From video description:
The very first print on my diy 3d laser printer. It should be a cube but it's just a small quadratic mess ;) It's using a 500mw 405nm laser on a custom made stepper motor driven xy-mirror deflection system. Using steppers instead of galvos might be unconventional, but saves you the necessity of high accuracy DACs in addition to a row of calibration steps and DSP. Steppers work just fine OOB with optical endstops while delivering quiet good accuracy proven on many FDM-machines out there. The z-Stage works well with a 0.9° stepper motor, but the surface of the print stage's not sticky enough to pull out the printed part out of the ptfe-covered vat.
However, mind that this is only a very first test, I only spilled a small spot of the expensive Spot-HT resin in the middle of the vat for testing the basic principle and functionality. All stepper motors are driven by a TB6560 based driver board. Main power source is a 300W pc power supply. I have implemented a fresh but teacup-flavored gcode-interpreter and a fully custom firmware on a chipkit max32 board, which offers speedy 80 MHz of floating point calculations for high-resolution vectorial mapping, pre-warping of incoming gcode and of course the necessary look-ahead, that is necessary for acceleration/deceleration.
Eventually it could achieve far more than 10.000 mm/s travel speed while still being able to pulse width modulate the laser intensity corresponding to it's current travel speed. For that, I will have to replace the current diy op-amp powered level shifter between the Max32 and the stepper driver with a FET-powered version, but for now it's running quiet well. In the video it's running at a low speed 500mm/s with a slow acceleration setting. Right now for testing I am using slic3r and the repetier host. Repetier is great, but one should really use skeinforge for professional printing. As you might have noticed the housing is a red IKEA box, which apparently seems to perfectly shield the 405nm laser light when closed (no guarantee for that, be careful with your eyesight when experimenting with lasers more than 1 mw). Thanks for watching, leave your comment, I'll be glad to see similar builds out there!