, the relation between abrasive particles with its related process parameters and material removal rate. The models show, material removal rate is in proportion to mold rotating tangential velocity, workpiece peripheral velocity, feeding speed of workpiece as well as normal polishing pressure parameters, and has non linear relation with die granule size and its structure.(2) the setting up of the module of the relation between surface roughness of workpiece and polishing process parameters, based on the method of regression analysis and orthogonal test, proclaims that the roughness of the work surface grows with the increase of polishing pressure, workpiece peripheral velocity as well as feeding speed, and reduces with the increase of the mold rotating tangential velocity. Applying the method of mathematical simulation and experimental validation to the study and analysis, we can see the fine consistency between simulation and experiment, which proves that the two methods of setting up modules are correct, and which has a directive significance in making rational planning for automatic mechanical polishing technique.Secondly, to meet the demand for highly efficient polishing, this study suggests a kind of automatic mechanical polishing technique for multi-position and multi-abrasive tools, which can respectively polish both external surface and internal surface of the workpiece. The key technique includes structure designs for polishing machine tools of multi-position and multi-abrasive tools, designs for multi-station shapes synchronizing controls, and designs for workholders. And based on this technique, a corresponding automatic control system for mechanical polishing machine tools of multi-position and multi-abrasive tools is designed. According to the fact that real productive process needs the self-adapting of the abrasive tool to the forms of workpiece, a method based on lead-through teaching for the data generation of polishing tool positions is proposed to be used in the automatic polishing system.Thirdly, in the connection with the existing polishing technique, it proposes a set of methods fit for the automatic mechanical polishing technique for stainless household appliances. By making respective programs according to the characteristics of the surface shapes of household alliances, it has designed an automatic mechanical polishing plan, which adopts spiral polishing tool-path as the path of the polishing tools, and it also has studied the tool path data computing methods. Through a series of experiments and with the help of the existing polishing experience, it provides a set of process fit for the technique of rough polish, half-finishing polish, and finishing polish in automatic mechanical polishing of household appliances.Fourthly, under the premise of the polishing quality being ensured, it tries hard to raise the working efficiency so as to optimize the experiment research on the automatic mechanical polishing technique parameter. By using the orthogonal experiment method, and taking material removal rate and surface roughness value respectively as the aim, the best combination of process parameters has been received under the given test condition. Experiment shows that workpiece surface material removal rate is in proportion to normal polishing pressure, mold tangent speed, workpiece peripheral velocity and feeding speed of workpiece; while, though the surface roughness is in proportion to normal polishing pressure, mold tangent speed and feeding speed of workpiece, it is inversely proportional to mold tangent speed.Fifthly, according to the research above, the batch experiment, by making good use of the best combinations of process parameters, is made on polishing electronic kettle on the mechanical polishing machine tool with multi-position and multi-abrasive tools, which shows that the quality of the polished surface of the workpiece is uniform and the value of the roughness is low, which meets the enterprise quality requirements with no pollution in the productive process and with the working efficiency being3times as high as the one of manual polishing, and proves the validity and superiority of the method of automatic mechanical polishing with multi-stations and multi-abrasive tools.更多还原