摘要
镁合金作为轻型金属材料,越来越多的应用在各个工业领域,尤其是在汽车工业中的应用得到了广泛的关注。镁合金铸件帮助整车轻量化,实现低碳减排目标,保护环境。本文中介绍了镁合金铸件在汽车零部件中的应用及前景,结合不同牌号合金的性能特点,说明了AM,AZ,AS,AE系镁合金材料在汽车不同部件中的应用,通过已投入生产的产品实例及研发中的新部件应用,展望了镁合金压铸的发展前景。丰田汽车事件给中国的汽车工业敲响了警钟,产品质量是企业的生命,是企业在日益激烈的国际化竞争中的立足之本,作为传统的热加工行业,产品质量问题及铸造缺陷长期困扰着压铸生产企业,如何提高压铸产品质量,最重要的是解决问题的思路和方法,找到企业适用的质量工具,加以使用和推广。本文针对某型号变速箱壳体铸件的质量改进,运用谢宁试验设计方法,首先通过对废品率及缺陷的历史统计数据分析,明确质量改进的目标和对象,将气孔缺陷作为本次研究的待解决问题(绿Y)。通过专业人员组成的团队对制造过程进行失效模式及影响分析,找出生产过程中直接或间接影响目标对象的各个环节及工艺,量化各失效模式的严重度、频度、探测度,按风险顺序指数进行排序,确定下一步研究对象,即研究变量族。确定研究变量族后,采用谢宁试验设计方法和工具,找出主因子红X,重要因子粉红X和浅粉红X。首先按谢宁试验设计方法安排试验,对试验数据运用成对比较和图基检验法,对各研究变量进行置信度排序。采用因素检索技术确定关键因子,通过对各试验因子的界定,确定最佳水平和最差水平,最佳判断极限和临界判断极限,交换各因子和求交运算来分离重要和非重要因子。再通过2~4析因试验计算重要因子的主效应及交互影响效应,找到主因子红X,重要因子粉红X和浅粉红X。按找到的关键因子的最佳水平来确定改进后的工艺参数设定。最后通过B_(VS.)C改进前后对比,验证了本次研究成效显著。谢宁试验设计方法的特点是思路清晰,无需组织大量试验和花费高额试验经费,在企业的日常生产中即可设计及实施试验,试验工具简单、算法容易,普通的工程技术人员通过培训就可以掌握,值得大力推广。
It’s the lightest structure metal Magnesium is being increasing used in industry, especially in automobiles. Magnesium castings light weight mass helps reduce automobile weight and achieve lower carbon emission therefore protecting the environment. In the thesis, magnesium casting applications will be discussed on automotive components. Magnesium alloys nowadays have developed so they can be used in various types of automotive roles. This paper will review current production automotive castings as well as new developing technology areas. We can look forward to the future growth of magnesium casting in the automotive field. Toyota recall is a good lesson to Chinese automotive industry. In nowadays when competition becomes increasingly fierce, the company need more focus on quality performance. As traditional hot working, diecasting companies were puzzled for quality issues and casting defects. To find the suitable quality tools which can help company to catch and solve the problems. In my thesis, will discuss to use Shainin DOE (Design of Experiments) to improve quality of magnesium transmission case. The first step is to define the object of study. We analyzed four months quality performance of transmission case, and found that the porosity issue was the top one defect in scrap rate reports. So the porosity is the problem should be figured out (Green Y). In the second stage, we use the Process Failure Mode and Effect Analysis (PFMEA) to search the processes which will affect the object. PFMEA was reviewed by a professional team, and defined the process parameters, the failure modes, the failure effects of each process, and qualified the Severity, the Occurrence, and the Detection, and assessed the Risk Priority Number (RPN). In the third stage, base on the variable family of Green Y, we use Shainin's DOE methods and tools to find out the Red X, Pink X and Pale Pink X. We design the experiments we need and perform it. To use Paired Comparisons and Tukey Test to process the testing data and provide clues to the Red X with their confidence level. Then, through the Variables Search method to find out the key factors. We defined the best level, the worst level, the best limit and the critical limit, and captured the main effects of important factors and the interaction effects between the factors. Then, to use the Full Factorial Analysis method to calculate the main effects and the interaction effects. And use the Analysis of Variance (ANOVA) method to find out the Red X, Pink X, and Pale Pink X, According to the best level of these key factors to perform the process parameters’setup. Finally, to use B versus C to confirm the effectiveness and persistence of the improvement. The result shows our improvement is effective and persistence. Utilize Shainin DOE, is very straight forward, tools are simple to use with calculations and formulas easy to handle. Graduates engineer with basic DOE training will have no problem using these tools. Shainin DOE doesn’t need to spend a lot of money and occupy production line long time. During the normal production we can arrange the experiments. This tool can be used in a wide variety of application.
