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

Hey there, I've recently come into possession of a laser cutter strong enough to cut acrylic, issue is the software to run it is terrible. So, I want to replace the XY axis controllers with those fro the Reprap project and 'print' it with the reprap host.

Hardware I can get working just fine. I'm not sure how to use the reprap host to do this though, and my searches haven't led me anywhere useful...

Can anyone help me?

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"Get busy living, or get busy dieing" - Red

... I've got recently one of this cheap Chinese CO2-lasercutters with the unusable 'MoshidrawLeft' software - should be similar to yours

In past I've modified the controller of my CNC-mill for laser-cutting by either using the original interface card with optimized postprocessor, or by replacing the card by an Arduino and driving it with some of the then recent softwares (could be repetier and pronterface) with success. It's essentially the same hardware/electronics-structure as the laser-cutter mechanics and can be used for other machines in this or similar configuration too.

Will do this with a Gen3 or ArduinoMega again, but can take a while, as another project is actually more urgent ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

That's the one I have! Ya the interface is garbage.

Getting hardware designed and set-up isn't an issue ( I do it all day at my job), how do you tell the interface softwares (hosts) to do the single layer on the outside edges? Is there an option for it?

... I'm mostly using programs, that converts bitmaps into vectors and export them as DXF - a good free program is Inkscape: [inkscape.org]

My other programs are comercial and really pricey, so not suitable for DIY ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

So if I understand correctly, there is no way to use the host software to control my laser if I mod in my own control board into the laser?

... of course, you can export a G-code file of a sliced special designed (to meet the exact outer shell) object without infill and run a script, that separates the single slices by occurencies of Z-commands, so you'll receive a sequence of files containing the contour paths of single sheets (if you create a 'thin' STL-object, then you get a single file).

And some of the host softwares (Skeinforge?) can be configured for FDM-printing, CNC-milling or laser-cutting - but I hadn't tested this in detail ...

For me it's easier to vectorize a bitmap-image and use one of the CAM-programs ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hmm thanks Viktor, I'll have to look into that for sure. I think I'm going to buy some upgraded electronics for my Mendel (currently Gen3, and I can't seem to get past its freezing problem..)

Which will free up my gen 3 electronics for the laser cutter. Turns out its a 40Watt CO2 laser, should be fun

Viktor,

I skipped buying upgraded hardware for my mendel, and just built up some really nice stepper drivers i modified to work myself. They work great.

Now I am looking to load some sort of G-Code interpreter onto the arduino and I am done. Can you recommend a firnware that can be made to do tis easily (maybe teacup?, 5D?)

I'm currently using pronterface to control my Reprap, well i will be when I find the bug in the Teacup firmware for the Gen3 electronics... but I'll take a look at skeinforge for the slicer

I'm using my Isel-Interface and the Isel-software, so no actual infos to soft-/firmwares - but my last tests were with skeinforge and the milling/lasercutting settings, could be worth a try.

In the next days I'll restart with my lasercutter too ... maybe with swapping the mobo with the old Gen3 or a RAMPS 1.2 - then I can test some of the actual firmwares too ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Oh excellent timing, let me know how yours goes. I'm going to start with an arduino and move up.from there

... removed the chinese mobo and checked, if the laser runs with standard TTL level - it burns

So it shouldn't be a big problem to replace the mobo with the Gen3 (or the ArduinoMega and two stepperr drivers) and test with skeinforge and the lasercutter configuration ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Yeah I got the steppers wired up last night, using an atmega328 to run them, it works great. The only thing I'm not sure of is if the laser drive is solid on, pwm, or frequency driven..

One of the guys I work with is a optical engineer, and we're going to go over it tomorrow.

There isn't much to running the laser cutter, why were you thinking of an arduino mega? Is there a loading issue with a smaller micro?

Edited 1 time(s). Last edit at 01/01/2013 07:28PM by Adam.m.Nelson.

... no issues, it's simply because I have a Gen3 and two Mega's (1280, 2560) and a RAMPS 1.2 shield (without Pololus) and several different stepper-drivers lying around

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

lol, yeah that's a good reason. I started reducing the latest teacup firmware last night, taking out all the temperature, extruder, and heater control. So far both axis are working, and all thats really left to do is fill in a G-Code handler that turns on/off the laser and i think we're set. While I am reducing the code I am using the Motherboard 1.2 setup, but will port it to the Atmega 328 afterwards.

I got the majority of the electronics and firmware up and running on a Mega, but I didn't realize that Skein forge still uses the extruder codes to plot the lasing. Is you plan to just change the on off for the extruder to control the laser?

Oh, I talked to our optical engineer today, and he said PWM control would likely give good results with these lasers.

... with my CNC-mill I've used one of the coolant-switches to activate the laser with DC.

Some time ago I've programmed an Atmega128-brick for adjustable DCtoPWM-conversion, so it can create predefinable pulses or even a simple 'logic', where I only shot a pulse when either the X- or the Y-driver (or both together) performs a step ... so the lines are assembled of uniform overlapping holes without the need to calculate energies_vs_spped-values to avoid overpowering at start-stop and in slower curves.

Be careful with PWM and the chinese PS! ... when burning with low power I hear a 'buzz'-noise from the lasertube - I think they generate RF-pulses to power the laser - switching with PWM can interfere with the RF!

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Hmm maybe I'll just stick to full power and faster move speeds. Did you have any issues with the Chinese end stops? I'm sure I wired them right, but they don't seem to work lol

Interesting read guys.

I would use a RAMPS for this type of project, (yes I know I'd be wasting 3 drivers...) just out of my own inexperience and liking things in one package. As soon as I started planning my reprap, I started to think of all of the 2D applications that could be accompished with the polished firmwares and electronics available openly under GPL. A laser cutter will definitely be a nice addition to my reprap.

