1、附录1模具快速制造技术的发展方向摘要:分析了快速原型制造技术(RPM) 和高速切削加工技术(HSM) 在模具制造中的应用,预测性地指出未来快速制模技术的发展方向。关键词: 快速制模技术；RT技术；HSM技术 俗话说:“没有规矩不成方圆”,这“规矩”在塑料加工中就是模具。在现代工业生产中,60 %90 %的工业产品需要使用模具加工,模具工业已经成为制造业中的一项基础产业,是技术成果转化的基础,同时又是高新技术产业的重要的领域,在欧美等工业发达国家被成为“点铁成金”的“磁力工业”。随着市场全球化以及竞争的不断加剧,产品更新换代的速度不断加快,多品种小批量将成为制造业的重要生产方式,在这种情况下,制
2、造业对产品原型的快速制造和模具的快速制造术提出了强烈要求。因此,快速制模技术呈现生机勃勃的发展趋势。作为快速制模技术的两大代表:基于快速原型技术的制模方法(RT) 、采用高速切削加工模具(HSM) 必然会在未来很长一段时间内得到更快的发展。1 模具快速原型制造技术1. 1 快速原型制造技术思想的提出快速原型制造技术(Rapid Prototyping Manufacture ,RPM) 在20 世纪80 年代后期源于美国,是近20 年来世界制造技术领域的一项重大突破,它是伴随着计算机技术、激光技术和新材料技术的发展而产生的,是一种全新的制造技术,它能将已具数学几何模型的设计迅速、自动地物化为具
3、有一定结构和功能的原型或零件。RPM技术获得零件的途径不同于传统的材料去除或材料变形方法,而是在计算机控制下基于离散/ 堆积原理,根据零件CAD 模型采用不同方法堆积材料最终完成零件的成形与制造技术,它具有高度柔性、技术的高度集成、设计制造一体化、快速性、自由形状制造、材料的广泛性的特点,被公认为是继NC 技术之后的一次技术革命。1. 2 RPM的一般工艺步骤由于RPM技术可以明显地缩短产品开发周期,提高产品开发的成功率,降低开发成本和投资风险,因此在产品开发的过程中得到了迅速的推广应用,RPM 技术得到了进一步的发展。自美国3DSYSTEM公司推出第一台商品SLA 快速成形机以来,已有十几种
4、不同的快速成形系统。其中比较成熟的有SLA(立体印刷) 、SGC(漏板光敏树脂固化) 、LOM(叠层制造) 、SLS(激光选区烧结) 、3D-P(三维印刷) 、FDM(熔积成形) 以及IJ-P(喷墨印刷) 等方法,一些专家认为喷墨技术是未来发展的趋势。虽然存在着各种各样的快速原型技术,但其基本思想都是利用计算机将复杂的三维物体转化为二维层,然后由点/ 线构成面(层) ,逐层成形得到最终的三维零件模型。其工艺步骤为:(1) 切片把三维CAD 模型转化为快速原形系统能够接受的数据格式,如STL 文件,运用切片软件将模型切成一系列指定厚度的薄片。(2) 扫描通过数控装置控制激光或其他作业装置,在当前
5、工作层上扫描出切片的截面形状,进行成形工作。在成形过程中,最基本的操作是扫描固化零件的截面,分层得到的截面信息是轮廓数据,要进行内部充填,必须由轮廓数据生成填充路径。(3) 进给移动放着半成品的工作台沿着Z 轴方向下降一定距离,重复上一步骤和本步骤,直到零件完全成形。(4) 后处理根据不同应用场合的需要,分别对零件进行后固化、上漆、烧结、渗铜等处理。1. 3 RPM技术在模具制造中的运用RPM技术制作的原型在许多情况下由于使用材料的限制,还不能替代最终的真实产品。为获得真实材料制作的产品,且快速形成一定批量的生产能力,便产生了基于RPM技术的快速模具RT(Rapid Tooling) 技术。R
6、T 采用RP 技术直接或间接制作模具,使模具的制造时间和成本大大缩短。(1) 用快速成型机直接制作模具由于一些快速成形机制作的工件有较好的机械强度和稳定性,因此可直接用作某些模具。目前,能够直接制造金属模具的快速原型工艺包括SLS、3D2P、SDM 和3D Welding等。最典型的工艺方法是美国DTM公司用RT 专利技术生产注塑模。(2) 用快速成型机间接制作模具由于快速原型直接制造模具在模具精度和性能控制方面比较困难,特殊的后处理设备与工艺使成本提高较大,模具尺寸也受到较大限制。相比之下,间接快速模具制造通过快速原型技术与传统的模具翻制技术相结合制造模具无论在模具精度、表面质量、机械性能与
7、使用寿命,还是在经济方面都能得到很好的控制。因此,目前基于RP 快速制模多为间接制模法。(3) 用快速成型件制作母模,复制软模具用快速成型件作母模,可浇注蜡、硅橡胶、环氧树脂等软材料构成软模具或先浇注硅橡胶、环氧树脂模,再浇注蜡模。其中蜡模用于熔模铸造。硅橡胶模可作试制用注塑模或低熔点合金铸造模。(4) 用快速成型件作母模,复制硬模具用快速成型件作母模或据其复制的软模具,可浇注陶瓷、金属基合成材料、金属,构成硬模具,从而批量生成塑料件或金属件。这种模具具有良好的机械加工性能,可进行局部的切削加工,以便获得更高的精度,或加入嵌块、冷却系统、浇注系统等。2 模具高速切削技术2. 1 高速切削概念的
8、提出高速切削理论是1931 年4 月德国物理学家Carl .J . Salomon 提出的。他指出,在常规切削速度范围内,切削温度随着切削速度的提高而升高,但当切削速度提高到一定值后,切削温度不但不升高反而会降低,且该切削速度值与工件材料的种类有关,对每一种工件材料都存在一个速度范围,在该速度范围内由于切削温度过高,刀具材料无法承受,即切削加工不可能进行,称该区为“死谷”。这一思想给后人一个非常重要的启示,即如能越过这一“死谷”,在高速区工作,有可能用现在刀具材料进行高速切削,切削温度与常规切削基本相同,从而可大幅度提高生产效率。高速切削是一个相对概念,到目前为止世界各国对高速切削的速度范围尚
