The recent messages about laser cutting rolls got me to thinking
about the machinery available to me at the "maker space" I belong to.
We have an 80-watt CO2 laser cutter with a 60 cm x 90 cm cutting area,
basically 2 feet by 3 feet.  80 watts is not all that powerful as these
things go, but it will do paper and cardboard quite well and I have
used it very successfully to cut blotter paper gasket rings and various
"fiber board" profiles.  It also does thin plywood and acrylic-type
materials up to about 1/4" thick.

We have been using it in its X-Y cutting mode, however, it also came
with a rotary attachment which is designed to do engraving on nominally
round or cylindrical objects such as wine glasses.  Oddly, no one in the
group has ever tried to set-up and use this attachment, so I might as
well be the first.

The first attached photo shows the open machine with the bed at its
usual position.  The second photo shows the bed lowered with the rotary
attachment sitting in place.  The third photo shows a "proof of concept"
setup with a derelict 11 1/4" spool frame supplying a finished QRS roll
to a take-up spool chucked into the rotary attachment.  Many other
components would be needed for an operational device such as a backing
surface under the paper, edge guides, etc.

In operation, the normal Y axis of the machine is re-directed as the
angular position of the attachment chuck.  In this configuration the
movement of the paper would be "bulk-drawn".  Whether or not this might
present timing issues remains to be analyzed, but it should be possible
to compensate for it in the data file.  Obviously, formats narrower
than 11-1/4" could also be accommodated by this configuration.

For formats wider than 11-1/4" a more complicated configuration would
have to be devised.  Since only the paper needs to be inside the cutting
compartment, the rotary attachment would be moved outside of the machine,
where it could be configured to still operate in a bulk-drawn mode, or
used to drive a "pinch-roller" type transport.  The gap at the lower
front edge of the safety cover is such that several thicknesses of
standard roll paper and probably most book music cardboard would pass
without having to modify the electrical interlock circuitry, which
could still be done if particularly thick cardboard is being cut.

The cutting software (LaserCut 5.3) uses a native file format of ECP,
however, it will import a wide variety of formats including PLT-HPGL,
AI, DXF, DST, BMP, NC, JPG, JPEG, GIF, PNG, TIF, TIFF, TGA, and PCX.
It should be a relatively simple exercise to give notes their
horizontal positions as well as their sizes.  Details such as making
Duo-Art "snake-bite" holes smaller than other holes would a trivial
exercise.  More problematic would be translating the effective tempo
into the proper angular position of the attachment chuck, for either
bulk-drawn or pinch-roller configurations.

I believe I can do all the necessary mechanics, but will need some
help with the software and conversion routines.  Spencer?

And yes, since this is a precise, controlled burning process, some
attention will need to be paid to fire suppression.  While it would
be impractical to flood the entire cutting compartment (which is
already under fairly strong negative pressure) with an inert gas such
as nitrogen, it should be possible to construct a smaller internal
compartment with (adjustable?) slits to accommodate the material
thickness and the cutting beam diameter such that just that compartment
could be flooded.

John Grant

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