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How Automotive Metal Forming Works

Advances in Automotive Metal Forming
Workers at a Hyundai car factory line up pressed metal parts used in its car assembly line in Beijing, China.
Workers at a Hyundai car factory line up pressed metal parts used in its car assembly line in Beijing, China.
AP Photo/Ng Han Guan

The most important thing to happen to automotive manufacturing and metal forming in the last half century is the computer. Computers are important to metal forming in two ways:

They guide the process. A computer can be used to make split second decisions to guide metal forming operations through complex sequences -- for instance, using a forging hammer against a workpiece in much the same way that an ancient blacksmith would, but with the augmented physical force of hydraulic machinery. The action of the hammer can be programmed in advance to produce shapes as complex as those created by a human artisan's hands. Similarly, computers can control the flow of the workpiece between multiple stages in the operation to produce the finished shape.

They simulate the process. A computer can be used to simulate the physical forces involved in metal forming so that new metal forming operations can be invented without having to use expensive machinery to experiment with new ideas. Sophisticated simulation software is available to replicate metal forming operations on the computer, so that scientists can see the result of applying heat and force to different kinds of metal. Mistakes made on the computer are much less costly than those made in the real world and allow the sort of trial and error that would be a waste of time on actual machinery.

Computer simulation is opening new vistas in metal forming. Many of the new metal forming technologies are based on a deep understanding of the micro-structure of various kinds of metal and the physical processes that go on inside metal subjected to pressure and heat. Some of the new processes are hybrids of old processes. There has also been a move toward hot-metal processes, which allow the use of metals that don't lend themselves well to cold processes.

These new technologies allow such innovations as the use of lighter metals that still retain the strength of traditional automotive parts. This is useful, say, in the manufacture of fuel efficient vehicles or battery-electric vehicles where the car body needs to be as light as possible to offset the considerable weight of the battery array. These technologies also allow auto parts to be manufactured less expensively without a drop in quality. For instance, electromagnetic forming techniques, in which the metal workpiece is exposed to a magnetic field that sets up an electric flow in the metal itself, can be used to speed up the forming process without the resulting tearing and wrinkling that would normally occur. This allows the use of processes not formerly possible in automated metal forming.

In the years since Henry Ford demonstrated the feasibility of inexpensive assembly line manufacture of cars and auto parts, the science and technology of metal forming have come a long way in showing the auto manufacturing industry how to produce extraordinary cars without an extraordinary price.

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