9、未作出明确的定义,通常把切削速度比常规速度高510 倍以上的切削称为高速切削。自从Salomon 提出高速切削概念并于同年申请专利以来,高速切削技术的发展经历了高速切削理论的探索、应用探索、初步应用和较成熟应用等四个阶段,现已在生产中得到了一定的推广应用。2. 2 高速切削的关键技术高速切削技术是在机床结构及材料、机床设计制造技术、高速主轴系统、快速进给系统、高性能CNC 控制系统、高性能刀具系统、高性能刀具材料及设计制造技术、高效高精度测量测试技术、高速切削机理、高速切削工艺等相关的硬件与软件技术的基础上综合而成的。因此,高速切削加工是一个复杂的系统工程。(1) 高速切削机床实现高速切削的最
10、关键技术是研究开发性能优良的高速切削机床。自20 世纪80年代中期以来,开发高速切削机床便成为国际机床工业技术发展的主流。国外近年来发展的高速铣加工,主轴转速可达4000100000r/ min ,快速进给可达50120m/ min ,加速度可达1 米/ 秒2 ,换刀时间提高到1s2s ,普遍采用油/ 气冷却装置。(2) 高速切削刀具技术由于高速切削采用非常高的切削速度,所以对刀具材料提出了更高的要求。现在已发展的刀具材料主要有聚晶金刚石(PCD) 、立方氮化硼(CBN) 、陶瓷(Ceramics) 涂层刀具和金属陶瓷(含氮TiC 基硬质合金) 刀具等。今后,刀具材料的发展方向应该是朝具有高温
11、力学性能、高化学稳定性和热稳定性及高抗热振性的刀具材料方向发展。为了克服传统加工中心使用的724 实心锥柄刀杆在高转速时的刚性不足的致命弱点,开发了“双定位刀杆”这种新结构刀柄的定位方式,这种定位方式是靠110 的锥部与主轴内锥面定心,同时刀柄凸缘端面与主轴前端面紧贴,从而获得高转速下的联接刚性。(3) CAM软件高速切削的实现不仅要求有好的机床和刀具等硬件技术,还必须有优秀的CAM软件与之相匹配。目前,CimatronE、UGNX、MasterCAM 等CAM软件都具有适合高速切削的编程模块。(4) 高速切削机理高速切削时,存在着连续切削和断续切削两种类型:高速切削高导热性低硬度合金或合金(
12、如低碳钢、铝合金等) 时易于形成连续切屑。目前,关于铝合金的高速切削机理研究已取得了比较成熟的成果,并已应用于铝合金高速切削的生产实践。其它材料,如铸铁、普通钢材、模具钢、钛合金和高温合金等材料的高速切削机理还有待于进一步的研究。2. 3 高速切削技术在模具制造中的应用高速切削技术是一种不同于传统加工的加工方式,相比而言,高速切削主轴转速高,切削进给速度高,切削量小,但单位时间内材料切除量却增加了36倍,因此大大提高了生产效率。也正由于它的快效性,在当今世界市场经济竞争激烈这一背景下,此项技术在很多领域得到发展,模具制造业便是高速加工应用的重要领域。模具凹模加工过去一直为电加工所垄断,但其加工
13、效率低,而高速加工切削力小,可铣淬60HRC 的模具钢,加工表面精度可达10m 甚至更高,表面粗糙度Ra 1m ,浅腔大曲率半径的模具完全可以用高速铣削代替电加工,有效地减少了电加工和抛光工作量;对深腔小曲率的可用高速铣削加工作为粗加工和半精加工,电加工只作为精加工。总之,高速切削技术在模具制造中的应用大大缩短了模具的制造周期,为模具工业开辟了崭新的天地。3 结语由于市场全球化以及竞争的加剧,模具市场对每一种模具技术最重要的、带有先决性的要求是其快速性,即从设计到进入市场的时间尽可能的短,这是RT技术和高速切削技术产生的根本原因。基于离散/ 堆积成型原理的RT 技术与基于净去除材料成型的高速切
14、削技术两者是相辅相成的,都得到了CNC 技术的支持。RT 技术可以说是真正意义的数字化制造,因为RT技术不但支持工具轨迹运动的控制,而且可以直接涉及到材料本身,因而可以完成更复杂形状加工,也可以制造具有功能梯度、材料梯度的模具,但也正是其成型原理,限制了它当前精度和表面粗糙度。相比而言,虽然高速数控切削技术只是数字化模拟加工,只能是对同种材料的切削加工,但在精度与表面粗糙度控制方面有着RT 技术无法比拟的优势,许多模具公司利用各自优势,同时采用两种技术。可以预见,未来的模具制造体系必然综合材料增长制造和去除加工两种原理,实现模具的快速制造。参考文献:1 李发致. 模具先进制造技术M . 北京:
15、机械工业出版社,2002.2 王运赣. 快速成形技术M . 武汉:华中理工大学出版社,1999.3 张永强. 高速切削及其关键技术的发展现状J . 航空精密制造技术,2001.4 杨洪旗,等. 汽车模具高速加工技术J . 模具工程,2004 (3) :2528.附录2Developing Trend of Quick Mold-making TechnologyAbstract : It analyzed the applications of rapid prototyping manufacture (RPM) and high speed manufacture (HSM) to Mol