引文
[1]黎文献,镁及镁合金,长沙:中南大学出版社,2005.11,1-20页
[2]耿浩然,铸造铝镁合金,北京:化学工业出版社,2006,139-150页
[3]张武城,铸造熔炼技术,北京:机械工业出版社,2004.5,36·47页
[4]陈元芳,压铸成形工艺及模具,北京:化学工业出版社,2008.5,48-64页
[5]赵浩峰,现代压力铸造技术,北京:中国标准出版社,2002.11,22-31页
[6]陈国桢,铸件缺陷和对策手册,北京:机械工业出版社,1996,114-125页
[7]张秀梅,道林@夏宁方法及其应用,哈尔滨理工大学学报,2001年5期
[8]曾海峰,张根保,夏宁DOE技术及其改进研究,第三届中国质量学术论坛,2008年
[9] Tanco.M, Viles E, Pazueta L. Are all design of experiments approches suitable for your company. Int ASSOC Engineers; unit 1. 1-F, 37-39. 2008
[10] B.L. Mordike, T. Ebert. Magnesium Properties - applications - potential. Materials Science and Engineering, A302 (2001) 37–45.
[11]舒远,杜世昌,基于谢宁DOE的背光灯片内部短路侦测研究,机械制造与自动化,2009年5期
[12]刘月滔,奚立峰,杜世昌,基于谢宁方法的同轴通信电缆绝缘附着力关键因素分析,电气技术与自动化,2010年1期
[13]刘文辉,霍兆华,王建东,缺陷模式及其影响分析(FMEA)在铸造生产中的应用,铸造, 1998.
[14]李逵,张志英,谢宁实验设计应用研究,河北工业科技,2008年4期
[15] Logothetis, N. A perspective on Shainin’s approach to experimental design for quality improvement. Quality and reliability engineering international. V016. 195-202
[16]徐哲,张淼玮,基于谢恩/博特试验设计的质量改进研究,航空标准化与质量, 2006:10-15
[17] Keki R.Bhote, Adi K.Bhote. World Class Quality Using Design of Experiments to Make it Happen. American Management Association, 2000
[18] Shainin P.D.A Common Sense Approach to Quality Management:Annual Quality Congress Proceedings,ASQC,1995.
[19] Andrew Thomas, Jiju Antony. Applying Shainin's variables search methodology in aerospace applications. Journal of Assembly Automation,2004.
[20] Sunil Sharma, Anuradha R Chetiya: Simplifying the six sigma toolbox through application of Shainin DOE techniques. Vikalpa. Vol 34. No 1. January– March (2009)
[21] Logothetis,N: A perspective on Shainin’s approach to experimental design for quality improvement. Quality and reliability engineering international. V016. 195-202
[22] Stefan H. Steiner, R. Jock MacKay, John S. Ramberg.:An overview of the Shainin system for quality improvement. Quality Engineering. Vol(20) .Issue 1 (2008), p.6-19
[23] Shainin P.D.A Common Sense Approach to Quality Management:Annual Quality Congress Proceedings, ASQC,1995.