I'm hoping to do this with a laser unit, RAMPS, firmware of choice, and Slic3r. Wondering if anyone's gotten good 2D gcode out of Slic3r?

I may have to buy one of those chinese lasers, and remove all electronics and put in a RAMPS with Marlin. :-)

Has anyone documented a 2D reprap-like machine? (For laser cutting or engraving etc?)

(After reading a little more in the area of the forums I see we can do hot swappable heads on our repraps, including laser. So I'll concentrate on that route...)

Edited 3 time(s). Last edit at 01/04/2013 02:24AM by xclusive585.

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I'm hoping to do this with a laser unit, RAMPS, firmware of choice, and Slic3r. Wondering if anyone's gotten good 2D gcode out of Slic3r?

First, there are simpler electronics than RAMPS: Sanguinololu and Generation 7 Electronics.

And Slic3r is made for - you guess it - slicing. For 2D applications, you'd want a better suited application. About all G-code generators for milling produce G-code which runs on RepRap firmwares just fine or with small tweaks.

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Generation 7 Electronics	Teacup Firmware	RepRap DIY

After looking into that "m7?" Laser unit on Ebay, I am for sure going to order one in the next two months.

1) Step one is going to be to replace the electronics with documented reprap electronics. (Ramps or whatever will be simplest for me as I'm far from an electrical engineer, I like the idea of using a ramps because it is an all inclusive solution, the only addon board I can picture needing would be to drive the laser perhaps?)

2) I assume the steppers in that unit can be driven with our typical drivers.

3) And the most important, how do we drive their laser with our electronics.

4) What softwares produce good 2d gcode and are as user friendly as slic3r?... (probably nothing.)


This sounds like a great project and I think a laser cutter would be a wonderful compliment to my printer.

Perhaps we could work together to document the reverse engineering and modding of this unit for the community.

Edited 1 time(s). Last edit at 01/04/2013 12:00PM by xclusive585.

I'm using the ramps settings in teacup firmware. Using skeinforge with the laser settings the slicing ends up using the same gcodes for as extruder on off, so I an just going to get rid of the step control there, and put "this pin on" "this pin off" logic in its place.

I think I fried the original end stops somehow, not too sure, but I have the XY axis moving nicely, and the actual lasing seems to be controled by a neg signal to the L pin on the laser power supply. VDX mentioned his made strange sounds when fed a PWM signal, so I am going to play around with it and figure that out.

Uhh, running modified Ramps settings on teacup firmware, Mega 2560, and off the shelf stepper drivers.

With the exception of removing the heater and temperature control code ( not really necessary if you disable them in the config files, i think) the firmware pretty works as is .

I finally got back into my blog that i was locked out of. Maybe I'll gets some pics posted and get a link to here. I told the wife I wouldn't work on the laser tonight, but that doesn't include playing on the laptop

cool Im on the same path, building a Mendel 90 look alike with just XY for small (1,5W 445nm) laser cutting projects as stencils for example. I also have a Gen7 1.2 board laying around that will do the actual driving with 2 pololus .

I d love to see yours working it would be a great encouragement

My 445nm laser diode (the usual M140) , has a quite "big" beam even with the g2 optics I use. would it be possible to put a lens to focus it more. having a stable focus distance isnt really a problem as the height from the burning material will be more or less stable

... my endstops are working, but they are routed to a 4-pin molex plug while the mobo has a 5-pin socket - so you have to check carefully how to set the plug correct

I'm replacing the electronics with a RAMPS 1.2 what's easy enough with the PS-laserdriver-combo - it has a test-pin for the laser that let the laser burn when shorted ... and a 'Laser'-pin from the mobo, that will do the same when shorted too ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

... for the 445nm-LD I've used one lens from the Casio-laserbank - see the pictures with the blue beam (and the cutted rabbit) here: [www.reprap.org]

Try to ask someone local selling this diodes, maybe he has the lenses too ... I have two spare LD-banks with together 48 of the lenses here and can give most of them away, if needed ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

thanks VXD, the lens you used is focusing lens, or collimating?

either way i will try to set it up first and then see how it goes

... I used a focussing lens - it's depending on the lens-specs (focus distance), if you can use a single lens or first have to collimating the beam.

But if you want to build a XY-scanning system, collimating and beamshaping is a must ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

focusing lens slourp

but i ll settle with what i have now and see how it goes.

back in the controlling the laser discussion,
as we use small diodes (1,5W) to do the job, couldnt we use the hot-end mosfet in controlling the on/off switching of the laser?

in my GEN7 electronics board I have I though I can cut the 12V line which goes at the hot-end and provide it with a 5V one, so the mosfet would switch a 5V source which is ideal for the 3,6-4V a diode laser needs.

... you need a special driver for the diodes or they will blow when connected to 5V - either a voltage regulator (optionally with monitoring feedback) ... or much simpler, a current regulator based on a LM317 or similar.

The LM needs some offset, so 5V wouldn't be enough for the diode - best is to switch the 12V with the MOSFET to the LM, which regulates the current through the diode according to the sense resistor.

I'm DC- or PWM-driving my IR-diodes (9Watts@9Amps-types) through a MOSFET and a couple of LM's, parallelizing the currents in coarse steps (jumpers/switches) from 1A to 8.6A and 'finetuning' over the PWM-ratio ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Im really sorry I never mentioned that I already have a driver based on these nice AMC7135 chips.

Those chips are really wonderful as the require minimum electronics and provide 350mA each . So this board that has 4 of them gives out 1400mA. The only problem, (and thats why Im switching to 5V input) is that these chips have top input voltage of 6V .

One can make a nice driver out of a PT1415 IC which can vary output with a sense resistor , but this reaches only up to 1.2A which is lower than what the M140 diode can be provided.