铝合金压铸工艺

1压铸产品基本工艺流程及影响铝合金压铸模寿命的因素【摘要】压铸工艺是将压铸机、压铸模和合金三大要素有机地组合而加以综合运用的过程。而压铸时金属按填充型腔的过程，是将压力、速度、温度以及时间等工艺因素得到统一的过程。模具结构设计、热处理工艺、模具制造及模具装配对铝合金压铸模寿命的影响。【关键词】压铸工艺压力速度温度时间寿命影响。2【摘要】压铸工艺是将压铸机、压铸模和合金三大要素有机地组合而加以综合运用的过程。而压铸时金属按填充型腔的过程，是将压力、速度、温度以及时间等工艺因素得到统一的过程。模具结构设计、热处理工艺、模具制造及模具装配对铝合金压铸模寿命的影响。【关键词】压铸工艺压力速度温度时间寿命影响。【摘要】压铸工艺是将压铸机、压铸模和合金三大要素有机地组合而加以综合运用的过程。而压铸时金属按填充型腔的过程，是将压力、速度、温度以及时间等工艺因素得到统一的过程。模具结构设计、热处理工艺、模具制造及模具装配对铝合金压铸模寿命的影响。【关键词】压铸工艺压力速度温度时间寿命影响。目录绪论·····························································1第一章概述····················································21.1压铸工艺概述···············································21.11压铸工艺原理···············································31.12压铸工艺的特点·············································51.13压铸工艺的应用范围·········································6第二章压铸合金···············································72.1压铸合金···················································72.11对压铸合金的基本要求······································832.12各类压铸铝合金·············································9第三章压铸件的结构设计······································133.1功能结构设计···············································133.11压铸件的尺寸精度及加工余量································143.12压铸件的表面质量··········································15第四章压铸工艺··············································164.1压力·····················································164.11压射压力··················································164.12胀模力···················································184.2速度·····················································194.21压射速度··················································194.22内浇口速度················································204.23内浇口速度与压射速度和压力的关系··························214.3温度·····················································224.31合金浇注温度··············································224.32内浇口速度对合金温度的影响································234.33压铸模的温度··············································244.4时间·····················································244.41填充时间和增压建压时间····································244.42持压时间和留模时间········································254.5压铸涂料·················································264.51压铸涂料的作用和压铸涂料的要求····························264.52压铸涂料的使用············································27第五章影响铝合金压铸模寿命的因素····························285.1模具结构设计的影响·········································285.2热处理工艺的影响···········································295.3模具制造的影响·············································305.4模具装配的影响·············································305.5模具的使用维护·············································314结论··························································32致谢辞························································33参考文献······················································345绪论压铸工艺是一种高效率的少、无切削金属的成型工艺，从19世纪初期用铅锡合金压铸印刷机的铅字至今已有150多年的历史。