16、d-making ,and pointed out the developing trend of quick mold-making technology.Key words : Quick mold-making technology ;Rapid prototyping manufacture ;High speed manufactureThe common saying say: have no rules not to become the square circle, this rules is the molding tool in plastics process. In m
17、odern industry produce,60% industry product with 90% needs to use the molding tool to process, the molding tool industry has already become a foundation industry within manufacturing industry, is the foundation of the technique result conversion, is the important realm of the high new technique indu
18、stry again at the same time, the flourishing nation of industry of etc. is become in the Europe and America the magnetic force industry of order the iron gold. Turn worse continuously along with the market globalization and competitions, the product renewal changes the speed of the generation to spe
19、ed continuously, have another the small batch quantity of species and will become the important mode of production of the manufacturing industry, in this kind of case, manufacturing industry to product prototype of the fast manufacturing techenology of the fast manufacturing and molding tool put for
20、ward the strong request. Therefore, make the mold technique to present the animate development trend quickly. The conduct and actions makes the two greatest representatives of technical molds quickly: make the mold method( RT), the adoption high speed to slice to pare to process the inevitable meeti
21、ng of molding tool( HSM) technically according to the fast prototype to get the faster development in very long period of time of future.1 Fast prototype of molding tool manufacturing technique1. 1 The fast prototype makes the technique to thought of put forwardThe fast prototype manufacturing techn
22、ique( the Rapid Prototyping Manufacture, RPM) expects to come from the United States after 80s in 20 centuries, is 20 a gravenesses of the manufacturing technique realm of the near in the last years worlds break, it is to accompany with the technical development of calculator technique, the laser te
23、chnique and new materials but output, is a kind of all new manufacturing technique, the design that its ability will has already had several models of mathematics is quick, of oneself the thing changes in to have the certain structure and the prototype or the spare parts of the function. The techniq
