While thumbing through RMC and MR I noticed a marked increase in the number of craftsman kits that now include "laser cut" parts and it occurred to me that I don't really know what this means.
Yes...I do know that it means a laser is used in some fashion to cut to very exact sizes, but what technology is being used? For example, is the laser mounted in a plotter head? Is it 2-D mirror
controlled? Does it cut multiple goods at once? Is it driven from some CAD system?
For a change, this is something I can talk about without going to a book for reference. For the past several years, I have worked on using lasers for manufacturing in the electronics industry. I can
tell you that they are probably using a CO2 or Nd:YAG laser, which is focused to a fine point at the part to be cut. Both emit light in the infrared part of the spectrum and cut by heating the
material to boiling point and evaporating or melting through.
There are two methods used to cut the pattern, either the laser beam is moved using mirrors or the part is moved using a X-Y positioning table. The choice depends on the cutting speed and the area to
be covered. Directing the laser by mirrors is very fast but has a limited work area. Probably the second method is used where a large x/y motion table is used.
This system has the advantage that a large sheet could be put in the machine and multiple parts cut from the one sheet unattended. The pattern is almost certainly designed on a CAD system and
downloaded to the laser cutting workstation. The X/Y table is then computer driven based on the CAD drawing.
It may be possible to cut multiple layers at once but the possibility of debris from the cutting process depositing on the other layers might discourage its use. The other drawback to multiple layer
cutting is that the layer the laser is focused on would have the best cut, the other layers would have cuts of lesser quality. It all depends on the quality and look the manufacturer wants in the
finished parts.
I would like to comment on Laser Cutting. I have not seen the any of the kits with "laser cut" parts but as I have been involved in designing photo-etched (chemical milled) brass kits for some years
I have been watching the advent of laser cutting with interest. As I see it, the two techniques are complementary. Photo-etching is not really practical for metal thickness over about 1mm so is used
for the smaller scales, while laser cutting, is which is much more expensive, is used for the model engineering scales (G1 and above). Of course you can't etch wood at all, or plastics easily, so
lasers could be used on these materials, but at the prices I been quoted 1 a foot run makes it a specialist technique, at least in this country.