由于压铸工艺在现代工业中用于生产各种金属零件具有独特的技术特点和显著的经济效益，因此长期以来人们围绕压铸工艺、压铸模具及压铸机进行了广泛的研究，取得了可喜的成果。中国压铸业不断追求技术进步，不断追求高品质生产。压铸总体水平与国外先进水平相比虽有差距，但从某些经常用来评价压铸技术水平的指标来看，这种差距正在缩小。压铸是一个高度依赖技术经验的行业，中国压铸专业人员不足、整体技术素质偏低。无国界的市场，使我国压铸企业面临发展壮大的机会，同时也面临着日益激烈的竞争风险。人才是企业生存和发展的根本，企业要不断地学习运用先进的生产技术，必须培养高素质的技术和管理人才。只有这样，才能使中国压铸业取得更大进步。目前，我国的铝合金压铸模具寿命与国外相比相差较大，延长模具寿命对于铝合金压铸行业的发展具有重要的意义。6第一章概述1.1压铸工艺概述压铸工艺是把压铸合金、压铸模和压铸机这三个生产要素有机组合和运用的过程。现就压铸工艺的发展历史及有代表性的事件做简要的回顾。1838年格·勃鲁斯首先用压铸法生产铅字。1839年一种活塞式压铸机获得了第一个压力铸造专利。1849年英国人斯都奇斯取得热压室压铸机专利。1885年奥·默根瑟勒在前人的基础上发明了一种铅字压铸机。1907年瓦格纳首先制成了气动活塞压铸机。1920年英国开发了冷压室压铸机，使压铸机有可能生产铝合金和镁合金等压铸件。1927年捷克人约瑟夫·波拉克设计了立式冷压室压铸机。1952年前苏联制造出了第一台立式冷压室压铸机。我国在60年代也制造出了此种压铸机。1958年真空压铸机在美国获得专利。1966年美国人GeneralMotors公司提出精、速、密压铸法。1969年美国人爱列克斯提出充氧压铸的无气孔压铸法。今后压铸生产的发展趋势是：压铸工艺要采用新技术，提高压铸件质量，扩大应用范围；压铸机要实现系列化、大型化及自动化；压铸模要提高使用寿命。总之，为压铸生产开辟更广阔的前景。压铸工艺流程图示71，压铸机调试2，压铸模安装4，模具预热、涂料7，合型（合模）10浇注压射11，保压12，开模、抽芯取件14，清理（整修）17，终检验3，压铸模设计与制造5，涂料配制6，模具清理8，合金熔炼保温9，嵌件准备13，表面质量检查15，时效处理16，铸件浸渗、喷丸处理81.11压铸工艺原理压铸工艺原理是利用高压将金属液高速压入一精密金属模具型腔内，金属液在压力作用下冷却凝固而形成铸件。冷、热室压铸是压铸工艺的两种基本方式，其原理如图1-1所示。冷室压铸中金属液由手工或自动浇注装置浇入压室内，然后压射冲头前进，将金属液压入型腔。在热室压铸工艺中，压室垂直于坩埚内，金属液通过压室上的进料口自动流入压室。压射冲头向下运动，推动金属液通过鹅颈管进入型腔。金属液凝固后，压铸模具打开，取出铸件，完成一个压铸循环。图1-1压铸工艺原理示意图a)冷室压铸原理b)热室压铸原理91.12压铸工艺的特点一、优点（1）可以制造形状复杂、轮廓清晰、薄壁深腔的金属零件。因为熔融金属在高压高速下保持高的流动性，因而能够获得其他工艺方法难以加工的金属零件。（2）压铸件的尺寸精度较高，可达IT11—13级，有时可达IT9级，表面粗糙度达Ra0.8—3.2um，互换性好。（3）材料利用率高。由于压铸件的精度较高，只需经过少量机械加工即可装配使用，有的压铸件可直接装配使用。其材料利用率约60%--80%，毛坯利用率达90%。（4）生产效率高。由于高速充型，充型时间短，金属业凝固迅速，压铸作业循环速度快。在各种铸造工艺中，压铸方法生产率最高，适合大批量生产。（5）方便使用镶嵌件。易于在压铸模具上设置定位机构，方便嵌铸镶嵌件，满足压铸件局部特殊性能要求。二、缺点（1）由于高速填充，快速冷却，型腔中气体来不及排出，致使压铸件常有气孔及氧化夹杂物存在，从而降低了压铸件质量。因高温时气孔内的气体膨胀会使压铸件表面鼓泡，因此，有气孔的压铸件不能进行热处理。（2）压铸机和压铸模费用昂贵，不适合小批量生产。（3）压铸件尺寸受到限制。因受到压铸机锁模力及装模尺寸的限制而不能压铸大型压铸件。（4）压铸合金种类受到限制。由于压铸模具受到使用温度的限制，目前主要用来压铸锌合金、铝合金、镁合金及铜合金。1.13压铸工艺的应用范围压铸生产效率高，能压铸形状复杂、尺寸精确、轮廓清晰、表面质量及强度、硬度都较高的压铸件，故应用较广，发展较快。目前，铝合金压铸件产量较多，其次为锌合金压铸件。压铸工艺主要用于汽车、拖拉机、电气仪表、电信器材、航天航空、医疗器10械及轻工日用五金行业。生产的主要零件有发动机汽缸体、汽缸盖、变速箱体、发动机罩、仪表及照相机的壳体及支架，管接头齿轮等。各种合金压铸件的质量和尺寸范围见表1-1.表1-1合金压铸件质量和尺寸范围合金质量平均壁厚外形尺寸最小孔径最大最小最大最小最大最小（mm)锌合金铝合金铜合金9200060000120000.30.14101012200.30.70.84001220*160*4.5-2--0.70.7-注：铜合金最大壁厚指局部尺寸。第二章压铸合金2.1压铸合金压铸合金是压铸生产的要素之一，要生产优良的压铸件，除了要有合理的零件构造、设计完善的压铸模和工艺性能优越