Replace Extruder with Laser (no mod)

Hello Forum,

has anyone tried to replace the extruder on a Mendel90 with a blue 445nm 1W laser _without any modifications_ to the electrical part?
I mean, without building a special driver etc. but have the laser operate with its own driver?
The common 1W lasers require around 1.1A @ 8-12V for the complete module+driver.

I do not know what the power consumption of the JHead 0.4mm heating elemtent is or if the electronics can provide enough power to the laser.
Maybe someone has an idea?

thanks!

At least one person has tried it on a Mendel90: [www.youtube.com] and quite a few have done it on other similar Reprap machines. Be sure to use eye protection for anybody in the same room. Lasers should really be enclosed with safety interlocks.

The heater takes a couple of Amps and the wiring should handle about 3A. The MOSFET on the Melzi is the same as used for the bed so can handle 10A.

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[www.hydraraptor.blogspot.com]

Considering you're thinking of using the hot end outputs to control the laser (I assume you'd attach some sort of current limiting circuit to the output) I'm not sure how you'd turn the laser on and off at the correct times.

People seem to be using inkscape to generate gcode from images.
I'm not sure what gcode inkscape would output to turn the laser on, but would you just "find and replace" with "M104 S999" as on and "M104 S0" as off? Or would modifying marlin be a better route, maybe designating a different pin for the laser?

I've also been thinking about doing this. I'm 1/2 way through building a tiny laser engraver out of a DVD drive. I figure I'll learn a bit about generating gcode and cutting with lasers on it then move onto modding my mendel90 with a larger laser.

@nophead:

thanks for the info, so the technical side should work.
Of course laser goggles are essential! I would not recommend working with lasers and not wearing the suitable goggles for the correct wavelength.


@isolt:
Is the DVD writer laser powerful enough for such things?
Considering the Gcode, I have actually no idea how this can be done. I want to use the laser setup to create PCBs and my layout program (Eagle) has a ULP for creating Gcode, so this could be an option.
But I guess the ULP (user language program) has to be modified slightly to not lift the drill etc but simply turn off the laser.
I want to use a laser that comes with its own driver and constant current power source. So basically just connect it to 8-12V and thats it. In theory, I do not know yet, if it is really that simple.
For example what is the weight of the lasermodule with driver, etc etc....

Edited 1 time(s). Last edit at 07/31/2014 02:42AM by muelli.

Some good other posts I found.
Laser engraving, how to get started?
RepRap to CNC Laser Engraving machine
below cho says "The G-code need to replace the M101 & 103 to M104 S0 & M104 S255." so looks like I was on the right track.

Issue 2 of the reprap magazine also had a good section on it.
It's even got a table of different laser wavelenghts and what they're good for. Looks like a red 250mW DVD writer laser would be perfect for burning black paint off PCB's for etching.
The magazine also goes into different laser modules, even some large ones that have fibre-optics.

thanks, will check the info

edit:
checked the sources, i guess i am out. looks way to complicated.

Edited 1 time(s). Last edit at 08/01/2014 05:44AM by muelli.

Yeah there's a lot of unknowns, that's part of why I'm starting small.
If you're interested I could post some updates if I achieve anything.

yes, so much unclear
what controller?
what firmware?
how to finally create gcode?
how to mount the laser or the fiber?
and of course the biggest issue, what laser?

I almost think it would be easier to build something from scratch...

Have a look at this, I have one on order

Lcheapo laser kit

Paul

Edited 1 time(s). Last edit at 08/01/2014 05:51PM by paulnd.

thanks, that solves some of the uncertainties!