24、ue of RPM acquires the path of the spare parts to differ from the traditional material to do away with or the material transform the method, but control in the calculator under according to long-lost pile up the principle, adopt the different method to pile up the material according to the spare par
25、ts CAD model mostComplete the spare parts to take shape eventually with the manufacturing technique, it has the height gentle and technical gather highly, design manufacturing the integral whole turn, fast, free shape manufacturing, characteristics of extensive of material, drive generally accepted
26、is after technique of NC of a technique revolution.1. 2 RPM general craft stepBecause the technique of RPM can shorten the product development period clearly, the success rate of the exaltation product development, lower the development cost and invest the risk, so got the quick expansion applicatio
27、n in the process of product develop, the technique of RPM got the further development. Since the 3 DSYSTEM company of the United States release the first Taiwanese business people the article SLA took shape the machine quickly, there has been more than ten different take shape the system quickly. Am
28、ong them more mature have the methods, such as SGC, LOM, SLS , 3 Ds- P printings, FDM and IJ- Petc., some experts think that the ink-jet technique is a futureThe trend of the development. Although exist the fast prototype technique of various each kind, its basic thoughts all make use of the calcula
29、tor to order complicated 3D object conversions are 2D Layer, then from/ the line constitutes to face( layer), pursue the layer takes shape to get end of 3D spare parts models .Its craft step is:(1) Slice 3D CAD model conversions for fast data format that the original shape system can accept, such as
30、 the document of STL, usage slice the software cut into model the thin slice that a series specify the thickness.(2) Scan to pass the number to control to equip to control laser or other home works device, at current job class up scan a slice to cut to face the shape, carry on taking shape the work.
