Electromagnetic manufacturing企业库|免费b2b网站

Electromagnetic manufacturing

电磁加工工艺

It's a knockout

新的工艺突破

Jan 14th 2010

From The Economist print edition

Engineers find a new way to punch holes through steel

工程师们发现在钢材上钻孔的新方法

ELECTROMAGNETIC pulses (EMPs) are usually associated with warfare. The idea is to use a blast of energy to fry the enemy’s computers and telecommunications gear. One common way proposed to do this is with an atomic bomb. In a less extreme fashion, however, EMPs have peaceful uses. They are already employed industrially to shape soft and light metals, such as aluminium and copper. Now a group of researchers at the Fraunhofer Institute for Machine Tools and Forming Technology in Chemnitz, Germany, has found a way to use an EMP device to shape and punch holes through industry’s metallic heavyweight—steel. This could transform manufacturing by doing away with the need to use large, heavy presses to make goods ranging from cars to washing machines.

一般来说，电磁脉冲（EMPs）和现代战争之间有着密切的关系。其原理是用突爆的（电磁）能量摧毁敌方的计算机和通讯设施。一般来说实现这个目的的手段是核爆。在受控的情况下，EMPs也有着非军事用途。在比如铝和铜这些质地柔韧并且密度小的金属成型工艺中，EMPs已经被成功的应用。最近，德国开姆尼茨的弗劳尔霍夫学院的机械制造和成型工艺方面的研究人员团队发现了一种利用EMP在钢材-重金属里面成型或开挖孔的新工艺。这将通过取代大型压力机冲孔改变制造工艺，从而在很多行业，从车辆到洗衣机的零部件制造广泛使用。

Verena Kr?usel and her colleagues performed their trick by beefing up an existing electromagnetic-forming machine. Such machines use a bank of capacitors to discharge a current rapidly through a coil. The coil converts the current into a powerful magnetic field. When the component to be worked is placed next to such a machine, the coil induces in it a corresponding field. Like poles repel, and the repulsion between the two fields is strong enough to make the metal distort.

Verena Kr?usel和她的同事们改进了现有的电磁成型设备。这种设备使用大量的电容通过线圈快速放电。线圈则产生强烈的磁场。当待加工部件在设备里就位后，线圈在其中产生感应磁场。由于同性相斥，因而两个磁场之间的排斥力足以使金属构件变形。

Dr Kr?usel and her colleagues boosted the power of their machine by strengthening its coil and speeding up the rate at which the capacitors dump their charge. The result is an extremely strong field—one that delivers enough pressure when it hits the steel to punch out the material next to it, leaving a hole behind. The impact pressure on the steel is about 3,500 atmospheres. That is the weight of three small cars pressing on an area only a centimetre or so square.

Dr Kr?usel和她的同事们通过强化线圈以及加快放电速率提高了这种设备的加工能力。表现在强大的电磁力的产生-也就是说当在钢材冲孔时，设备可以提供足够的压力使钢材成型。在钢材上的冲击压力达到3，500个大气压。相当于在一个平方厘米的截面上施加三辆小型汽车的重量。

The result is that the machine is able to punch holes 30mm in diameter through the type of sheet steel used to build car bodies, which is usually around 1mm thick. The group have also used their machine to punch holes in hardened steel, including stainless steel. And, besides punching holes in steel, such a machine could also be used to form shapes out of the metal without the need to use a mould or a die.

这个结果使得这种设备可以在建造轿车车体的通常厚度为1mm左右的钢板上冲出直径达30mm的孔。用他们研发的设备甚至可以加工淬火钢，包括不锈钢。这样的设备还可以在不使用凹模和凸模的情况下使金属成型。

Firms such as Germany’s giant carmaker Volkswagen are sponsoring the project because forming steel components with an EMP device provides a number of advantages. Although using a heavy press to bend metal and cut holes in it is fast, the tearing action at the edges of the holes leaves ragged, sharp tailings, known as burrs. This means that parts stamped out this way have to be cleaned up, usually by hand, which increases production costs. The need to keep replacing the stamps and dies used by the press, as they become blunt, also adds to the expense.

由于使用EMP设备有着很多的益处，很多公司比如德国大众赞助了这个研发项目。虽然用冲床弯曲金属或在金属上面冲孔加工时间短，但是冲压加工会在孔缘产生毛边，也就是孔边缘上不规则的，锐利的毛刺。这意味着冲压的零件需要xx毛边，通常需要通过手工打磨。这也增加了制造成本。冲床使用的模具在变钝时的更换也增加了费用。

Lasers are one alternative. They can cut cleaner holes in steel, but they are slower than stamping because they need to burn their way around the part. They are also expensive to operate. An electromagnetic punch, however, stamps its hole without tearing the metal, which means no burrs are left behind, and it never gets blunt. In fact, says Dr Kr?usel, her machine can punch a hole clean through a sheet of steel in a fifth of second—compared with the 1.4 seconds needed by a laser.

激光是另一中选择。激光可以在金属上切割出光洁度很高的孔。但是激光加工的速度慢于冲床。因为激光加工需要沿包围曲线进行。而且操作成本也高。EMP机床加工，由于再冲孔时不撕裂金属，所以不产生毛边，并且从来不会变钝。Dr Kr?usel说，事实上，她们的设备可以在五分之一秒内在一张板材上冲出一个光洁的孔。而激光切割需要1.4秒。

The team members are now carrying out further development work on the coil. They expect factories to take up the idea quickly, because it is a modification of equipment that is already familiar. The size of holes that can be cut depends on the size of the coil, so specific coils will be needed for each application. Specific punches, however, are needed for traditional presses, so this would not seem to be a deterrent—especially as an EMP device should be able to deliver consistently accurate blows without wearing itself out. A hole, new technology, as it were.

这个团队依然在持续改进设备的线圈。他们希望工厂能迅速采用这种工艺。因为这只是对现有设备的改进。需加工的孔径和线圈的尺寸相对应。也就是说不同的工艺应用需要特定的线圈。事实上，传统的冲压机也需要特定的冲压模具。所以这个并不构成障碍。尤其是由于EMP能提供连续的保持不变的加工精度，同时并不会磨损设备上的冲压部件。一种新的成孔技术，就是如此。