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外文翻译系 别 机械工程系专 业机械设计制造及其自动化班 级学 号姓 名指导教师负责教师 外文翻译原文:Large, Complex Technical MouldingIts a frequently debated issue: should a custom moulder specialize, whether it be in a certain process, market, or material, or is a generalist more likely to succeed? IMI recently visited Coko Kunststoffwerk in Bad Salzuflen, Germany, to see a company that has most definitely specialized in a type of injection moulded product, and in doing so, has become a solid success. Coko decided to specialize in large parts: housings, panels, cabinets, and other shapes where the shot is measured in kilograms, the flow paths are long, and the moulds weigh multiple tons. When it comes to technology, however, Coko is less of a specialist. Because of the large variety among what we can generally call large parts, Coko has had to master a number of injection moulding technologies. It uses conventional injection moulding, structural foam, two-component moulding including foam-core sandwich moulding, and most recently, gas-assisted injection moulding. The company builds its own moulds in a tool shop designed around producing large and what is increasingly becoming very complicated tooling. Coko is not a newcomer. It began 60 years ago in the plastics business as an extruder. The company grew, expanded into injection moulding, opened the tool shop, and gradually began developing the expertise in larger parts. Injection moulding is the companys only plastics processing focus now. Thomas Schromber, who is Cokos manager of customer support, started our tour in the mouldmaking shop. And he did that very deliberately. Coko strongly believes in being a single source for its clients. The company slogan, loosely translated, says We give form to your products. Schromber says the customer can come in with an idea, a sketch, or a rough design, and Coko will take it from there. The overwhelming majority come in with solid product designs, but in any case, Coko feels that the mould is the foundation of the entire production process, so it must be perfect. They do send up to 25 percent of their mouldmaking work outside, but only the least complicated moulds, and even then only to toolmakers close-by and well-trusted. Fortunately, Bad Salzuflen is one of those not-so-uncommon islands of the plastics business in Germany, and a number of skilled toolmakers are in the neighbourhood.Making Big Moulds The mouldmaking operation is in a building of 1,400 sq m separate from the injection moulding operations. Two shifts are staffed by 60 craftsmen five and sometimes six days per week. The machining equipment, almost all CNC driven, includes straightforward large-piece roughing stations, small finishing machines, and EDM systems, and culminates in an automated machining station from Makino whose programming includes automated selection and mounting of the proper tool from among 59 in its ready rack. Some 70 percent of the work is done by erosion. Workpieces can be as heavy as 13 tons and as large as 2,000 x 1,500 x 1,000 cm (780 x 585 x 390 inches). A large machine using a very long coring tool was acquired so cooling channels through large mould pieces could be made in a single continuous operation from one side. Eliminating the rotation of the workpiece needed to bore from two sides improved channel accuracy and reduced machining time. Noting the various years that the machines were acquired, Schromber mentioned that Coko accepts continuing investment in new machining technologies as normal. You absolutely must be current in this business.Mould Design At the back of the machine shop is a door leading to a product