31、 In take shape process, the most basic operation is to scan solid turn the spare parts to cut the noodles, the layering get of cut and face the information is the outline data, to carry on the internal to fill, must be is born by the outline data to fill the path.(3) Enter to the work pedestal that
32、the ambulation puts the semi-processed goods along the Z stalk direction descends the certain distance, repeat is suddenly up the one step and this step, until the spare parts takes shape completely.(4) Handle behind according to the demand of the different and applied situation, distinguish to the
33、spare parts after carry on solidly turn, apply paint, burn the knot, the copper etc. processing.1. 3 The technique of RPM is in molding tool make of usage The prototype of the RPM technique creation under the condition of many because of usage there strict of the material, cant still act for the end
34、 and true product. In order to acquire the product of the true material creation, and the fast formation production ability of the certain batch quantity, produced then according to the RPM technical and fast molding tool RT( the Rapid Tooling) technique .The RT adoption RP technique is direct or th
35、e indirectly manufacture the molding tool, making the manufacturing time and cost of the molding tool shortenned consumedly.(1) Use to model the direct manufacture molding tool of machine quickly because of some take shape the work piece that mechanism make to compare quickly good of machine strengt
36、h and stability, so can used to some molding tools directly. Currently, can make the fast prototype craft of the metals molding tool to include SLS,3 D2Ps, SDM and 3 D Welding etc. directly .The most typical craft method is an American company of DTM to produce to note the mold of the RT patent tech
37、nique.(2) Use model the machine indirectly manufacture molding tool quickly because of fast prototype direct manufacturing the molding tool controls the aspect in the molding tool accuracy and function more difficult, the special empress handles the equipments and crafts to make cost exaltation comp
38、are greatly, the molding tool size also is subjected to limit greatly more. Compare under, the indirect fast molding tool manufacturing turns over to make the technique to combine together to make the molding tool through fast prototype technique and traditional molding tools regardless in the moldi
39、ng tool accuracy, surface quantity, the machine function and service life, still can get the good control in economic aspects. Therefore, make the mold quickly according to the RP currently much for the indirectly system mold method.(3) Use to model a manufacture female die quickly, make duplicate t
40、he soft molding tool to use to model the piece to make the female die quickly, can sprinkle to note the soft materials, such as wax, rubber of Si and the wreath oxygen resin.etc. to constitute the soft molding tool or sprinkle to note the rubber of Si , the wreath oxygen resin mold first, then sprin
41、kle to note the wax mold. Among them, the wax mold used for the molds cast. The Si rubber mold can make to manufacture use to note the mold or low to order the metal alloy foundry mold on a trial basis to.(4) Use to model the piece to make the female die quickly, make duplicate the hard molding tool
42、 to use to model the piece to make the female die quickly or according to soft molding tool that it make duplicate, can sprinkle to note the porcelain and ceramics, the metals to synthesize the material, metals, constitute the hard molding tool, thus the batch quantity born plastics piece or metals
43、piece. This kind of molding tool has the good machine to process the function, can carry on slice of parts pare to process, in order to acquire the higher accuracy, or join the piece, cooling system and sprinkle to note system etc.2 The molding tool high speed slices to pare the technique2. 1 The hi
44、gh speed slices to pare the concept to put forwardThe high speed slices to pare the theories is the German physicist Carl of April of 1931 J . The Salomon put forward of .He point out that within the scope of the normal regulations slices to pare the speed, slice to pare the temperature along with s
45、lice the exaltation of pare the speed but go up, but slice to pare the speed to raise the certain value after, slicing to pare the temperature not only does not go up and will lower on the contrary, but also should slice the category of pare the speed value and a material of work relevant, exist a s
46、peed scope to a materials of each work, in the speeds scope because of slicing to pare the temperature to lead high, the knife have the material and cant bear, then slice to pare to process to impossibly carry on, calling that area as die valley. This thoughts a count for much apocalypse to posterit
47、y, namely such as can cross this die valley, at the high-speed area work, use the knife probably to have the material to carry on high speeds slice to pare now, slice to pare the temperature and normal regulations to slice to pare basic homology, thus can the significant exaltation produce the effic
48、iency. It is an opposite concept that high speed slice to pare, so far the speed scope that international community slices to pare to the high speed didntyet make an explicit definition, usually slice to pare the speed higher than the normal regulations speed more than 5-1000% slice to pare to be ca
49、lled the high speed to slice to pare. Since the Salomon put forward high speeds slicing to pare the concept and apply for the patent at the same year, the high speed slices to pare the technical development to experience the high speed to slice the quest, application of pare the theories to investigate, first step applied and more mature application et
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