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A Guide to Laser Cutting Technology, Part 1

(April 2009) posted on Tue Apr 21, 2009

Laser cutters have evolved from prototyping tools to highly-productive finishing systems. Read on to learn about developments in lasers, control software, and other facets of the technology that make laser cutting systems a viable option for any shop currently using conventional, tool-based cutting machines.

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By Markus Klemm

Quality and the soft-marking standard
Laser cutting systems that were engineered just a few years ago were often not up to the challenges of cutting complex designs, especially when there were many sharp angles in the artwork. One can still find inferior laser cutting systems being sold today that similarly are plagued by quality problems, usually evidenced by burn-throughs or pinholes at the start and stop of cutting sequences.

For example, Figures 3A-3C show the difficulties that less sophisticated laser cutting machines face whenever turns are required in sharp edges and compare those difficulties to the performance of more capable systems. In Figure 3A you can see the telltale black burn-through marks at turning points that show where the lasers lingered too long. A good analogy is that of a car making a turn, where there is usually a need to decelerate in order to make the turn. In this laser cutting example, the deceleration of the laser beam was so pronounced that it burned through at critical turning points.

Figure 3B shows results from a laser cutting machine that has just the opposite problem. In attempting to avoid the burn-throughs shown in Figure 3A, the lasers were accelerated. However, the control of this acceleration was inadequate. Instead of the sharp corners that the artwork requires, the edges are rounded. Here, the laser beams are moving too fast to make the sharp corner details.

Newer systems avoid the problems seen in older machines, not because they use better lasers, but because they incorporate better software algorithms to improve control of the mirrors that direct the laser beam. These algorithms support soft marking, where the laser movements are better synchronized with artwork geometry and tightly controlled during the entire cutting sequence. This eliminates burn-through problems while creating the sharp angles required (Figure 3C). Soft marking is no small feat for the control software of laser cutting systems to achieve, and only manufacturers that have made significant R&D investments in better software engineering can deliver the defect-free soft marking that most applications require.


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