display room packed with a wide variety of large parts. Past that is a staircase up to the Konstruktion department. In German that word also means design, and this mould design department is as up-to-date as the machining facilities. Coko switched to CAD/CAM systems eight years ago, and today designers are busily working at Silicon Graphics workstations and smaller PCs using both 3-D (Intergraph) and 2-D CAD software. Coko accepts CAD files in all the standard formats and says client files are supplied mostly in 2-D. Schromber noted that for reasons of speed, 2-D is almost always employed at Coko for the shape of the product prior to actually designing the mould. The reason that 2-D files are considerably smaller than 3-D. The computer can incorporate modifications and redraw a design more quickly, so the work goes faster. 3-D, he continued, has become indispensable for todays mould designing because so many of the parts are very complicated. Thick and thin sections with little transition, lots of undercuts and rib patterns ?with and without gas channels ?all making for complex moulds with many core pulls, slides, and unscrewing mechanisms. In addition to the computer hardware, Cokos design group has a number of large drafting tables holding design plots of large moulds in progress. When the designs are complicated and the moulds are big, which is most of the time at Coko, it is difficult to see the whole design and the details simultaneously on a computer monitor. Standing, or more accurately, walking in front of life-size renderings, gives Cokos designers another way to use their experience (they have built more than 7,000 moulds) to catch potential problems.Big Injection Machines Coko has roughly 300 working moulds and 45 injection moulding machines with clamp forces ranging from 60 to 2,000 metric tons. Most are larger than 500 tons and most, along with their robots, are from Battenfeld. Six machines between 200 and 400 tons are from Krauss-Maffei, also equipped with robots. Because Coko changes 12 to 15 of those large moulds each day, the Stabliy quick mould change system was adopted a few years ago. It reduces the average mould changing time by 80 percent. The companys reason for using a 60-ton machine can be summed up in one word: assemblies. Coko has substantially added to its business by providing clients with complete assemblies. The small machines support that capability by making the small parts needed. All machines are gas-assist-ready, and all but the smallest have already run gas-assisted moulds. Coko has been using gas assist for more than six years, but Schromber says product designers are still learning the options gas assist gives and the restrictions it removes. As they learn they naturally create more products that use those advantages. Because of that learning curve and the unique design and function possibilities, not to mention process cost reduction offered by gas assist, Coko sees continued growth in this area. Coko has a central 2 Airmould gas system, consisting of a gas generation unit that extracts nitrogen from the ambient air and a gas pressure control system. It can supply gas to as many as five machines doing rod-type parts or 10 doing flat parts, and the system is expandable as demand grows. To increase flexibility now, Coko uses Battenfelds Airmould Mono-Module. Compact and wheel-mounted, this gas pressure control unit can be rolled alongside any press in the shop and connected to the preinstalled interface in the machines controller.Handling the Materials Mix More than 7,000 tons of thermoplastic material are used each year, mostly PP, PS, and PE (stored in five 