Grad Student Invents Cheap Laser Cutter

An anonymous reader writes "Peter Jansen, a PhD student and member of the RepRap community, has constructed a working prototype of an inexpensive table-top laser cutter built out of old CD/DVD drives as an offshoot of his efforts to design an under $200 open-source Selective Laser Sintering (SLS) 3D printer. Where traditional laser cutters use powerful, fixed-focus beams, this new technique dynamically adjusts the focal point of the laser using a reciprocating motion similar to a reciprocating saw, allowing a far less powerful and inexpensive laser diode to be used. The technique is currently limited to cutting black materials to a depth of only a few millimeters, but should still be useful and enabling for Makers and other crafters. The end-goal is to create a hybrid inexpensive 3D printer that can be easily reconfigured for 2D laser cutting, providing powerful making tools to the desktop."

Comments

I was not aware what RepRap was

[cortesoft]

http://en.wikipedia.org/wiki/RepRap_Project

Cool. I want a self replicating replicator!

Re:As opposed to doers?

[AdamHaun]

It's a reference to the subculture embodied by this Make.

Re:Actually optical choppers are very useful

[TubeSteak]

Come to think of it, I have no idea how a CD or DVD burner controls its laser. Maybe the laser can be turned on and off fast enough.

The laser is continuously* on and usually at a fixed distance.
The laser head can move up and down if it needs to change the focal length to try and re-read errors.

The spinning disc also provides the time + convection for heat to dissipate and not melt the plastic.

*or not depending on whatever caching mechanism the drive has...
which isn't the same thing as saying it can't be turned on/off rapidly, just that there's no need.