飞机制造：钛合金正常情况下对刀具的挑战

没有任何东西比飞机制造更需要寻找新型材料。原因很简单：一方面，材料必须能够承受特别高的应力，具体性能取决于在飞机上所使用的位置。例如，如果用在涡轮机上，就应使用具备极耐高温性的钢材。但与此同时，为了尽可能减少燃料消耗，降低飞机的总体高度也是非常重要的。经过综合考虑，钛合金被认定为一种非常理想的材料。许多美国的应用案例证明这同时也对用于加工钛合金材料的刀具提出了新的挑战。

Nowhere is the search for new materials more intense than in the field of aircraft construction. The reasons for this are easy to see: on the one hand, depending on where in the aircraft they are used, the materials must withstand particularly high stresses – in the turbines, for instance, extremely heat-resistant grades of steel are used. At the same time, however, it is important to lower the total weight of the aircraft and so minimize fuel consumption. Taken together, this makes titanium an extremely desirable material. The challenges this presents to the tools used for machining titanium are illustrated by a number of applications from the USA.

甚至这种钛合金材料本身就是一种高科技。凡对于金属需要暴露处于于极高应力下的情况，目前钛合金都是不可或缺的。无论在医疗技术器械方面还是在汽车制造行业，它都得到了广泛的应用。

Even the material itself is high-tech. Wherever metals are exposed to extreme stresses, titanium alloys are now indispensable. They are used in medical technology as much as they are in automobile construction.

但是，在飞机制造方面，钛合金金属真正为自己赢得了殊荣。这种材料的多种强度是其在此应用领域的独特优势。钛合金重量轻、对震动和风力作用不敏感，而且加热后热膨胀率低。同时，由于它能够像铝合金金属一样快速形成一个表面钝化层，因此具有耐化学侵蚀作用。然而，这些起积极作用的特性也促使钛合金对任何加工刀具提出了挑战。正如LMT ONSRUD（蓝帜昂思路）公司的 Scott Feimster先生所解释的一样：“钛合金因其特殊的物理性能而难以加工。它是一种传热性较低的材料，因此热量迅速积聚在切削刀具上。再者它还是一种金属，所以能够与切削刀具中的材料形成合金并传递化学反应，从而会给刀具带来擦伤、焊接、涂敷热熔、弥散和快速磨损等影响。”为此，很多公司一直在寻找新型刀具解决方案。

But it is in aircraft construction that titanium has really earned its laurels. The wide range of the material's strengths is uniquely advantageous here. Titanium alloys are light in weight, insensitive to shocks and blows, and only undergo low expansion when heated. At the same time, they are resistant to chemical attack because, like aluminum, they quickly develop a protective, passivating surface layer. The positive properties just described, however, also directly contribute to the challenge that titanium alloys present to any machining tools, as Scott Feimster from LMT ONSRUD explains: “Titanium is difficult to machine due to its physical properties. Titanium is a poor heat conductor so the heat can build up quickly on the cutting tool. Because titanium is a reactive metal it can alloy and chemically react with material in the cutting tools which cause galling, welding, smearing and rapid destruction of the cutting tool.” For these reasons, many companies are constantly on the search for new tool solutions.

刀具性能在飞机制造行业得到验证

Tools proven in the aircraft industry

直接从LMT ONSRUD（蓝帜昂思路）搜索这种解决方案并非是一件不同寻常的事。该公司总部设在芝加哥附近的Libertyville，可提供多个各系列的切削刀具产品，而且这些产品已经在飞机制造行业经过了多年的验证，尤其是钛合金的加工。以下两个示例验证了符合飞机制造要求的典型挑战：

It is not uncommon for the search to lead directly to LMT ONSRUD. The wide spectrum of cutting tools from the company, whose headquarters are in Libertyville, near Chicago, has been proven over many years in the aircraft industry – and particularly includes the machining of titanium alloys. The two following examples illustrate typical challenges met in aircraft construction:

·           在制造飞机发动机组件时，经常需要加工深度大且结构复杂的几何体，尤其对于一家美国供应商公司更是如此。该公司的生产计划员规划师一直寻找用于切削6AL-4V钛合金的更经济型刀具解决方案。“以前所用的刀具无法达到预期的深度。为了在组件部件内加工出较深、较窄的凹槽，刀具需要具备较长的长度。这样一来，不仅刀具容易折断，而且钛合金的表面加工质量也很差，” Feimster先生解释称。LMT ONSRUD（蓝帜昂思路）可为各企业提供一种“即插即用”型解决方案：通过使用两种具有不同长度的EMC系列钛合金修整器精铣刀（根据组件部件的几何结构进行选择），可提高加工质量。同时，另一个优势在于，刀具的使用寿命也大大延长。

·           Machining geometries with high depth and complexity is a regular task when manufacturing components for aircraft engines, and this is exactly the field of one American supplier company. The production planners there were looking for a more economical tool solution for cutting the titanium alloy 6AL-4V. "The tool that was previously in use was out of its depth. In order to machine the deep, narrow pockets in the component, the cutter necessarily has to be unusually long. Not only did the tool break frequently, but the machining quality on the surface of the titanium alloy was poor," explained Feimster. LMT ONSRUD was able to offer the company a "plug and play" solution: by using two different titanium finishers of different lengths (depending on the geometry of the component) from the EMC series, the machining quality was improved. At the same time, the tools had the attraction of a significantly better tool life.

·           通过使用LMT ONSRUD（蓝帜昂思路）生产的4刃钛粗切合金粗铣刀器为另一个飞机制造公司加工控制杆，也达到了类似的效果。研发这种刀具的目标是增加每个刀具所能加工的组部件数量。“到目前为止所使用的刀具只能加工50个左右的组件部件。这就需要更换刀具。对工厂管理层而言，更换刀具是非常简单的事。另一方面，LMT ONSRUD（蓝帜昂思路）生产的4刃钛合金粗铣刀粗切器的使用寿命可延长至加工约75个组件部件，”LMT ONSRUD（蓝帜昂思路）公司的John Hansen先生说道。

·           Similar results were achieved through the application of the 4-flute titanium rougher from LMT ONSRUD for machining a control lever at another aircraft construction company. The goal was to increase the number of components made by each tool. "The cutters used until now could only make about 50 components. At that point it was necessary to change the tool. This was just too little for the factory management. The lifetime of a 4-flute titanium rougher from LMT Onsrud, on the other hand, extends over about 75 parts", explains John Hansen of LMT ONSRUD.

其它部门领域– 具有可比性价值的性能提升

Other sectors – comparable performance jumps

供电部门的一个应用示例证明了为什么说钛金属钛合金对加工刀具的挑战不仅限于飞机制造业。对于高应力组件部件的生产，如：盐水或氯化水水泵内的此类组件部件，许多制造商当然会使用钛合金。在一家美国公司，其水泵传感器是采用6AL-4V钛合金制造的。“通过使用LMT ONSRUD（蓝帜昂思路）生产的8刃钛修整器合金精铣刀，我们取得了巨大的成功，”LMT ONSRUD（蓝帜昂思路）公司的Bill Trites先生称，确认了该产品在飞机制造方面的积极作用。“每个每把刀具所能加工的组件部件的数量，从3个（使用以前的刀具）增加至36个（新型刀具），同时，加工进给速度也由原来的1.2英寸/分钟提升至8英寸/分钟。”