30-ton-capacity silos) but there is also a high percentage of technical materials including PC, ABS, blends, nylon, PPO, and others, but no thermosets or elastomers. Everything is checked for melt flow index and dryness on arrival. The central material handling system, designed by Coko and supplied principally by Azo with some components from Motan, was installed several years ago. Material blending and feeding is gravimetrically controlled and the system, located logically between the materials storage area and the production floor, has contributed measurably to Cokos overall productivity. Pointing to a stacked collection of full, reusable Gecon containers from GE Plastics, Schromber noted how such seemingly simple things can contribute to productivity. The pallet-mounted containers are rigid and high-capacity, meaning faster, yet more secure handling into and out of storage. When empty, the container structure collapses onto the pallet for return to the manufacturer, eliminating much of the time and money formerly spent on disposal of one-trip containers.Customer Support Technology Walking between two long rows of injection moulding machines, one sees solid moulded shapes, skin-over-foam sandwich moulded panels, two-colour parts, structural foam housings to be plated or painted, and gas-assisted structures that ignore many of the old rules on part shape, flow length, and wall thickness. Is that a bit baffling to a client? Absolutely not, says Schromber. Its not the clients job to select mould and moulding technology, even though the more experienced often have very clear ideas about production from the start. Cokos first step with the customer is to look at the performance specifications for the part or assembly. The important thing here is the application of know-how. The choice of injection technologies depends on far more things than the physical dimensions of the part. How does the part function? What are the critical performance requirements? What is its competition in its market? What are the projected quantities, and the cost parameters? They search for anything to give the client an advantage.Gas-Assist Advantage Coko began using gas-assist technology six years ago. Having decided to enter that field, they found expertise at the Institute for Kunststoffverarbeitung (IKV), The Institute for Plastics Processing that is affiliated to RWTH, the University of Aachen, Germany. That plastics think-tank, some 500 persons strong, was already well into the subject and had a large knowledge base. Schromber, who is a University of Aachen graduate, joined Coko at about the same time. The affiliation with IKV continues as a working relationship for Coko. Gas assist is an area where expertise acquired through hands-on experience is critical. IKV, for example, has produced a remarkable video that shows the gas-assist process as it is occurring inside the mould. It first had to make a mould with a transparent window. What one learns in the video can be summed up simply: gas does not always do what you logically think it would. Very often it does not travel symmetrically through a part, even a symmetrical part, and the video clearly shows this. Coko was also involved in the production of the video. Schromber says that Coko now almost always injects gas directly into the mould rather than through the nozzle. If gas flow is not symmetrical and you send it through the nozzle, the gate will most likely have to be off center. The mould would have to be mounted off center on the platen, bringing you face-to-face with loss of platen parallelism. Coko frequently uses multiple gas injection ports to precisely control