共查询到20条相似文献,搜索用时 187 毫秒
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热塑性弹性体(TPE)具有独特的性能,因此能够取代弹性体和热塑性塑料而获得大量应用。热塑性弹性体的可加工性如同热塑性树脂一样,对此,不需要对材料进行硫化。在生产部件时所用的短期时间和能量消耗说明热塑性弹性体与需要高生产费用的弹性体相比具有明显的优点。这种趋势能够看出这两种材料的增长率。热塑性弹性体与弹性体年增长率2~3%相比,前者的年增长率为5~6%。热塑性弹性体的典型应用范围是汽车、消费者、保养产品,电子,家用器具,运动与玩具,工业,建筑及半成品等。 相似文献
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随着塑料材料的广泛应用,塑料超声波焊接技术快速发展,并在塑料焊接中表现优异.近年来,超声波焊接在塑料焊接行业中的应用越来越广,但焊接作业时即使准备充分,焊接不良的现象依然经常出现.因此,对塑料超声波焊接的影响参数进行了重点阐述,指出了未来塑料超声波焊接的发展趋势. 相似文献
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曲其飞 《现代制造技术与装备》2009,(6):44-45
对压力容器制作过程中接管与壳体焊接质量控制问题进行了分析,对其加以控制,主要从焊接工艺、坡口加工和装配、焊接材料、焊接检验等方面阐述怎样控制. 相似文献
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30万吨/年合成氨气化炉耐热Cr-Mo钢焊接材料的研制 总被引:2,自引:0,他引:2
南化公司化机厂为国家重点工程南化大化肥项目承制了一批压力容器、换热器及辅助装置。其中两台气化炉是该系统中最关键的大型设备 ,该设备在系统运行时处于高温高压状态 ,其特点为 :炉体材料为Cr-Mo耐热钢 ,设备直径较大且炉壁较厚(见图 1 ) ,故设计和制造的技术要求很高。为确保制造质量 ,这两台设备的主体部件筒体和封头均选用ASME标准中SA387Gr1 2CL2材料 ,由国外制成部件后进口 ,再由南化化机厂进行装配、焊接、检测、试验 ,制成整台设备交付使用。主体材料均为进口的耐热钢 ,焊接材料的技术要求也须与主体材料相匹配 ,… 相似文献
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刘中青 《机械工人(热加工)》1990,(5):33-33
不用热源的超声波焊接,在焊接领域中是一种新技术,目前只有少数国家开始应用,超声波是声波的一种,其频率超过20000Hz。 所谓不用热源的超声波焊接,就是用超声波振动转换成能量进行焊接。超声波焊接的机理是利用高频的弹性机械振动,使焊件接触面之间产生高速的相对磨擦运动,把金属表面的氧化膜破坏掉。由于温度的升高,使金属麦 相似文献
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汽车车门装配用焊接夹具是为车门零件装配焊接作业提供便利的一种工具。在现阶段汽车制造企业中,焊接夹具在使用过程存在一定问题,其中最为突出的是装配精度、焊接精度不够,因此影响产品质量。所以,本文主要分析汽车车门装配用焊接夹具设计要点、设计需要考虑的影响因素等,进而重点探究汽车车门装配用焊接夹具结构改进设计对策,目的在于提高装配精度、焊接精度,实现高质量、高效生产制造。 相似文献
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超薄石英晶片超精密抛光实验的研究 总被引:1,自引:0,他引:1
为了解决超薄石英晶片高表面质量的加工问题,以及寻求一种高效低成本的加工方法,将一种新的超精密抛光工艺应用到超薄石英晶片的加工中。给出了加工过程中的抛光原理,制定出了在研磨和抛光过程中的最优实验条件,并对加工后超薄石英晶片的粗糙度和厚度做了详细的分析;讨论了磨粒的尺寸对表面粗糙度和材料去除率的影响,同时对加工过程的材料去除机理做了论述,以表面粗糙度和厚度为评价目标对超薄石英晶片的加工特性和表面质量进行了评价。研究结果表明:使用该实验的工艺加工超薄石英晶片可以得到厚度为99.4μm、表面粗糙度为0.82nm的超光滑表面;同时,该研究还发现通过延长抛光时间可以减小石英晶片的表面残余应力,可有效控制石英晶片四角“翘曲”现象,得到更好的平面度和平行度。 相似文献
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金刚石钻头的研究与应用现状 总被引:1,自引:0,他引:1
随着新型复合材料的应用日益广泛,以及精密和超精密加工技术的不断进步,金刚石刀具获得了迅速发展。本文对包括电镀型金刚石钻头、钎焊式金刚石钻头、CVD金刚石钻头、聚晶金刚石(PCD)钻头在内的各种金刚石钻头的研究和应用现状进行了综合评述。 相似文献
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金刚石立铣刀的研究及应用 总被引:1,自引:1,他引:0
随着精密和超精密加工的发展和新材料的不断出现,金刚石刀具得到广泛的发展。大量文献都报道了车削的例子,铣削和钻削的很少。本文对单晶金刚石、聚晶金刚石、CVD金刚石在立铣刀中的应用进行了综述。 相似文献
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M. Y. Tsai S. M. Wang C. C. Tsai T. S. Yeh 《The International Journal of Advanced Manufacturing Technology》2015,78(9-12):1511-1521
The application field of silicon carbide (SiC) as a next-generation compound semiconductor is expanding because of its significant advantages: high power, high frequency, low coefficient of thermal expansion, and high thermal conductivity. Many researchers have investigated SiC polishing for the manufacturing of semiconductor substrates using SiC. However, because SiC is a chemically and mechanically stable material, these researchers have faced difficulties due to its very low polishing rate (95–540 nm/h). Therefore, methods are required for increasing the material removal rate of SiC. The aim of this study was to investigate the increase in removal rate during the polishing of single-crystal SiC subjected to simultaneous polishing and dressing by using a diamond-impregnated polishing