[ Ref.
[ https://www.mmdigest.com/Archives/Digests/202404/2024.04.13.01.html 
[ https://www.mmdigest.com/Archives/Digests/202404/2024.04.13.01.html 

A Low Cost DIY Laser Roll Cutter

I have written in the past about my low-cost laser roll cutter project.
Things were working quite well and I had a design for which all parts
are readily available from stock and reasonably priced or that can be
made with a low-cost laser engraver.

I am known for my persistence continuing when most people would give
up. I have spent months on little details of the software and the
mechanical design. The system worked pretty well but did not meet
my high standards for accuracy, simplicity of build, et cetera. Just
today, a few hours ago, I verified that the system works remarkably
well and exceeds my expectations. A few details:

I had the machine working pretty well with 40-pound brown craft paper
but this is a bit thick for a piano roll and would make it impossible
to fit really long rolls on a normal size spool. I now have the machine
working reliably with 30-pound and thinner paper.

I just did a test with really cheap paint masking paper that is
more like 25-pound. Handling this limp paper accurately was a major
challenge and required major modifications to the paper guiding system.
The drawings for the new paper rack should be done later today.

I did upgrade the X-axis stepper motor to a better one than the one
that comes with a cheap engraver; now the speed of the machine is
better than I had hoped for. For a typical roll with expression coding
(which requires complete traversal of the page when cutting) the cut
speed looks like about 19 feet of music roll per hour. A typical 25-
to 30-foot-long dance roll could be made in less than 1.5 hours.

Piotr Barcz has been testing the software and has developed easy
methods to reliably master rolls both from the major scan formats
and from new music. At this point the software can handle almost
anything thrown at it if the right steps are taken.

A benefit of this system compared to conventionally perforated rolls
is that there can be essentially no step rate (or "ratchet") to which
the holes need to be quantized. This means that the most subtle timing
effects of new music can be preserved and also that shorter rolls
with slow tempi can be made to save paper or to fit very long works on
a roll without sacrificing timing. Basically the rolls can be analog,
not step based.

A few people are following my design (without the latest improvements)
with varying degrees of success.

My current design can handle a spool of about 200 feet of paper but in
the next day or two I hope to build a paper feeder that will allow the
use of large rolls exceeding 1200 feet or more. This will make my low
cost machine almost capable of small scale production. Adding a higher
power laser and better motors could reduce the cutting time even more.

From the beginning I wrote the conversion software for MIDI to Gcode to
be very flexible. Virtually any roll can be cut, from little 20-note
organ rolls to whatever size one builds the machine to accommodate.
Hole spacing and size, as well as many other parameters, are completely
under the control of the user. All settings are saved in configuration
files for later use or sharing.

People who know me know that I have little tolerance for BS. I do
not hype my work and I am as critical of what I do as of what others
do. I am really impressed with my machine and the fact that I did
not give up.

Spencer Chase
Garberville, California
http://www.spencerserolls.com/ 
spencer@spencerserolls.com.geentroep [delete ".geentroep" to reply]

[ Some photos are at http://spencerserolls.com/Laser-roll-cutter.html 
[ -- Robbie