Cricut diode-laser mod?

[Raymond Lulling]

Was wondering if any one has tinkered with small DIY diode based laser cut/etch tools.

I just purchased a Cricut and am already wondering about switching the chase tool with a diode laser.

Still intend to buy something much better at some point soon. But for now the Cricut should give me a lot of fun, regardless of the chosen tools.

I am thinking the laser might need a pressure sensitive tip to engage the beam whenever the actuator engages the work surface. Probably polished brass, maybe nylon. Then a simple low power diode based emitter in a tool that fits the Cricut Collette. If you dont have a Cricut, the print head has two tool slots. Each is a collect mounted to an actuator. When a cut is started the machine will engage the specified tool by depressing it to the work surface. When between strokes or cuts the tool will lift from the surface. So as I see it the options are hack the actuator and use the 5V to switch on the Diode or use a mechanical depression system as a switch to detect tool engagement.

Any ideas? Any one have a solution of their own?

[EschewObfuscation]

I do not know the details of your laser module, so maybe I'm telling you things you already have covered, but just for thoroughness' sake, I'll mention that "raw" modules emit a beam that has a very wide dispersion angle; they require a converging lens, usually billed as a "collimation" lens (a misnomer, but we'll go with it) to achieve a reasonably parallel beam. To do cutting or etching, you'll need a second lens out front to further converge your beam to a short focal length cone, so the narrowest point (the "waist") is at the surface, or slightly below the surface, of your material.

Since the new converging beam is conical and rather tight, the distance from your laser to the work piece is critical. Moving the laser will complicate the task of being repeatably at the same distance. I'd suggest you want to completely disable the tool carrier's vertical motion, and instead intercept that signal and use it to switch the laser on and off.

Another consideration is the cricut *probably* allows some time for the tool motion to complete before it begins the X/Y motion of its program, so if you switch the laser immediately, it may burn a hole while waiting for the motion to begin. So I'd suggest you plan on a one shot or other RC delay to add some adjustable number of milliseconds between receiving the tool-move signal and actually lighting up the laser. Turn off should be immediate, of course.

Since the cricut is intended for dragging a cutting tool about, it's unlikely its firmware cares very much about maintaining constant speed through its program. You may find it has a programmed X speed and a programmed Y speed, and when it's running diagonally, it moves faster. Or maybe not, I dunno. Just tossing that out as something to look for. If that's the case, you may need some extra logic along the line of "if only X or Y is active, run laser at 60% duty cycle, if both are in motion, run it at 100%". Just a possibility.

Good luck, have fun. :)

[Raymond Lulling]

By default focal length should not change. Least what little shifting is done will be no more than 1 mill. This because the knife they use is very small. The only thing that varies is the tension, which is user collectable.

Motion delay is less than 1 second. So if the switch were pressure sensitive, laser would not engage until almost the same moment the carriage begins to move.

Otherwise all points taken. Not expecting to use a raw emitter. But some enthusiasts have been known to hack pointers and other laser tools to make their own custom cutting tool.

Was really very curious to see of this flock, who has done what?