distribution of the gas pressure, taking advantage of hot runner technology to have custom-positioned gates. Also, the timing of the gas into those ports is often sequenced. There is, however, a way to decide where to position the gas ports and gates and how to sequence and pressurize themPrototyping and Simulation Most of us agree that prototyping and mould simulation is good policy before cutting metal on any mould. When a mould is going to be as large as Cokos normally are, with the correspondingly large investment, Coko feels there cant be too much prototyping and simulation. If the client doesnt provide a product prototype, Coko turns to one of several nearby companies with stereolithography (STL) facilities. Prototype moulds can be made internally in a shop that regularly produces aluminum production moulds for its structural foam parts. When it comes to moulding simulation, Coko again uses its affiliation with IKV to advantage. IKV has developed and commercialized its own mould design software package, Cadmould-3D, which includes extensive mould simulation. IKV and Coko create as many simulations as they need to be totally sure of the design. The payoff from the simulation is a lot more than positioning gas ports and nozzles. Using Cadmould, IKV provides Coko with a full set of baseline processing parameters for the machine: temperatures for the mould and the material, injection pressure, holding temperature, pressure and time, and more. As much as Coko benefits from this extensive preparation, its clients benefit more. The flat panel for a Canon copier shown above proves the point. Formerly, the part had been made in Japan of painted structural foam. There were sink marks opposite the mounting bosses and other thick sections, and the overall quality level was not what Canon wanted. So Coko changed it to a solid part with gas assist. The painting cost was immediately eliminated. Average thickness was reduced by half. So was the overall weight, and along with it, the material cost. The cycle time went from more than three minutes in foam to less than 90 seconds for the part shown. And those quality problems are history. These more than just plain moulding projects dont appear by chance. To secure them, Coko has built an extensive assembly operation that includes inserts and outserts, ultrasonic and vibration welding, screen and pad printing, hot stamping, and a complete painting facility that includes EMI shielding. What doesnt take place in house, such as metallizing, can be done by someone in the neighbourhood. Coko is offering its customers a single point of responsibility for large, complex parts and supplying the know-how to give the customer significant benefits. The formula is working.13译文:庞大而又复杂的模具 行内人士经常讨论这样的一个话题: 是否要制定一个模具工的规范呢,一个只精通某个过程,市场或材料的人与一个通才哪一个更有可能成功呢?为了寻找答案,IMI 最近拜访了德国Bad Salzuflen的Coko Kunststoffwerk,看到了这样的一家公司,它在注射模具产品生产中几乎都制定了明确的规范,并且该做法取得了相当大的成功。Coko 决定专门制造大的产品:比如壳,嵌板,橱柜和其他如填料需要用公斤来计算的,流道很长而且模具重达几吨的零件。然而,当提到技术的时, Coko并不能完全称得上是一个专家。因为在我们通常称呼大的零配件有许许多多的样式,Coko 必须精通大量的注射模塑技术。他们使用传统的注射模具,结构性泡沫,和包括夹有泡沫塑料核的复合式注塑模具,以及最近使用的气体辅助注射模具。 Coko 也并不是一个新手。它在60年以前以塑料生意起家。然后公司慢慢成长,扩大了注射模具,开办了工具中心,而且逐渐地开始在较大的零配件中开发专门技术。 注射模具现在是该公司加工塑料的唯一焦点。Coko公司的客户支持部经理Thomas Schromber让我们从模具加工中心开始参观。很明显这是他故意安排的。Coko 强烈地相信它的客户就是一个单独的财源。公司口号简单地翻译就是 我们把形状给你的产品 。Schromber说,客户能带来一个方案,一个草图, 或一个大致的设计,而且 Coko将会从中采纳一些。一般来说,绝大多数设计是实体产品的设计,但是无论如何,Coko 感觉模具是整个的生产过程的基础,因此,它一定要完美。他们把25%的模具制造送到外面加工,只留下最不复杂的铸模,而且仅仅只给那些值得信赖和高技术的技工加工。值得一提的是,Bad Salzuflen 在德国并不只是该行业中如此不寻常的一员,而是有许多大的加工公司也和他们一样。制造大的模具模具制造是在一间1,400平方米的车间内并和注射模具注射车间分开。二个错模就够60个工艺员每个星期工作五天有时候甚至是六天。而机器的设备几乎都是CNC驱动,包括笔直而又大的原料工作台,小的修整机器和EDM 系统, 以及一台来自Makino的极品自动机器工作台,它有包括自动选择和能从有59个工具的工具库中取出合适工具的装置,70% 的一些工作是由冲蚀来完成的。