pad. Two types of pads—containing 1 and 5 wt% nanodiamond—were fabricated, and their performances were compared with that of a polyurethane polishing pad. A novel arrangement of conditioners was created in brazed diamond patterns, which were radially arranged in a cluster with 3–4 grits per cluster. Furthermore, a combined diamond disk was developed. The surface characteristics of the nanodiamond-impregnated pads, as well as the surface roughness, surface damage, and removal rate of the SiC polished with these pads and diamond disks, were investigated and compared with the corresponding attributes displayed by a polyurethane polishing pad and a conventional diamond disk. Experimental results showed that the removal rate of SiC with dressing was approximately 73 % higher than that of without dressing. The novel conditioner resulted in a dressing rate approximately two times higher and a removal rate approximately 38 % higher than those obtained by using the conventional diamond disk. In addition, SiC polishing tests revealed that the nanodiamond-impregnated polishing pads provided better surface roughness with no damage, as well as a removal rate approximately 2.5 times higher than that provided by the polyurethane polishing pad. 相似文献
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回顾了超精密加工技术的发展,主要包括超精密加工设备的开发历程,以及超精密单点金刚石切削技术基础,并对微工程技术作一简要介绍;重点论述微结构自由曲面的微纳切削技术,包括单点金刚石车削(Single point diamond turning, SPDT),快刀伺服加工(Fast tool servo, FTS),金刚石微凿切(Diamond micro chiseling, DMC),光栅铣削等技术。指出微结构自由曲面测量领域面临的挑战和存在的问题,包括接触式测量和非接触式测量。通过几个典型微结构自由曲面的加工及测量的应用进行举例说明;最后介绍我国在超精密加工机床领域内的研制情况,展望了超精密切削技术未来发展趋势。 相似文献
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高性能CVD金刚石薄膜涂层刀具的制备和试验研究 总被引:10,自引:0,他引:10
采用电子增强热丝EACVD法,以WC-Co硬质合金刀具为衬底制备金刚石涂层刀具,研究了提高涂层附着力的衬底预处理新方法,探讨了抑制Co催石墨化作用的有效措施,提出了改善金刚石薄膜表面粗糙度CVD后处理新工艺。研究结果表明,采用了Ar-H2微波等离子体刻蚀脱碳预处理方法对于提高金刚石薄膜涂层的附着力有明显效果,添加适量粘结促进剂,可有效地抑制CVD沉积过程中钴向表层扩散引起的催石墨化作用。采用分步沉积新工艺是减小金刚石薄膜表面粗糙度的有效方法。所制备的高附着力和低粗糙度的金刚石薄膜涂层刀具切削性能明显改善,对实现高效高精度切削加工具有十分重要的意义。 相似文献
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This article investigates the failure mechanisms of CVD diamond wafers and thin films during a fast dynamic friction polishing process. To explore the evolution of temperature and stress fields, a comprehensive finite element analysis was systematically carried out, with the aid of experimental examination. It was found that the discontinuity and sharp change of the stresses across the film-substrate interface causes debonding failure of a CVD diamond thin film specimen. In the case of a CVD diamond wafer, however, the high surface tensile stress and bulk bending is responsible for the cracking. It was concluded that specimen cracking is sensitive to the polishing pressure, and that the polishing window for the CVD thin films is smaller. Polishing time is a critical factor, because a longer time corresponds to a higher thermal stress. This article points out that using the combination of a smaller polishing load and a greater sliding speed is a good option in selecting polishing parameters. To minimize cracking, a stepwise polishing process can be used. With the proper parameters obtained in this study, very smooth, high-quality surfaces of CVD diamond wafers and thin films can be produced in a short polishing duration of minutes. 相似文献