Welcome! Log In Create A New Profile

Advanced

How do you use the reprap host with a laser cutter?

Posted by Adam.m.Nelson 
VDX
Re: How do you use the reprap host with a laser cutter?
January 09, 2013 10:11AM
... the lifetime of your diode will rise dramatically with lower current and better cooling!

I'm driving my 9Amp-diodes most of the time with 2 to 4 Amps only, what's enough for most cutting/engraving/sintering jobs ... and the highest setting on my board is 8.6Amps - but I have some 25W and 50W-lasers too, when in need for more power winking smiley


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: How do you use the reprap host with a laser cutter?
January 10, 2013 09:42AM
I have used LM317T or LM338T based constant current circuit
[www.rog8811.com]
with about 0.8-1 ohm resistor.
I use that with M140 blue lased diode and it works well with12v input grinning smiley

If I put that driver with laserdiode to heatbed( or hotend) connection and
drive that with M140 S100 and M140 S0 G code commands. So the driver gets 12 or 0 volts.
Could this setup work?
VDX
Re: How do you use the reprap host with a laser cutter?
January 10, 2013 10:50AM
... yes, this should work - I'm driving my 5Amps- or 9Amps-drivers with TTL-PWM through an opto-coupler, that activates a MOSFET, that switches the PS (8Volts @6Amps or 12 Volts @20Amps) to the LM's ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Re: How do you use the reprap host with a laser cutter?
January 11, 2013 01:25PM
I just tried driving heatbed mosfet connection connected to LM338 based driver to laser diode and... it works nicely smileys with beer
Hand driving heatbed On/Off tests.
Re: How do you use the reprap host with a laser cutter?
January 12, 2013 11:00AM
Hm, in Marlin fimware in configuration_adv.h
setting
#define BED_CHECK_INTERVAL 2000 //ms
causes some problems confused smiley
now trying to find suitable value or solution to direct Pinout control with G-code (Fan etc)

New solution, because Bed check lags too much:
I changed in firmware in pins.h
#define HEATER_BED_PIN 4 // (bed) old 12
then pin 12 is now "free", actually bed mosfet
and I can use G-code
M42 S255 P12 or
M42 S0 P12
to switch laser on/off smoking smiley
But...
Still in practice Marlin do some interesting buffering, which M42 executes commands in strange way,
actually when movements actually happens, some futurologist logic drinking smiley

Edited 2 time(s). Last edit at 01/12/2013 03:33PM by Tertzoid.
Re: How do you use the reprap host with a laser cutter?
January 15, 2013 01:22PM
Latest trial with M400 "wait for buffer to clear" which helps thumbs up
[github.com]

and then test G-Code looks like this:
...
G1 X10 Y10
M42 S255 P12
G1 F800
G1 X30 Y10
M400
G1 F700
M42 S0 P12
G1 X30 Y15
M400
M42 S255 P12
G1 X10 Y15
M400
M42 S0 P12
G1 F600
G1 X10 Y20
M400
...
Re: How do you use the reprap host with a laser cutter?
February 09, 2013 09:41AM
Now I'm frustrated to that laser diode, it heats up quickly and power drops within half minute or so sad smiley
Enough to cut paper, but not even 1.5 mm balsa after about 30 secs.
I tried peltier element but it's cooling had to be quite powerful to work I think.
Re: How do you use the reprap host with a laser cutter?
February 09, 2013 09:44AM
Lliquid cool with a resevoire of ice water?
VDX
Re: How do you use the reprap host with a laser cutter?
February 09, 2013 04:42PM
... what's the current to the diode?

If it's dropping significant in power due to high temp, then you'll overpowering it, so it will duy soon!

I used my blue 1Watt-diode with 0.8Watts and a medium sized passive cooler for some ten minutes continuous burning without overheating.

Have some 9Watt-LED's that needs 21Amps fo full power - but they need water cooling or will overheat with a 20Watt-peltier in less then a minute!


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org]
Call for the project "garbage-free seas" - [reprap.org]
Sorry, only registered users may post in this forum.

Click here to login