工件可能是像13吨一样的重和大得如 2,000 x 1,500 x 1,000 cm.(780 x 390 x 585英寸)大小尺寸,该大机器需要空心装置以致于冷却通风管贯穿整个大的模具工件,这样就可以单独地从一面连续地操作了。钻孔加工中的铁屑要准确地从两个侧槽排除并且要尽量减少加工时间。在注意到不同年数的机器时,Schromber提到了Coko在新的机制技术方面接受连续的投资的事很普通。你绝对要走该行业的前列。模具设计在加工中心的后面是一扇通到一个被装满各式各样的大零配件的产品展览厅的门。过去那只是通往Konstruktion部门楼梯口。在德国语中那一个词也是设计的意思,而且这一个铸模设计部门像机器设施一样的先进。Coko在八年前就转换到电脑辅助设计/ 电脑辅助制造系统了,而且今天设计者正在忙碌地在矽图形学工作站和使用安装了3-D(Intergraph) 和2D的电脑辅助设计软件的较小PC机。Coko接收各种标准格式的CAD文件并且大部分的客户都只提供2D的图形文件。Schromber注意到影响速度的理由,2-D的图表在Coko为模具设计生产最先被使用。原因是2D的文件比3D的占的内存小得多。小型计算机就能更快组合和修正而且很快地可以重画一个设计,因此,工作也很快。不过他继续提到3-D已经对今天的铸模设计变得不可缺少了,因为大多数的零配件非常复杂。比如厚的和小的组件之间的过渡,许多模型凹腔和肋的薄断面样式 、有或没有气体通风槽、所有制造复杂铸模拉杆,滑块,和锁紧装置。除了计算机硬件之外,Coko设计组有若干个大的草绘工作台,并把大模具分割成几部分进行绘制工程图。在Coko大部份的时间内,设计都很复杂而且模具都很大,这样就难以在一个计算机上同时地见到整个的设计和细目。这样就需要在整体尺寸的绘制之前绘制的标准化件或很精确的零件图.这也给了Coko设计者们另外的一个方法来使用他们的经验(他们已经建造超过7,000个模具)去发掘潜在的问题。庞大的注射机Coko大略有300个工作的模具件和45个夹紧力在6到2000吨范畴内的注射机。 大部分的注射机的夹紧力超过500吨并且大多数是装配了Battenfeld生产的机器人。 有六台来自Krauss-Maffei的机器是在200和400个吨之间,不过也装备机器人。因为Coko每天变更那些大的铸模中的12到15个, 稳定而又快的模具变换系统已被采纳多年了。它能减少平均80% 的平均铸模变换时间。公司使用一部 60吨的机器理由总结为一个词: 组合。Coko实质上已经充分地扩展到提供完整的装配给客户了。小的机器也用于制造小的零配件需要。所有的机器是气体辅助装备,而且几乎就算是最小的都有气动辅助的铸模。虽然Coko使用气体辅助装置已经超过六年了,但Schromber仍然说产品设计者正在学习如何选择更好地使用气体辅助装置和限制它的不利因素。当他们学会了他们就能利用这些优势自然地生产出更多的产品。因为这样可以学习曲线和独特的设计以及功能可能性,更不用说气体辅助能减低生产成本,Coko好像要在这一个领域中继续发展。Coko拥有一个在中央有2个空气模具的气体系统,它有一个可抽取来自周围空气中的氮气和一个气压控制的气体产生机构,它提供的气压可为多达五台机器去做杆类的零件或十台去做平面的零件,而且这个系统可根据需要来扩张它的功能。为了增加工作的灵活性,Coko使用Battenfeld的空气模具的单一模具,组件等,该气压控制机构在车间内可沿着任何压力卷动并且连接到被预先安装的机器控制器的界面控制。操作材料混合每年有超过7000吨的热塑性材料被使用,大部分是PP,PS和PE,但是也有一个部分材料占有相当高的比重,如PC,ABS,聚合物,尼龙,但不包括热固性塑料和人工橡胶,所有的材料都要进行抵达上的熔化流量分度和干燥检查。该核心的材料操作系统在几年前就安装了,它由COKO设计和由来自MOTAN的AZO来提供一些主要的组件。物质的混合和补浇测定是严格控制的,而且该系统合乎逻辑地布局在材料储蓄区域和生产产品之间,已经可以测定地认为该系统已是影响 Coko的全部生产力的因素。指着被堆积的来自GE塑料公司的一个充满又可再度回收GECON容器,schromber 提到了如此表面上简单的事物能如何成为生产力的因素。用草席垫着坚固且高容量的容器, 这样就意谓着即使更快的运输速度也仍然可以比较安心的进出仓储。当空的时候,容器结构在返回制造者时会在草席上自动崩溃,因此省去了许多以前花费在单程容器上的时间和金钱客户支持技术步行在二长排的注射机之间,发现一台机器看上去很结实模具形状的,表面上泡沫上夹心嵌板,两块有颜色的零件,结构上泡沫状的实际是镀金或描画的,并且气体辅助的结构会忽略许多关于零件形状的旧尺寸,流道长度和型腔壁厚,这对客户会有阻碍吗?完全不是,shromber 说,选择模具和模具技术这不是客户所要做的,即使它很有经验并一开始就有了非常清晰地关于产品的方案。Coko客户的第一步骤是让他们看看零件装配的规范,这最重要的是实际知识的运用,注射技术的选择仰赖较多的事物超过零件的实际尺寸。零件如何动作呢? 决定性的运转需求是什么? 它在市场中的竞争力怎样? 该项目的质量和费用参数如何?他们寻找一切可以为客户创造利益的方案。气体- 辅助的优势Coko六年前就开始使用气体辅助技术,在决定进入这一领域时他们发现IKV在这方面很擅长,该塑料研究所和德国的一所大学RWTH有密切关系,这可是一个塑料人才库,它有500多个很善长于该课题并都有很扎实的理论基础,Schromber就是一所 Aachen 大学的毕业生,在大约同一个时间加入了Coko公司。和IKV 继续密切合作如同他加入Coko工作一样。 气体辅助领域是一个需要专家亲自操作获得经验的工作,这一点非常重要,比如说IKV就摄制了一个特别的显示发生在模腔内部的气体辅助过程的录像。它首先要制造一个带有透明窗口的模具,当你看到这份录像时,你就会得到一个很简单的结论:气体并不像你觉得很合乎逻辑地那样,它经常并不是对称地通过零件,即使是一个对称的零件,而且该录像清楚地显示COKO也参与了录像的制作。Schromber说,Coko现在几乎是直接地往模腔里注射气体而不需经过喷嘴,如果气体流程不对称,而且你又是经过喷嘴注入的话,浇口就很有可能偏心,模具也就被安装在偏离定模板的中心,那你就不得不面对定模板并行所带来的损失。Coko时常使用多种气体注射口以便更精确地控制气压的分布,利用热横流道技术有娴熟地放置的浇口。同时,气体安排进入那些口之内是有顺序的。然而,这有一个方法决定该哪里放置气体口和浇口以及如何排序和给它们加压。原型制作和模拟我们大部份同意在加工任何模具块之前来制作原型和模具模拟是一个不错的工序。 当一个模具和COKO公司正常模具一样大小以及有相应大的资金时,COKO觉得它们没有太多原型制作和模拟的资金。如果客户不提供产品原型,COKO则会向附近几家有STL设备的公司帮忙,模具原型则可在车间内部加工出来,不过通常是铝制的模具并且内部是泡沫型的零件。当它得到模塑模拟的时候, Coko 再一次利用它和IKV学会密切关系的优势。IKV 已经发展而且开放买卖它自己的铸模设计软件包,Cadmould-3D立体,含广泛的铸模模拟。当他们需要完全地确定设计的时候,IKV和Coko提供的模拟可以和实际生产的一样多。模拟的精彩部分是放置很多的气体口和喷嘴。为了更好地使用 Cadmould,IKV 提供一套完整的数据线给Coko为机器处理叁数:模具和材料的温度,注射压力,保持温度,压力和时间等等。很多的时候当Coko受益于充分的准备时,它的客户获益更多。为日本的佳能公司制造复印机纯平显示器就证明了这一点,以前,零件是在日本已经制好并涂上了泡沫剂,会有下沉的轮毂和其他的厚断面的印记,而且总体的质量水平达不到佳能公司所期望的,所以COKO用气体辅助系统给它换了一个结实的零件,喷涂的费用也马上节省了,平均厚度以及总体质量也都减少了一半,这样连同材料的费用也减少了,显示器零件的生产周期也从以前用泡沫制造时的三分钟减少到现在的不到90秒,而且那些质量问题也变成了历史。这些 超过简单模塑 计划不是偶然出现的。为了安全起见,Coko已经建造一个含嵌入和嵌出件,超声波和振动焊接,屏幕和填补印刷,热冲锻加工件,和一个含 EMI 屏隔的完全涂刷设施的组合操作。不像在金属处理的车间加工一样了,能在附近控制台被工人操作。Coko正与制造大而复杂零件的客户提供了单点负责制,而且提供实际知识以便给客户获得更重要的利益。该项规则正在实行着。
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