In part one, we learned how improved engineering and advances in software have made laser cutting systems ideal for higher volume applications and products with detailed cutting requirements. Here the discussion concludes with a look at systems integration, component options, and other factors to weigh before purchasing laser cutting equipment.
By Markus Klemm
In the previous installment, we considered the improved speed and accuracy that today’s high-end laser cutting systems provide. As noted in part 1, development of sophisticated software algorithms is largely responsible for these improvements. Such software also eliminates the need for double scan laser heads, making it possible to get equal or better performance out of single scan heads.
The idea behind double scan-head systems is that by using two lasers instead of one, you can increase laser cutting speed. In fact, systems with double scan heads are at times no faster or even a tad slower than single scan-head laser cutters that use higher wattage lasers coupled with more sophisticated control software. Using two lasers at once to double production speed may sound good, but it actually creates significant quality issues and cannot truly double speed because of the physical constraints of putting two laser scan heads next to each other and the compromises that this forces the manufacturer to make.
When you are stitching two halves of the web width together, it often is possible to have more parts on one side of the web than the other, as shown in Figure 1. In such a scenario, with a double scanhead machine, you will lose productivity because the laser on the overloaded side will cause a slower web speed. To solve this problem, manufacturers of double scan head systems usually position the two laser scan heads as close together as possible across the web width to create the greatest possible overlap between their two cutting fields.
However, for wider material there is always an interplay between the size of the scan heads, how closely they are positioned together, the laser spot size that results, the extent to which there is overlap in the cutting area, and the amount of stitching required. If the scan heads are so large that they cannot be placed very close together, there will be less overlap in the cutting area and more need to stitch, which is an eventual challenge to quality, as shown in Figure 2. Alternately, if small scan heads are used and positioned closely together, there might be a greater overlap in cutting area but the laser spot size would need to be much larger, as much as 280+ microns, which also is a challenge to quality.
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