Fabricators are learning the gains are to the swift.

Author:Burdel, Thomas
Position:Ultra-fast lasers

High-speed cutting has always been a prime concern in manufacturing, especially for fabricators. Their search for higher positioning, cutting, and processing speeds started with the first laser system for sheet metal parts, which was introduced in 1978, based on a turret-punch frame using a sheet dragger and a fixed laser beam delivery system.

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The initial process of a laser beam moving around sheet metal to cut a part or hole was a slow method when compared with punching a hole in less than a fraction of a second. Laser-beam divergences had not been mastered, and laser power was only about 500W. However, the quest for higher processing speeds was on, leading to the first flying-optics system in 1979. For approximately 10 years, laser productivity gradually increased until the early 1990s, when flying-optic systems evolved with increased laser power (close to 3,000W) and faster CNCs combined with better drives, allowing more than 5,000ipm positioning speeds.

It seemed by the mid-1990s the physical limit of large-gantry machines handling 5'x10' sheets with tremendous mass and high forces was reached. The introduction of linear drive motor technology changed that by offering speeds over 10,000ipm and high dynamics, allowing the processing of 600 holes per minute in thin sheet metal. This was accomplished by combining positioning speed with new, instant piercing technology and great acceleration forces between 1G and 3Gs. Any higher speed would require extremely heavy, expensive, and non-economical machine frames, as forces increased exponentially with the increase of speed and mass.

Dual-head cutting machines were also introduced in the mid-1990s as a seemingly straightforward solution to double the productivity of a laser-cutting machine. But this solution required two laser resonators, two beam-delivery systems, two Z-axes and cutting heads. Two identical parts were produced simultaneously with those machines, but because of additional costs and other drawbacks, this approach did not succeed.

Real breakthrough

Incremental progress in positioning and cutting speeds from 1997 until 2004 was made, as higher laser power became available and piercing technology became more refined. In 2005, a real breakthrough arrived with the introduction of two additional parallel-kinematic-drive axes on the cutting head, effectively creating two machines in one--a highly dynamic and light cutting head and a machine with a large work...

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